UC2914
UC3914
SLUS425C − DECEMBER 2003 − REVISED JULY 2004
5 V to 35 V HOT SWAP
POWER MANAGER
FEATURES
D
5-V to 35-V Operation
D
Precision Maximum Current Control
D
Precision Fault Threshold
D
Programmable Average Power Limiting
D
Programmable Overcurrent Limit
D
Shutdown Control
D
Charge Pump for Low R
DS(on)
High-Side
D
D
D
D
Drive
Latch Reset Function Available
Output Drive V
GS
Clamping
Fault Output Indication
18-Pin DIL and SOIC Packages
DESCRIPTION
The UC3914 family of hot swap power managers
provides complete power management, hot swap
and fault handling capability. Integrating this part
and a few external components, allows a board to
be swapped in or out upon failure or system
modification without removing power to the
hardware, while maintaining the integrity of the
powered system. Complementary output drivers
and diodes have been integrated for use with
external capacitors as a charge pump to ensure
sufficient gate drive to the external N-channel
MOSFET transistor for low R
DS(on)
. All control and
housekeeping functions are integrated and
externally programmable and include the fault
current level, maximum output sourcing current,
maximum fault time and average power limiting of
the external FET. The UC3914 features a duty
ratio current limiting technique, which provides
peak load capability while limiting the average
power dissipation of the external pass transistor
during fault conditions. The fault level is fixed at
50 mV with respect to VCC to minimize total
dropout.
The fault current level is set with an external
current sense resistor. The maximum allowable
sourcing current is programmed by using a
resistor divider from VCC to REF to set the voltage
on IMAX. The maximum current level, when the
output appears as a current source is (V
VCC
−
V
IMAX
)/R
SENSE
.
This part is offered in both 18-pin DW wide-body
(SOIC) and dual-in-line (DIL) packages.
SIMPLIFIED APPLICATION DIAGRAM
6
9
18
16
IMAX
VCC
2
VCC
OSC PMP REF
1
PMPB
UC2914/UC3914
5
7
OSCB
VPUMP
SENSE
17
OUT
4
VOUT
10
SD
FAULT
GND
1
LR
13
VOUTS
11
12
PLIM 14
CT
15
VOUT
UDG−03114
VCC
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
Copyright
2003, Texas Instruments Incorporated
www.ti.com
1
PRODUCT PREVIEW
TI [ TEXAS INSTRUMENTS ]
