Advanced Power
Electronics Corp.
3A SINK/SOURCE BUS TERMINATION REGULATOR
FEATURE
S
DESCRIPTIOON
Ideal for DDR-I, DDR-II and DDR-III VTT Applications
Sink and Source 3A Continuous Current
Integrated Power MOSFETs
Generates Termination Voltage for SSTL_2, SSTL_18,
HSTL, SCSI-2 and SCSI-3 Interfaces.
High Accuracy Output Voltage at Full-Load
Output Adjustment by Two External Resistors
Low External Component Count
Shutdown for Suspend to RAM (STR) Functionality
with High-Impedance Output
Current Limiting Protection
On-Chip Thermal Protection
Available in TO-252-5L & ESOP-8 Packages
VIN and VCNTL No Power Sequence Issue
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIO
N
Desktop PCs, Notebooks, and Workstations
Graphics Card Memory Termination
Set Top Boxes, Digital TVs, Printers
Embedded Systems
Active Termination Buses
DDR-I, DDR-II and DDR-III Memory Systems
Data and specifications subject to change without notice
201011055
AP1270
TYPICAL APPLICATION
1
The AP1270 is a simple, cost-effective and high-
speed linear regulator designed to generate termination
voltage in double data rate (DDR) memory system to
comply with the JEDEC SSTL_2 and SSTL_18 or other
specific interfaces such as HSTL, SCSI-2 and SCSI-3
etc. devices requirements. The regulator is capable of
actively sinking or sourcing up to 3A while regulating an
output voltage to within 40mV. The output termination
voltage cab be tightly regulated to track 1/2VDDQ by two
external voltage divider resistors or the desired output
voltage can be pro-grammed by externally forcing the
REFEN pin voltage.
The AP1270 also incorporates a high-speed
differential amplifier to provide ultra-fast response in
line/load transient. Other features include extremely low
initial offset voltage, excellent load regulation, current
limiting in bi-directions and on-chip thermal shut-down
protection.
The AP1270 are available in the TO-252-5L &
ESOP-8 (Exposed Pad) surface mount packages.
R1 = R2 = 100KΩ, RTT = 50Ω / 33Ω / 25Ω
COUT,min = 10uF (Ceramic) + 1000uF under the worst case testing condition
CSS = 1µF, CIN = 470µF(Low ESR), CCNTL = 47µF
VIN VCNTL
REFEN VOUT
GND
RTT
EN
VIN=2.5V/1.8V/1.5V
VCNTL=3.3V
R1
R2CSS
CIN
COUT
CCNTL
2N7002 AP1270
RDUMMY
Advanced Power
Electronics Corp. AP1270
ABSOLUTE MAXIMUM RATINGS(Note1)
Input Voltage (VIN) ------------------------------------------
-
6V
CNTL Pin Voltage (VCNTL) --------------------------------
-
6V
Power Dissipation (PD) ------------------------------------
-
Internally Limited
Storage Temperature Range (TST) ---------------------
-
-65 to +150°C
Lead Temperature (Soldering, 10sec.) ---------------- 260°C
ESOP-8 28°C/W
TO-252-5L 6°C/W
Note1 : Exceeding the absolute maximum rating may damage the device.
OPERATING RATING(Note2)
Input Voltage (VIN) ------------------------------------------
-
2.5V to 1.5V +3%
CNTL Pin Voltage (VCNTL) --------------------------------
-
5.5V or 3.3V +5%
Junction Temperature Range (TJ) ----------------------
-
-40 to +125°C
Ambient Temperature Range (TA) ---------------------- -40 to +85°C
Note2 : The device is not guaranteed to function outside its operating conditions.
ORDERING / PACKAGE INFORMATION
(VIN=1.8V, VCNTL=3.3V, VREFEN=0.9V, COUT=10uF(Ceramic), TA =25oC, unless otherwise specified)
Parameter SYM TEST CONDITION MIN TYP MAX UNITS
VCNTL Operation Current ICNTL IOUT = 0A - 1 2.5 mA
Standby Current ISTBY VREFEN < 0.2V (Shutdown), RLOAD = 180Ω-50 90 uA
Output Offset Voltage(Note3) VOS IOUT = 0A -20 - 20
IOUT = 10mA ~ 3A -20 - 20
IOUT = -10mA ~ -3A -20 - 20
Current Limit ILIM 3.2 - - A
Thermal Shutdown Temperature TSD 3.3V < VCNTL < 5V 130 160 -
Thermal Shutdown Hysteresis ΔTSD 3.3V < VCNTL < 5V - 30 -
VIH Enable 0.65 - -
VIL Shutdown - - 0.2
Note3. VOS offset is the voltage measurement defined as VOUT subtracted from VREFEN.
Note4. Regulation is measured at constant junction temperature by using a 5ms current pulse. Devices are tested for load regulation
in the load range from 0A to 3A.
2
Thermal Resistance from Junction to Case (Rthjc)
ELECTRICAL SPECIFICATIONS
Input
Output (DDR / DDRII / DDRIII)
Load Regulation(Note4) ΔVLoad mV
Protection
oC
REFEN Shutdown
Shutdown Threshold V
(Top View )
1
2
3
4
8
7
6
5
REFEN
ESOP-8
NC
NCGND
VIN
NC
VCNTL
VOUT
GND
Rth
j
a = 75oC/W
AP1270X-HF
MP : ESOP-8
Halogen-Free
H : TO-252-5L
TO-252-5L
1VIN
4VREFEN
3VCNTL
2GND
5VOUT
( Top View )
(Side View)
Metal
Tab
VCNTL
Rth
j
a = 40oC/W
Advanced Power
Electronics Corp. AP1270
PIN DESCRIPTIONS
PIN SYMBOL PIN DESCRIPTION
VIN Power Input Voltage.
GND Ground Pin
VOUT Output Voltage
VCNTL Gate Drive Voltage
REFEN Reference Voltage Input and Chip Enable
BLOCK DIAGRA
APPLICATION INFORMATION
Input Capacitor and Layout Consideration
3
+
-EA
Current Limit
Thermal Protection
REFEN
VOUT
VIN
VCNTL
Place the input bypass capacitor as close as possible to the AP1270. A low ESR capacitor
larger than 470uF is recommended for the input capacitor. Use short and wide traces to minimize
parasitic resistance and inductance.
Inappropriate layout may result in large parasitic inductance and cause undesired oscillation
between AP1270 and the preceding powe converter.
Advanced Power
Electronics Corp. AP1270
Consideration while designs the resistance of voltage divider
Thermal Consideration
4
Make sure the sinking current capability of pull-down NMOS if the lower resistance was
chosen so that the voltage on VREFEN is below 0.2V. In addition, the capacitor and voltage divider
form the lowpass filter. There are two reasons doing this design; one is for output voltage soft-start
while another is for noise immunity.
AP1270MP regulators have internal thermal limiting circuitry designed to protect the device
during overload conditions.For continued operation, do not exceed maximum operation junction
temperature 125oC. The power dissipation definition in device is:
PD = (VIN - VOUT) x IOUT + VIN x IQ
The maximum power dissipation depends on the thermal resistance of IC package, PCB
layout, the rate of surroundings airflow and temperature difference between junction to ambient.
The maximum power dissipation can be calculated by following formula:
PD(MAX) = ( TJ(MAX) -TA ) / Rthja
Where TJ(MAX) is the maximum operation junction temperature 125oC, TA is the ambient
temperature and the Rthja is the junction to ambient thermal resistance. The junction to ambient
thermal resistance (Rthja is layout dependent) for ESOP-8 package (Exposed Pad) is 75oC/W on
standard JEDEC 51-7 (4 layers, 2S2P) thermal test board. The maximum power dissipation at TA =
25oC can be calculated by following formula:
PD(MAX) = (125oC - 25oC) / 75oC/W = 1.33W
The thermal resistance Rthja of ESOP-8 (Exposed Pad) is determined by the package design
and the PCB design. However, the package design has been decided. If possible, it's useful to
increase thermal performance by the PCB design. The thermal resistance can be decreased by
adding copper under the expose pad of ESOP-8 package. We have to consider the copper couldn't
stretch infinitely and avoid the tin overflow.
Advanced Power
Electronics Corp. AP1270
TYPICAL PERFORMANCE CHARACTERISTICS
5
VIN = 1.8V, VCNTL = 3.3V, IOUT = 0A, Source test VIN = 1.8V, VCNTL = 3.3V, IOUT = 10mA, Source test
IOUT = 0A, Source test
Load Transient (Source test) Load Transient (Sink test)
VIN = 1.8V, VCNTL = 3.3V VIN = 1.8V, VCNTL = 3.3V
VREF = 0.9V Supplied by a regulatorVREF = 0.9V Supplied by a regulator
IOUT = 0A, Source test
V
IN
VOUT
IOUT
V
IN
VOUT
IOUT
Output Voltage vs. Temperature
0.7
0.8
0.9
1
1.1
-50 -25 0 25 50 75 100 125
Temperature (oC)
Output Voltage (V)
Shutdown Threshold vs. Temperature
0.25
0.3
0.35
0.4
0.45
0.5
0.55
-50 -25 0 25 50 75 100 125
Temperature (oC)
Shutdown Threshold (V)
Turn On
Turn Off
VIN Current vs. Temperature
6
7
8
9
10
11
12
13
14
15
16
-50 -25 0 25 50 75 100 125
Temperature (oC)
VIN Current (uA)
VCNTL Current vs. Temperature
1.5
2
2.5
3
3.5
4
-50 -25 0 25 50 75 100 125
Temperature (oC)
VCNTL Current (mA)
VIN=1.8V, VCNTL=5V
VIN=1.8V, VCNTL=5V
VIN=1.8V, VCNTL=3.3V
VIN=1.5V, VCNTL=5V
VIN=1.5V, VCNTL=3.3V
VIN=1.8V, VCNTL=3.3V
Advanced Power
Electronics Corp. AP1270
TYPICAL PERFORMANCE CHARACTERISTICS
6
Source Current Limit vs. Temperature
4
4.5
5
5.5
-50 -25 0 25 50 75 100 125
Temperature (oC)
Source Current Limit (A)
Sink Current Limit vs. Temperature
3
3.5
4
4.5
5
5.5
-50 -25 0 25 50 75 100 125
Temperature (oC)
Sink Current Limit (A)
VIN=1.8V, VCNTL=3.3V
VIN=1.8V, VCNTL=5V
VIN=1.8V, VCNTL=3.3V
VIN=1.8V, VCNTL=5V
Advanced Power
Electronics Corp. AP1270
MARKING INFORMATION
ESOP-8
TO-252-5L
7
1270MP
YWWSSS
Part Number
Date Code (YWWSSS)
YLast Digit Of The Year
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Package Code
Part Number
Package Code
1270H
YWWSSS Date Code (YWWSSS)
YLast Digit Of The Year
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