MAX5936/MAX5937
-48V Hot-Swap Controllers with V
IN
Step Immunity and No R
SENSE
________________________________________________________________ Maxim Integrated Products 1
19-3281; Rev 1; 1/05
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
General Description
The MAX5936/MAX5937 are hot-swap controllers for
-10V to -80V rails. The MAX5936/MAX5937 allow circuit
line cards to be safely hot-plugged into a live back-
plane without causing a glitch on the power supply.
These devices integrate a circuit-breaker function
requiring no R
SENSE
.
The MAX5936/MAX5937 provide a controlled turn-on
for circuit cards, limiting inrush, preventing glitches on
the power-supply rail, and preventing damage to board
connectors and components. Before startup, the
devices perform a Load Probe™ test to detect the
presence of a short-circuit condition. If a short-circuit
condition does not exist, the device limits the inrush
current drawn by the load by gradually turning on the
external MOSFET. Once the external MOSFET is fully
enhanced, the MAX5936/MAX5937 provides overcur-
rent and short-circuit protection by monitoring the volt-
age drop across the R
DS(ON)
of the external power
MOSFET. The MAX5936/MAX5937 integrate a 400mA
fast GATE pulldown to guarantee that the power
MOSFET is rapidly turned off in the event of an overcur-
rent or short-circuit condition.
The MAX5936/MAX5937 protect the system against
input voltage (V
IN
) steps by providing V
IN
step immuni-
ty. The MAX5936/MAX5937 provide an accurate UVLO
voltage. The MAX5936 has an open-drain, active-low
PGOOD output and the MAX5937 has an open-drain,
active-high PGOOD output.
The MAX5936/MAX5937 are offered with 100mV,
200mV, and 400mV circuit-breaker thresholds, in addi-
tion to a non-circuit-breaker option. These devices are
offered in latched and autoretry fault management, are
available in 8-pin SO packages, and specified for the
extended (-40°C to +85°C) temperature range (see the
Selector Guide).
Applications
Servers
Telecom Line Cards
Network Switches
Solid-State Circuit Breaker
Network Routers
Features
♦ -10V to -80V Operation
♦ No R
SENSE
Required
♦ Drives Large Power MOSFETS
♦ Programmable Inrush Current Limit During Hot
Plug
♦ 100mV, 200mV, 400mV, and No-Circuit-Breaker
Threshold Options
♦ Circuit-Breaker Fault with Transient Rejection
♦ Shorted Load Detection (Load Probe) Before
Power MOSFET Turn-On
♦ ±2.4% Accurate Undervoltage Lockout (UVLO)
♦ Autoretry and Latched Fault Management
Available
♦ Low Quiescent Current
GATE
LPV
EE
1
2
8
7
PGOOD
(PGOOD)
V
OUT
UVLO
STEP_MON
GND
SO
TOP VIEW
3
4
6
5
MAX5936
MAX5937
( ) FOR THE MAX5937.
Pin Configuration
Load Probe is a trademark of Maxim Integrated Products, Inc.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX5936_ _ESA -40°C to +85°C 8 SO
MAX5937_ _ESA -40°C to +85°C 8 SO
Note: The first “_” represents A for the autoretry and L for the
latched fault management option.
The second “_” represents the circuit-breaker threshold.
See the Selector Guide for additional information.
Selector Guide and Typical Operating Circuit appear at end
of data sheet.
MAX5936/MAX5937
-48V Hot-Swap Controllers with V
IN
Step Immunity and No R
SENSE
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V
EE
, V
OUT
, PGOOD (PGOOD), LP,
STEP_MON to GND............................................+0.3V to -85V
PGOOD (PGOOD) to V
OUT
....................................-0.3V to +85V
PGOOD (PGOOD), LP, STEP_MON to V
EE
............-0.3V to +85V
GATE to V
EE
...........................................................-0.3V to +20V
UVLO to V
EE
.............................................................-0.3V to +6V
Input Current
LP (internally, duty-cycle limited).........................................1A
PGOOD (PGOOD) (continuous) .....................................80mA
GATE (during 15V clamp, continuous) ...........................30mA
GATE (during 2V clamp, continuous) .............................50mA
GATE (during gate pulldown, continuous)......................50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
ELECTRICAL CHARACTERISTICS
(V
EE
= -10V to -80V, V
IN
= GND - V
EE
, V
STEP_MON
=V
EE
, R
LP
= 200Ω, UVLO open, T
A
= -40°C to +85°C, unless otherwise noted.
Typical values are at V
EE
= -48V, T
A
= +25°C.) (Notes 1, 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range V
EE
Referenced to GND -80 -10 V
Operating Supply Current I
CC
0.95 1.4 mA
V
UVLO,R
lV
EE
l increasing -33.5 -31.0 -29.5
Default V
EE
Undervoltage Lockout
V
UVLO,F
lV
EE
l decreasing -28
V
UVLO Reference Threshold,
V
EE
Rising
V
UVLO_REF
,
R
V
UVLO
increasing 1.219 1.25 1.281 V
UVLO Reference Threshold,
V
EE
Falling
V
UVLO_REF
,
F
V
UVLO
decreasing 1.069 1.125 1.181 V
UVLO Input Resistance 20 50 kΩ
UVLO Transient Rejection t
OVREJ
0.8 1.5 2.25 ms
Power-Up Delay (Note 3) t
ONDLY
80 220 380 ms
V
EE
and UVLO Glitch Rejection
(Note 4)
t
REJ
0.8 1.5 2.25 ms
V
OUT
to V
EE
Leakage Current V
EE
= -80V, V
OUT
= GND 0.01 1 µA
LP to V
EE
Leakage Current V
EE
= -80V, V
LP
= GND 0.01 1 µA
V
IN
= 10V 6.5 6.8 7.2
External Gate-Drive Voltage V
GS
V
GATE
- V
EE
14 ≤ V
IN
≤ 80V 8.1 10 12.8
V
I
CLAMP
= 9mA 13.5 16
MOSFET fully
enhanced
I
CLAMP
= 20mA 17 19.5
I
CLAMP
= 1mA 2.1 2.55
GATE to V
EE
Clamp Voltage
Power-off,
V
EE
= GND
I
CLAMP
= 10mA 2.5 2.9
V
Open-Loop Gate-Charge Current V
GATE
= V
EE
, V
OUT
= GND -66 -52 -35 µA
V
IN
> 10V 9 14.1
GATE Pulldown Switch
On-Resistance
R
GATE
V
GATE
- V
EE
=
500mV
V
IN
> 14V 7.5 12.5
Ω
Output-Voltage Slew Rate SR l dV
OUT
/dt l 2.4 9 14.8 V/ms