Rainbow Electronics MAX5943 - Manual (Page 19)

MAX5943
FireWire Current Limiter and Low-Drop
ORing Switch Controller
______________________________________________________________________________________ 19
Chip Information
TRANSISTOR COUNT: 2324
PROCESS: BiCMOS
SENSE GATE1
OR_ADJ ONQ1 GND
MAX5943 EQUIVALENT CIRCUIT
LATCH ILIM
FAULT
ON
GATE2 OUT
Q1 Q2
LOAD DISCONNECT
SWITCH VERY-LOW-DROP
ORing DIODE
CURRENT-LIMIT/CIRCUIT-BREAKER
AND INRUSH CONTROL
IN
TO
FireWire
PORT
FireWire
PORT
SUPPLY
MAX5943A
TIM
R3
+ V IS -
R SENSE
R1
R2
Typical Operating Circuit
PART
CURRENT
LIMITER/
CIRCUIT
BREAKER
DEFAULT
TIMEOUT
(ms)
PROGRAMMABLE
TIMEOUT RANGE
MAX5943A Current limit 2 1.04ms to 11.05ms
MAX5943B Circuit breaker 0.5 32.5µs to 345µs
MAX5943C Circuit breaker 1 65µs to 690µs
MAX5943D Circuit breaker 2 130µs to 1.38ms
MAX5943E Circuit breaker 4 260µs to 2.76ms
Selector Guide
30mΩ
SI7958DP SI7958DP
SENSE GATE1
OR_ADJ ONQ1 GND LATCH ILIM
FAULT
ON
GATE2 OUT
Q1 Q2
IN
+
-
V IN = 12V
TO
FireWire
PORT FireWire
PORT
SUPPLY
MAX5943A
TIM
4kΩ 10kΩ 1kΩ
7.15kΩ
Typical Application Circuit