LTC2925C ................................................ 0°C to 70°C
LTC2925I .............................................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MS Package ...................................................... 300°C
pin conFiguraTion
SENSEN
SENSEP
TOP VIEW
V
CC
SENSEP
SENSEN
ON
SDTMR
SD1
SD2
SD3
RAMPBUF
1
2
3
4
5
6
7
8
9
24 SCTMR
23 PGTMR
22 PGI
21 STATUS
20
FAULT
19 GATE
18 RAMP
17 REMOTE
16 FB1
15 TRACK1
14 TRACK2
13 FB2
ON 1
SDTMR 2
SD1
3
SD2
4
SD3
5
RAMPBUF 6
7
GND
8
FB3
9 10 11 12
TRACK3
FB2
TRACK2
TRACK1
25
TOP VIEW
PGTMR
SCTMR
V
CC
PGI
18 STATUS
17
FAULT
16 GATE
15 RAMP
14 REMOTE
13 FB1
24 23 22 21 20 19
GND 10
FB3 11
TRACK3 12
GN PACKAGE
24-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 85°C/W
UF PACKAGE
24-LEAD (4mm
×
4mm) PLASTIC QFN
EXPOSED PAD (PIN 25)
PCB GND CONNECTION OPTIONAL
T
JMAX
= 125°C,
θ
JA
= 37°C/W
orDer inForMaTion
http://www.linear.com/product/LTC2925#orderinfo
TUBE
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2925CGN#PBF
LTC2925CGN#TRPBF
LTC2925CGN
24-Lead Plastic SSOP
0°C to 70°C
LTC2925IGN#PBF
LTC2925IGN#TRPBF
LTC2925IGN
24-Lead Plastic SSOP
–40°C to 85°C
LTC2925CUF#PBF
LTC2925CUF#TRPBF
2925
24-Lead (4mm
×
4mm) Plastic QFN
0°C to 70°C
LTC2925IUF#PBF
LTC2925IUF#TRPBF
2925
24-Lead (4mm
×
4mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
2925fd
For more information
www.linear.com/LTC2925
LTC2925
elecTrical characTerisTics
SYMBOL
V
CC
I
CC
PARAMETER
Input Supply Range
Input Supply Current
I
FBx
= 0, I
TRACKx
= 0, I
RAMPBUF
= 0
I
FBx
= –1mA, I
TRACKx
= –1mA,
I
RAMPBUF
= –3mA
V
CC(UVL)
∆V
GATE
I
GATE
Input Supply Undervoltage Lockout
External N-Channel Gate Drive (V
GATE
– V
CC
)
GATE Pin Current
V
CC
Rising
I
GATE
= –1µA
Gate On, V
GATE
= 0V, No Faults
Gate Off, V
GATE
= 5V, No Faults
Gate Off, V
GATE
= 5V, Short-Circuit or
Power Good Timeout
V
ON(TH)
∆V
ON(HYST)
V
ON(FC)
I
ON(IN)
ON Pin Threshold Voltage
ON Pin Hysteresis
ON Pin Fault Clear Threshold Voltage
ON Pin Input Current
V
ON
= 1.2V, V
CC
= 5.5V
V
ON
Rising
∆V
CC(UVL, HYST)
Input Supply Undervoltage Lockout Hysteresis
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V unless otherwise noted.
CONDITIONS
l
l
l
l
MIN
2.9
TYP
1.5
10.5
MAX
5.5
3
15
2.7
6
–13
13
50
1.250
150
0.5
±100
60
70
10
10
30
0.4
0.4
0.4
±1
150
200
±5
±5
0.82
0.82
±10
2.5
30
–65
3
1.4
–13
1.4
–15
1.4
–14
1.4
UNITS
V
mA
mA
V
mV
V
µA
µA
mA
V
mV
V
nA
mV
mV
µA
µA
mV
V
V
V
µA
mV
mV
%
%
V
V
nA
V
Ω
µA
µA
V
µA
V
µA
V
µA
V
2.3
5
–7
7
5
1.214
30
0.3
40
30
–1
–1
–30
2.5
25
5.5
–10
10
20
1.232
75
0.4
0
50
50
5
5
0
0.2
0.2
0.2
0
90
100
0
0
∆V
RS-SENSE(TH)
Sense Resistor Overcurrent Voltage Threshold 1V < V
SENSEP
< V
CC
(V
SENSEP
– V
SENSEN
)
0V < V
SENSEP
< 1V
SENSEN Pin Input Current
0V < V
SENSEN
< V
CC
I
SENSEN
I
SENSEP
V
OS
V
FAULT(OL)
V
SDx(OL)
V
STATUS(OL)
I
RAMP
V
RAMPBUF(OL)
V
RAMPBUF(OH)
I
ERROR(%)
V
TRACKx
I
FB(LEAK)
V
FB(CLAMP)
R
REMOTE
I
SCTMR(UP)
I
SCTMR(DN)
V
SCTMR(TH)
I
SDTMR(UP)
V
SDTMR(TH)
I
PGI(UP)
V
PGI(TH)
I
PGTMR(UP)
V
PGTMR(TH)
SENSEP Pin Input Current
Ramp Buffer Offset (V
RAMPBUF
– V
RAMP
)
FAULT
Output Low Voltage
SDx
Output Low Voltage
STATUS Output Low Voltage
RAMP Pin Input Current
RAMPBUF Low Voltage
RAMPBUF High Voltage (V
CC
– V
RAMPBUF
)
I
FBx
to I
TRACKx
Current Mismatch
I
ERROR(%)
= (I
FBx
– I
TRACKx
)/I
TRACKx
TRACK Pin Voltage
I
FB
Leakage Current
V
FB
Clamp Voltage
REMOTE Feedback Switch Resistance
Short-Circuit Timer Pull-Up Current
Short-Circuit Timer Pull-Down Current
Short-Circuit Timer Threshold Voltage
Shutdown Timer Pull-Up Current
Shutdown Timer Threshold Voltage
Power Good Input Pull-Up Current
Power Good Input Threshold Voltage
Power Good Timer Pull-Up Current
Power Good Timer Threshold Voltage
V
PGTMR
= 1V
V
PGI
= 0V
V
SDTMR
= 1V
0V < V
SENSEP
< V
CC
V
RAMPBUF
= V
CC
/2, I
RAMPBUF
= 0A
I
FAULT
= 3mA
I
SDx
= 1mA, V
CC
= 2.3
I
STATUS
= 3mA
0V < RAMP < V
CC
, V
CC
= 5.5V
I
RAMPBUF
= 3mA
I
RAMPBUF
= –3mA
I
TRACKx
= –10µA
I
TRACKx
= –1mA
I
TRACKx
= –10µA
I
TRACKx
= –1mA
V
FB
= 1.5V, V
CC
= 5.5V
1µA < I
FB
< 1mA
2V < V
REMOTE
< V
CC
V
SCTMR
= 1V
V
SCTMR
= 1V
0.78
0.78
1.6
–35
1
1.1
–7
1.1
–5
0.8
–8
1.1
0.8
0.8
2.1
15
–50
2
1.23
–10
1.23
–10
–10
1.23
l
l
l
l
l
l
2925fd
For more information
www.linear.com/LTC2925
3
LTC2925
elecTrical characTerisTics
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All currents into the device pins are positive; all currents out of
device pins are negative. All voltages are referenced to ground unless
otherwise specified.
Note 3:
The GATE pin is internally limited to a minimum of 11.5V. Driving
this pin to voltages beyond the clamp may damage the part.
Typical perForMance characTerisTics
I
CC
vs V
CC
12
10
8
I
CC
(mA)
6
4
2
0
I
TRACKx
= I
FBx
= 0mA
I
RAMPBUF
= 0mA
9
12
Specifications are at T
A
= 25°C
V
GATE
vs I
GATE
15
V
GATE
vs V
CC
I
TRACKx
= I
FBx
= 1mA
I
RAMPBUF
= 3mA
V
GATE
(V)
11
10
V
GATE
(V)
10
V
CC
= 5.5V
V
CC
= 2.9V
5
2.5
3
3.5
4
V
CC
(V)
4.5
5
5.5
2925 G01
8
2
3
4
V
CC
(V)
5
6
2925 G02
0
0
5
I
GATE
(µA)
10
15
2925 G03
I
GATE
Fast Pull-Down vs
Temperature
50
V
GATE
= 5V
70
65
V
RAMPBUF(OL)
(mV)
V
RAMPBUF(OL)
vs Temperature
110
100
V
RAMPBUF(OH)
vs Temperature
45
I
GATE
(mA)
40
V
CC
= 5.5V
35
V
CC
= 2.9V
55
50
45
40
35
V
CC
= 2.9V
V
RAMPBUF(OH)
(mV)
60
V
CC
= 2.9V
90
80
70
60
50
75
100
2925 G05
V
CC
= 5.5V
30
V
CC
= 5.5V
25
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
2925 G04
30
–50 –25
50
25
TEMPERATURE (°C)
0
40
–50
–25
50
25
0
TEMPERATURE (°C)
75
100
2925 G06
4
2925fd
For more information
www.linear.com/LTC2925
LTC2925
Typical perForMance characTerisTics
V
SDx(OL)
vs V
CC
1.0
0.805
V
CC
= 5.5V
I
TRACKx
= 1mA
0.800
V
SDx(OL)
(V)
0.6
V
TRACKx
(V)
V
CC
= 2.9V
I
TRACKx
= 1mA
0.795
V
CC
= 2.9V
I
TRACKx
= 10µA
V
CC
= 5.5V
I
TRACKx
= 10µA
Specifications are at T
A
= 25°C
Tracking Cell Error vs I
TRACKx
5
V
TRACK
vs Temperature
0.8
V
TRACKx
I
FBx
–1 (%)
•
0.8V
I
TRACKx
4
3
0.4
2
1
I
SDx
= 5mA
0.2
0
I
SDx
= 10µA
0
1
2
3
V
CC
(V)
4
5
2925 G07
0.790
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
2925 G08
0
0
0.5
1
1.5
2 2.5 3 3.5
I
TRACKx
(mA)
4
4.5
5
2925 G09
pin FuncTions
GN/UF Packages
V
CC
(Pin 1/Pin 22):
Positive Supply Input. The operating
supply input range is 2.9V to 5.5V. An undervoltage lockout
circuit resets the part when the supply is below 2.5V. V
CC
should be bypassed to GND with a 0.1µF capacitor.
SENSEP (Pin 2/Pin 23):
Circuit Breaker Positive Sense
Input. SENSEP and SENSEN measure the voltage across
the sense resistor and trigger the circuit breaker function
when the current exceeds the level programmed by the
sense resistor for longer than a short-circuit timer cycle
(see SCTMR). If unused, tie SENSEN and SENSEP to V
CC
.
SENSEN (Pin 3/Pin 24):
Circuit Breaker Negative Sense
Input. SENSEN connects to the low side of the current
sense resistor. SENSEP and SENSEN monitor the current
through the external FET by measuring the voltage across
the sense resistor. The circuit breaker turns off the FET when
the sense voltage exceeds 50mV for longer than a short
circuit timer cycle (see SCTMR). If the short-circuit timer
times out, the GATE pin will be pulled low immediately to
protect the FET. If unused, tie SENSEN and SENSEP to V
CC
.
ON (Pin 4/Pin 1):
On Control Input. The ON pin has a threshold
of 1.23V with 75mV of hysteresis. An active high will cause
10µA to flow from the GATE pin, ramping up the supplies.
An active low pulls 10µA from the GATE pin, ramping the
supplies down. Pulling the ON pin below 0.4V resets the
electronic circuit breaker in the LTC2925. If a resistive
divider connected to V
CC
drives the ON pin, the supplies will
automatically start up when V
CC
is fully powered.
SDTMR (Pin 5/Pin 2):
Shutdown Timer. A capacitor from
SDTMR to GND sets the delay time between the ON pin
transitioning high (which releases the
SDx
pins) and the sup-
plies beginning to ramp-up. Float SDTMR when it is unused.
SD1, SD2, SD3
(Pins 6, 7, 8/Pins 3, 4, 5):
Outputs for
Slave Supply Shutdowns. The
SDx
pins are open-drain
outputs that hold the shutdown (RUN/SS) pins of the slave
supplies low until the ON pin is pulled above 1.23V. The
SDx
pins will be pulled low again when RAMP <100mV
and ON <1.23V. If a slave supply is capable of operating
with an input supply that is lower than the LTC2925’s
minimum operating voltage of 2.9V, the
SDx
pins can be
used to hold off the slave supplies. Each
SDx
pin is capable
of sinking greater than 1mA with supplies as low as 2.3V.
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