MAX15068 Datasheet, PDF (10/17 Pages) Maxim Integrated Products – Dual ORing, Single Hot-Swap Controller

MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Pin Description (continued)
PIN
NAME
FUNCTION
Power Status Output. Open-drain output that is normally pulled high by a 10µA current source to a
10
PG
diode below V_S. PG can be pulled above V_S using an external pullup. PG pulls low when the MOSFET
gate drive between GATE and OUT exceeds the gate-to-source volt­age of 4.2V and V_OUT is greater
than 90% of V_CSP. Leave PG unconnected if unused.
Fault Status Output. Open-drain output that is normally pulled high by a 10µA current source to a diode
11
FAULT
below V_S. FAULT can be pulled above V_S using an external pullup. FAULT pulls low when the circuit
breaker is tripped after an overcurrent fault timeout. Leave FAULT unconnected if unused.
Priority Control Input. When low, it enables the external ideal diode MOSFET in the IN2 supply path
12
PC
and a high turns it off. Connect PC to an external resistive divider from IN1 to make IN1 the higher
priority input supply when IN1 and IN2 are equal. Connect PC to GND if not used.
Timer Capacitor Terminal. Connect a capacitor between CDLY and GND to set 12ms/µF duration for
13
CDLY
current limit before the external hot-swap MOSFET is turned off. The duration of the off-time is 600ms/
µF, resulting in a 2% duty cycle.
Enable Input. Connect EN to GND to enable hot-swap control. If EN is pulled high, the hot-swap
14
EN
MOSFET is not allowed to turn on. A 10µA current source pulls up EN to a diode below V_S. Upon EN
going low when ON is high, an internal timer provides a 100ms startup delay for debounce, after which
the fault is cleared.
On Control Input. When above 1.2V, it turns on the external hot-swap MOSFET and when below
15
ON
1.1V, it turns it off. Connect ON to an external resistive divider from CSP to monitor the supply
undervoltage condition. Pulling voltage of ON pin below 0.6V resets the electronic circuit
breaker.
16
CB
Current-Limit Threshold Setting. Connect the CB pin to V_S, GND, or leave CB unconnected to set the
circuit-breaker threshold. See Table 1 for details.
17
OUT
Load Output. Connect OUT to the source of the external hot-swap MOSFET.
Hot-Swap MOSFET Gate Drive Output. Connect this pin to the gate of the external n-channel
MOSFET for hot-swap control. An internal 10µA current source charges the MOSFET gate. An internal
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GATE
clamp limits the gate voltage to 11V above OUT and a diode voltage below OUT. During turn-off, a
500µA pulldown current discharges GATE to ground. During an output short to ground, a fast 200mA
pulldown current discharges GATE to OUT.
Charge Pump 1 Output. Connect a capacitor from CP1 to IN1 pin. The value of this capacitor should
19
CP1
be 10x or greater than the gate capacitance of the external MOSFET for ideal diode control. The
charge stored on this capacitor is used to pull up the gate during a fast turn-on.
ORing MOSFET 1 Gate Control Output. Connect OG1 to the gate of an external n-channel MOSFET
20
OG1
for ideal diode control. The gate voltage is set to approximately 11V above and a diode voltage below
IN1. During fast turn-on, a 1A pullup switch charges OG1 from CP1. During fast turn-off, a 3A pulldown
switch discharges OG1 to IN1.
—
EP
Exposed Pad. Connect EP to the ground plane to provide a low thermal resistance path from the IC
junction to the PCB. Do not use EP as an electrical connection to GND.
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