ISL6112
4
FN6456.1
August 25, 2011
Pin Configuration
ISL6112
(48 LD 7X7 QFN)
TOP VIEW
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
13 14 15 16 17 18 19 20 21 22 23 24
48 47 46 45 44 43 42 41 40 39 38 37
GND
(EXPOSED BOTTOM PAD)
FAULT
B
CFILTERB
12VGATEB
GND
12VINB
PWRGD
B
NC
12VSENSEB
FORCE_ON
B
12VOUTB
VSTBYB
3VINB
FAULT
A
CFILTERA
12VGATEA
GPI_A0
12VINA
PWRGD
A
NC
12VSENSEA
FORCE_ON
A
12VOUTA
VSTBYA
3VINA
Pin Descriptions
PIN NUMBER    PIN NAME
PIN FUNCTION
5, 32
12VINA, 12VINB  Provides 12VMAIN power supply and the high side of the sense resistor inputs. This must be a Kelvin
connection between IC and sense resistor. An undervoltage lockout circuit (UVLO) prevents the switches from
turning on while this input is less than its lockout threshold.
12, 25
3VINA, 3VINB   Provides 3.3VMAIN power supply and the high side of the sense resistor inputs. This must be a Kelvin
connection between IC and sense resistor. An undervoltage lockout circuit (UVLO) prevents the switches from
turning on while this input is less than its lockout threshold.
16, 21     3VOUTA, 3VOUTB  3.3VOUT. Connected to 3.3V FET source. These are used to monitor the 3.3V output voltages for Power-Good
status.
10, 27    12VOUTA, 12VOUTB 12VOUT. Connected to 12V FET drain. These are used to monitor the 3.3V output voltages for Power-Good
status.
8, 29
12VSENSEA,
12VSENSEB
12VMAIN low side of sense resistor connection. When either current limit threshold of the load current across
the sense resistor = 50mV is reached, the related 12VGATE pin is modulated to maintain a constant voltage
across the sense resistor and thus a constant current into the load. If the 50mV threshold is exceeded for t
FLT
,
the isolation protection is tripped, and the GATE pin for the affected supplys external MOSFET is immediately
pulled high. This must be a Kelvin connection between IC and sense resistor.
13, 24
3VSENSEA,
3VSENSEB
3.3VMAIN low side of sense resistor connection. When either current limit threshold of the load current across
the sense resistor = 50mV is reached, the related 3V GATE pin is modulated to maintain a constant voltage
across the sense resistor and thus a constant current into the load. If the 50mV threshold is exceeded for t
FLT
,
the isolation protection is tripped, and the GATE pin for the affected supplys external MOSFET is immediately
pulled low. This must be a Kelvin connection between IC and sense resistor.
3, 34
12VGATEA
12VGATEB
12V gate drive outputs. Each pin connects to the gate of an external P-Channel MOSFET. During power-up, the
CGATE and the CGS of the MOSFETs are connected to a 25礎(chǔ) current sink. This controls the value of dv/dt
seen at the source of the MOSFETs. During current limit events, the voltage at this pin is adjusted to maintain
constant current through the switch for a period of t
FLT
. Whenever an overcurrent, thermal shutdown, or input
undervoltage fault condition occurs, the GATE pin for the affected slot is immediately brought high. These pins
are charged by an internal current source during power-down.