Datasheet LTC3407-3 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | Dual Synchronous, 1.8V/0.8A and 3.3V/0.8A 2.25MHz Step-Down DC/DC Regulator |
| Seiten / Seite | 16 / 1 — FEATURES. DESCRIPTION. Very Low Quiescent Current: Only 40μA. 1.8V at … |
| Dateiformat / Größe | PDF / 269 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTION. Very Low Quiescent Current: Only 40μA. 1.8V at 800mA/3.3V at 800mA. High Effi ciency: Up to 95%
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LTC3407-3 Dual Synchronous, 1.8V/0.8A and 3.3V/0.8A 2.25MHz Step-Down DC/DC Regulator
FEATURES DESCRIPTION
n
Very Low Quiescent Current: Only 40μA
The LTC®3407-3 is a dual, constant frequency, synchro- n
1.8V at 800mA/3.3V at 800mA
nous step down DC/DC converter. Intended for low power n
High Effi ciency: Up to 95%
applications, it operates from 3.3V to 5.5V input voltage n
2.25MHz Constant Frequency Operation
range and has a constant 2.25MHz switching frequency, n
High Switch Current: 1.2A on Each Channel
allowing the use of tiny, low cost capacitors and inductors n
No Schottky Diodes Required
with a profi le ≤1.0mm. Internal synchronous 0.35Ω, 1.2A n
Low RDS(ON) Internal Switches: 0.35Ω
power switches provide high effi ciency without the need n
VIN: 3.3V to 5.5V
for external Schottky diodes. n Current Mode Operation for Excellent Line A user selectable mode input is provided to allow the user and Load Transient Response to trade-off noise ripple for low power effi ciency. Burst n Short-Circuit Protected Mode® operation provides high effi ciency at light loads, n Low Dropout Operation: 100% Duty Cycle while pulse-skipping mode provides low noise ripple at n Ultralow Shutdown Current: IQ < 1μA light loads. n Power-On Reset Output n Externally Synchronizable Oscillator To further maximize battery life, the P-channel MOSFETs n Small Thermally Enhanced 3mm × 3mm DFN Package are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent current of only
APPLICATIONS
40μA. In shutdown, the device draws <1μA. n PDAs/Palmtop PCs L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n Digital Cameras owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. n Cellular Phones n Portable Media Players n PC Cards n Wireless and DSL Modems
TYPICAL APPLICATION LTC3407-3 Effi ciency/Power Loss
100 1 V V IN OUT = 3.3V 3.3V TO 5.5V 90 10μF 100k RUN2 V 80 IN RUN1 VOUT = 1.8V 0.1 POWER LOSS (W) MODE/SYNC POR RESET 70 LTC3407-3 2.2μH 2.2μH 60 VOUT2 VOUT1 SW2 SW1 V 0.01 OUT = 3.3V 3.3V 1.8V 50 VOUT = 1.8V V V OUT2 OUT1 EFFICIENCY (%) 10μF 10μF 40 GND 0.001 34073 TA01 30 VIN = 5V 20 Burst Mode OPERATION NOTE: IN DROPOUT, THE OUTPUT TRACKS THE INPUT VOLTAGE NO LOAD ON OTHER CHANNEL 10 0.000 1 10 100 1000
Figure 1. 1.8V/3.3V at 800mA Step-Down Regulators
LOAD CURRENT (mA) 34073 TA01b 34073fb 1
FEATURES DESCRIPTION
n
Very Low Quiescent Current: Only 40μA
The LTC®3407-3 is a dual, constant frequency, synchro- n
1.8V at 800mA/3.3V at 800mA
nous step down DC/DC converter. Intended for low power n
High Effi ciency: Up to 95%
applications, it operates from 3.3V to 5.5V input voltage n
2.25MHz Constant Frequency Operation
range and has a constant 2.25MHz switching frequency, n
High Switch Current: 1.2A on Each Channel
allowing the use of tiny, low cost capacitors and inductors n
No Schottky Diodes Required
with a profi le ≤1.0mm. Internal synchronous 0.35Ω, 1.2A n
Low RDS(ON) Internal Switches: 0.35Ω
power switches provide high effi ciency without the need n
VIN: 3.3V to 5.5V
for external Schottky diodes. n Current Mode Operation for Excellent Line A user selectable mode input is provided to allow the user and Load Transient Response to trade-off noise ripple for low power effi ciency. Burst n Short-Circuit Protected Mode® operation provides high effi ciency at light loads, n Low Dropout Operation: 100% Duty Cycle while pulse-skipping mode provides low noise ripple at n Ultralow Shutdown Current: IQ < 1μA light loads. n Power-On Reset Output n Externally Synchronizable Oscillator To further maximize battery life, the P-channel MOSFETs n Small Thermally Enhanced 3mm × 3mm DFN Package are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent current of only
APPLICATIONS
40μA. In shutdown, the device draws <1μA. n PDAs/Palmtop PCs L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n Digital Cameras owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. n Cellular Phones n Portable Media Players n PC Cards n Wireless and DSL Modems
TYPICAL APPLICATION LTC3407-3 Effi ciency/Power Loss
100 1 V V IN OUT = 3.3V 3.3V TO 5.5V 90 10μF 100k RUN2 V 80 IN RUN1 VOUT = 1.8V 0.1 POWER LOSS (W) MODE/SYNC POR RESET 70 LTC3407-3 2.2μH 2.2μH 60 VOUT2 VOUT1 SW2 SW1 V 0.01 OUT = 3.3V 3.3V 1.8V 50 VOUT = 1.8V V V OUT2 OUT1 EFFICIENCY (%) 10μF 10μF 40 GND 0.001 34073 TA01 30 VIN = 5V 20 Burst Mode OPERATION NOTE: IN DROPOUT, THE OUTPUT TRACKS THE INPUT VOLTAGE NO LOAD ON OTHER CHANNEL 10 0.000 1 10 100 1000
Figure 1. 1.8V/3.3V at 800mA Step-Down Regulators
LOAD CURRENT (mA) 34073 TA01b 34073fb 1