LTC2925CGN(RevD) View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC2925CGN
(Rev.:RevD)
(Rev.:RevD)
Linear Technology
LTC2925CGN Datasheet PDF : 26 Pages
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LTC2925
Typical Performance Characteristics Specifications are at TA = 25°C
VSDx(OL) vs VCC
1.0
0.8
0.6
0.4
0.2
0
0
ISDx = 5mA
ISDx = 10µA
1
2
3
4
5
VCC (V)
2925 G07
VTRACK vs Temperature
0.805
VCC = 5.5V
ITRACKx = 1mA
VCC = 5.5V
ITRACKx = 10µA
0.800
0.795
VCC = 2.9V
ITRACKx = 1mA
VCC = 2.9V
ITRACKx = 10µA
0.790
–50
–25 0 25 50
TEMPERATURE (°C)
75 100
2925 G08
Tracking Cell Error vs ITRACKx
5
4
3
2
1
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
ITRACKx (mA)
2925 G09
Pin Functions GN/UF Packages
VCC (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. VCC
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 VCC.
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 VCC.
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 VCC drives the ON pin, the supplies will
automatically start up when VCC 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.
For more information www.linear.com/LTC2925
2925fd
5
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