APW7037/A/B
Electrical Characteristics (Cont.)
A
Unless otherwise specified, these specifications apply over VCC=5V, VC=12V and T =0 to 70°C. Typical
A
values refer to T =25°C.
APW7037/A/B
Unit
Symbol
Parameter
Test Conditions
Min. Typ. Max.
GATE DRIVERS
L
HDRV Rising Time
HDRV Falling Time
LDRV Rising Time
LDRV Falling Time
Dead Band Time
C = 1500pF
20
15
50
50
nS
nS
nS
L
C = 1500pF
L
C = 1500pF
25
50
L
C = 1500pF
25
50
nS
nS
50
150
250
PROTECTION
FBUV
FB
V
FB Under-Voltage Threshold V Falling
APW7037
0.4
0.6
0. 4
0.4
0.5
20
0.8
0. 5
0.5
APW7037A 0.3
APW7037B 0.3
V
SD
V
Shutdown Threshold Voltage Pull the voltage of SS pin
Soft-Start Current SS=0
V
10
30
SS
I
µA
Functional Pin Description
FB (Pin 1)
Connect this pin to the output (VOUT) of the PWM con- are measured with respect to this pin.
verter via an external resistor divider to provide a volt-
HDRV (Pin 5)
age set by the resistor divider is determined using the Connect this pin to the gate of the high-side power
age feedback path for the converter. The output volt-
MOSFET. This pin provides the gate drive for the
MOSFET.
following formula :
ROUT
VOUT = VREF x
(
)
1+
RGND
VC (Pin 6)
where ROUT is the resistor connected from VOUT to FB
, and RGND is the resistor connected from FB to ground.
This pin provides bias voltage to the high-side
The voltage at this pin is also monitored for Under- MOSFET driver. A bootstrap circuit may be used to
pump a boot voltage for enforcing the driving capabil-
ity of the gate driver and improving the performance of
the MOSFET.
Voltage protection.
VCC (Pin 2)
Connect this pin to input voltage from 5V to 20V. This
pin provides the bias for the control circuitry and the
COMP (Pin 7)
low-side power MOSFET driver (LDRV). The voltage This pin is the output of the error amplifier. Add an
external resistor-capacitor network to provide a loop
compensation for the PWM converter.
at this pin is monitored for Power-On Reset (POR)
purpose.
SS (Pin 8)
LDRV (Pin 3)
Connect a capacitor from this pin to ground.This
Connect this pin to the gate of the low-side power
MOSFET. This pin provides the gate drive for the capacitor, along with an internal 20uA current source,
sets the soft-start interval of the PWM converter and
prevents the outputs from overshoot as well as limits
the input current. Pull this pin below 0.5V can shut-
down the converter.
MOSFET.
GND (Pin 4)
Signal and power ground for the IC. All voltage levels
Copyright ANPEC Electronics Corp.
Rev. A.6 - Apr, 2005
4
www.anpec.com.tw
ANPEC [ ANPEC ELECTRONICS COROPRATION ]
