1
FEATURES
DESCRIPTION
APPLICATIONS
V
0.9V/1.15V
upto400mA
OUT
VIN
GND
EN
FB
TPS62270DRV
VSEL
L
2.2 Hm
SW
C
10 F
OUT
m
0.9V
1.15V
V =2Vto6V
IN
C
4.7 F
IN
m
GND
COUT
U1
CIN
VOUT
VIN
L1
Totalarea
21.5mm²
6.5mm
3.3mm
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
2.25 MHz 400-mA Step Down Converter With Selectable VOUT
2
•High Efficiency Step Down Converter•Output Current up to 400 mA
The TPS62270 device is a high efficiencysynchronous step down DC-DC converter optimized•V
IN
Range From 2V to 6V for Li-Ion Batteries
for battery powered portable applications. It providesWith Extended Voltage Range
up to 400 mA output current from a single Li-Ion cell.•2.25 MHz Fixed Frequency Operation
With an input voltage range of 2 V to 6 V the device•Pin-Selectable Fixed Output Voltage
supports Li-Ion batteries with extended voltage range,•Power Save Mode for Highest Efficiency
and is ideal to power portable applications like mobilephones and other portable equipment.•Automatic transition between PFM and PWMMode
The TPS62270 operates at 2.25 MHz fixed switching•Voltage Positioning in PFM Mode
frequency and enters Power Save Mode operation atlight load currents to maintain high efficiency over the•Typical 15- µA Quiescent Current
entire load current range. The Power Save Mode is•100% Duty Cycle for Lowest Dropout
optimized for low output voltage ripple.•Available in 2 × 2 × 0,8 mm SON Package
With the VSEL pin, two different fixed output voltages•Allows < 1 mm Solution Height
can be selected. This function features a dynamicvoltage scaling for low power processor cores.
In the shutdown mode, the current consumption is•Low Power Processor Supply
reduced to less than 1 µA. TPS62270 allows the use•Cell Phones, Smart-phones
of small inductors and capacitors to achieve a small•Navigation Systems
solution size.•Low Power DSP Supply
The TPS62270 is available in a 2 mm × 2 mm, 6-pin•Portable Media Players
SON package.•Digital Cameras
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2PowerPad is a trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Copyright © 2007 – 2009, Texas Instruments IncorporatedProducts conform to specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.
ABSOLUTE MAXIMUM RATINGS
DISSIPATION RATINGS
RECOMMENDED OPERATING CONDITIONS
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
OUTPUT VOLTAGE
(2)
PACKAGE PACKAGET
A
PART NUMBER
(1)
ORDERING
(1)DESIGNATOR MARKINGVSEL = 1 VSEL = 0
TPS62270 1.15 V 0.9 V DRV TPS62270DRV CCX– 40 ° C to 85 ° C TPS62272 3.3V 2.1V DRV TPS62272DRV OAMTPS62273 3.3V 2.5V DRV TPS62273DRV CGW
(1) The DRV (SON2x2) package is available in tape on reel. Add R suffix to order quantities of 3000 parts per reel, add T suffix to orderquantities of 250 parts per reel.(2) contact TI for other fixed output voltage options.
over operating free-air temperature range (unless otherwise noted)
(1)
VALUE UNIT
Input voltage range
(2)
– 0.3 to 7 VVoltage range at EN, VSEL – 0.3 to VIN +0.3, ≤7 VVoltage on SW – 0.3 to 7 VPeak output current Internally limited AHBM Human body model 2
kVESD rating
(3)
CDM Charge device model 1Machine model 200 VT
J
Maximum operating junction temperature – 40 to 125 ° CT
stg
Storage temperature range – 65 to 150 ° C
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratingsonly and functional operation of the device at these or any other conditions beyond those indicated under recommended operatingconditions is not implied. Exposure to absolute – maximum – rated conditions for extended periods may affect device reliability.(2) All voltage values are with respect to network ground terminal.(3) The human body model is a 100 pF capacitor discharged through a 1.5k Ωresistor into each pin. The machine model is a 200 pFcapacitor discharged directly into each pin.
POWER RATING DERATING FACTORPACKAGE R
θJA
FOR T
A
≤25 ° C ABOVE T
A
= 25 ° C
DRV 76 ° C/W 1300 mW 13 mW/ ° C
over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
V
IN
Supply Voltage 2 6 VT
A
Operating ambient temperature – 40 85 ° CT
J
Operating junction temperature – 40 125 ° C
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Product Folder Link(s): TPS62270 TPS62272 TPS62273
ELECTRICAL CHARACTERISTICS
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
Over full operating ambient temperature range, typical values are at T
A
= 25 ° C. Unless otherwise noted, specifications applyfor condition V
IN
= EN = 3.6V. External components C
IN
= 4.7 µF 0603, C
OUT
= 10 µF 0603, L = 2 µH, see the parametermeasurement information.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY
V
IN
Input voltage range 2 6 V2.5 V ≤V
IN
≤6 V 400I
OUT
Output current mA2 V ≤V
IN
≤2.5 V 150I
OUT
= 0 mA, device not switching 15I
Q
Operating quiescent current µAI
OUT
= 0 mA, device switching with no load,
18V
OUT
= 1.15VI
SD
Shutdown current EN = GND 0.1 1 µAFalling 1.85UVLO Undervoltage lockout threshold VRising 1.95
ENABLE, VSEL
V
IH
High level input voltage, EN, VSEL 2 V ≤V
IN
≤6 V 1 V
IN
VV
IL
Low Level Input Voltage, EN, VSEL 2 V ≤V
IN
≤6 V 0 0.4 VI
IN
Input bias Current, EN, VSEL EN, VSEL = GND or VIN 0.01 1.0 µA
POWER SWITCH
High side MOSFET on-resistance V
IN
= V
GS
= 3.6V, T
A
= 25 ° C 240 480 m ΩR
DS(on)
Low side MOSFET on-resistance V
IN
= V
GS
= 3.6V, T
A
= 25 ° C 180 380 m Ω
Forward current limit MOSFET high-side andI
LIMF
V
IN
= V
GS
= 3.6 V 0.56 0.7 0.84 Alow sideThermal shutdown Increasing junction temperature 140T
SD
° CThermal shutdown hysteresis Decreasing junction temperature 20
OSCILLATOR
f
SW
Oscillator frequency 2 V ≤V
IN
≤6 V 2 2.25 2.5 MHz
OUTPUT
1.16VSEL = 1 1.13 1.15
7PWM operation, 2 V ≤V
IN
≤6 V,TPS62270
FB pin connected to V
OUT
(1)
0.88 0.91VSEL = 0 0.96 4V
OUT
Output voltage PWM VVSEL = 1 3.23 3.3 3.37PWM operation, 2 V ≤V
IN
≤6 V,TPS62272
FB pin connected to V
OUT
(1)
VSEL = 0 2.06 2.1 2.14VSEL = 1 3.23 3.3 3.37PWM operation,TPS62273
FB pin connected to V
OUT
(1)
VSEL = 0 2.45 2.5 2.55VSEL = 1 1.16TPS62270
VSEL = 0 0.91VSEL = 1 3.34Output voltage in PFM mode, voltageV
OUT
TS62272 Vpositioning
VSEL = 0 2.12VSEL = 1 3.34TPS62273
VSEL = 0 2.53t
Start
Start-up time Time from active EN to reach 95% of V
OUT
500 µst
Ramp
V
OUT
ramp up time Time to ramp from 5% to 95% of V
OUT
250 µsI
lkg
Leakage Current into SW pin V
IN
= 3.6 V, V
IN
= V
OUT
= V
SW
, EN = GND
(2)
0.1 1 µA
(1) For V
IN
= V
OUT
+ 0.6 V(2) In fixed output voltage versions, the internal resistor divider network is disconnected from FB pin.
Copyright © 2007 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 3
Product Folder Link(s): TPS62270 TPS62272 TPS62273
PIN ASSIGNMENTS
SW
VSEL
FB EN
GND
VIN
1
2
34
5
6
Power
Pad
TopviewDRVpackage
Zero-Pole
AMP.
Integrator
Error Amp.
PFMComparator
PWM
Comp.
VREF
Control
Stage
GateDriver
Anti
Shoot-Through
Current
LimitComparator
Current
LimitComparator
VREF+1%
FB
FB
VIN
GND
2.25MHz
Oscillator
SW1
EN
VIN
Softstart
VOUT RAMP
CONTROL
Thermal
Shutdown
Reference
0.6VVREF
Undervoltage
Lockout1.8V Limit
HighSide
Limit
LowSide
Sawtooth
Generator
FB
RI3
RI1
RI..N
VSEL
GND
InternalVoltage
SettingNetwork
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
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TERMINAL FUNCTIONS
TERMINAL I/O DESCRIPTION
NO.NAME
(SON)
V
IN
5 PWR VIN power supply pin.GND 6 PWR GND supply pinEN 4 I This is the enable pin of the device. Pulling this pin to low forces the device into shutdown mode. Pulling thispin to high enables the device. This pin must be terminated.SW 1 OUT This is the switch pin and is connected to the internal MOSFET switches. Connect the inductor to thisterminalFB 3 I Feedback Pin for the internal regulation loop. Connect the external resistor divider to this pin. In case of fixedoutput voltage option, connect this pin directly to the output capacitorVSEL 2 I Voltage Select input. Please refer to table ordering information for available output voltage selections.
FUNCTIONAL BLOCK DIAGRAM
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PARAMETER MEASUREMENT INFORMATION
VIN
GND
EN
FB
TPS6227XDRV
C
4.7 F
IN
m
VSEL
L
2.2 Hm
SW
C
10 F
OUT
m
V
upto400mA
OUT
VIN
High
Low
L:MIPSA2520D2R22.0 H
C :GRM188R60J106M4.7 F
C :GRM188R60J106M10 F
m
m
m
IN
OUT
TYPICAL CHARACTERISTICS
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
Table of Graphs
Figure
Efficiency vs Output Current Figure 1Efficiency vs Output Current Figure 2Efficiency vs Output Current Figure 3Output voltage vs Output Current Figure 4Output Voltage vs Output Current Figure 5Output Voltage vs Output Current Figure 6Output Voltage vs Output Current Figure 7Output Voltage vs Output Current Figure 8Output Voltage vs Output Current Figure 9PWM Mode Operation Figure 10PFM Mode Operation Figure 11Load Transient Response PFM Mode Figure 12Load Transient Response PFM/PWM Mode Figure 13Load Transient Response PFM/PWM Mode Figure 14VSEL Output Voltage Response Figure 15Startup in 10 ΩLoad at 1.15 V Output Voltage Figure 16Startup in 100 ΩLoad at 0.9 V Output Voltage Figure 17Startup in 220 ΩLoad at 2.1 V Output Voltage Figure 18Startup in 220 ΩLoad at 3.3 V Output Voltage Figure 19Quiescent Current vs Input Voltage Figure 20Shutdown Current vs Input Voltage Figure 21Static Drain Source On-state Resistance vs Input Voltage Figure 22Static Drain Source On-state Resistance vs Input Voltage Figure 23
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Product Folder Link(s): TPS62270 TPS62272 TPS62273
0
10
20
30
40
50
60
70
80
90
100
Efficiency-%
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
V =5V
I
V =3.3V
I
V =2.7V
I
V =2.3V
I
V =4.2V
I
V =3.6V
I
V =0.9V,
VSEL =V ,
L =2 HMIPSA2520D2R2,
C =10 F
O
I
O
m
m
V =0.9V
O
0
10
20
30
40
50
60
70
80
90
100
0.00001 0.0001 0.001 0.01 0.1 1
Efficiency-%
I -OutputCurrent- A
O
V =1.15V
O
V =3.3V
I
V =3.6V
I
V =5V
I
V =2.7V
I
V =2.3V
I
V =1.15V,
VSEL =V ,
L =2 HMIPSA2520D2R2,
C =10 F
O
I
O
m
m
V =4.2V
I
1.1
1.15
1.2
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
V -OutputVoltage(DC)-V
O
V =1.15V,
T =25°C
O
A
PFMMODE,VoltagePositioning
V =3.6V
I
V =4.2V
IV =5V
I
V =2.3V
IV =2.7V
IV =3.3V
I
50
60
65
70
75
80
85
90
95
100
Efficiency-%
0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
V =5V
I
V =3.3V
I
V =4.2V
I
V =2.1V,
VSEL =GND,
L =2.2 H,
C =10 F
O
O
m
m
V =2.7V
I
55
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
www.ti.com
EFFICIENCY EFFICIENCYvs vsOUTPUT CURRENT OUTPUT CURRENT
Figure 1. Figure 2.
TPS62272 EFFICIENCY OUTPUT VOLTAGEvs vsOUTPUT CURRENT OUTPUT CURRENT
Figure 3. Figure 4.
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1.1
1.15
1.2
V -OutputVoltage(DC)-V
O
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
V =1.15V,
T =85°C
O
A
PFMMODE,VoltagePositioning
V =3.6V
IV =4.2V
IV =5V
I
V =2.3V
IV =2.7V
IV =3.3V
I
0.870
0.880
0.890
0.900
0.910
0.920
0.930
PFMMODE,VoltagePositioning
V =2.3V
IV =3.3V
I
V =2.7V
I
V =4.2V
IV =5V
I
V =3.6V
I
V =0.9V,
T =25°C
O
A
V -OutputVoltage(DC)-V
O
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
0.870
0.880
0.890
0.900
0.910
0.920
0.930
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
V -OutputVoltage(DC)-V
O
V =0.9V,
T =-40°C
O
A
PFMMODE,VoltagePositioning
V =2.7V
I
V =3.3V
I
V =3.6V
IV =4.2V
I
V =5V
I
V =2.3V
I
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
OUTPUT VOLTAGE OUTPUT VOLTAGEvs vsOUTPUT CURRENT OUTPUT CURRENT
Figure 5. Figure 6.
OUTPUT VOLTAGE OUTPUT VOLTAGEvs vsOUTPUT CURRENT OUTPUT CURRENT
Figure 7. Figure 8.
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Timebase-1 s/Divm
SW2V/Div
V 50mV/Div
OUT
I 200mA/Div
L
V =3.6V,
V =1.15V,
I =150mA
IN
OUT
OUT
0.870
0.880
0.890
0.900
0.910
0.920
0.930
V -OutputVoltage(DC)-V
O
0.00001 0.0001 0.001 0.01 0.1 1
I -OutputCurrent- A
O
PFMMODE,VoltagePositioning
V =0.9V,
T =85°C
O
A
V =2.3V
IV =2.7V
IV =3.3V
I
V =3.6V
IV =4.2V
IV =5V
I
Timebase-5 s/Divm
SW2V/Div
V 50mV/Div
OUT
I 200mA/Div
L
V =3.6V,
V =1.15V,
I =10mA
IN
OUT
OUT
50mA
5mA
Timebase-50 s/Divm
V 50mV/Div
OUT
I 200mA/Div
L
V =3.6V,
V =0.9V,
I =5mA to50mA
IN
OUT
OUT
I 50mA/Div
OUT
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
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OUTPUT VOLTAGE
vsOUTPUT CURRENT PWM MODE OPERATION
Figure 9. Figure 10.
PFM MODE OPERATION LOAD TRANSIENT RESPONSE PFM MODE
Figure 11. Figure 12.
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200mA
50mA
1.15V
VoltagePositioning
Timebase-20 s/Divm
V 50mV/Div
OUT
I 200mA/Div
L
V =3.6V,
V =1.15V,
I =50mA to200mA
IN
OUT
OUT
I 200 mA/Div
OUT
200mA
VoltagePositioning
50mA
Timebase-20 s/Divm
V 50mV/Div
OUT
I 200mA/Div
L
V =3.6V,
V =0.9V,
I =150mA to200mA
IN
OUT
OUT
I 200mA/Div
OUT
SW2V/Div
EN2V/Div
Timebase-100 s/Divm
V 1V/Div
OUT
I 20mA/Div
IN
V =3.6V,
V =1.15V,
R =10 ,
VSEL =V
IN
OUT
LOAD
IN
W
VSEL 500mV/Div
1.15V/86mA
0.9V/68mA
Timebase-20 s/Divm
V 100mV/Div
OUT
I 500mA/Div
L
V =3.6V,
V =0.9V/1.15V,
R =13.3
IN
OUT
LOAD W
TPS62270 , TPS62272
TPS62273
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........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
LOAD TRANSIENT RESPONSE PFM/PWM MODE LOAD TRANSIENT RESPONSE PFM/PWM MODE
Figure 13. Figure 14.
STARTUP IN 10 ΩLOADVSEL OUTPUT VOLTAGE RESPONSE AT 1.15 V OUTPUT VOLTAGE
Figure 15. Figure 16.
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TimeBase-200 s/Divm
V 2V/Div
OUT
I 200mA/Div
L
SW5V/Div
V 2V/Div
IN
V =rampupto5V
R =220
VSEL =GND
EN=
IN
Load
V =2.1V
V
OUT
IN
W
SW2V/Div
EN2V/Div
Timebase-100 s/Divm
V 1V/Div
OUT
I 20mA/Div
IN
V =3.6V,
V =0.9V,
R =100 ,
VSEL =GND
IN
OUT
LOAD W
TimeBase-200 s/Divm
V 2V/Div
OUT
I 200mA/Div
L
SW5V/Div
V 2V/Div
IN
V =rampupto5V
R =220
VSEL =
EN=
IN
Load
V =3.3V
V
OUT
IN
W
VIN
V -InputVoltage-V
IN
8
10
12
14
16
18
20
2 2.5 3 3.5 4 4.5 5 5.5 6
I -QuiescentCurrent- A
Qm
T =85 C
A
º
T =25 C
A
º
T =-40 C
A
º
EN=VIN,
DeviseNotSwitching
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
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STARTUP IN 100 ΩLOAD STARTUP IN 220 ΩLOADAT 0.9 V OUTPUT VOLTAGE AT 2.1 V OUTPUT VOLTAGE
Figure 17. Figure 18.
QUIESCENT CURRENTSTARTUP IN 220 ΩLOAD vsAT 3.3 V OUTPUT VOLTAGE INPUT VOLTAGE
Figure 19. Figure 20.
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
2 2.5 3 3.5 4 4.5 5 5.5 6
EN=GND
V -InputVoltage-V
IN
I -ShutdownCurrentintoVIN- A
SD m
T =85 C
A
º
T =25 C
A
º
T =-40 C
A
º
0
0.1
0.2
0.3
0.4
0.7
0.8
2 2.5 3 3.5 4 4.5 5
HighSideSwitch
0.5
0.6
V -InputVoltage-V
IN
R -StaticDrain-SourceOn-StateResistance-
DS(on) W
T =85 C
A
º
T =-40 C
A
º
T =25 C
A
º
0
0.05
0.1
0.15
0.2
0.35
0.4
2 2.5 3 3.5 4 4.5 5
0.25
0.3
R -StaticDrain-SourceOn-StateResistance-
DS(on) W
V -InputVoltage-V
IN
T =85 C
A
º
T =-40 C
A
º
LowSideSwitch
T =25 C
A
º
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
SHUTDOWN CURRENT STATIC DRAIN SOURCE ON-STATE RESISTANCEvs vsINPUT VOLTAGE INPUT VOLTAGE
Figure 21. Figure 22.
STATIC DRAIN SOURCE ON-STATE RESISTANCE
vsINPUT VOLTAGE
Figure 23.
Copyright © 2007 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 11
Product Folder Link(s): TPS62270 TPS62272 TPS62273
DETAILED DESCRIPTION
OPERATION
Power Save Mode
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
www.ti.com
The TPS62270 step down converter operates with typically 2.25 MHz fixed frequency pulse width modulation(PWM) at moderate to heavy load currents. At light load currents the converter automatically enters Power SaveMode and operates then in PFM mode.
During PWM operation the converter use a unique fast response voltage mode controller scheme with inputvoltage feed-forward to achieve good line and load regulation allowing the use of small ceramic input and outputcapacitors. At the beginning of each clock cycle initiated by the clock signal, the High Side MOSFET switch isturned on. The current flows now from the input capacitor via the High Side MOSFET switch through the inductorto the output capacitor and load. During this phase, the current ramps up until the PWM comparator trips and thecontrol logic will turn off the switch. The current limit comparator will also turn off the switch in case the currentlimit of the High Side MOSFET switch is exceeded. After a dead time preventing shoot through current, the LowSide MOSFET rectifier is turned on and the inductor current will ramp down. The current flows now from theinductor to the output capacitor and to the load. It returns back to the inductor through the Low Side MOSFETrectifier.
The next cycle will be initiated by the clock signal again turning off the Low Side MOSFET rectifier and turning onthe on the High Side MOSFET switch.
If the load current decreases, the converter will enter Power Save Mode operation automatically. During PowerSave Mode the converter skips switching and operates with reduced frequency in PFM mode with a minimumquiescent current to maintain high efficiency.
The transition from PWM mode to PFM mode occurs once the inductor current in the Low Side MOSFET switchbecomes zero, which indicates discontinuous conduction mode.
During the Power Save Mode the output voltage is monitored with a PFM comparator. As the output voltage fallsbelow the PFM comparator threshold of VOUT +1%, the device starts a PFM current pulse. For this the HighSide MOSFET switch will turn on and the inductor current ramps up. After the On-time expires the switch will beturned off and the Low Side MOSFET switch will be turned on until the inductor current becomes zero.
The converter effectively delivers a current to the output capacitor and the load. If the load is below the deliveredcurrent the output voltage will rise. If the output voltage is equal or higher than the PFM comparator threshold,the device stops switching and enters a sleep mode with typical 15 µA current consumption.
In case the output voltage is still below the PFM comparator threshold, further PFM current pulses will begenerated until the PFM comparator threshold is reached. The converter starts switching again once the outputvoltage drops below the PFM comparator threshold.
With a fast single threshold comparator, the output voltage ripple during PFM mode operation can be kept verysmall. The PFM Pulse is timing controlled, which allows to modify the charge transferred to the output capacitorby the value of the inductor. The resulting PFM output voltage ripple depends in first order on the size of theoutput capacitor and the inductor value. Increasing output capacitor values and/or inductor values will minimizethe output ripple.
The PFM mode is left and PWM mode entered in case the output current can not longer be supported in PFMmode.
12 Submit Documentation Feedback Copyright © 2007 – 2009, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62272 TPS62273
Outputvoltage
Vout(PWM)
Vout+1%
PFMComparator
threshold
VoltagePositioning
Lightload
PFMMode
moderatetoheavyload
PWMMode
100% Duty Cycle Low Dropout Operation
Undervoltage Lockout
Output Voltage Selection VSEL
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
Figure 24. Power Save Mode
The device starts to enter 100% duty cycle Mode once the input voltage comes close the nominal output voltage.In order to maintain the output voltage, the High Side MOSFET switch is turned on 100% for one or more cycles.
With further decreasing VIN the High Side MOSFET switch is turned on completely. In this case the converteroffers a low input-to-output voltage difference. This is particularly useful in battery-powered applications toachieve longest operation time by taking full advantage of the whole battery voltage range.
The minimum input voltage to maintain regulation depends on the load current and output voltage, and can becalculated as:Vin
min
= Vout
max
+ lout
max
× (R
DS(on)
max + R
L
)
With
Iout
max
= maximum output current plus inductor ripple currentR
DS(on)
max = maximum P-channel switch R
DS(on)
.R
L
= DC resistance of the inductorVout
max
= nominal output voltage plus maximum output voltage tolerance
The undervoltage lockout circuit prevents the device from malfunctioning at low input voltages and fromexcessive discharge of the battery and disables the output stage of the converter. The undervoltage lockoutthreshold is typically 1.85V with falling V
IN
.
The VSEL pin features output voltage selection. The output voltages are set with an internal high precisionfeedback divider network. No further external components for output voltage setting or compensation arerequired. This features smallest solution size.
Connecting the VSEL pin to an external logic control signal allows simple dynamic voltage scaling for low powerprocessors cores. During operation of the device, the output voltage can be changed with VSEL pin.
This allows setting the core voltage of an processor according to its operating mode and helps to optimize powerconsumption. Table 1 shows an overview of the selectable output voltages.
Copyright © 2007 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 13
Product Folder Link(s): TPS62270 TPS62272 TPS62273
Enable
Soft Start
Short-Circuit Protection
Thermal Shutdown
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
www.ti.com
Table 1. VSEL Output Voltage Selection
OUTPUT VOLTAGE VOUTDEVICE
VSEL = low VSEL = high
TPS62270 0.9 V 1.15 VTPS62272 2.1V 3.3VTPS62273 2.5V 3.3V
The device is enabled setting EN pin to high. During the start up time t
Start up
the internal circuits are settled.Afterwards the device activates the soft start circuit. The EN input can be used to control power sequencing in asystem with various DC/DC converters. The EN pin can be connected to the output of another converter, to drivethe EN pin high and getting a sequencing of supply rails.
The TPS62270 has an internal soft start circuit that controls the ramp up of the output voltage. The outputvoltage ramps up from 5% to 95% of its nominal value within typ. 250 µs. This limits the inrush current in theconverter during start up and prevents possible input voltage drops when a battery or high impedance powersource is used. The Soft start circuit is enabled after the start up time t
Start up
has expired.
The High Side and Low Side MOSFET switches are short-circuit protected with maximum output current = I
LIMF
.Once the High Side MOSFET switch reaches its current limit, it is turned off and the Low Side MOSFET switch isturned on. The High Side MOSFET switch can only turn on again, once the current in the Low Side MOSFETswitch decreases below its current limit.
As soon as the junction temperature, T
J
, exceeds 150 ° C (typical) the device goes into thermal shutdown. In thismode, the High Side and Low Side MOSFETs are turned-off. The device continues its operation when thejunction temperature falls below the thermal shutdown hysteresis.
14 Submit Documentation Feedback Copyright © 2007 – 2009, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62272 TPS62273
APPLICATION INFORMATION
VIN
GND
EN
FB
TPS62270DRV
VSEL
L
2.2 Hm
SW
C
10 F
OUT
m
0.9V
1.15V
V
0.9V/1.15V
upto400mA
OUT
V =2Vto6V
IN
C
4.7 F
IN
m
OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR)
Inductor Selection
DIL+Vout 1*Vout
Vin
L ƒ
(1)
ILmax +Ioutmax )
DIL
2
(2)
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
Figure 25. TPS62270DRV Application Circuit
The TPS62270 is designed to operate with inductors in the range of 1.5 µH to 4.7 µH and with output capacitors inthe range of 4.7 µF to 22 µF. The part is optimized for operation with a 2.2 µH inductor and 10 µF output capacitor.Larger or smaller inductor values can be used to optimize the performance of the device for specific operationconditions. For stable operation, the L and C values of the output filter may not fall below 1 µH effectiveinductance and 3.5 µF effective capacitance.
The inductor value has a direct effect on the ripple current. The selected inductor has to be rated for its dcresistance and saturation current. The inductor ripple current ( ΔI
L
) decreases with higher inductance andincreases with higher V
I
or V
O
.
The inductor selection has also impact on the output voltage ripple in PFM mode. Higher inductor values will leadto lower output voltage ripple and higher PFM frequency, lower inductor values will lead to a higher outputvoltage ripple but lower PFM frequency.
Equation 1 calculates the maximum inductor current under static load conditions. The saturation current of theinductor should be rated higher than the maximum inductor current as calculated with Equation 2 . This isrecommended because during heavy load transient the inductor current will rise above the calculated value.
With:
f = Switching Frequency (2.25 MHz typical)L = Inductor ValueΔI
L
= Peak to Peak inductor ripple currentI
Lmax
= Maximum Inductor current
A more conservative approach is to select the inductor current rating just for the maximum switch current of thecorresponding converter.
Accepting larger values of ripple current allows the use of low inductance values, but results in higher outputvoltage ripple, greater core losses, and lower output current capability.
The total losses of the coil have a strong impact on the efficiency of the DC/DC conversion and consist of boththe losses in the dc resistance (R
(DC)
) and the following frequency-dependent components:•The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies)•Additional losses in the conductor from the skin effect (current displacement at high frequencies)•Magnetic field losses of the neighboring windings (proximity effect)•Radiation losses
Copyright © 2007 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 15
Product Folder Link(s): TPS62270 TPS62272 TPS62273
Output Capacitor Selection
IRMSCout +Vout 1*Vout
Vin
L ƒ 1
2 3
Ǹ
(3)
DVout +Vout 1*Vout
Vin
L ƒ ǒ1
8 Cout ƒ)ESRǓ
(4)
Input Capacitor Selection
TPS62270 , TPS62272TPS62273
SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009 ...........................................................................................................................................
www.ti.com
Table 2. List of Inductors
DIMENSIONS
INDUCTOR TYPE SUPPLIER[mm
3
]
2.5 × 2.0 × 1.0 MIPS2520 FDK2.5 × 2.0 × 1.2 MIPSA2520 FDK2.5 × 2.0 × 1.0 KSLI-252010AG2R2 Hitachi Metals2.5 × 2.0 × 1.2 LQM2HPN2R2MJ0L Murata
The advanced fast-response voltage mode control scheme of the TPS62270 allows the use of tiny ceramiccapacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple and arerecommended. The output capacitor requires either an X7R or X5R dielectric. Y5V and Z5U dielectric capacitors,aside from their wide variation in capacitance over temperature, become resistive at high frequencies.
At nominal load current, the device operates in PWM mode and the RMS ripple current is calculated as:
At nominal load current, the device operates in PWM mode and the overall output voltage ripple is the sum of thevoltage spike caused by the output capacitor ESR plus the voltage ripple caused by charging and discharging theoutput capacitor:
At light load currents the converter operates in Power Save Mode and the output voltage ripple is dependent onthe output capacitor and inductor value. Larger output capacitor and inductor values minimize the voltage ripplein PFM mode and tighten DC output accuracy in PFM mode.
An input capacitor is required for best input voltage filtering, and minimizing the interference with other circuitscaused by high input voltage spikes. For most applications, a 4.7 µF to 10 µF ceramic capacitor is recommended.Because ceramic capacitor loses up to 80% of its initial capacitance at 5 V, it is recommended that 10 µF inputcapacitors be used for input voltages >4.5V. The input capacitor can be increased without any limit for betterinput voltage filtering. Take care when using only small ceramic input capacitors. When a ceramic capacitor isused at the input and the power is being supplied through long wires, such as from a wall adapter, a load step atthe output or VIN step on the input can induce ringing at the VIN pin. This ringing can couple to the output andbe mistaken as loop instability or could even damage the part by exceeding the maximum ratings.
Table 3. List of Capacitors
CAPACITANCE TYPE SIZE mm
3
SUPPLIER
4.7 µF GRM188R60J475K 0603: 1.6 × 0.8 × 0.8 mm
3
Murata10 µF GRM188R60J106M69D 0603: 1.6 × 0.8 × 0.8 mm
3
Murata
16 Submit Documentation Feedback Copyright © 2007 – 2009, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62272 TPS62273
LAYOUT CONSIDERATIONS
GND
COUT
U1
CIN
VOUT
VIN
L1
Totalarea
21.5mm²
6.5mm
3.3mm
TPS62270 , TPS62272
TPS62273
www.ti.com
........................................................................................................................................... SLVS799C – NOVEMBER 2007 – REVISED JANUARY 2009
As for all switching power supplies, the layout is an important step in the design. Proper function of the devicedemands careful attention to PCB layout. Care must be taken in board layout to get the specified performance. Ifthe layout is not carefully done, the regulator could show poor line and/or load regulation, stability issues as wellas EMI problems. It is critical to provide a low inductance, impedance ground path. Therefore, use wide andshort traces for the main current paths. The input capacitor should be placed as close as possible to the IC pinsas well as the inductor and output capacitor.
Connect the GND Pin of the device to the PowerPad™ of the PCB and use this pad as a star point. Use acommon Power GND node and a different node for the Signal GND to minimize the effects of ground noise.Connect these ground nodes together to the PowerPad™ (star point) underneath the IC. Keep the common pathto the GND PIN, which returns the small signal components and the high current of the output capacitors asshort as possible to avoid ground noise. The FB line should be connected right to the output capacitor and routedaway from noisy components and traces (e.g., SW line).
Figure 26. Suggested Board Layout
Copyright © 2007 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 17
Product Folder Link(s): TPS62270 TPS62272 TPS62273
PACKAGING INFORMATION
Orderable Device Status (1) Package
Type Package
Drawing Pins Package
Qty Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
TPS62270DRVR ACTIVE SON DRV 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62270DRVRG4 ACTIVE SON DRV 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62270DRVT ACTIVE SON DRV 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62270DRVTG4 ACTIVE SON DRV 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62272DRVR ACTIVE SON DRV 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62272DRVT ACTIVE SON DRV 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62273DRVR ACTIVE SON DRV 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62273DRVRG4 ACTIVE SON DRV 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62273DRVT ACTIVE SON DRV 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS62273DRVTG4 ACTIVE SON DRV 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
(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.
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.
PACKAGE OPTION ADDENDUM
www.ti.com 5-Mar-2009
Addendum-Page 1
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
TPS62270DRVR SON DRV 6 3000 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
TPS62270DRVT SON DRV 6 250 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
TPS62272DRVR SON DRV 6 3000 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
TPS62272DRVT SON DRV 6 250 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
TPS62273DRVR SON DRV 6 3000 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
TPS62273DRVT SON DRV 6 250 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2
PACKAGE MATERIALS INFORMATION
www.ti.com 18-Dec-2010
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
TPS62270DRVR SON DRV 6 3000 203.0 203.0 35.0
TPS62270DRVT SON DRV 6 250 203.0 203.0 35.0
TPS62272DRVR SON DRV 6 3000 203.0 203.0 35.0
TPS62272DRVT SON DRV 6 250 203.0 203.0 35.0
TPS62273DRVR SON DRV 6 3000 203.0 203.0 35.0
TPS62273DRVT SON DRV 6 250 203.0 203.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 18-Dec-2010
Pack Materials-Page 2
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