LTC1876 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC1876
Linear Technology
'LTC1876' PDF : 36 Pages View PDF
LTC1876
TYPICAL PERFOR A CE CHARACTERISTICS
Input Source/Capacitor
Instantaneous Current (Figure 1)
IIN
2A/DIV
VIN
200mV/DIV
VSW1
10V/DIV
VSW2
10V/DIV
Load Step (Figure 1)
VOUT
200mV/DIV
IOUT
2A/DIV
VIN = 15V
1µs/DIV
VOUT = 5V
IOUT5 = IOUT3.3 = 2A
1876 G31
VIN = 15V
VOUT = 5V
LOAD STEP = 0A TO 3A
CONTINUOUS MODE
Load Step (Figure 1)
VOUT
200mV/DIV
IOUT
2A/DIV
VIN = 15V
20µs/DIV
VOUT = 5V
LOAD STEP = 0A TO 3A
Burst Mode OPERATION
1876 G30
Burst Mode Operation (Figure 1)
Constant Frequency (Burst
Inhibit) Operation (Figure 1)
VOUT
20mV/DIV
VOUT
20mV/DIV
IOUT
0.5A/DIV
IOUT
0.5A/DIV
VIN = 15V
VOUT = 5V
VFCB = OPEN
IOUT = 20mA
10µs/DIV
1876 G32
VIN = 15V
VOUT = 5V
VFCB = 5V
IOUT = 20mA
2µs/DIV
1876 G33
PIN FUNCTIONS
RUN/SS1, RUN/SS2 (Pins 1, 23): Combination of Soft-Start,
Run Control Inputs and Short-Circuit Detection Timers. A
capacitor to ground at each of these pins sets the ramp time
to full output current. Forcing either of these pins back below
1V causes the IC to shut down the circuitry required for that
particular controller. Latchoff overcurrent protection is also
invoked via this pin as described in the Applications Informa-
tion section.
SENSE1+, SENSE2+ (Pins 2, 14): The (+) Input to each
Differential Current Comparator. The ITH pin voltage and
controlled offsets between the SENSE– and SENSE+ pins in
conjunction with RSENSE set the current trip threshold.
8
SENSE1–, SENSE2– (Pins 3, 13): The (–) Input to the
Differential Current Comparators.
VOSENSE1, VOSENSE2 (Pins 4, 12): Receives the remotely-
sensed feedback voltage for each controller from an external
resistive divider across the output.
FREQSET (Pin 5): Frequency Control Input to the Oscillator.
This pin can be left open, tied to ground, tied to INTVCC or
driven by an external voltage source. This pin can also be used
with an external phase detector to build a true phase-locked
loop.
STBYMD (Pin 6): Control pin that determines which circuitry
remains active when the controllers are shut down and/or
1876fa
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