UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Integrated 0.15-
Power MOSFET
D
7-V to 15-V Operation
D
Digital-Programmable Current Limit from
0 A to 3 A
D
100-
A I
CC
When Disabled
D
Programmable On Time
D
Programmable Start Delay
D
Fixed 2% Duty Cycle
D
Thermal Shutdown
D
Fault-Output Indicator
D
Maximum-Output Current Can Be Set to 1 A
Above the Programmed-Fault Level or to a
Full 4 A
D
Power SOIC and TSSOP, Low Thermal
Resistance Packaging
description
The UCC3915 programmable hot swap power manager provides complete power-management, hot-swap
capability, and circuit breaker functions. The only external component required to operate the device, other than
power supply bypassing, is the fault-timing capacitor, C
T
. All control and housekeeping functions are integrated,
and externally programmable. These include the fault current level, maximum output sourcing current,
maximum fault time, and startup delay. In the event of a constant fault, the internal fixed 2% duty cycle ratio limits
average output power.
The internal 4-bit DAC allows programming of the fault-level current from 0 A to 3 A with 0.25-A resolution. The
IMAX control pin sets the maximum-sourcing current to 1 A above the trip level or to a full 4 A of output current
for fast output capacitor charging. (continued)
block diagram
UDG-99174
6
7
8
9
1 A
ABOVE
FAULT
+
+
OVER CURRENT
COMPARATOR
CURRENT FAULT
LEVEL 03 A
10
H = 4 A
MAX
CURRENT
LEVEL
4 A
ON TIME
CONTROL
2% DUTY
CYCLE
03 A
0.25
RES
11
13
12
4
5
B3
B2
B1
B0
4 BIT DAC
GND
HEAT SINK
GND PINS
CT
CHARGE
PUMP
+
+
16
LINEAR CURRENT
AMPLIFIER
2
3
VOUT
REVERSE VOLTAGE
COMPARATOR
30 mV
FAULT
THERMAL
SHUTDOWN
INTERNAL
BIAS
+
1
15
14 VOUT
VIN
CURRENT SENSE
H = OPEN
1.5 V
SHTDWN
IMAX
VOUT
VIN
POWER
FET *
NOTE: Pin numbers refer to DIL-16 and SOIC-16 packages.
Copyright
2000, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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.
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
description (continued)
When the output current is below the fault level, the output MOSFET is switched on with a nominal ON resistance
of 0.15
. When the output current exceeds the fault level, but is less than the maximum-sourcing level, the
output remains switched on, but the fault timer starts, charging CT. Once CT charges to a preset threshold, the
switch is turned off, and remains off for 50 times the programmed fault time. When the output current reaches
the maximum sourcing level, the MOSFET transitions from a switch to a constant current source.
The UCC3915 can be put into sleep mode, drawing only 100
A of supply current. Other features include an
open-drain fault-output indicator, thermal shutdown, undervoltage lockout, 7-V to 15-V operation, and
low-thermal resistance SOIC and TSSOP power packages.
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
VIN
15.5 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VOUT VIN
.0.3 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FAULT sink current
50 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FAULT voltage
0.3 V to 8 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output current
Self limiting
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TTL input voltage
0.3 to VIN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature, T
stg
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Junction temperature, T
J
55
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature (soldering, 10 sec.)
300
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Currents are positive into, negative out of the specified terminal. Consult Packaging Section of the Interface Products Data Book (TI Literature
Number SLUD002) for thermal limitations and considerations of packages.
package information
DIL-16, SOIC-16
N, DP Package
(TOP VIEW)
TSSOP-24,
PWP Package
(TOP VIEW)
*Pin 5 serves as lowest impedance to the electrical
ground; Pins 4, 12, and 13 serve as heat sink/ground.
These pins should be connected to large etch areas to
help dissipate heat. For N Package, pins 4, 12, and 13
are N/C.
*Pin 9 serves as lowest impedance to the electrical ground;
other GND pins serve as heat sink/ground. These pins should
be connected to large etch areas to help dissipate heat.
B3
N/C
N/C
GND*
GND*
FAULT
VIN
EGND*
GND*
GND*
VIN
N/C
GND*
SHTDWN
GND*
B2
GND*
GND*
CT
12
11
10
9
8
7
6
5
4
3
2
1
13
14
15
16
17
18
19
20
21
22
23
24
IMAX
VOUT
VOUT
B1
B0
FAULT
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
VOUT
VOUT
GND*
GND*
CT
IMAX
B0
SHTDWN
VIN
VIN
GND*
EGND*
B3
B2
B1
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
electrical characteristics, these specifications apply for T
A
= 40
C to 85
C for the UCC2915 and
0
C to 70
C for the UCC3915, VIN = 12 V, IMAX = 0.4 V, SHTDWN = 2.4 V, T
A
= T
J
, (unless otherwise
stated)
supply
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Voltage input range
7.0
15.0
V
Supply current
1.0
2.0
mA
Sleep mode current
SHTDWN = 0.2 V,
no load
100
150
A
Output leakage
SHTDWN = 0.2 V
20
A
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
output
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
IOUT = 1 A (10 V to 12 V)
0.15
0.3
V
IOUT = 2 A (10 V to 12 V)
0.3
0.6
V
Voltage drop
IOUT = 3 A (10 V to 12 V)
0.45
0.9
V
Voltage drop
IOUT = 1 A,
VIN = 7 V and 15 V
0.2
0.4
V
IOUT = 2 A,
VIN = 7 V and 15 V
0.4
0.8
V
IOUT = 3 A,
VIN = 7 V,
12 V MAX
0.6
1.2
V
Initial startup time
See Note 2
100
s
Short circuit response
See Note 2
100
ns
Thermal shutdown
See Note 2
165
C
Thermal hysteresis
See Note 2
10
C
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
NOTE 2: Ensured by design. Not production tested.
DAC
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Code = 00000011 (device off)
Code = 0100
0.07
0.25
0.45
A
Code = 0101
0.32
0.50
0.70
A
Code = 0110
0.50
0.75
0.98
A
Code = 0111
0.75
1.00
1.3
A
Trip current
Code = 1000
1.0
1.25
1.6
A
Tri current
Code = 1001
1.25
1.50
1.85
A
Code = 1010
1.5
1.75
2.15
A
Code = 1011
1.70
2.00
2.4
A
Code = 1100
1.90
2.25
2.7
A
Code = 1101
2.1
2.50
2.95
A
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
electrical characteristics, these specifications apply for T
A
= 40
C to 85
C for the UCC2915 and
0
C to 70
C for the UCC3915, VIN = 12 V, IMAX = 0.4 V, SHTDWN = 2.4 V, T
A
= T
J
, (unless otherwise
stated)
DAC (continued)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Trip c rrent
Code = 1110
2.30
2.75
3.25
A
Trip current
Code = 1111
2.50
3.0
3.50
A
Max output current over trip
(current source mode)
Code = 0100 to 1111,
IMAX = 0 V
0.35
1.0
1.65
A
Max output current
(current source mode)
Code = 0100 to 1111,
IMAX = 2.4 V
3.0
4.0
5.2
A
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
fault timer
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
CT charge current
VCT = 1.0 V
83
62
47
A
CT discharge current
VCT = 1.0 V
0.8
1.2
1.8
A
Output duty cycle
VOUT = 0 V
1.0%
1.9%
3.3%
CT fault threshold
1.2
1.5
1.7
V
CT reset threshold
0.4
0.5
0.6
V
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
shutdown
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Shutdown threshold
1.1
1.5
1.9
V
Shutdown hysteresis
150
mV
Input current
100
500
nA
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
open drain output (FAULT)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
High level output current
FAULT = 5 V
250
A
Low level output voltage
IOUT = 5 mA
0.2
0.8
V
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
TTL input dc characteristics
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
TTL input voltage high
2.0
V
TTL input voltage low
0.8
V
TTL input high current
VIH = 2.4 V
3
10
A
TTL input low current
VIL = 0.4 V
1
A
NOTE 1: All voltages are with respect to GND. Current is positive into and negative out of the specified terminal.
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
pin descriptions
B0 B3: These pins provide digital input to the DAC, which sets the fault-current threshold. They can be used
to provide a digital soft-start and adaptive-current limiting.
CT: A capacitor connected to ground sets the maximum-fault time. The maximum-fault time must be more than
the time required to charge the external capacitance in one cycle. The maximum-fault time is defined as
T
FAULT
= 16.1
10
3
C
T
. Once the fault time is reached the output will shutdown for a time given by
T
SD
= 833
10
3
C
T
, this equates to a 1.9% duty cycle.
FAULT: Open-drain output, which pulls low upon any fault or interrupt condition, or thermal shutdown.
IMAX: When this pin is set to a logic low, the maximum-sourcing current will always be 1 A above the
programmed-fault level. When set to a logic high, the maximum-sourcing current will be a constant 4 A for
applications which require fast charging of load capacitance.
SHTDWN: When this pin is brought to a logic low, the IC is put into a sleep mode drawing typically less than
100
A of I
CC
.The input threshold is hysteretic, allowing the user to program a startup delay with an external
RC circuit.
VIN: Input voltage to the UCC3915. The recommended voltage range is 7 V to 15 V. Both VIN pins should be
connected together and connected to the power source.
VOUT: Output voltage from the UCC3915. Both VOUT pins should be connected together and connected to
the load. When switched the output voltage will be approximately V
IN
(0.15
I
OUT
). VOUT must not exceed
VIN by greater than 0.3 V.
APPLICATION INFORMATION
UDG-99175
6
7
8
9
11
10
B0
B1
B2
B3
IMAX
16
3
2
4
12
13
5
14
15
1
SHTDWN
VOUT
VIN
FAULT
CT
GND
HEAT SINK
GND PINS
UCC3915
RL
COUT
VOUT
CSD
RSD
VIN
CIN
D1
CT
S1
S2
S3
S4
S5
DIP
SWITCH
S6
VIN
VIN
R1
LED
5 V
Figure 1. Evaluation Circuit
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
6
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
protecting the UCC3915 from voltage transients
The parasitic inductance associated with the power distribution can cause a voltage spike at V
IN
if the load
current is suddenly interrupted by the UCC3915. It is important to limit the peak of this spike to less than 15 V
to prevent damage to the UCC3915. This voltage spike can be minimized by:
D
Reducing the power distribution inductance (e.g., twist the positive (+) and negative () leads of the power
supply feeding V
IN
, locate the power supply close to the UCC3915 or use PCB power and ground planes).
D
Decoupling V
IN
with a capacitor, C
IN
(refer to Figure 1), located close to the V
IN
pins. This capacitor is
typically 1
F or less to limit the inrush current.
D
Clamping the voltage at V
IN
below 15 V with a Zener diode, D1(refer to Figure 1), located close to the V
IN
pins.
Figure 2. Load Current, Timing-Capacitor Voltage, and Output Voltage of the UCC3915
Under Fault Conditions
estimating maximum load capacitance
For hot-swap applications, the rate at which the total output capacitance can be charged depends on the
maximum-output current available and the nature of the load. For a constant-current, current-limited
application, the output will come up if the load asks for less than the maximum available short-circuit current.
To ensure recovery of a duty cycle from a short-circuited load condition, there is a maximum total output
capacitance which can be charged for a given unit on time (fault time). The design value of on or fault time can
be adjusted by changing the timing capacitor C
T
.
UCC2915, UCC3915
15 V PROGRAMMABLE HOT SWAP POWER MANAGER
SLUS198C FEBUARY 2000 - REVISED - JUNE 2001
7
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
For worst-case constant-current load of value just less than the trip limit; C
OUT(max)
can be estimated from:
C
OUT(max)
[
I
MAX
*
I
LOAD
16.1
103
C
T
V
OUT
Where V
OUT
is the output voltage.
For a resistive load of value R
L
, the value of C
OUT(max)
can be estimated from:
C
OUT(max)
[
16.1
103
C
T
R
L
n
1
1
*
V
OUT
I
MAX
R
L
Long C
T
times must consider the maximum temperature. Thermal shutdown protection may be the limiting fault
time.
safety recommendations
Although the UCC3915 is designed to provide system protection for all fault conditions, all integrated circuits
can ultimately fail short. For this reason, if the UCC3915 is intended for use in safety-critical applications where
UL or some other safety rating is required, a redundant safety device such as a fuse should be placed in series
with the device. The UCC3915 will prevent the fuse from blowing for virtually all fault conditions, increasing
system reliability and reducing maintenance cost, in addition to providing the hot-swap benefits of the device.
IMPORTANT NOTICE
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any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
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pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its products to the specifications applicable at the time of sale in accordance with
TI's standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary
to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except
those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer's applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
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Resale of TI's products or services with
statements different from or beyond the parameters stated by TI for
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Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright
2001, Texas Instruments Incorporated
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