Datasheet LTC3548-2 (Analog Devices) - 5
| Hersteller | Analog Devices |
| Beschreibung | Dual Synchronous, Fixed/Adjustable Output, 2.25MHz Step-Down DC/DC Regulator |
| Seiten / Seite | 16 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specifi ed. … |
| Dateiformat / Größe | PDF / 418 Kb |
| Dokumentensprache | Englisch |
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specifi ed. Effi ciency vs Load Current. PIN FUNCTIONS
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LTC3548-2
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specifi ed. Effi ciency vs Load Current Effi ciency vs Load Current Effi ciency vs Load Current
100 100 100 VIN = 2.7V VIN = 3.6V 95 95 95 VIN = 3.6V VIN = 5V 90 VIN = 2.7V 90 90 VIN = 4.2V 85 85 85 VIN = 4.2V 80 80 80 75 75 75 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 70 V 70 70 OUT2 = 1.5V VOUT2 = 2.5V VOUT2 = 3.3 V Burst Mode OPERATION Burst Mode OPERATION Burst Mode OPERATION 65 NO LOAD ON OTHER CHANNEL 65 NO LOAD ON OTHER CHANNEL 65 NO LOAD ON OTHER CHANNEL CIRCUIT OF FIGURE 3 CIRCUIT OF FIGURE 3 CIRCUIT OF FIGURE 3 60 60 60 1 10 100 1000 1 10 100 1000 1 10 100 1000 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA) 35482 G13 35482 G14 35482 G15
PIN FUNCTIONS VOUT1 (Pin 1):
Output Voltage Feedback for Channel 1. An
SW2 (Pin 7):
Regulator 2 Switch Node Connection to the internal resistive divider divides the output voltage down Inductor. This pin swings from VIN to GND. for comparison to the internal reference voltage.
POR (Pin 8):
Power-On Reset. This common-drain logic
RUN1 (Pin 2):
Regulator 1 Enable. Forcing this pin to output is pulled to GND when the output voltage falls below VIN enables regulator 1, while forcing it to GND causes –8.5% of regulation and goes high after 117ms when both regulator 1 to shut down. This pin must be driven; do channels are within regulation. not fl oat.
RUN2 (Pin 9):
Regulator 2 Enable. Forcing this pin to
VIN (Pin 3):
Input Power Supply. Must be closely decoupled VIN enables regulator 2, while forcing it to GND causes to GND. regulator 2 to shut down. This pin must be driven; do not fl oat.
SW1 (Pin 4):
Regulator 1 Switch Node Connection to the Inductor. This pin swings from VIN to GND.
VFB2 (Pin 10):
Output Feedback. Receives the feedback voltage from the external resistive divider across the output.
GND (Pin 5):
Ground. This pin is not connected internally. Normal voltage for this pin is 0.6V. Connect to PCB ground for optimum shielding.
Exposed Pad (GND) (Pin 11):
Ground. Connect to the
MODE/SYNC (Pin 6):
Combination Mode Selection and (–) terminal of C Oscillator Synchronization. This pin controls the opera- OUT, and (–) terminal of CIN. Must be connected to PCB ground for electrical contact and rated tion of the device. When tied to VIN or GND, Burst Mode thermal performance. operation or pulse-skipping mode is selected, respectively. Do not fl oat this pin. The oscillation frequency can be synchronized to an external oscillator applied to this pin and pulse-skipping mode is automatically selected. 35482fb 5
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specifi ed. Effi ciency vs Load Current Effi ciency vs Load Current Effi ciency vs Load Current
100 100 100 VIN = 2.7V VIN = 3.6V 95 95 95 VIN = 3.6V VIN = 5V 90 VIN = 2.7V 90 90 VIN = 4.2V 85 85 85 VIN = 4.2V 80 80 80 75 75 75 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 70 V 70 70 OUT2 = 1.5V VOUT2 = 2.5V VOUT2 = 3.3 V Burst Mode OPERATION Burst Mode OPERATION Burst Mode OPERATION 65 NO LOAD ON OTHER CHANNEL 65 NO LOAD ON OTHER CHANNEL 65 NO LOAD ON OTHER CHANNEL CIRCUIT OF FIGURE 3 CIRCUIT OF FIGURE 3 CIRCUIT OF FIGURE 3 60 60 60 1 10 100 1000 1 10 100 1000 1 10 100 1000 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA) 35482 G13 35482 G14 35482 G15
PIN FUNCTIONS VOUT1 (Pin 1):
Output Voltage Feedback for Channel 1. An
SW2 (Pin 7):
Regulator 2 Switch Node Connection to the internal resistive divider divides the output voltage down Inductor. This pin swings from VIN to GND. for comparison to the internal reference voltage.
POR (Pin 8):
Power-On Reset. This common-drain logic
RUN1 (Pin 2):
Regulator 1 Enable. Forcing this pin to output is pulled to GND when the output voltage falls below VIN enables regulator 1, while forcing it to GND causes –8.5% of regulation and goes high after 117ms when both regulator 1 to shut down. This pin must be driven; do channels are within regulation. not fl oat.
RUN2 (Pin 9):
Regulator 2 Enable. Forcing this pin to
VIN (Pin 3):
Input Power Supply. Must be closely decoupled VIN enables regulator 2, while forcing it to GND causes to GND. regulator 2 to shut down. This pin must be driven; do not fl oat.
SW1 (Pin 4):
Regulator 1 Switch Node Connection to the Inductor. This pin swings from VIN to GND.
VFB2 (Pin 10):
Output Feedback. Receives the feedback voltage from the external resistive divider across the output.
GND (Pin 5):
Ground. This pin is not connected internally. Normal voltage for this pin is 0.6V. Connect to PCB ground for optimum shielding.
Exposed Pad (GND) (Pin 11):
Ground. Connect to the
MODE/SYNC (Pin 6):
Combination Mode Selection and (–) terminal of C Oscillator Synchronization. This pin controls the opera- OUT, and (–) terminal of CIN. Must be connected to PCB ground for electrical contact and rated tion of the device. When tied to VIN or GND, Burst Mode thermal performance. operation or pulse-skipping mode is selected, respectively. Do not fl oat this pin. The oscillation frequency can be synchronized to an external oscillator applied to this pin and pulse-skipping mode is automatically selected. 35482fb 5