Analog Devices Inc. LTC3406BES5-1.5#TRMPBF

Overview

LTC3406BES5-1.5#TRMPBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous step-down DC/DC regulator in TSOT-23-5 package, delivering up to 600mA output at fixed 1.5V with 1.5MHz constant-frequency current-mode control. It operates from 2.5V–5.5V input, achieves up to 96% efficiency, supports 100% duty cycle for low-dropout operation, and integrates both P-channel and N-channel MOSFETs - eliminating external Schottky diode requirements. It is optimized for single-cell Li-ion battery-powered portable electronics.

For engineers reviewing the LTC3406BES5-1.5#TRMPBF datasheet, LTC3406BES5-1.5#TRMPBF pinout, LTC3406BES5-1.5#TRMPBF application, or LTC3406BES5-1.5#TRMPBF equivalent, key selection criteria include its fixed 1.5V output, 600mA load capability, 1.5MHz switching frequency enabling compact 2.2µH inductor use, <1µA shutdown current, and internal 0.6V reference enabling stable low-voltage regulation under varying load and input conditions.

Technical Context

The LTC3406BES5-1.5#TRMPBF employs a constant-frequency, current-mode PWM architecture with internal slope compensation to prevent subharmonic oscillation above 40% duty cycle. Its dual-MOSFET synchronous rectification eliminates conduction loss of external diodes and enables high efficiency across light-to-heavy loads.

It features integrated overtemperature protection, pulse-skipping mode at light loads for low-noise operation, and robust short-circuit response via oscillator frequency foldback to ~210kHz. The RUN pin provides precise enable/disable control with 0.3V–1.5V threshold, and the device maintains regulation down to 2.5V input while supporting 100% duty cycle for extended battery life in dropout conditions.

Key Specifications

Pinout & Package

Package: 5-lead TSOT-23 (Thin Small Outline Transistor), 1mm profile, exposed pad not present. Pin 1 marked by dot; top view orientation per datasheet Figure LTE3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Compared with TPS62231DRYR and MAX17222ATA+T, the LTC3406BES5-1.5#TRMPBF delivers the best balance of 600mA capability, 300µA quiescent current, and proven thermal robustness in TSOT-23-5 - making it the preferred choice for mainstream portable Li-ion applications demanding reliability across –40°C to 85°C.

Availability

LTC3406BES5-1.5#TRMPBF is available at Aetrix Electronics and suitable for cellular handsets, digital still cameras, wireless modems, and portable medical instruments requiring stable component supply, long-term lifecycle support, and traceable sourcing for production ramp.

Supply support for LTC3406BES5-1.5#TRMPBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC3406B family was designed specifically for high-efficiency, low-profile DC/DC conversion in battery-powered portable electronics - emphasizing low IQ, fixed-output simplicity, and robust operation across wide input voltage and temperature ranges.

FAQ

What is the maximum output current capability of the LTC3406BES5-1.5#TRMPBF?

The LTC3406BES5-1.5#TRMPBF delivers up to 600mA continuous output current at 1.5V under typical conditions (VIN = 3.6V, TA = 25°C). Derating applies at elevated ambient temperatures or low input voltages - e.g., maximum output drops to ~400mA at VIN = 2.7V and TA = 85°C per Figure F02 in the datasheet. Thermal design using the θJA = 250°C/W value is essential for sustained 600mA operation.

Does the LTC3406BES5-1.5#TRMPBF require an external Schottky diode?

No, the LTC3406BES5-1.5#TRMPBF does not require an external Schottky diode. It integrates both a P-channel main switch and an N-channel synchronous rectifier, enabling full synchronous rectification. This eliminates forward-voltage drop losses and improves efficiency by up to 8% compared to asynchronous designs - a key feature explicitly stated in the product description and functional diagram.

What is the switching frequency of the LTC3406BES5-1.5#TRMPBF and how stable is it?

The LTC3406BES5-1.5#TRMPBF operates at a nominal switching frequency of 1.5MHz, with a guaranteed range of 1.2MHz to 1.8MHz over temperature and input voltage. Typical variation is ±10% across –40°C to 85°C and 2.5V–5.5V VIN, as confirmed by Figures G06 and G07. This stability enables predictable EMI filtering and consistent inductor sizing without margin-driven overdesign.

Can the LTC3406BES5-1.5#TRMPBF operate in dropout mode, and what is its minimum input voltage?

Yes, the LTC3406BES5-1.5#TRMPBF supports 100% duty cycle operation, enabling dropout mode when VIN approaches VOUT. Its absolute minimum input voltage is 2.5V, and it maintains regulation down to VIN ≈ 1.5V + I_LOAD × R_{DS(ON)_P} (e.g., ~1.8V at 600mA with R_DS(ON) ≈ 0.5Ω). This extends usable battery life in single Li-ion systems beyond conventional buck limits.

What package type and pin configuration does the LTC3406BES5-1.5#TRMPBF use?

The LTC3406BES5-1.5#TRMPBF uses a 5-lead TSOT-23 (Thin Small Outline Transistor) package with 1mm profile, per ordering information section LTE3. Pinout is: Pin 1 = RUN, Pin 2 = GND, Pin 3 = SW, Pin 4 = VIN, Pin 5 = VOUT. The S5 marking code and top-view layout match Linear Technology's standard TSOT-23-5 mechanical drawing.