ISL6174 Datasheet, PDF (3/16 Pages) Intersil Corporation – Dual Low Voltage Circuit Breaker

Pinout
ISL6174
28 LEAD QFN
TOP VIEW
28 27 26 25 24 23 22
SNS1 1
21 SNS2
VO1 2
20 VO2
SS1 3
19 SS2
GT1 4
18 GT2
FLT1 5
17 FLT2
PG1 6
16 PG2
TCB1 7
15 TCB2
8 9 10 11 12 13 14
Pin Descriptions
PIN NAME
FUNCTION
DESCRIPTION
1
SNS1 Current Sense Input This pin is connected to the current sense resistor and control MOSFET Drain node. It provides
current sense signal to the internal comparator in conjunction with VS1 pin.
2
VO1 Output Voltage 1
This pin is connected to the control MOSFET switch source, which connects to a load. Internally, this
voltage is used for SS control.
3
SS1 Soft-Start Duration Set A capacitor from this pin to ground sets the output soft-start ramp slope. This capacitor is charged by
Input
the internal 10µA current source setting the soft-start ramp. The output voltage ramp tracks the SS
ramp by controlled enhancement of FET gate. Once ramp-up is completed, the capacitor continues
to charge to the CPVDD voltage rail. If common capacitor is used (by tying SS1, SS2 together and
the capacitor to GND from the connection) then both the outputs track each other as they ramp up.
4
GT1 Gate Drive Output
Direct connection to the gate of the external N-Channel MOSFET. At turn-on the Gate will charge to
4 X Vbias or 10V(max) from the 24µA source.
5
FLT1 Fault Output
This is an open drain output. It asserts (pulls low) once the circuit breaker delay (determined by the
TCB timeout cap) has expired. This output is valid for Vbias>1V.
6
PG1 Power Good Output This is an active low, open drain output. When asserted (logic zero), it indicates that the voltage on
UV1 pin is more than 643mV (633mV + 10mV hysteresis). This output is valid at VBIAS >1V.
7
TCB1 Circuit Breaker Delay A capacitor from this pin to ground sets the delay from the onset of an over current event to channel
Timer
shutdown (circuit breaker delay). Once the voltage on TCB cap reaches V_{CT_Vth} the GATE output is
pulled down and the FLT is asserted.
The time for circuit breaker delay (t_CB) = (C_TCB*1.178)/10µA.
8
DNC Do not connect
Do not connect
9
GND Chip Gnd
This pin is also internally shorted to the metal tab at the bottom of the IC.
10 PGND
Charge pump ground. Both GND and PGND must be tied together externally.
11
CPQ- Charge Pump Capacitor Flying cap lowside.
Low Side
3
FN6830.0
December 19, 2008