LTC3548EDD Datasheet, PDF (5/16 Pages) Linear Technology – Dual Synchronous, 400mA/800mA, 2.25MHz

LTC3548
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Efficiency vs Load Current
100
2.7V
3.6V
90
4.2V
80
70
60
V_OUT = 2.5V, CHANNEL 1
50 Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
CIRCUIT OF FIGURE 3
40
1
10
100
LOAD CURRENT (mA)
1000
3548 G10
Efficiency vs Load Current
100
95
90 _2.7V
85
80
3.6V
4.2V
75
70 _{VOUT = 1.5V, CHANNEL 1}
65
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
60 ^{CIRCUIT OF FIGURE 3}
1
10
100
LOAD CURRENT (mA)
1000
3548 G14
Efficiency vs Load Current
100
95
90
85
2.7V
80
4.2V
75
70 _{VOUT = 1.2V, CHANNEL 1}
65
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
60 ^{CIRCUIT OF FIGURE 3}
1
10
100
LOAD CURRENT (mA)
3.6V
1000
3548 G13
PIN FUNCTIONS
V_FB1 (Pin 1): Output Feedback. Receives the feedback
voltage from the external resistive divider across the
output. Nominal voltage for this pin is 0.6V.
RUN1 (Pin 2): Regulator 1 Enable. Forcing this pin to V_IN
enables regulator 1, while forcing it to GND causes regulator
1 to shut down. This pin must be driven; do not float.
V_IN (Pin 3): Main Power Supply. Must be closely decoupled
to GND.
SW1 (Pin 4): Regulator 1 Switch Node Connection to the
Inductor. This pin swings from V_IN to GND.
GND (Pin 5): Ground. This pin is not connected internally.
Connect to PCB ground for optimum shielding.
MODE/SYNC (Pin 6): Combination Mode Selection and
Oscillator Synchronization. This pin controls the operation
of the device. When tied to V_IN or GND, Burst Mode
operation or pulse-skipping mode is selected, respectively.
Do not float this pin. The oscillation frequency can be
synchronized to an external oscillator applied to this pin
and pulse-skipping mode is automatically selected.
SW2 (Pin 7): Regulator 2 Switch Node Connection to the
Inductor. This pin swings from V_IN to GND.
POR (Pin 8): Power-On Reset . This common-drain logic
output is pulled to GND when the output voltage falls
below –8.5% of regulation and goes high after 117ms
when both channels are within regulation.
RUN2 (Pin 9): Regulator 2 Enable. Forcing this pin to V_IN
enables regulator 2, while forcing it to GND causes regulator
2 to shut down. This pin must be driven; do not float.
V_FB2 (Pin 10): Output Feedback. Receives the feedback
voltage from the external resistive divider across the output.
Nominal voltage for this pin is 0.6V.
Exposed Pad (GND) (Pin 11): Power Ground. Connect to
the (–) terminal of C_OUT, and (–) terminal of C_IN. Must be
connected to electrical ground on PCB.
3548fc
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