Analog Devices Inc. LTC3202EDD

Overview

LTC3202EDD from Analog Devices (formerly Linear Technology) is a low-noise, constant-frequency fractional charge pump DC/DC converter optimized for white LED backlighting. It delivers up to 125mA output current with regulated voltage or current mode operation, operates from 2.7V to 4.5V input, uses no inductors, and features programmable 0.2V/0.4V/0.6V feedback set points via D0/D1 pins for LED brightness control in portable displays.

For engineers reviewing the LTC3202EDD datasheet, LTC3202EDD pinout, LTC3202EDD application, or LTC3202EDD equivalent, key selection considerations include its 1.5MHz fixed-frequency operation, thermal shutdown protection, automatic soft-start, <1µA shutdown current, and compatibility with 3mm × 3mm DFN packaging for space-constrained handheld devices.

Technical Context

The LTC3202EDD implements a two-phase nonoverlapping 1.5MHz oscillator to drive internal switches that configure flying capacitors first in series (for charging from VIN) then in parallel stacked on VIN to achieve ~1.5× voltage gain. Regulation is achieved by comparing FB voltage against one of three DAC-set reference voltages (0.2V/0.4V/0.6V) and modulating charge pump strength accordingly.

It supports both current-mode (via external sense resistor) and voltage-mode (via resistive divider) configurations. The device includes CMOS-compatible D0/D1 control inputs, thermal shutdown at ~160°C, short-circuit current limiting (~250mA), and an exposed PGND pad (Pin 11) requiring direct connection to the PCB ground plane for thermal and electrical performance.

Key Specifications

Pinout & Package

Package: 10-lead, 3mm × 3mm plastic DFN with exposed power ground pad (Pin 11). Requires soldering of exposed pad to solid PCB ground plane for thermal management (θJA = 44°C/W) and noise reduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED driver applications.

Compared with LTC3201EMS and LTC3200EMS, the LTC3202EDD offers superior thermal resistance (θJA = 44°C/W vs. 120°C/W), lower operating current, and a compact DFN package-making it optimal for space- and power-constrained portable LED backlighting where reliability and efficiency are critical.

Availability

LTC3202EDD is available at Aetrix Electronics and suitable for smartphone backlighting, tablet display drivers, portable media player UI lighting, and industrial handheld terminal displays requiring stable component supply and long-term production continuity.

Supply support for LTC3202EDD 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 all Linear ICs including the LTC3202EDD.

The LTC3202EDD belongs to Linear's precision charge pump LED driver family, designed specifically for low-noise, inductorless white LED backlighting in battery-powered portable electronics with stringent size and efficiency requirements.

FAQ

What is the maximum continuous output current capability of the LTC3202EDD?

The LTC3202EDD is rated for up to 125mA continuous output current under typical conditions (VIN = 3.3V, TA = 25°C, COUT = 1µF). Its short-circuit current limit is ~250mA, and thermal shutdown activates above ~160°C junction temperature-so actual sustained current depends on PCB thermal design and ambient temperature. The LTC3202EDD achieves this without inductors using a 2:3 fractional charge pump topology.

How does the LTC3202EDD implement LED brightness control?

The LTC3202EDD provides digital brightness control via two CMOS-compatible pins (D0 and D1) that select one of three internal DAC reference voltages at the FB pin: 0.2V, 0.4V, or 0.6V. When used in current-mode configuration with an external sense resistor (e.g., 36Ω), this sets LED current to ~5.6mA, ~11.1mA, or ~16.7mA per string. The LTC3202EDD also supports analog dimming via PWM applied to both D0 and D1 simultaneously.

Can the LTC3202EDD be used in voltage regulation mode, and how is the output voltage set?

Yes, the LTC3202EDD supports voltage regulation mode. The output voltage is set using a resistive divider (R1/R2) from VOUT to FB and FB to GND. The formula is VOUT = VFB × (1 + R1/R2), where VFB is selected as 0.2V, 0.4V, or 0.6V via D0/D1. For example, with VFB = 0.6V and R1/R2 = 6, VOUT = 4.2V. Note that higher gain ratios increase closed-loop output resistance-LTC3202EDD's nominal 0.35Ω rises proportionally.

What are the critical layout requirements for the LTC3202EDD's flying capacitors?

The LTC3202EDD requires two 1µF X5R or X7R ceramic flying capacitors (C1, C2) connected between C1+/C1− and C2+/C2−. Polarized capacitors (tantalum/aluminum) must never be used-voltage reversal occurs during startup. Capacitors must be placed as close as possible to the IC to minimize loop area and dv/dt coupling. Layout guidelines specify short, direct traces and avoidance of routing sensitive nodes near high-dv/dt pins (C1±, C2±); a grounded Faraday shield is recommended between them and adjacent traces.

Does the LTC3202EDD require external compensation components for stability?

No, the LTC3202EDD is internally compensated and does not require external compensation components. Stability relies on proper selection of the output capacitor (COUT ≥ 0.6µF, low-ESR X5R/X7R ceramic) and adherence to layout best practices-including grounding the exposed PGND pad (Pin 11) to a solid ground plane. Using undersized or high-ESR COUT can cause ringing or instability; the LTC3202EDD's control loop uses COUT as its dominant pole.