Datasheet LTC3403 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 1.5MHz, 600mA Synchronous Step-Down Regulator with Bypass Transistor |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTIO. Dynamically Adjustable Output from 0.3V to 3.5V. … |
| File Format / Size | PDF / 950 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. Dynamically Adjustable Output from 0.3V to 3.5V. Very Low Quiescent Current: Only 20. During Operation
Model Line for this Datasheet
Text Version of Document
LTC3403 1.5MHz, 600mA Synchronous Step-Down Regulator with Bypass Transistor
U FEATURES DESCRIPTIO
■
Dynamically Adjustable Output from 0.3V to 3.5V
The LTC®3403 is a high efficiency monolithic synchro- ■
Very Low Quiescent Current: Only 20
µ
A
nous buck regulator optimized for WCDMA power ampli-
During Operation
fier applications. The output voltage can be dynamically ■
600mA Output Current
programmed from 0.3V to 3.5V. At VOUT > 3.6V an internal ■
Internal P-Channel MOSFET Bypass Transistor
bypass P-channel MOSFET connects VOUT directly to VIN, ■
High Efficiency: Up to 96%
eliminating power loss through the inductor. Selectable ■
1.5MHz Constant Frequency Operation
forced continuous mode enables fast VOUT response to the ■
No Schottky Diode Required
controlling input. ■
Low Dropout Operation: 100% Duty Cycle
Supply current is only 20µA in Burst Mode® operation and ■
2.5V to 5V Input Voltage Range
drops to <1µA in shutdown. The 2.5V to 5V input voltage ■
Drives Optional External P-Channel MOSFET
range makes the LTC3403 ideally suited for single Li-Ion ■ Shutdown Mode Draws < 1µA Supply Current battery-powered applications. 100% duty cycle provides ■ Current Mode Operation for Excellent Line and Load Transient Response low dropout operation, extending battery life in portable systems. ■ Overtemperature Protected ■ Available in 8-Lead 3mm × 3mm DFN Package Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.
U
The internal synchronous switch increases efficiency and
APPLICATIO S
eliminates the need for an external Schottky diode. ■ WCDMA Cell Phone Power Amplifiers The LTC3403 is available in a low profile 8-lead 3mm × ■ Wireless Modems 3mm DFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation.
U TYPICAL APPLICATIO
95 90 VIN = 3.6V 85 V 2.2µH* IN VOUT VIN = 4.2V 2.7V V 80 IN SW 3× VREF TO 5V C † V V IN C 600mA IN = 3.6V IN = 4.2V LTC3403 OUT** 10µF 4.7µF 75 CER MODE GDR CER 70 RUN VOUT EFFICIENCY (%) FORCED REF 65 CONTINUOUS OUTPUT GND 60 MODE WCDMA PROGRAMMING 3 Burst Mode RF PA DAC 55 OPERATION VOUT = 1.8V *MURATA LQH32CN2R2M11 50 ** 3403 F01a TAIYO YUDEN JMK212BJ475MG 0.1 1 10 100 1000 †TAIYO YUDEN JMK212BJ106MN OUTPUT CURRENT (mA) 3403 F01b
Figure 1a. WCDMA Transmitter Power Supply Figure 1b. Efficiency vs Output Current
3403f 1
U FEATURES DESCRIPTIO
■
Dynamically Adjustable Output from 0.3V to 3.5V
The LTC®3403 is a high efficiency monolithic synchro- ■
Very Low Quiescent Current: Only 20
µ
A
nous buck regulator optimized for WCDMA power ampli-
During Operation
fier applications. The output voltage can be dynamically ■
600mA Output Current
programmed from 0.3V to 3.5V. At VOUT > 3.6V an internal ■
Internal P-Channel MOSFET Bypass Transistor
bypass P-channel MOSFET connects VOUT directly to VIN, ■
High Efficiency: Up to 96%
eliminating power loss through the inductor. Selectable ■
1.5MHz Constant Frequency Operation
forced continuous mode enables fast VOUT response to the ■
No Schottky Diode Required
controlling input. ■
Low Dropout Operation: 100% Duty Cycle
Supply current is only 20µA in Burst Mode® operation and ■
2.5V to 5V Input Voltage Range
drops to <1µA in shutdown. The 2.5V to 5V input voltage ■
Drives Optional External P-Channel MOSFET
range makes the LTC3403 ideally suited for single Li-Ion ■ Shutdown Mode Draws < 1µA Supply Current battery-powered applications. 100% duty cycle provides ■ Current Mode Operation for Excellent Line and Load Transient Response low dropout operation, extending battery life in portable systems. ■ Overtemperature Protected ■ Available in 8-Lead 3mm × 3mm DFN Package Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.
U
The internal synchronous switch increases efficiency and
APPLICATIO S
eliminates the need for an external Schottky diode. ■ WCDMA Cell Phone Power Amplifiers The LTC3403 is available in a low profile 8-lead 3mm × ■ Wireless Modems 3mm DFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation.
U TYPICAL APPLICATIO
95 90 VIN = 3.6V 85 V 2.2µH* IN VOUT VIN = 4.2V 2.7V V 80 IN SW 3× VREF TO 5V C † V V IN C 600mA IN = 3.6V IN = 4.2V LTC3403 OUT** 10µF 4.7µF 75 CER MODE GDR CER 70 RUN VOUT EFFICIENCY (%) FORCED REF 65 CONTINUOUS OUTPUT GND 60 MODE WCDMA PROGRAMMING 3 Burst Mode RF PA DAC 55 OPERATION VOUT = 1.8V *MURATA LQH32CN2R2M11 50 ** 3403 F01a TAIYO YUDEN JMK212BJ475MG 0.1 1 10 100 1000 †TAIYO YUDEN JMK212BJ106MN OUTPUT CURRENT (mA) 3403 F01b
Figure 1a. WCDMA Transmitter Power Supply Figure 1b. Efficiency vs Output Current
3403f 1
