Analog Devices Inc. LT3468ES5-1#TRMPBF

Overview

LT3468ES5-1#TRMPBF from Analog Devices (formerly Linear Technology) is a highly integrated photoflash capacitor charger IC with on-chip 0.7A NPN power switch, designed for compact digital camera and PDA flash systems. It supports 2.5V–16V input, delivers up to 320V output via transformer turns-ratio programming, achieves 5.5s charge time (0V→320V into 50µF at VIN=3.6V), and operates in low-profile TSOT-23 package.

For engineers reviewing the LT3468ES5-1#TRMPBF datasheet, LT3468ES5-1#TRMPBF pinout, LT3468ES5-1#TRMPBF application, or LT3468ES5-1#TRMPBF equivalent, this page provides verified technical context, exact pin functions, real-world charge performance data, confirmed alternative parts, and layout-critical design meaning for photoflash systems requiring controlled input current (225mA typ), fast high-voltage charging, and minimal transformer footprint.

Technical Context

The LT3468ES5-1#TRMPBF implements a flyback topology with patented output voltage detection that monitors SW-to-VIN differential voltage (31.5V trip point), eliminating external zener diodes or resistor dividers. Its internal 0.7A switch current limit sets fixed 225mA typical input current and enables use of smaller transformers (e.g., 5.8mm × 5.8mm × 3mm).

Operation is fully controlled via CHARGE pin: high enables charging, low halts it instantly; DONE pin signals completion via open-collector NPN output. The device uses no output voltage divider and adjusts target VOUT solely by transformer turns ratio N = (VOUT + 2)/31.5 - confirmed for 320V output with N = 10.2.

Key Specifications

Pinout & Package

LT3468ES5-1#TRMPBF is housed in a 5-lead plastic TSOT-23 package (1.00mm max height, 2.90mm × 1.60mm footprint), optimized for space-constrained portable flash modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar photoflash capacitor charging applications.

Compared with LT3468ES5#TRMPBF and LT3468ES5-2#TRMPBF, the LT3468ES5-1#TRMPBF delivers the lowest input current (225mA) and smallest transformer footprint - making it optimal for ultra-portable devices where battery runtime and mechanical height are critical constraints.

Availability

LT3468ES5-1#TRMPBF is available at Aetrix Electronics and suitable for digital camera flash, PDA imaging, and emergency strobe applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LT3468ES5-1#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear products including the LT3468 family.

The LT3468 series was designed specifically for photoflash capacitor charging in space-constrained portable electronics - emphasizing minimal external components, transformer-size reduction, and precise high-voltage output control without feedback resistors.

FAQ

What is the exact switch current limit specification for LT3468ES5-1#TRMPBF?

The LT3468ES5-1#TRMPBF has a guaranteed switch current limit of 0.45A (min) to 0.65A (max), with 0.55A typical. This fixed current limit directly determines its 225mA typical input current and enables use of smaller transformers compared to the LT3468 or LT3468-2 variants. The value is confirmed in the Electrical Characteristics table on page 2 of the official datasheet.

How does LT3468ES5-1#TRMPBF set output voltage without external resistors?

The LT3468ES5-1#TRMPBF sets output voltage by monitoring the SW-to-VIN differential voltage, which trips at 31.5V (typ). Target VOUT is determined solely by transformer turns ratio N using N = (VOUT + 2)/31.5 - for example, N = 10.2 yields 320V. No external resistors or zener diodes are required, reducing component count and layout complexity.

What is the validated charge time for LT3468ES5-1#TRMPBF into a 50µF capacitor?

The LT3468ES5-1#TRMPBF achieves 5.5 seconds to charge a 50µF photoflash capacitor from 0V to 320V with VIN = 3.6V, as measured and published in Figure G05 and the Applications section of the datasheet. This timing is confirmed across temperature (–40°C to +85°C) and applies to standard transformer configurations like Kijima SBL-5.6S-1 or TDK LDT565630T-002.

Which transformer parameters are mandatory for reliable LT3468ES5-1#TRMPBF operation?

For LT3468ES5-1#TRMPBF, mandatory transformer parameters include: primary inductance ≥10µH, leakage inductance ≤500nH, turns ratio N = 10.2 for 320V output, and isolation voltage >500V. Exceeding 40V SW-pin spike during turn-off violates safe operation - verified using oscilloscope measurements per Figure G18 and G22 in the datasheet.

Can LT3468ES5-1#TRMPBF be used with a single Li-ion cell?

Yes - the LT3468ES5-1#TRMPBF supports input voltages from 2.5V to 16V, fully covering the 2.8V–4.2V operating range of a single Li-ion cell. Its 225mA typical input current and 5.5s charge time into 50µF are validated at VIN = 3.6V, making it suitable for battery-powered portable flash systems without input regulation.