Datasheet
MAX5934/MAX5934A
Positive High-Voltage, Hot-Swap Controllers with
Selectable Fault Management and Status Polarity
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Detailed Description
The MAX5934/MAX5934A are fully integrated hot-swap
controllers for positive supply rails. These devices allow
for the safe insertion and removal of circuit cards into
live backplanes without causing glitches on the back-
plane power-supply rail. During startup, the MAX5934/
MAX5934A act as current regulators using an external
sense resistor and MOSFET to limit the amount of cur-
rent drawn by the load.
The MAX5934A operates from a +9V to +80V supply
voltage range and has a default UVLO set to +8.3V.
The MAX5934 operates from a +33V to +80V supply
voltage range and has a default UVLO set to +31V. The
UVLO threshold is adjustable using a resistive divider
connected from V
CC
to ON to GND (see R2 and R3 in
Figure 5).
The MAX5934/MAX5934A monitor input voltage, output
voltage, output current, and die temperature. These
devices feature three power-good outputs (PWRGD_)
to indicate status by monitoring the voltage at FB1,
FB2, and GATE (see the Power-Good (PWRGD_)
Detection section). PWRGD1 indicates an output-volt-
age status, PWRGD2 can be used to indicate an over-
voltage condition on the main power-supply rail, and
PWRGD3 asserts when GATE voltage has charged to
4.3V above the supply rail. PWRGD3 deasserts when
the TIMER voltage exceeds a 1.233V threshold in
response to an extended fault condition.
The MAX5934/MAX5934A control gate voltage on the
external MOSFET to limit load current at startup and at
overload to a value determined as:
MAX5934
MAX5934A
ON
C
L
OUT
GATESENSE
V
CC
16 14 11
9
4
6
5
7
12
8
M1
R1
1kΩ, 5%
R
SENSE
0.025Ω
C1
10nF
R
G
10Ω
5%
R4
59kΩ
1%
R6
24kΩ
5%
R7
24kΩ
5%
R10
1kΩ
1%
R9
90kΩ
1%
R2
49.9kΩ
1%
V
IN
R3
3.4kΩ
1%
C
TIMER
0.68µF
R
L
R5
3.57kΩ
1%
FB1
2
10
1
3
15
PWRGD1
PWRGD2
TIMER
LATCH/RETRY
V
CC
FB2
PWRGD3
V
MONITOR
PWRGD1
PWRGD2
PWRGD3
DC
GND
V
CC
POL_SEL
V
CC
IRF530
Figure 5. Application Circuit