Analog Devices Inc. LTC3423EMS

Overview

LTC3423EMS from Analog Devices (formerly Linear Technology) is a high-efficiency, fixed-frequency, synchronous step-up DC/DC converter optimized for single-cell battery inputs (0.5V–1.5V) delivering up to 600mA at 1.8V. It integrates a 0.16Ω N-channel MOSFET switch and 0.21Ω P-channel synchronous rectifier, operates with VDD supply (2.7V–5.5V), and supports programmable switching frequency up to 3MHz via external resistor. Used in handheld instruments and GPS receivers requiring low-quiescent-power boost regulation.

For engineers reviewing the LTC3423EMS datasheet, LTC3423EMS pinout, LTC3423EMS application, or LTC3423EMS equivalent, key selection criteria include its 1A switch current limit, 38µA Burst Mode quiescent current, 1.5V–5.5V adjustable output range, and MSOP-10 package compatibility with space-constrained portable designs.

Technical Context

The LTC3423EMS employs current-mode control with adaptive slope compensation for stable loop response and excellent transient performance. Its internal architecture includes lossless peak current sensing, an 85µmhos transconductance error amplifier, and a dedicated VDD pin powering internal circuitry independently of VIN.

Burst Mode operation-enabled by pulling MODE/SYNC high-reduces quiescent current to 38µA at light loads while maintaining regulation; fixed-frequency mode (MODE/SYNC low or driven by external clock) ensures low-noise operation. The IC requires ≥2.7V on VDD to start and supports synchronization to external clocks with pulse widths of 100ns–2µs.

Key Specifications

Pinout & Package

The LTC3423EMS is housed in a thermally enhanced 10-lead MSOP package (3.0mm × 3.0mm × 1.1mm height), with exposed pad for improved thermal dissipation. Pin 1 is Rt (timing resistor), Pin 2 is MODE/SYNC (Burst Mode enable/sync input), Pin 3 is VIN (input voltage sense), Pin 4 is SW (switch node), Pin 5 is GND (signal/power ground), Pin 6 is VDD (internal circuit power), Pin 7 is VOUT (regulated output), Pin 8 is FB (feedback input), Pin 9 is VC (error amplifier output), and Pin 10 is SHDN (shutdown control).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous boost converter applications.

Compared with LTC3423EMS, LTC3401EMS removes the VDD dependency but adds PGOOD - making it less suitable for ultra-low-VIN hold-up scenarios; LTC3424EMS offers direct pin-compatible scaling to 2A, preserving layout while increasing output capability.

Availability

LTC3423EMS is available at Aetrix Electronics and suitable for handheld instrumentation, GPS receivers, and cordless phone subsystems requiring stable component supply with guaranteed long-term availability.

Supply support for LTC3423EMS 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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC series.

The LTC3423EMS belongs to Linear's micropower synchronous boost converter family, designed specifically for battery-powered portable electronics demanding high efficiency at ultralow input voltages and minimal quiescent current.

FAQ

What is the minimum input voltage required for LTC3423EMS to start up?

The LTC3423EMS requires ≥2.7V applied to the VDD pin to power internal circuitry and initiate startup. Once running, VIN can drop as low as 0.5V while maintaining regulation - but VDD must remain ≥2.7V throughout operation. This dual-supply architecture enables reliable startup from weak or aging single-cell batteries.

Can LTC3423EMS operate without an external Schottky diode?

Yes, the LTC3423EMS integrates a 0.21Ω P-channel synchronous rectifier that replaces the external Schottky diode. This reduces conduction losses and improves efficiency up to 95%. An external Schottky (e.g., MBRM120T3) may be added across the PMOS switch to further reduce voltage drop during NMOS-to-PMOS transition, but it is not required for basic operation.

How does Burst Mode operation affect output ripple on LTC3423EMS?

In Burst Mode, the LTC3423EMS delivers energy in short bursts until regulation is achieved, then sleeps - resulting in variable-frequency ripple with typical steady-state amplitude <3%. While this increases low-frequency ripple content, it reduces average quiescent current to 38µA. For noise-sensitive applications, fixed-frequency mode (MODE/SYNC low) is recommended.

What is the purpose of the VDD pin on LTC3423EMS, and how should it be decoupled?

The VDD pin supplies power to the LTC3423EMS internal control circuitry and must be held between 2.7V and 5.5V. It is independent of VIN and enables operation even when VIN falls below 1V post-startup. A 2.2µF X5R/X7R ceramic capacitor must be placed as close as possible to the VDD and GND pins to ensure stable startup and low-noise operation.

Is LTC3423EMS pin-compatible with LTC3424EMS?

Yes, the LTC3423EMS and LTC3424EMS share identical pinout, package (MSOP-10), and footprint. The primary difference is switch current rating: LTC3423EMS supports 1A peak (≤600mA continuous), while LTC3424EMS supports 2A peak (≤1.5W). This allows direct replacement for higher-power requirements without PCB changes - provided thermal design accommodates increased dissipation.