ISL6161_14 Datasheet, PDF (3/11 Pages) Intersil Corporation – Dual Power Distribution Controller

ISL6161
Pin Descriptions
PIN NUMBER SYMBOL
FUNCTION
DESCRIPTION
1
12VS 12V Source
Connect to source of associated external N-Channel MOSFET switch to sense output
voltage.
2
12VG 12V Gate
Connect to the gate of associated N-Channel MOSFET switch. A capacitor from this node to
ground sets the turn-on ramp. At turn-on this capacitor will be charged to ~17.4V by a 10µA
current source.
3
V_DD Chip Supply
Connect to 12V supply. This can be either connected directly to the +12V rail supplying the
load voltage or to a dedicated V_DD +12V supply. If the former is chosen, special attention to
V_DD decoupling must be paid to prevent sagging as heavy loads are switched on.
4
NC Not Connected
5
ENABLE Enable/Reset
ENABLE is used to turn-on and reset the chip. Both outputs turn-on when this pin is driven
low. After a current limit time-out, the chip is reset by the rising edge of a reset signal applied
to the ENABLE pin. This input has 100µA pull-up capability, which is compatible with 3V and
5V open drain and standard logic.
6
3VG 3V Gate
Connect to the gate of the external 3V N-Channel MOSFET. A capacitor from this node to
ground sets the turn-on ramp. At turn-on, this capacitor will be charged to ~11.4V by a 10µA
current source.
7
3VS 3 Source
Connect to the source side of 3V external N-Channel MOSFET switch to sense output
voltage.
8
3VISEN 3V Current Sense
Connect to the load side of the 3V sense resistor to measure the voltage drop across this
resistor between 3VS and 3VISEN pins.
9
PGOOD Power-Good indicator Indicates that all output voltages are within specification. PGOOD is driven by an open drain
N-Channel MOSFET. It is pulled low when any output is not within specification.
10
C_TIM Current Limit Timing Connect a capacitor from this pin to ground. This capacitor controls the time between the
Capacitor
onset of current limit and chip shutdown (current limit time-out). The duration of current limit
time-out (in seconds) = 200kΩ x C_TIM (Farads).
11
C_PUMP Charge Pump
Capacitor
Connect a 0.1µF capacitor between this pin and V_DD (pin 3). Provides charge storage for
12VG drive.
12
GND Chip Ground
13
R_ILIM Current Limit Set
A resistor connected between this pin and ground determines the current level at which
Resistor
current limit is activated. This current is determined by the ratio of the R_ILIM resistor to the
sense resistor (R_SENSE). The current at current limit onset is equal to
10µA x (R_ILIM/R_SENSE). The ISL6161 is limited to a 10kΩ min. value (OC Vth = 100mV)
resistor whereas the ISL6161 can accommodate a 5kΩ resistor for a lower OC Vth (50mV).
14
12VISEN 12V Current Sense Connect to the load side of sense resistor to measure the voltage drop across this resistor.
3
FN9104.4
October 2, 2008