UCC3916DP Datasheet, PDF (1/7 Pages) Texas Instruments – SCSI Termpower Manager

UCC3916
SCSI Termpower Manager
FEATURES
• Integrated Circuit Breaker Function
• Integrated 0.2 Power FET
• SCSI, SCSI-2, SCSI-3 Compliant
• 1µA ICC When Disabled
• Programmable On Time
• Accurate 1.65A Trip Current and
2.0A Max Current
• Fixed 3% Duty Cycle
• Uni-Directional Switch
• Thermal Shutdown
DESCRIPTION
The UCC3916 SCSI termpower manager provides complete power man-
agement, hot swap capability, and circuit breaker functions with minimal ex-
ternal components. For most applications, the only external component
required to operate the device, other than supply bypassing, is a timing ca-
pacitor which sets the fault time.
The current trip level is internally set at 1.65A, and the maximum current
level is also internally programmed for 2A. While the output current is below
the trip level of 1.65A, the internal power MOSFET is switched on at a nom-
inal 220mΩ. When the output current exceeds the trip level but remains
less than the maximum current level, the MOSFET remains switched on,
but the fault timer starts charging CT. Once the fault time is reached, the cir-
cuit will shut off for a time which equates to a 3% duty cycle. Finally, when
the output current reaches the maximum current level, the MOSFET transi-
tions from a switch to a constant current source.
The UCC3916 is designed for uni-directional current flow, emulating a diode
in series with the power MOSFET.
The UCC3916 can be put in a sleep mode, drawing only 1µA of supply cur-
rent.
Other features include thermal shutdown and low thermal resistance Small
Outline Power package.
BLOCK DIAGRAM
MAXIMUM
CURRENT
LEVEL
2A
CHARGE
PUMP
REVERSE VOLTAGE
COMPARATOR
50mV
OUTPUT
CURRENT SENSE
1
VIN
4V TO 6V
LINEAR
CURRENT
AMPLIFIER
H=OPEN
POWER
FET
CURRENT
TRIP LEVEL
1.65A
ON TIME CONTROL
3% DUTY CYCLE
OVER CURRENT
COMPARATOR
THERMAL
SHUTDOWN
1.5V
8 OUTPUT
23674
GND GND GND GND _CT
4 HEATSINK PINS
INTERNAL
BIAS
+
–
5
SHTDWN
SLUS206A - JANUARY 2000
UDG-99172