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