Micrel, Inc.
MIC2085/2086
May 2006
4
M9999-050406
(408) 955-1690
Pin Description (Cont.)
Pin Number
MIC2086
Pin Number
MIC2085
Pin Name Pin Function
18
15
SENSE
Circuit Breaker Sense Input: A resistor between this pin and VCC sets the
current limit threshold. Whenever the voltage across the sense resistor exceeds
the slow trip current limit threshold (V
TRIPSLOW
), the GATE voltage is adjusted to
ensure a constant load current. If V
TRIPSLOW
(48mV) is exceeded for longer than
time period t
OCSLOW
, then the circuit breaker is tripped and the GATE pin is
immediately pulled low. If the voltage across the sense resistor exceeds the fast
trip circuit breaker threshold, V
TRIPFAST
, at any point due to fast, high amplitude
power supply faults, then the GATE pin is immediately brought low without delay.
To disable the circuit breaker, the SENSE and VCC pins can be tied together.
The default V
TRIPFAST
for either device is 95mV. Other fast trip thresholds are
available: 150mV, 200mV, or OFF (V
TRIPFAST
disabled). Please contact factory for
availability of other options.
19, 20
16
VCC
Positive Supply Input: 2.3V to 16.5V. The GATE pin is held low by an internal
undervoltage lockout circuit until VCC exceeds a threshold of 2.18V.If VCC
exceeds 16.5V, an internal shunt regulator protects the chip from VCC and
SENSE pin voltages up to 33V.