LTC3407-2_15 Datasheet, PDF (5/16 Pages) Linear Technology – Dual Synchronous, 800mA, 2.25MHz Step-Down DC/DC Regulator

LTC3407-2
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Efficiency vs Load Current
100
95
90
3.6V
2.7V
85
80
4.2V
75
70 _{VOUT = 1.2V}
65
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
60 ^{CIRCUIT OF FIGURE 1}
1
10
100
LOAD CURRENT (mA)
1000
3407 G13
Efficiency vs Load Current
100
95
90 _2.7V
85
3.6V
4.2V
80
75
70 _{VOUT = 1.5V}
65
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
60 ^{CIRCUIT OF FIGURE 1}
1
10
100
LOAD CURRENT (mA)
1000
3407 G14
Line Regulation
0.5
0.4
V_OUT = 1.8V
I_OUT = 200mA
0.3 ^{TA = 25°C}
0.2
0.1
0
–0.1
–0.2
–0.3
–0.4
–0.5
2
3
4
V_IN (V)
5
6
3407 G15
PIN FUNCTIONS
V_FB1 (Pin 1): Output Feedback. Receives the feedback volt-
age 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 shielding.
MODE/SYNC (Pin 6): Combination Mode Selection and
Oscillator Synchronization. This pin controls the opera-
tion 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 is not
within ±8.5% of regulation and goes high after 117ms
when both s 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.
34072fc
5