Copyright
ANPEC Electronics Corp.
Rev. A.4 - Jan., 2006
APW7120
www.anpec.com.tw
1
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise
customers to obtain the latest version of relevant information to verify before placing orders.
5V to 12V Supply Voltage, 8-PIN, Synchronous Buck PWM Controller
Operating with Single 5~12V Supply Voltage
or two Supply Voltages
Drive Dual Low Cost N-Channel MOSFETs
- Adaptive Shoot-Through Protection
Built-in Feedback Compensation
- Voltage-Mode PWM Control
- 0~100% Duty Ratio
- Fast Transient Response
2% 0.8V Reference
- Over Line, Load Regulation and
Operating Temp.
Programmable Over-Current Protection
- Using R
DS(ON)
of Low-Side MOSFET
Hiccup-Mode Under-Voltage Protection
118% Over-Voltage Protection
Adjustable Output Voltage
Small Converter Size
- 300kHz Constant Switching Frequency
- Small SOP-8 Package
Built-In Digital Soft-Start
Shutdown Control using an External MOSFET
Lead Free Available (RoHS Compliant)
Features
Applications
General Description
The APW7120 is a fixed 300kHz frequency, voltage
mode, synchronous PWM controller. The device drives
two low cost N-channel MOSFETs and is designed to
work with single 5~12V or two supply voltage(s),
providing excellent regulation for load transients.
The APW7120 integrates controls, monitoring and
protection functions into a single 8-pin package to
provide a low cost and perfect power solution.
A power-on-reset (POR) circuit monitors the VCC
supply voltage to prevent wrong logic controls. An
internal 0.8V reference provides low output voltage
down to 0.8V for further applications. An built-in digital
soft-start with fixed soft-start interval prevents the
output voltage from overshoot as well as limiting the
input current. The controller's over-current protection
monitors the output current by using the voltage drop
across the low-side MOSFET's R
DS(ON)
, eliminating the
need of a current sensing resistor. Additional under
voltage and over voltage protections monitor the
voltage on FB pin for short-circuit and over-voltage
protections. The over-current protection cycles the
soft-start function until 4 over-current events are
counted.
Pulling and holding the voltage on OCSET pin below
0.15V with an open drain device shuts down the
controller.
Pinouts
1
2
3
4
8
7
6
5
PHASE
OCSET
FB
VCC
BOOT
UGATE
GND
LGATE
SOP-8
Motherboard
Graphics Card
High Current, up to 20A, DC-DC Converters
Copyright
ANPEC Electronics Corp.
Rev. A.4 - Jan., 2006
APW7120
www.anpec.com.tw
2
APW7120
Handling Code
Temp. Range
Package Code
Package Code
K : SOP-8
Operating Ambient Temp. Range
E : -20 to 70 C
Handling Code
TU : Tube TR : Tape & Reel
Lead Free Code
L : Lead Free Device Blank : Original Device
APW7120 K :
APW7120
XXXXX
XXXXX - Date Code
Lead Free Code
Ordering and Marking Information
Block Diagram
Note: ANPEC lead-free products contain molding compounds/die attach materials and 100% matte tin plate
termination finish; which are fully compliant with RoHS and compatible with both SnPb and lead-free soldiering
operations. ANPEC lead-free products meet or exceed the lead-free requirements of IPC/JEDEC J STD-020C
for MSL classification at lead-free peak reflow temperature.
3VCC
Power On
Reset
VCC
OCSET
UGATE
LGATE
Oscillator
Gate
Control
V
REF
0.8V
Soft-Start
and Fault
Logic
F
OSC
300kHz
PHASE
Gm
Amplifier
FB
PWM
Inhibit
40uA
COMP
67%V
REF
UV
GND
POR
Soft-Start
OC
BOOT
Regulator
3VCC
OV
118%V
REF
3VCC
0.4V
0.15V
Enable
2.5V
Copyright
ANPEC Electronics Corp.
Rev. A.4 - Jan., 2006
APW7120
www.anpec.com.tw
3
Application Circuit
Symbol
Parameter
Rating
Unit
V
CC
VCC Supply Voltage (VCC to GND)
-0.3 ~ 16
V
V
BOOT
BOOT Voltage (BOOT to PHASE)
-0.3 ~ 16
V
UGATE Voltage (UGATE to PHASE)
<400nS pulse width
>400nS pulse width
-5 ~ V
BOOT
+0.3
-0.3 ~ V
BOOT
+0.3
V
LGATE Voltage (LGATE to GND)
<400nS pulse width
>400nS pulse width
-5 ~ V
CC
+0.3
-0.3 ~ V
CC
+0.3
V
PHASE Voltage (PHASE to GND)
<400nS pulse width
>400nS pulse width
-10 ~ 30
-0.3 ~ 16
V
V
I/O
Input Voltage (OCSET, FB to GND)
-0.3 ~ 7
V
Maximum Junction Temperature
150
o
C
T
STG
Storage Temperature
-65 ~ 150
o
C
T
SDR
Maximum Soldering Temperature, 10 Seconds
300
o
C
V
ESD
Minimum ESD Rating (Human Body Mode) (Note 2)
2
kV
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Note 2: The device is ESD sensitive. Handling precautions are recommended.
Absolute Maximum Ratings
C3, C4 : 820
F/16V , ESR=25 m
C6, C7 : 1000
F/6.3V, ESR=30 m
V
IN
+5/12V
V
OUT
1.8V/15A
C 5
1uF
C3, C4
820uF x2
C 6 , C 7
1000uF x2
L2
1.5uH
Q1
APM2512
UGATE
LGATE
4
BOOT
1
GND
3
VCC
5
PHASE
8
Q2
APM2512
C 1
1uF
2
U 1
APW7120
FB
6
OCSET
7
R 2
1.2k
C 2
0.1uF
Q3
2N7002
Shutdown
R 4
2.2
L1
1uH
R 5
+5V/12V
C 8
0.1uF
R 1
1.5k
R 3
200
D 1
1N4148
V
BIAS
Copyright
ANPEC Electronics Corp.
Rev. A.4 - Jan., 2006
APW7120
www.anpec.com.tw
4
Symbol
Parameter
Range
Unit
V
CC
VCC Supply Voltage
4.5 ~ 13.2
V
V
OUT
Converter Output Voltage
0.8 ~ 80%V
IN
V
V
IN
Converter Input Voltage
2.2 ~ 13.2
V
I
OUT
Converter Output Current
0 ~ 20
A
T
A
Ambient Temperature
-20 ~ 70
o
C
T
J
Junction Temperature
-20 ~ 125
o
C
Note 4: Please refer to the typical application circuit.
Thermal Characteristics
Recommended Operating Conditions
(Note 4)
Symbol
Parameter
Value
Unit
JA
Junction-to-Ambient Resistance in free air (Note 3)
160
o
C/W
Note 3:
JA
is measured with the component mounted on a high effective thermal conductivity test board in free air.
Electrical Characteristics
Unless otherswise specified, these specifications apply over V
CC
= 12V, V
BOOT
= 12V and T
A
= -20 ~ 70
o
C.
Typlcal values are at T
A
= 25
o
C.
APW7120
Symbol
Parameter
Test Conditions
Min Typ Max
Unit
SUPPLY CURRENT
I
VCC
VCC Nominal Supply Current
UGATE and LGATE Open
-
2.1
6
mA
VCC Shutdown Supply Current
-
1.5
4
mA
POWER-ON RESET
Rising VCC Threshold
3.8
4.1
4.4
V
Hysteresis
0.3 0.45 0.6
V
OSCILLATOR
F
OSC
Free Running Frequency
250 300 350
kHz
V
OSC
Ramp Amplitude
-
1.5
-
V
P-P
Copyright
ANPEC Electronics Corp.
Rev. A.4 - Jan., 2006
APW7120
www.anpec.com.tw
5
APW7120
Symbol
Parameter
Test Conditions
Min
Typ Max
Unit
REFERENCE VOLTAGE
V
REF
Reference Voltage
Measured at FB Pin
-
0.8
-
V
Accuracy
T
A
=-20~70
C
-2.0
-
+2.0 %
Line Regulation
V
CC
=12 ~ 5V
-
0.05 0.5
%
ERROR AMPLIFIER
DC Gain
-
86
-
dB
F
P1
First Pole Frequency
-
0.4
-
Hz
F
Z
Zero Frequency
-
0.4
-
kHz
F
P2
Second Pole Frequency
-
430
-
kHz
Average UGATE Duty Range
0
-
85
%
FB Input Current
-
-
0.1
A
PWM CONTROLLER GATE DRIVERS
UGATE Source
V
BOOT-PHASE
=12V, V
UGATE-PHASE
=6V
1.0
2.0
-
A
UGATE Sink
V
BOOT-PHASE
=12V, V
UGATE-PHASE
=1V
-
3.5
7
LGATE Source
V
CC
=12V, V
LGATE
=6V
1.0
1.9
-
A
LGATE Sink
V
CC
=12V, V
LGATE
=1V
-
2.6
5
T
D
Dead-Time
Guaranteed by Design
-
40
100 nS
PROTECTIONS
I
OCSET
OCSET Current Source
V
PHASE
=0V, Normal Operation
35
40
45
A
Over-Current Reference Voltage T
A
=-20~70
C
0.37
0.4 0.43 V
U
VFB
FB Under-Voltage Threshold
Rising V
FB
64
67
70
%
FB Under-Voltage Hysteresis
-
45
-
mV
Over-Voltage Threshold
Rising V
FB
115
118 121 %
SOFT-START AND SHUTDOWN
T
SS
Soft-Start Interval
2
3.8
5
mS
OCSET Shutdown Threshold
Falling V
OCSET
0.1
0.15 0.3
V
OCSET Shutdown Hysteresis
-
40
-
mV
Electrical Characteristics (Cont.)
Unless otherswise specified, these specifications apply over V
CC
= 12V, V
BOOT
= 12V and T
A
= -20 ~ 70
o
C.
Typlcal values are at T
A
= 25
o
C.
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