Datasheet LTC3408 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | 1.5MHz, 600mA Synchronous Step-Down Regulator with Bypass Transistor |
| Pages / Page | 12 / 5 — TYPICAL PERFOR A CE CHARACTERISTICS (From Figure 1). Output Ripple … |
| File Format / Size | PDF / 165 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS (From Figure 1). Output Ripple Waveform. Load Step Response. REF Transient. VOUT vs VREF
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LTC3408
W U TYPICAL PERFOR A CE CHARACTERISTICS (From Figure 1) Output Ripple Waveform Load Step Response
V V OUT OUT 100mV/DIV 10mV/DIV IL 500mA/DIV IL 100mA/DIV ILOAD 500mA/DIV V 3408 G16 3408 G17 IN = 3.6V 200ns/DIV VIN = 3.6V 20µs/DIV VREF = 0.6V VREF = 0.6V ILOAD = 0A ILOAD = 0mA TO 600mA
REF Transient VOUT vs VREF
4.5 VIN = 4.2V IL = 100mA 4.0 VREF IL = 600mA 0.5V/DIV 3.5 3.0 2.5 (V) VOUT OUTV 2.0 1V/DIV 1.5 1.0 V 3408 G18 IN = 4.2V 40µs/DIV 0.5 VREF = 0V TO 1.4V RLOAD = 5Ω 0 0 0.5 1.0 1.5 VREF (V) 3408 G19
U U U PI FU CTIO S VOUT (Pins 1, 8):
Output Voltage Feedback Pin. An internal
RUN (Pin 5):
Run Control Input. Forcing this pin above resistive divider divides the output voltage down by 3 for 1.5V enables the part. Forcing this pin below 0.3V shuts comparison to the external reference voltage. The drain of down the device. In shutdown, all functions are disabled the P-channel bypass MOSFET is connected to this pin. drawing <1µA supply current. Do not leave RUN floating.
VIN (Pins 2, 7):
Main Supply Pin. Must be closely de-
REF (Pin 6):
External Reference Input. Controls the output coupled to GND, Pin 3, with a 10µF or greater ceramic voltage to 3× the applied voltage at REF. Also turns on the capacitor. bypass MOSFET when VREF > 1.2V.
GND (Pin 3):
Ground Pin.
Exposed Pad (Pin 9):
Connect to GND, Pin 3.
SW (Pin 4):
Switch Node Connection to Inductor. This pin connects to the drains of the internal main and synchro- nous power MOSFET switches. 3408f 5
W U TYPICAL PERFOR A CE CHARACTERISTICS (From Figure 1) Output Ripple Waveform Load Step Response
V V OUT OUT 100mV/DIV 10mV/DIV IL 500mA/DIV IL 100mA/DIV ILOAD 500mA/DIV V 3408 G16 3408 G17 IN = 3.6V 200ns/DIV VIN = 3.6V 20µs/DIV VREF = 0.6V VREF = 0.6V ILOAD = 0A ILOAD = 0mA TO 600mA
REF Transient VOUT vs VREF
4.5 VIN = 4.2V IL = 100mA 4.0 VREF IL = 600mA 0.5V/DIV 3.5 3.0 2.5 (V) VOUT OUTV 2.0 1V/DIV 1.5 1.0 V 3408 G18 IN = 4.2V 40µs/DIV 0.5 VREF = 0V TO 1.4V RLOAD = 5Ω 0 0 0.5 1.0 1.5 VREF (V) 3408 G19
U U U PI FU CTIO S VOUT (Pins 1, 8):
Output Voltage Feedback Pin. An internal
RUN (Pin 5):
Run Control Input. Forcing this pin above resistive divider divides the output voltage down by 3 for 1.5V enables the part. Forcing this pin below 0.3V shuts comparison to the external reference voltage. The drain of down the device. In shutdown, all functions are disabled the P-channel bypass MOSFET is connected to this pin. drawing <1µA supply current. Do not leave RUN floating.
VIN (Pins 2, 7):
Main Supply Pin. Must be closely de-
REF (Pin 6):
External Reference Input. Controls the output coupled to GND, Pin 3, with a 10µF or greater ceramic voltage to 3× the applied voltage at REF. Also turns on the capacitor. bypass MOSFET when VREF > 1.2V.
GND (Pin 3):
Ground Pin.
Exposed Pad (Pin 9):
Connect to GND, Pin 3.
SW (Pin 4):
Switch Node Connection to Inductor. This pin connects to the drains of the internal main and synchro- nous power MOSFET switches. 3408f 5
