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DControls Boost Preregulator to Near-Unity
Power Factor
DLimits Line Distortion
DWorld Wide Line Operation
DOver-Voltage Protection
DAccurate Power Limiting
DAverage Current Mode Control
DImproved Noise Immunity
DImproved Feed-Forward Line Regulation
DLeading Edge Modulation
D150-µA Typical Start-Up Current
DLow-Power BiCMOS Operation
D12-V to 17-V Operation
DFrequency Range 6 kHz to 220 kHz
description
The UCCx817/18 family provides all the functions necessary for active power factor corrected preregulators.
The controller achieves near unity power factor by shaping the ac input line current waveform to correspond
to that of the ac input line voltage. Average current mode control maintains stable, low distortion sinusoidal line
current.
Designed in Texas Instrument’s BiCMOS process, the UCC2817/UCC2818 offers new features such as lower
start-up current, lower power dissipation, overvoltage protection, a shunt UVLO detect circuitry, a leading-edge
modulation technique to reduce ripple current in the bulk capacitor and an improved, low-offset (±2 mV) current
amplifier to reduce distortion at light load conditions.
block diagram
UDG-98182
VREF9
2
16
1
15
10
5
4
DRVOUT
GND
CAI
VCC
OVP/EN
VAOUT 1.9 V
PKLMT
7.5 V
REFERENCE
UVLO
16 V/10 V (UCC2817)
10.5 V/10 V (UCC2818) VCC
3
OSCILLATOR
12
RT 14
CT
SQ
R
PWM
LATCH
+
−PWM
CAOUT
+
−
+
−
+
−
SS
VOLTAGE
ERROR AMP 8.0 V
13
7
11VSENSE
VFF 8
IAC 6
MOUT
MIRROR
2:1
X2
+
−
7.5 V
ENABLE
OVP
÷
X
XMULT
OSC
CLK
CLK
CURRENT
AMP
16 V (FOR UCC2817 ONLY)
+
−
0.33 V ZERO POWER
R
+
−
Copyright 2006 − 2009, Texas Instruments Incorporated
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"&#"0 !)) '!!&"&#+
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
D, DW, N, and PW PACKAGES
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GND
PKLMT
CAOUT
CAI
MOUT
IAC
VAOUT
VFF
DRVOUT
VCC
CT
SS
RT
VSENSE
OVP/EN
VREF
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description (continued)
UCC2817 offers an on-chip shunt regulator with low start-up current, suitable for applications utilizing a
bootstrap supply. UCC2818 is intended for applications with a fixed supply (VCC).
Available in the 16-pin D, DW, N and PW packages.
absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Supply voltage VCC 18 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply current ICC 20 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate drive current, continuous 0.2 A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate drive current 1.2 A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, CAI, MOUT, SS 8 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, PKLMT 5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, VSENSE, OVP/EN 10 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input current, RT, IAC, PKLMT 10 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input current, VCC (no switching) 20 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum negative voltage, DRVOUT, PKLMT, MOUT −0.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power dissipation 1 W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Junction temperature, TJ−55°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature, Tstg −65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature, Tsol (soldering, 10 seconds) 300°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power dissipation 1 W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
†Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
AVAILABLE OPTIONS
PACKAGE DEVICES
T = T
SOIC (D) PACKAGE SOIC (DW) PACKAGE PDIP (N) PACKAGE TSSOP (PW) PACKAGE
TA = TJTurn-on
Threshold
16 V
Turn-on
Threshold
10.2 V
Turn-on
Threshold
16 V
Turn-on
Threshold
10.2 V
Turn-on
Threshold
16 V
Turn-on
Threshold
10.2 V
Turn-on
Threshold
16 V
Turn-on
Threshold
10.2 V
−40°C to 85°C UCC2817D UCC2818D UCC2817DW UCC2818DW UCC2817N UCC2818N UCC2817PW UCC2818PW
0°C to 70°C UCC3817D UCC3818D UCC3817DW UCC3818DW UCC3817N UCC3818N UCC3817PW UCC3818PW
THERMAL RESISTANCE TABLE
PACKAGE θjc(°C/W) θja(°C/W)
SOIC−16 (D) 22 40 to 70 (1)
SOIC−16 (DW) 26 89 to 102 (1)
PDIP−16 (N) 12 25 to 50 (1)
TSSOP−16 (PW) 14 (2) 123 to 147 (2)
NOTES: (1) Specified θja (junction to ambient) is for devices mounted to 5-inch2 FR4 PC board with one ounce copper
where noted. When resistance range is given, lower values are for 5 inch2 aluminum PC board. Test PWB
was 0.062 inch thick and typically used 0.635-mm trace widths for power packages and 1.3-mm trace
widths for non-power packages with a 100-mil x 100-mil probe land area at the end of each trace.
(2). Modeled data. If value range given for θja, lower value is for 3x3 inch. 1 oz internal copper ground plane,
higher value is for 1x1-inch. ground plane. All model data assumes only one trace for each non-fused
lead.
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electrical characteristics, TA = 0°C to 70°C for the UCC3817 and TA = −40°C to 85°C for the UCC2817, TA
= TJ, VCC = 12 V, RT = 22 kΩ, CT = 270 pF, (unless otherwise noted)
supply current section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Supply current, off VCC = (VCC turn-on threshold −0.3 V) 150 300 µA
Supply current, on VCC = 12 V, No load on DRVOUT 2 4 6 mA
UVLO section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
VCC turn-on threshold (UCCx817) 15.4 16 16.6 V
VCC turn-off threshold (UCCx817) 9.4 9.7 V
UVLO hysteresis (UCCx817) 5.8 6.3 V
Maximum shunt voltage (UCCx817) IVCC = 10 mA 15.4 17 17.5 V
VCC turn-on threshold (UCCx818) 9.7 10.2 10.8 V
VCC turn-off threshold (UCCx818) 9.4 9.7 V
UVLO hysteresis (UCCx818) 0.3 0.5 V
voltage amplifier section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input voltage
TA = 0°C to 70°C 7.387 7.5 7.613 V
Input voltage TA = −40°C to 85°C 7.369 7.5 7.631 V
VSENSE bias current VSENSE = VREF, VAOUT = 2.5 V 50 200 nA
Open loop gain VAOUT = 2 V to 5 V 50 90 dB
High-level output voltage IL = −150 µA 5.3 5.5 5.6 V
Low-level output voltage IL = 150 µA 0 50 150 mV
over voltage protection and enable section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Over voltage reference VREF
+0.48 VREF
+0.50 VREF
+0.52 V
Hysteresis 300 500 600 mV
Enable threshold 1.7 1.9 2.1 V
Enable hysteresis 0.1 0.2 0.3 V
current amplifier section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input offset voltage VCM = 0 V, VCAOUT = 3 V −3.5 0 2.5 mV
Input bias current VCM = 0 V, VCAOUT = 3 V −50 −100 nA
Input offset current VCM = 0 V, VCAOUT = 3 V 25 100 nA
Open loop gain VCM = 0 V, VCAOUT = 2 V to 5 V 90 dB
Common-mode rejection ratio VCM = 0 V to 1.5 V, VCAOUT = 3 V 60 80 dB
High-level output voltage IL = −120 µA 5.6 6.5 6.8 V
Low-level output voltage IL = 1 mA 0.1 0.2 0.5 V
Gain bandwidth product See Note 1 2.5 MHz
NOTES: 1. Ensured by design, not production tested.
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electrical characteristics, TA = 0°C to 70°C for the UCC3817 and TA = −40°C to 85°C for the UCC2817, TA
= TJ, VCC = 12 V, RT = 22 kΩ, CT = 270 pF, (unless otherwise noted)
voltage reference section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input voltage
TA = 0°C to 70°C 7.387 7.5 7.613 V
Input voltage TA = −40°C to 85°C 7.369 7.5 7.631 V
Load regulation IREF = 1 mA to 2 mA 0 10 mV
Line regulation VCC = 10.8 V to 15 V, See Note 2 0 10 mV
Short-circuit current VREF = 0 V −20 −25 −50 mA
NOTES: 2. Reference variation for VCC < 10.8 V is shown in Figure 8.
oscillator section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Initial accuracy TA = 25°C 85 100 115 kHz
Voltage stability VCC = 10.8 V to 15 V −1 1 %
Total variation Line, temp 80 120 kHz
Ramp peak voltage 4.5 5 5.5 V
Ramp amplitude voltage
(peak to peak) 3.5 4 4.5 V
peak current limit section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
PKLMT reference voltage −15 15 mV
PKLMT propagation delay 150 350 500 ns
multiplier section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
IMOUT, high line, low power output
current, (0°C to 85°C) IAC = 500 µA, VFF = 4.7 V, VAOUT = 1.25 V 0 −6 −20 µA
IMOUT, high line, low power output
current, (−40°C to 85°C) IAC = 500 µA, VFF = 4.7 V, VAOUT = 1.25 V 0 −6 −23 µA
IMOUT, high line, high power output
current IAC = 500 µA, VFF = 4.7 V, VAOUT = 5 V −70 −90 −105 µA
IMOUT, low line, low power output
current IAC = 150 µA, VFF = 1.4 V, VAOUT = 1.25 V −10 −19 −50 µA
IMOUT, low line, high power output
current IAC = 150 µA, VFF = 1.4 V, VAOUT = 5 V −268 −300 −345 µA
IMOUT, IAC limited output current IAC = 150 µA, VFF = 1.3 V, VAOUT = 5 V −250 −300 −400 µA
Gain constant (K) IAC = 300 µA, VFF = 3 V, VAOUT = 2.5 V 0.5 1 1.5 1/V
IMOUT, zero current
IAC = 150 µA, VFF = 1.4 V, VAOUT = 0.25 V 0 −2 µA
IMOUT, zero current IAC = 500 µA, VFF = 4.7 V, VAOUT = 0.25 V 0 −2 µA
IMOUT, zero current, (0°C to 85°C) IAC = 500 µA, VFF = 4.7 V, VAOUT = 0.5 V 0 −3 µA
IMOUT, zero current, (−40°C to 85°C) IAC = 500 µA, VFF = 4.7 V, VAOUT = 0.5 V 0 −3.5 µA
Power limit (IMOUT x VFF) IAC = 150 µA, VFF = 1.4 V, VAOUT = 5 V −375 −420 −485 µW
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electrical characteristics, TA = 0°C to 70°C for the UCC3817 and TA = −40°C to 85°C for the UCC2817, TA
= TJ, VCC = 12 V, RT = 22 kΩ, CT = 270 pF, (unless otherwise noted)
feed-forward section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
VFF output current IAC = 300 µA −140 −150 −160 µA
soft start section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
SS charge current −6 −10 −16 µA
gate driver section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Pullup resistance IO = –100 mA to −200 mA 5 12 Ω
Pulldown resistance IO = 100 mA 2 10 Ω
Output rise time CL = 1 nF, RL = 10 Ω, VDRVOUT = 0.7 V to 9.0 V 25 50 ns
Output fall time CL = 1 nF, RL = 10 Ω, VDRVOUT = 9.0 V to 0.7 V 10 50 ns
Maximum duty cycle 93 95 99 %
Minimum controlled duty cycle At 100 kHz 2 %
zero power section
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Zero power comparator threshold Measured on VAOUT 0.20 0.33 0.50 V
pin descriptions
CAI: (current amplifier noninverting input) Place a resistor between this pin and the GND side of current sense
resistor. This input and the inverting input (MOUT) remain functional down to and below GND.
CAOUT: (current amplifier output) This is the output of a wide bandwidth operational amplifier that senses line
current and commands the PFC pulse-width modulator (PWM) to force the correct duty cycle. Compensation
components are placed between CAOUT and MOUT.
CT: (oscillator timing capacitor) A capacitor from CT to GND sets the PWM oscillator frequency according to:
f[ǒ0.6
RT CTǓ
The lead from the oscillator timing capacitor to GND should be as short and direct as possible.
DRVOUT: (gate drive) The output drive for the boost switch is a totem-pole MOSFET gate driver on DRVOUT.
Use a series gate resistor to prevent interaction between the gate impedance and the output driver that might
cause the DRVOUT to overshoot excessively. See characteristic curve (Figure 13) to determine minimum
required gate resister value. Some overshoot of the DRVOUT output is always expected when driving a
capacitive load.
GND: (ground) All voltages measured with respect to ground. VCC and REF should be bypassed directly to
GND with a 0.1-µF or larger ceramic capacitor.
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pin descriptions (continued)
IAC: (current proportional to input voltage) This input to the analog multiplier is a current proportional to
instantaneous line voltage. The multiplier is tailored for very low distortion from this current input (IIAC) to
multiplier output. The recommended maximum IIAC is 500 µA.
MOUT: (multiplier output and current amplifier inverting input) The output of the analog multiplier and the
inverting input of the current amplifier are connected together at MOUT. As the multiplier output is a current, this
is a high-impedance input so the amplifier can be configured as a differential amplifier. This configuration
improves noise immunity and allows for the leading-edge modulation operation. The multiplier output current
is limited to ǒ2 IIACǓ. The multiplier output current is given by the equation:
IMOUT +IIAC (VVAOUT *1)
VVFF2 K
where K +1
V is the multiplier gain constant.
OVP/EN: (over-voltage/enable) A window comparator input that disables the output driver if the boost output
voltage is a programmed level above the nominal or disables both the PFC output driver and resets SS if pulled
below 1.9 V (typ).
PKLMT: (PFC peak current limit) The threshold for peak limit is 0 V. Use a resistor divider from the negative side
of the current sense resistor to VREF to level shift this signal to a voltage level defined by the value of the sense
resistor and the peak current limit. Peak current limit is reached when PKLMT voltage falls below 0 V.
RT: (oscillator charging current) A resistor from RT to GND is used to program oscillator charging current. A
resistor between 10 kΩ and 100 kΩ is recommended. Nominal voltage on this pin is 3 V.
SS: (soft-start) VSS is discharged for VVCC low conditions. When enabled, SS charges an external capacitor
with a current source. This voltage is used as the voltage error signal during start-up, enabling the PWM duty
cycle to increase slowly. In the event of a VVCC dropout, the OVP/EN is forced below 1.9 V (typ), SS quickly
discharges to disable the PWM.
Note: In an open-loop test circuit, grounding the SS pin does not ensure 0% duty cycle. Please see the
application section for details.
VAOUT: (voltage amplifier output) This is the output of the operational amplifier that regulates output voltage.
The voltage amplifier output is internally limited to approximately 5.5 V to prevent overshoot.
VCC: (positive supply voltage) Connect to a stable source of at least 20 mA between 10 V and 17 V for normal
operation. Bypass VCC directly to GND to absorb supply current spikes required to charge external MOSFET
gate capacitances. To prevent inadequate gate drive signals, the output devices are inhibited unless VVCC
exceeds the upper under-voltage lockout voltage threshold and remains above the lower threshold.
VFF: (feed-forward voltage) The RMS voltage signal generated at this pin by mirroring 1/2 of the IIAC into a single
pole external filter. At low line, the VFF voltage should be 1.4 V.
VSENSE: (voltage amplifier inverting input) This is normally connected to a compensation network and to the
boost converter output through a divider network.
VREF: (voltage reference output) VREF is the output of an accurate 7.5-V voltage reference. This output is
capable of delivering 20 mA to peripheral circuitry and is internally short-circuit current limited. VREF is disabled
and remains at 0 V when VVCC is below the UVLO threshold. Bypass VREF to GND with a 0.1-µF or larger
ceramic capacitor for best stability. Please refer to Figures 8 and 9 for VREF line and load regulation
characteristics.
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APPLICATION INFORMATION
The UCC3817 is a BiCMOS average current mode boost controller for high power factor, high efficiency
preregulator power supplies. Figure 1 shows the UCC3817 in a 250-W PFC preregulator circuit. Off-line
switching power converters normally have an input current that is not sinusoidal. The input current waveform
has a high harmonic content because current is drawn in pulses at the peaks of the input voltage waveform.
An active power factor correction circuit programs the input current to follow the line voltage, forcing the
converter to look like a resistive load to the line. A resistive load has 0° phase displacement between the current
and voltage waveforms. Power factor can be defined in terms of the phase angle between two sinusoidal
waveforms of the same frequency:
PF +cosQ
Therefore, a purely resistive load would have a power factor of 1. In practice, power factors of 0.999 with THD
(total harmonic distortion) of less than 3% are possible with a well-designed circuit. Following guidelines are
provided to design PFC boost converters using the UCC3817.
NOTE: Schottky diodes, D5 and D6, are required to protect the PFC controller from electrical over stress during
system power up.
UDG-98183
1
11
7
16GND DRVOUT
R17
20Ω
15
C3
1µF CER
VCC
C2
100µF AI EI
14
C1
560pF
13 C4 0.01µF
12 R1 12k
R3 20k R2
499k
R4
249k
R5
10k
C5 1µF
9
4
10
VREF
VCC
CT
SS
RT
VSENSE
OVP/EN
VREF
VAOUT
3
8
2
VFF
C6 2.2µF
C7 150nF
R7 100k
6
5
R9
4.02k
C8 270pF
R8 12k
D6
R10
4.02k
D5
R11
10k
R12
2k
R14
0.25Ω
3W
C13
0.47µF
600V
C14
1.5µF
400V
R13
383k
IAC R18
24k
R15
24k
R16
100Ω
VCC
C10
1µFC11
1µF
D7 D8
L1
1mH
D2
6A, 600V
D1
8A, 600V
C12
220µF
450V
VOUT
385V−DC
+
−
PKLIMIT
CAOUT
CAI
MOUT
IAC
VO
UCC3817
VLINE
85−270 V
AC
VREF
C9 1.2nF
R6 30k
6A 600V
D3 Q1
F1
VO
D4
R19
499k
R20 274k
R21
383k
AC2
AC1
C15 2.2µF
IRFP450
Figure 1. Typical Application Circuit
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APPLICATION INFORMATION
power stage
LBOOST : The boost inductor value is determined by:
LBOOST +ǒVIN(min) DǓ
(DI fs)
where D is the duty cycle, ∆I is the inductor ripple current and fS is the switching frequency. For the example
circuit a switching frequency of 100 kHz, a ripple current of 875 mA, a maximum duty cycle of 0.688 and a
minimum input voltage of 85 VRMS gives us a boost inductor value of about 1 mH. The values used in this
equation are at the peak of low line, where the inductor current and its ripple are at a maximum.
COUT : Two main criteria, the capacitance and the voltage rating, dictate the selection of the output capacitor.
The value of capacitance is determined by the holdup time required for supporting the load after input ac voltage
is removed. Holdup is the amount of time that the output stays in regulation after the input has been removed.
For this circuit, the desired holdup time is approximately 16 ms. Expressing the capacitor value in terms of output
power, output voltage, and holdup time gives the equation:
COUT +ǒ2 POUT DtǓ
ǒVOUT2*VOUT(min)2Ǔ
In practice, the calculated minimum capacitor value may be inadequate because output ripple voltage
specifications limit the amount of allowable output capacitor ESR. Attaining a suf ficiently low value of ESR often
necessitates the use of a much larger capacitor value than calculated. The amount of output capacitor ESR
allowed can be determined by dividing the maximum specified output ripple voltage by the inductor ripple
current. In this design holdup time was the dominant determining factor and a 220-µF, 450-V capacitor was
chosen for the output voltage level of 385 VDC at 250 W.
Power switch selection: As in any power supply design, tradeoffs between performance, cost and size have
to be made. When selecting a power switch, it can be useful to calculate the total power dissipation in the switch
for several different devices at the switching frequencies being considered for the converter. Total power
dissipation in the switch is the sum of switching loss and conduction loss. Switching losses are the combination
of the gate charge loss, COSS loss and turnon and turnoff losses:
PGATE +QGATE VGATE fs
PCOSS +1
2 COSS V2OFF fs
PON )POFF +1
2 VOFF IL ǒtON )tOFFǓ fs
where Q GATE is the total gate charge, VGATE is the gate drive voltage, fS is the clock frequency, C OSS is the drain
source capacitance of the MOSFET, IL is the peak inductor current, tON and tOFF are the switching times
(estimated using device parameters RGATE, QGD and VTH) and VOFF is the voltage across the switch during the
off time, in this case VOFF = VOUT.
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APPLICATION INFORMATION
Conduction loss is calculated as the product of the RDS(on) of the switch (at the worst case junction temperature)
and the square of RMS current:
PCOND +RDS(on) K I2RMS
where K is the temperature factor found in the manufacturer’s RDS(on) vs. junction temperature curves.
Calculating these losses and plotting against frequency gives a curve that enables the designer to determine
either which manufacturer’s device has the best performance at the desired switching frequency, or which
switching frequency has the least total loss for a particular power switch. For this design example an IRFP450
HEXFET from International Rectifier was chosen because of its low RDS(on) and its VDSS rating. The IRFP450’s
RDS(on) of 0.4 Ω and the maximum VDSS of 500 V made it an ideal choice. An excellent review of this procedure
can be found in the Unitrode Power Supply Design Seminar SEM1200, Topic 6, Design Review: 140 W, [Multiple
Output High Density DC/DC Converter].
softstart
The softstart circuitry is used to prevent overshoot of the output voltage during start up. This is accomplished
by bringing up the voltage amplifier’s output (VVAOUT) slowly which allows for the PWM duty cycle to increase
slowly. Please use the following equation to select a capacitor for the softstart pin.
In this example tDELAY is equal to 7.5 ms, which would yield a CSS of 10 nF.
CSS +10 mA tDELAY
7.5 V
In an open-loop test circuit, shorting the softstart pin to ground does not ensure 0% duty cycle. This is due to
the current amplifiers input offset voltage, which could force the current amplifier output high or low depending
on the polarity of the offset voltage. However, in the typical application there is sufficient amount of inrush and
bias current to overcome the current amplifier’s offset voltage.
multiplier
The output of the multiplier of the UCC3817 is a signal representing the desired input line current. It is an input
to the current amplifier, which programs the current loop to control the input current to give high power factor
operation. As such, the proper functioning of the multiplier is key to the success of the design. The inputs to the
multiplier are VAOUT, the voltage amplifier error signal, IIAC, a representation of the input rectified ac line
voltage, and an input voltage feedforward signal, VVFF. The output of the multiplier, IMOUT, can be expressed
as:
IMOUT +IIAC ǒVVAOUT *1Ǔ
K VVFF2
where K is a constant typically equal to 1
V.
The electrical characteristics table covers all the required operating conditions for designing with the
multiplier. Additionally, curves in figures 10, 11, and 12 provide typical multiplier characteristics over its entire
operating range.
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
10 www.ti.com
APPLICATION INFORMATION
multiplier (continued)
The IIAC signal is obtained through a high-value resistor connected between the rectified ac line and the IAC
pin of the UCC3817/18. This resistor (RIAC) is sized to give the maximum IIAC current at high line. For the
UCC3817/18 the maximum IIAC current is about 500 µA. A higher current than this can drive the multiplier out
of its linear range. A smaller current level is functional, but noise can become an issue, especially at low input
line. Assuming a universal line operation of 85 VRMS to 265 VRMS gives a RIAC value of 750 kΩ. Because of
voltage rating constraints of standard 1/4-W resistor, use a combination of lower value resistors connected in
series to give the required resistance and distribute the high voltage amongst the resistors. For this design
example two 383-kΩ resistors were used in series.
The current into the IAC pin is mirrored internally to the VFF pin where it is filtered to produce a voltage feed
forward signal proportional to line voltage. The VFF voltage is used to keep the power stage gain constant; and
to provid input power limiting. Please refer to Texas Instruments application note SLUA196 for detailed
explanation on how the VFF pin provides power limiting. The following equation can be used to size the VFF
resistor ( R VFF) to provide power limiting where VIN(min) is the minimum RMS input voltage and RIAC is the total
resistance connected between the IAC pin and the rectified line voltage.
RVFF +1.4 V
VIN(min) 0.9
2 RIAC
[30 kW
Because the VFF voltage is generated from line voltage it needs to be adequately filtered to reduce total
harmonic distortion caused by the 120 Hz rectified line voltage. Refer to Unitrode Power Supply Design
Seminar, SEM−700 Topic 7, [Optimizing the Design of a High Power Factor Preregulator.] A single pole filter
was adequate for this design. Assuming that an allocation of 1.5% total harmonic distortion from this input is
allowed, and that the second harmonic ripple is 66% of the input ac line voltage, the amount of attenuation
required by this filter is:
1.5 %
66 % +0.022
With a ripple frequency (fR) of 120 Hz and an attenuation of 0.022 requires that the pole of the filter (fP) be placed
at:
fP+120 Hz 0.022 [2.6 Hz
The following equation can be used to select the filter capacitor (CVFF) required to produce the desired low pass
filter.
CVFF +1
2 p RVFF fP[2.2 mF
The R MOUT resistor is sized to match the maximum current through the sense resistor to the maximum multiplier
current. The maximum multiplier current, or IMOUT(max), can be determined by the equation:
IMOUT(max) +
IIAC@VIN(min) ǒVVAOUT(max) *1VǓ
K VVFF2(min)
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
11
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APPLICATION INFORMATION
multiplier (continued)
IMOUT(max) for this design is approximately 315 µA. The RMOUT resistor can then be determined by:
RMOUT +VRSENSE
IMOUT(max)
In this example VRSENSE was selected to give a dynamic operating range of 1.25 V, which gives an RMOUT of
roughly 3.91 kΩ.
voltage loop
The second major source of harmonic distortion is the ripple on the output capacitor at the second harmonic
of the line frequency. This ripple is fed back through the error amplifier and appears as a 3rd harmonic ripple
at the input to the multiplier. The voltage loop must be compensated not just for stability but also to attenuate
the contribution of this ripple to the total harmonic distortion of the system. (refer to Figure 2).
RIN
RD+
−
Rf
Cf
VREF
VOUT
CZ
Figure 2. Voltage Amplifier Configuration
The gain of the voltage amplifier, GVA, can be determined by first calculating the amount of ripple present on
the output capacitor. The peak value of the second harmonic voltage is given by the equation:
VOPK +PIN
ǒ2p fR COUT VOUTǓ
In this example VOPK is equal to 3.91 V. Assuming an allowable contribution of 0.75% (1.5% peak to peak) from
the voltage loop to the total harmonic distortion budget we set the gain equal to:
GVA +ǒDVVAOUTǓ(0.015)
2 VOPK
where ∆VVAOUT is the effective output voltage range of the error amplifier (5 V for the UCC3817). The network
needed to realize this filter is comprised of an input resistor, R IN, and feedback components Cf, CZ, and Rf. The
value of RIN is already determined because of its function as one half of a resistor divider from VOUT feeding
back to the voltage amplifier for output voltage regulation. In this case the value was chosen to be 1 MΩ. This
high value was chosen to reduce power dissipation in the resistor. In practice, the resistor value would be
realized by the use of two 500-kΩ resistors in series because of the voltage rating constraints of most standard
1/4-W resistors. The value of Cf is determined by the equation:
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
12 www.ti.com
APPLICATION INFORMATION
voltage loop (continued)
Cf+1
ǒ2p fR GVA RINǓ
In this example Cf equals 150 nF. Resistor Rf sets the dc gain of the error amplifier and thus determines the
frequency of the pole of the error amplifier. The location of the pole can be found by setting the gain of the loop
equation to one and solving for the crossover frequency. The frequency, expressed in terms of input power , can
be calculated by the equation:
fVI2+PIN
ǒ(2p)2 DVVAOUT VOUT RIN COUT CfǓ
fVI for this converter is 10 Hz. A derivation of this equation can be found in the Unitrode Power Supply Design
Seminar SEM1000, Topic 1, [A 250-kHz, 500-W Power Factor Correction Circuit Employing Zero Voltage
Transitions].
Solving for Rf becomes:
Rf+1
ǒ2p fVI CfǓ
or Rf equals 100 kΩ.
Due to the low output impedance of the voltage amplifier, capacitor CZ was added in series with RF to reduce
loading on the voltage divider. To ensure the voltage loop crossed over at fVI, CZ was selected to add a zero
at a 10th of fVI. For this design a 2.2-µF capacitor was chosen for CZ. The following equation can be used to
calculate CZ.
CZ+1
2 p fVI
10 Rf
current loop
The gain of the power stage is:
GID(s) +ǒVOUT RSENSEǓ
ǒs LBOOST VPǓ
RSENSE has been chosen to give the desired differential voltage for the current sense amplifier at the desired
current limit point. In this example, a current limit of 4 A and a reasonable dif ferential voltage to the current amp
of 1 V gives a RSENSE value of 0.25 Ω. VP in this equation is the voltage swing of the oscillator ramp, 4 V for
the UCC3817. Setting the crossover frequency of the system to 1/10th of the switching frequency, or 10 kHz,
requires a power stage gain at that frequency of 0.383. In order for the system to have a gain of 1 at the crossover
frequency, the current amplifier needs to have a gain of 1/GID at that frequency. GEA, the current amplifier gain
is then:
GEA +1
GID +1
0.383 +2.611
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
13
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APPLICATION INFORMATION
current loop (continued)
RI is the RMOUT resistor, previously calculated to be 3.9 kΩ. (refer to Figure 3). The gain of the current amplifier
is Rf/RI, so multiplying RI by GEA gives the value of Rf, in this case approximately 12 kΩ. Setting a zero at the
crossover frequency and a pole at half the switching frequency completes the current loop compensation.
CZ+1
2 p Rf fC
CP+1
2 p Rf fs
2
RI
+
−
Rf
CP
CAOUT
CZ
Figure 3. Current Loop Compensation
The UCC3817 current amplifier has the input from the multiplier applied to the inverting input. This change in
architecture from previous Texas Instruments PFC controllers improves noise immunity in the current amplifier.
It also adds a phase inversion into the control loop. The UCC3817 takes advantage of this phase inversion to
implement leading-edge duty cycle modulation. Synchronizing a boost PFC controller to a downstream dc-to-dc
controller reduces the ripple current seen by the bulk capacitor between stages, reducing capacitor size and
cost and reducing EMI. This is explained in greater detail in a following section. The UCC3817 current amplifier
configuration is shown in Figure 4.
+
−
+
−
RSENSE +−
MULT
ZfPWM
COMPARATOR
CA
QBOOST
LBOOST
VOUT
Figure 4. UCC3817 Current Amplifier Configuration
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
14 www.ti.com
APPLICATION INFORMATION
start up
The UCC3818 version of the device is intended to have VCC connected to a 12-V supply voltage. The UCC3817
has an internal shunt regulator enabling the device to be powered from bootstrap circuitry as shown in the typical
application circuit of Figure 1. The current drawn by the UCC3817 during undervoltage lockout, or start-up
current, is typically 150 µA. Once VCC is above the UVLO threshold, the device is enabled and draws 4 mA
typically. A resistor connected between the rectified ac line voltage and the VCC pin provides current to the shunt
regulator during power up. Once the circuit is operational, the bootstrap winding of the inductor provides the
VCC voltage. Sizing of the start-up resistor is determined by the start-up time requirement of the system design.
IC+CDV
Dt
R+VRMS (0.9)
IC
Where IC is the charge current, C is the total capacitance at the VCC pin, ∆V is the UVLO threshold and ∆t is
the allowed start-up time.
Assuming a 1 second allowed start-up time, a 16-V UVLO threshold, and a total VCC capacitance of 100 µF,
a resistor value of 51 kΩ is required at a low line input voltage of 85 VRMS. The IC start-up current is sufficiently
small as to be ignored in sizing the start-up resistor.
capacitor ripple reduction
For a power system where the PFC boost converter is followed by a dc-to-dc converter stage, there are benefits
to synchronizing the two converters. In addition to the usual advantages such as noise reduction and stability,
proper synchronization can significantly reduce the ripple currents in the boost circuit’s output capacitor.
Figure 5 helps illustrate the impact of proper synchronization by showing a PFC boost converter together with
the simplified input stage of a forward converter. The capacitor current during a single switching cycle depends
on the status of the switches Q1 and Q2 and is shown in Figure 6. It can be seen that with a synchronization
scheme that maintains conventional trailing-edge modulation on both converters, the capacitor current ripple
is highest. The greatest ripple current cancellation is attained when the overlap of Q1 offtime and Q2 ontime
is maximized. One method of achieving this is to synchronize the turnon of the boost diode (D1) with the turnon
of Q2. This approach implies that the boost converter’s leading edge is pulse width modulated while the forward
converter is modulated with traditional trailing edge PWM. The UCC3817 is designed as a leading edge
modulator with easy synchronization to the downstream converter to facilitate this advantage. Table 1 compares
the ICB(rms) for D1/Q2 synchronization as offered by UCC3817 vs. the ICB(rms) for the other extreme of
synchronizing the turnon of Q1 and Q2 for a 200-W power system with a VBST of 385 V.
UDG-97130-1
Figure 5. Simplified Representation of a 2-Stage PFC Power Supply
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
15
www.ti.com
APPLICATION INFORMATION
capacitor ripple reduction (continued)
UDG-97131
Figure 6. Timing Waveforms for Synchronization Scheme
Table 1. Effects of Synchronization on Boost Capacitor Current
VIN = 85 V VIN = 120 V VIN = 240 V
D(Q2) Q1/Q2 D1/Q2 Q1/Q2 D1/Q2 Q1/Q2 D1/Q2
0.35 1.491 A 0.835 A 1.341 A 0.663 A 1.024 A 0.731 A
0.45 1.432 A 0.93 A 1.276 A 0.664 A 0.897 A 0.614 A
Table 1 illustrates that the boost capacitor ripple current can be reduced by about 50% at nominal line and about
30% at high line with the synchronization scheme facilitated by the UCC3817. Figure 7 shows the suggested
technique for synchronizing the UCC3817 to the downstream converter. With this technique, maximum ripple
reduction as shown in Figure 6 is achievable. The output capacitance value can be significantly reduced if its
choice is dictated by ripple current or the capacitor life can be increased as a result. In cost sensitive designs
where holdup time is not critical, this is a significant advantage.
An alternative method of synchronization to achieve the same ripple reduction is possible. In this method, the
turnon of Q 1 i s synchronized to the turnoff of Q2. While this method yields almost identical ripple reduction and
maintains trailing edge modulation on both converters, the synchronization is much more dif ficult to achieve and
the circuit can become susceptible to noise as the synchronizing edge itself is being modulated.
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
16 www.ti.com
APPLICATION INFORMATION
capacitor ripple reduction (continued)
CT
RT
RT
CT
D2
D1
C1
Gate Drive
From Down
Stream PWM
UCC3817
Figure 7. Synchronizing the UCC3817 to a Down-Stream Converter
Figure 8
141210
7.45
7.50
7.55
7.60
7.40
VCC − Supply Voltage − V
13119
VREF − Reference Voltage − V
REFERENCE VOLTAGE
vs
SUPPLY VOLTAGE
Figure 9
REFERENCE VOLTAGE
vs
REFERENCE CURRENT
0 5 10 15 20 25
7.495
7.500
7.505
7.510
7.490
VREF − Reference Voltage − V
IVREF − Reference Current − mA
SLUS395J - FEBRUARY 2000 - REVISED MARCH 2009
17
www.ti.com
APPLICATION INFORMATION
Figure 10
MULTIPLIER OUTPUT CURRENT
vs
VOLTAGE ERROR AMPLIFIER OUTPUT
0.0 1.0 2.0 3.0 4.0 5.0
50
200
250
350
0
100
300
150
IMOUT - Multiplier Output Current − µA
VAOUT − Voltage Error Amplifier Output − V
IAC = 150 µA
VFF = 1.4 V
IAC = 300 µA
VFF = 3.0 V
IAC = 500 µA
VFF = 4.7 V
Figure 11
MULTIPLIER GAIN
vs
VOLTAGE ERROR AMPLIFIER OUTPUT
1.0 2.0 3.0 4.0 5.0
0.7
1.1
1.3
1.5
0.5
0.9 IAC = 300 µA
IAC = 500 µA
IAC = 150 µA
Multiplier Gain − K
VAOUT − Voltage Error Amplifier Output − V
Figure 12
VFF − Feedforward Voltage − V
1.0 2.0 3.0 4.0 5.0
100
300
400
500
0
200
VAOUT = 3 V
VAOUT = 2 V
VAOUT = 4 V
VAOUT = 5 V
(VFF × IMOUT) − µW
MULTIPLIER CONSTANT POWER PERFORMANCE
0.0
Figure 13
10 12 14 16 20
10
14
15
17
8
12
18
9
11
13
16
RECOMMENDED MINIMUM GATE RESISTANCE
vs
SUPPLY VOLTAGE
RGATE - Recommended Minimum Gate Resistance − Ω
VCC − Supply Voltage − V
PACKAGE OPTION ADDENDUM
www.ti.com 30-Jul-2011
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status (1) Package Type Package
Drawing Pins Package Qty Eco Plan (2) Lead/
Ball Finish MSL Peak Temp (3) Samples
(Requires Login)
UCC2817D ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2817DG4 ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2817DTR ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2817DTRG4 ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2817DW ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2817DWG4 ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2817N ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC2817NG4 ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC2818D ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2818DG4 ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2818DTR ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2818DTRG4 ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC2818DW ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2818DWG4 ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2818DWTR ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2818DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2818N ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
PACKAGE OPTION ADDENDUM
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Addendum-Page 2
Orderable Device Status (1) Package Type Package
Drawing Pins Package Qty Eco Plan (2) Lead/
Ball Finish MSL Peak Temp (3) Samples
(Requires Login)
UCC2818NG4 ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC2818PW ACTIVE TSSOP PW 16 90 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC2818PWG4 ACTIVE TSSOP PW 16 90 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3817D ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3817DG4 ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3817DTR ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3817DTRG4 ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3817DW ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3817DWG4 ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3817DWTR ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3817DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3817N ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC3817NG4 ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC3818D ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3818DG4 ACTIVE SOIC D 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3818DTR ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3818DTRG4 ACTIVE SOIC D 16 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
UCC3818DW ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
PACKAGE OPTION ADDENDUM
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Addendum-Page 3
Orderable Device Status (1) Package Type Package
Drawing Pins Package Qty Eco Plan (2) Lead/
Ball Finish MSL Peak Temp (3) Samples
(Requires Login)
UCC3818DWG4 ACTIVE SOIC DW 16 40 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818DWTR ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818N ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC3818N/81511 OBSOLETE PDIP N 16 TBD Call TI Call TI
UCC3818NG4 ACTIVE PDIP N 16 25 Green (RoHS
& no Sb/Br) CU NIPDAU N / A for Pkg Type
UCC3818PW ACTIVE TSSOP PW 16 90 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818PWG4 ACTIVE TSSOP PW 16 90 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818PWTR ACTIVE TSSOP PW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
UCC3818PWTRG4 ACTIVE TSSOP PW 16 2000 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
PACKAGE OPTION ADDENDUM
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Addendum-Page 4
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF UCC2818 :
•Automotive: UCC2818-Q1
•Enhanced Product: UCC2818-EP
NOTE: Qualified Version Definitions:
•Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects
•Enhanced Product - Supports Defense, Aerospace and Medical Applications
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
UCC2817DTR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1
UCC2818DTR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1
UCC2818DWTR SOIC DW 16 2000 330.0 16.4 10.85 10.8 2.7 12.0 16.0 Q1
UCC3817DTR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1
UCC3817DWTR SOIC DW 16 2000 330.0 16.4 10.85 10.8 2.7 12.0 16.0 Q1
UCC3818DTR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1
UCC3818DWTR SOIC DW 16 2000 330.0 16.4 10.85 10.8 2.7 12.0 16.0 Q1
UCC3818PWTR TSSOP PW 16 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1
PACKAGE MATERIALS INFORMATION
www.ti.com 27-Jan-2012
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
UCC2817DTR SOIC D 16 2500 333.2 345.9 28.6
UCC2818DTR SOIC D 16 2500 333.2 345.9 28.6
UCC2818DWTR SOIC DW 16 2000 346.0 346.0 33.0
UCC3817DTR SOIC D 16 2500 333.2 345.9 28.6
UCC3817DWTR SOIC DW 16 2000 346.0 346.0 33.0
UCC3818DTR SOIC D 16 2500 333.2 345.9 28.6
UCC3818DWTR SOIC DW 16 2000 346.0 346.0 33.0
UCC3818PWTR TSSOP PW 16 2000 346.0 346.0 29.0
PACKAGE MATERIALS INFORMATION
www.ti.com 27-Jan-2012
Pack Materials-Page 2
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