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LINEAR LTC3548 Data Sheet Handbook

Summary

This highly efficient dual, constant-frequency step-down DC/DC regulator is designed for advanced low-power applications requiring reliable voltage regulation between 2.5V and 5.5V. The manual provides comprehensive technical documentation, including detailed electrical specifications, efficiency curves across various load currents, and deep operational guides on features like Burst Mode and Pulse Skip Mode. It is essential reading for embedded systems designers working on portable devices such as PDAs, digital cameras, and wireless modems who require maximum battery runtime and high performance in a minimized footprint.

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Page 1 Text Content

查询LT3407供应商

POW ER LOSS (m

LTC3548

Dual Synchronous, 400m A/800m A, 2.25MHz

Step-Down DC/DC Regulator FEATURES DESCRIPTIO High Efficiency: Up to 95% The LTC®3548 is a dual, constant frequency, synchronous Very Low Quiescent Current: Only 40µA step down DC/DC converter. Intended for low power 2.25MHz Constant Frequency Operation applications, it operates from 2.5V to 5.5V input voltage High Switch Current: 0.7A and 1.2A range and has a constant 2.25MHz switching frequency, No Schottky Diodes Required allowing the use of tiny, low cost capacitors and inductors Low RDS(ON) Internal Switches: 0.35Ω with a profile ≤1.2mm. Each output voltage is adjustable Current Mode Operation for Excellent Line from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A and Load Transient Response power switches provide high efficiency without the need Short-Circuit Protected for external Schottky diodes.

Low Dropout Operation: 100% Duty Cycle

A user selectable mode input is provided to allow the user

Ultralow Shutdown Current: IQ < 1µA

to trade-off noise ripple for low power efficiency. Burst

Output Voltages from 5V down to 0.6V

Mode® operation provides high efficiency at light loads,

Power-On Reset Output

while Pulse Skip Mode provides low noise ripple at light

Externally Synchronizable Oscillator

loads.

Small Thermally Enhanced MSOP and 3mm × 3mm

DFN Packages To further maximize battery runtime, the P-channel

EF FI CI EN CY

MOSFETs are turned on continuously in dropout (100%

APPLICATIO duty cycle), and both channels draw a total quiescent

PDAs/Palmtop PCs current of only 40µA. In shutdown, the device draws <1µA. , LTC and LT are registered trademarks of Linear Technology Corporation. All other

Digital Cameras

trademarks are the property of their respective owners. Burst Mode is a registered Cellular Phones trademark of Linear Technology Corporation. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.

Portable Media Players PC Cards Wireless and DSL Modems

TYPICAL APPLICATIO

LTC3548 Efficiency Curve

VIN = 2.8V TO 5.5V

RUN2 VIN RUN1 MODE/SYNC POR RESET EFFICIENCY

LTC3548

VOUT2 = 2.5V VOUT1 = 1.8V

SW2 SW1

AT 400m A AT 800m A POWER LOSS

VFB2 VFB1

887k 604k VIN = 3.3V, VOUT = 1.8V

Burst Mode OPERATION

CHANNEL 1, NO LOAD ON CHANNEL 2

3548 TA01

LOAD CURRENT (m A)

Figure 1. 2.5V/1.8V at 400m A/800m A Step-Down Regulators 3548 TA02

Page Summary Contents For LINEAR LTC3548 Data Sheet Handbook

Page 1 查询LT3407供应商 POW ER LOSS (m LTC3548 Dual Synchronous, 400m A/800m A, 2.25MHz Step-Down DC/DC Regulator FEATURES DESCRIPTIO High Efficiency: Up to 95% The LTC®3548 is a dual, constant frequency, synchro...
Page 2 LTC3548 ABSOLUTE AXI RATI GS (Note 1) VIN Voltages.................................................–0.3V to 6V Ambient Operating Temperature VFB1, VFB2, RUN1, RUN2 Range (Note 2) –40°C to 85°C Voltage...
Page 3 EF FI CI EN CY LTC3548 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V, unless ...
Page 4 RE FE RE NC VO LT AG (V EF FI CI EN CY EF FI CI EN CY LTC3548 TYPICAL PERFOR A CE CHARACTERISTICS Reference Voltage vs Temperature RDS(ON) vs Input Voltage RDS(ON) vs Junction Temperature 0.615 VIN = ...
Page 5 LTC3548 PI FU CTIO S VFB1 (Pin 1): Output Feedback. Receives the feedback be synchronized to an external oscillator applied to this pin voltage from the external resistive divider across the and pulse...
Page 6 LTC3548 BLOCK DIAGRA REGULATOR 1 MODE/SYNC BURST CLAMP VIN SLOPE COMP SLEEP ITH BURST 5Ω EA ICOMP RS LATCH SWITCHING LOGIC UVDET AND BLANKING ANTI CIRCUIT SHOOT- OVDET IRCMP SHUTDOWN PGOOD1 COUNTER0.6...
Page 7 LTC3548 OPERATIO decrease causes the error amplifier to increase the ITH mode can be used. In this mode, the LTC3548 continues voltage until the average inductor current matches the new to switch at a...
Page 8 LTC3548 APPLICATIO S I FOR ATIO begins when the peak inductor current falls below a level Table 1. Representative Surface Mount Inductors set by the burst clamp. Lower inductor values result in PART V...
Page 9 LTC3548 APPLICATIO S I FOR ATIO capacitors, such as Sanyo POSCAP, Panasonic Special requires the designer to check loop stability over the Polymer (SP), and Kemet A700, offer very low ESR, but operati...
Page 10 LTC3548 APPLICATIO S I FOR ATIO Checking Transient Response OUT ⎟0 The regulator loop response can be checked by looking at the load transient response. Switching regulators take several cycles to res...
Page 11 LTC3548 APPLICATIO S I FOR ATIO produce the most improvement. Percent efficiency can be include these “system” level losses in the design of a expressed as: system. The internal battery and fuse resis...
Page 12 LTC3548 APPLICATIO S I FOR ATIO regulator operating in a 70°C ambient temperature is 2µA with the 0.6V feedback voltage makes R1~300k. A approximately: close standard 1% resistor is 280k, and R2 is th...
Page 13 LTC3548 APPLICATIO S I FOR ATIO VIN = 2.5V* TO 5.5V VIN C1 R5 10µF RUN2 VIN RUN1 100k CIN POWER-ON RUN2 VIN RUN1 MODE/SYNC POR RESET MODE/SYNC POR LTC3548 4.7µH 2.2µH LTC3548 VOUT2 = 2.5V* VOUT1 = 1.8...
Page 14 LTC3548 TYPICAL APPLICATIO S 1mm Profile Core and I/O Supplies VIN = 3.6V TO 5.5V RUN2 VIN RUN1 POWER-ON MODE/SYNC POR RESET L2 LTC3548 L1 VOUT2 = 3.3V VOUT1 = 1.8V SW2 EF FI CI SW1 EN CY AT 400m A AT...
Page 15 LTC3548 PACKAGE DESCRIPTIO DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) R = 0.115 0.38 ± 0.10 TYP (2 SIDES)2.15 ±0.05 (4 SIDES) (2 SIDES) PIN 1 PACKAGE TOP MARK OUTLINE ...
Page 16 LTC3548 TYPICAL APPLICATIO EF FI CI EN CY 2mm Height Lithium-Ion Single Inductor Buck-Boost Regulator and a Buck Regulator VIN = 2.8V TO 4.2V C1 R5 10µF RUN2 VIN RUN1 100k POWER-ON MODE/SYNC POR RESET...

Manual Details

Brand Linear
Pages 16
File Size 237.86 KB
Published June 01, 2026
67 views

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Frequently Asked Questions

What input voltage range does the LTC3548 support?

The device operates from a 2.5V to 5.5V input voltage.

How low is the current draw when operating in shutdown mode?

In shutdown, the device draws a total quiescent current of less than 1µA.

Does the regulator maintain a constant switching frequency?

Yes, it has a constant 2.25MHz switching frequency for reliable operation.

What feature helps optimize efficiency at light loads?

Burst Mode provides high efficiency when operating at light loads.