LTC3407A Datasheet, PDF (5/16 Pages) Linear Technology – Dual Synchronous 600mA, 1.5MHz Step-Down DC/DC Regulator

LTC3407A
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Efficiency vs Load Current
100
90 ^2.7V
80
4.2V
3.3V
70
60
50
40
30
20
10 V_OUT = 2.5V Burst Mode OPERATION
0 ^{CIRCUIT OF FIGURE 3}
1
10
100
LOAD CURRENT (mA)
1000
3407A G11
Efficiency vs Load Current
100
90 ^{Burst Mode OPERATION}
80
70
60
PULSE SKIP MODE
50
40
30
20
10 ^VIN ^{= 3.6V, V}OUT ^{= 1.8V}
NO LOAD ON OTHER CHANNEL
0
1
10
100
LOAD CURRENT (mA)
1000
3407A G12
Load Regulation
4
3
2
1 ^{Burst Mode OPERATION}
0
PULSE SKIP MODE
–1
–2
–3 _{VIN = 3.6V, VOUT = 1.8V}
NO LOAD ON OTHER CHANNEL
–4
1
10
100
LOAD CURRENT (mA)
1000
3407A G13
Efficiency vs Load Current
100
3.3V
90
2.7V
80
4.2V
70
60
50
40
30
20
10
V_OUT = 1.2V Burst Mode OPERATION
0
1
10
100
LOAD CURRENT (mA)
1000
3407A G14
Efficiency vs Load Current
100
90
3.3V
2.7V
80
70 ^4.2V
60
50
40
30
20
10
V_OUT = 1.5V Burst Mode OPERATION
0
1
10
100
LOAD CURRENT (mA)
1000
3407A G15
Line Regulation
0.5
0.4
V_OUT = 1.8V
I_OUT = 200mA
0.3
0.2
0.1
0
–0.1
–0.2
–0.3
–0.4
–0.5
2
3
4
V_IN (V)
5
6
3407A G16
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.
RUN/SS1 (Pin 2): Regulator 1 Enable and Soft-Start Input.
Forcing this pin to V_IN enables regulator 1, while forcing it
to GND causes regulator 1 to shut down. Connect external
RC-network with desired time-constant to enable soft-start
feature. 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): Main Ground. Connect to the (–) terminal
of C_OUT, and (–) terminal of C_IN.
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.
3407afa
5