LTC3407A TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specifi ed.Effi ciency vs Load CurrentEffi ciency vs Load CurrentLoad Regulation 100 100 4 2.7V 90 90 Burst Mode OPERATION 3 4.2V 80 3.3V 80 2 70 70 Burst Mode OPERATION 60 60 1 PULSE SKIP MODE 50 50 0 ERROR(%) PULSE SKIP MODE 40 40 EFFICIENCY (%) OUT –1 EFFICIENCY (%) V 30 30 –2 20 20 10 V V –3 V OUT = 2.5V Burst Mode OPERATION 10 IN = 3.6V, VOUT = 1.8V IN = 3.6V, VOUT = 1.8V CIRCUIT OF FIGURE 3 NO LOAD ON OTHER CHANNEL NO LOAD ON OTHER CHANNEL 0 0 –4 1 10 100 1000 1 10 100 1000 1 10 100 1000 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA) 3407A G11 3407A G12 3407A G13 Effi ciency vs Load CurrentEffi ciency vs Load CurrentLine Regulation 100 100 0.5 3.3V 3.3V VOUT = 1.8V 90 90 0.4 IOUT = 200mA 2.7V 2.7V 80 80 0.3 4.2V 70 70 4.2V 0.2 60 60 0.1 50 50 0 ERROR (%) 40 40 –0.1 EFFICIENCY (%) EFFICIENCY (%) OUTV 30 30 –0.2 20 20 –0.3 10 10 –0.4 VOUT = 1.2V Burst Mode OPERATION VOUT = 1.5V Burst Mode OPERATION 0 0 –0.5 1 10 100 1000 1 10 100 1000 2 3 4 5 6 LOAD CURRENT (mA) LOAD CURRENT (mA) VIN (V) 3407A G16 3407A G14 3407A G15 PIN FUNCTIONS VFB1 (Pin 1): Output Feedback. Receives the feedback volt- SW1 (Pin 4): Regulator 1 Switch Node Connection to the age from the external resistive divider across the output. Inductor. This pin swings from VIN to GND. Nominal voltage for this pin is 0.6V. GND (Pin 5): Main Ground. Connect to the (–) terminal RUN/SS1 (Pin 2): Regulator 1 Enable and Soft-Start Input. of COUT, and (–) terminal of CIN. Forcing this pin to VIN enables regulator 1, while forcing it MODE/SYNC (Pin 6): Combination Mode Selection and to GND causes regulator 1 to shut down. Connect external Oscillator Synchronization. This pin controls the opera- RC-network with desired time-constant to enable soft-start tion of the device. When tied to V feature. This pin must be driven; do not fl oat. IN or GND, Burst Mode operation or pulse skipping mode is selected, respectively. VIN (Pin 3): Main Power Supply. Must be closely decoupled Do not fl oat this pin. The oscillation frequency can be to GND. synchronized to an external oscillator applied to this pin and pulse skipping mode is automatically selected. 3407afa 5