Datasheet LTC1701, LTC1701B (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | 1MHz Step-Down DC/DC Converter in SOT-23 |
| Seiten / Seite | 12 / 1 — FEATURES. DESCRIPTIO. Tiny 5-Lead SOT-23 Package. Uses Tiny Capacitors … |
| Dateiformat / Größe | PDF / 188 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTIO. Tiny 5-Lead SOT-23 Package. Uses Tiny Capacitors and Inductor. High Frequency Operation: 1MHz
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LTC1701/LTC1701B 1MHz Step-Down DC/DC Converters in SOT-23
U FEATURES DESCRIPTIO
■
Tiny 5-Lead SOT-23 Package
The LTC®1701/LTC1701B are the industry’s first SOT-23 ■
Uses Tiny Capacitors and Inductor
step-down, current mode, DC/DC converters. Intended for ■
High Frequency Operation: 1MHz
low to medium power applications, they operate from 2.5V ■
High Output Current: 500mA
to 5.5V input voltage range and switch at 1MHz, allowing ■
Low RDS(ON) Internal Switch: 0.28
Ω the use of tiny, low cost capacitors and inductors 2mm or ■ High Efficiency: Up to 94% less in height. The output voltage is adjustable from 1.25V ■ Current Mode Operation for Excellent Line to 5V. A built-in 0.28Ω switch allows up to 0.5A of output and Load Transient Response current at high efficiency. OPTI-LOOPTM compensation ■ Short-Circuit Protected allows the transient response to be optimized over a wide ■ Low Quiescent Current: 135µA (LTC1701) range of loads and output capacitors. ■ Low Dropout Operation: 100% Duty Cycle The LTC1701 incorporates automatic power saving Burst ■ Ultralow Shutdown Current: IQ < 1µA ModeTM operation to reduce gate charge losses when the ■ Peak Inductor Current Independent of Inductor Value load current drops below the level required for continuous ■ Output Voltages from 5V Down to 1.25V operation. The LTC1701B operates continuously to very
U
low load currents to provide low ripple at the expense of
APPLICATIO S
light load efficiency. With no load, the LTC1701 draws only 135µA. In shutdown, both devices draw less than 1µA, ■ PDAs/Palmtop PCs making them ideal for current sensitive applications. ■ Digital Cameras ■ Cellular Phones Their small size and switching frequency enables a ■ Portable Media Players complete DC/DC converter function to consume less than ■ PC Cards 0.3 square inches of PC board area. ■ Handheld Equipment , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation.
U TYPICAL APPLICATION Efficiency Curve
L1 V 4.7µH V IN OUT 100 2.5V TO VIN SW (2.5V/ VIN = 3.3V 5.5V 500mA) 95 VOUT = 2.5V D1 R4 R2 90 1M LTC1701 LTC1701 + 121k 85 C1 + 10µF C2 80 ITH/RUN VFB 47µF 75 R3 GND R1 LTC1701B 5.1k 121k 70 C3 EFFICIENCY (%) 65 330pF 60 C1: TAIYO YUDEN JMK316BJ106ML 1701 F01a C2: SANYO POSCAP 6TPA47M 55 D1: MBRM120L 50 L1: SUMIDA CD43-4R7 1 10 100 1000
Figure 1. 2.5V/500mA Step-Down Regulator
LOAD CURRENT (mA) 1701 F01b 1
U FEATURES DESCRIPTIO
■
Tiny 5-Lead SOT-23 Package
The LTC®1701/LTC1701B are the industry’s first SOT-23 ■
Uses Tiny Capacitors and Inductor
step-down, current mode, DC/DC converters. Intended for ■
High Frequency Operation: 1MHz
low to medium power applications, they operate from 2.5V ■
High Output Current: 500mA
to 5.5V input voltage range and switch at 1MHz, allowing ■
Low RDS(ON) Internal Switch: 0.28
Ω the use of tiny, low cost capacitors and inductors 2mm or ■ High Efficiency: Up to 94% less in height. The output voltage is adjustable from 1.25V ■ Current Mode Operation for Excellent Line to 5V. A built-in 0.28Ω switch allows up to 0.5A of output and Load Transient Response current at high efficiency. OPTI-LOOPTM compensation ■ Short-Circuit Protected allows the transient response to be optimized over a wide ■ Low Quiescent Current: 135µA (LTC1701) range of loads and output capacitors. ■ Low Dropout Operation: 100% Duty Cycle The LTC1701 incorporates automatic power saving Burst ■ Ultralow Shutdown Current: IQ < 1µA ModeTM operation to reduce gate charge losses when the ■ Peak Inductor Current Independent of Inductor Value load current drops below the level required for continuous ■ Output Voltages from 5V Down to 1.25V operation. The LTC1701B operates continuously to very
U
low load currents to provide low ripple at the expense of
APPLICATIO S
light load efficiency. With no load, the LTC1701 draws only 135µA. In shutdown, both devices draw less than 1µA, ■ PDAs/Palmtop PCs making them ideal for current sensitive applications. ■ Digital Cameras ■ Cellular Phones Their small size and switching frequency enables a ■ Portable Media Players complete DC/DC converter function to consume less than ■ PC Cards 0.3 square inches of PC board area. ■ Handheld Equipment , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation.
U TYPICAL APPLICATION Efficiency Curve
L1 V 4.7µH V IN OUT 100 2.5V TO VIN SW (2.5V/ VIN = 3.3V 5.5V 500mA) 95 VOUT = 2.5V D1 R4 R2 90 1M LTC1701 LTC1701 + 121k 85 C1 + 10µF C2 80 ITH/RUN VFB 47µF 75 R3 GND R1 LTC1701B 5.1k 121k 70 C3 EFFICIENCY (%) 65 330pF 60 C1: TAIYO YUDEN JMK316BJ106ML 1701 F01a C2: SANYO POSCAP 6TPA47M 55 D1: MBRM120L 50 L1: SUMIDA CD43-4R7 1 10 100 1000
Figure 1. 2.5V/500mA Step-Down Regulator
LOAD CURRENT (mA) 1701 F01b 1