MAX5920AESA+T Maxim Integrated Products, MAX5920AESA+T Datasheet - Page 14

• Manufacturer Part Number: MAX5920AESA+T
• Description: IC HOT-SWAP CTRLR -48V 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Hot-Swap Controllerr

Specifications of MAX5920AESA+T

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: -20 V ~ -80 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

pulled high by the module’s internal pullup current
source, turning the module off. When the DRAIN volt-
age drops below V
than ∆V
pulls low, enabling the module.
The PWRGD signal can also be used to turn on an LED
or optoisolator to indicate that the power is good
(Figure 14) (see the Component Selection Procedure
section).
When the DRAIN voltage of the MAX5920B is high with
respect to V
internal MOSFET Q3 is turned off so that I1 and the inter-
nal MOSFET Q2 clamp the PWRGD pin to the DRAIN pin.
MOSFET Q2 sinks the module’s pullup current, and the
module turns off.
When the DRAIN voltage drops below V
GATE voltage is greater than ∆V
Q3 turns on, shorting I1 to V
pullup current in the module pulls the PWRGD pin high,
enabling the module.
The GATE pin goes high when the following startup con-
ditions are met: the UV pin is high, the OV pin is low, the
supply voltage is above V
less than 50mV. The gate is pulled up with a 45µA current
source and is regulated at 13.5V above V
-48V Hot-Swap Controller
with External R
Figure 14. Using PWRGD to Drive an Optoisolator
14
______________________________________________________________________________________
GATE
EE
- V
(Figure 12) or the GATE voltage is low, the
GH
-48V RTN
GATE Pin Voltage Regulation
DL
-48V
, Q2 turns on and the PWRGD pin
*DIODES INC. SMAT70A.
**OPTIONAL.
and the GATE voltage is greater
*
(SHORT PIN)
-48V RTN
UVLOH
6.49kΩ
549kΩ
EE
10kΩ
1%
1%
1%
R4
R5
R6
and turning Q2 off. The
, and (V
GATE
UV
OV
SENSE
V
- V
EE
SENSE
GH
0.02Ω
5%
R1
DL
, MOSFET
SENSE
- V
and the
EE
. The
EE
) is
MAX5920A
C1**
470nF
25V
V
DD
MAX5920A/MAX5920B include an internal clamp that
ensures the GATE voltage of the external MOSFET never
exceeds 18V. During a fast-rising V
keeps the GATE and SENSE potentials as close as possi-
ble to prevent the FET from accidentally turning on. When
a fault condition is detected, the GATE pin is pulled low
with a 50mA current.
The MAX5920A/MAX5920B include internal die-tempera-
ture monitoring. When the die temperature reaches the
thermal-shutdown threshold, T
MAX5920B pull the GATE pin low and turn off the external
MOSFET. If a good thermal path is provided between the
MOSFET and the MAX5920A/MAX5920B, the device
offers thermal protection for the external MOSFET.
Placing the MAX5920A/MAX5920B near the drain of the
external MOSFET offers the best thermal protection
because most of the power is dissipated in its drain.
After a thermal shutdown fault has occurred, the
MAX5920A/MAX5920B turn the external FET off. To
clear a thermal shutdown fault condition, toggle the UV
pin or cycle the power to the device. The device keeps
the external FET off for a minimum time of t
is toggled, allowing the MOSFET to cool down. The
device restarts after the temperature drops 20°C below
the thermal-shutdown threshold.
IRF530
GATE
Q1
R2
10Ω
5%
1kΩ
5%
R3
15nF
100V
C2
PWRGD
DRAIN
R7**
51kΩ
5%
MOC207
PWRGD
Thermal Shutdown
OT
C3
100µF
100V
DD
, the MAX5920A/
, the clamp also
OFF
after UV