Microchip Technology MIC3289-16YD6-TR

Overview

MIC3289-16YD6-TR from Micrel is a 1.2MHz PWM white LED driver IC with internal Schottky diode and true 1-wire digital control, designed for constant-current backlighting in portable devices. It delivers up to 500mA switch current, operates from 2.5V–6.5V input, features 250mV feedback reference voltage, ±5% LED current accuracy, and 16V overvoltage protection - enabling efficient drive of up to four series white LEDs in cell phones and GPS systems.

For engineers reviewing the MIC3289-16YD6-TR datasheet, MIC3289-16YD6-TR pinout, MIC3289-16YD6-TR application, or MIC3289-16YD6-TR equivalent, key selection considerations include its single-wire logarithmic 16-step dimming interface, shutdown current <1µA, TSOT23-6 package footprint, and compatibility with Li-ion and multi-cell alkaline/NiMH battery sources.

Technical Context

The MIC3289-16YD6-TR implements a constant-frequency current-mode PWM boost regulator architecture with integrated bipolar switch and internal Schottky diode. Its 1.2MHz oscillator enables compact external passive sizing while minimizing input ripple and EMI.

Feedback is derived from a 250mV reference applied across an external sense resistor, enabling precise LED current regulation independent of forward voltage variation. The device uses a true 1-wire digital interface with programmable startup brightness and edge-triggered mode switching (Count Up/Down) for deterministic brightness control without continuous processor intervention.

Key Specifications

Pinout & Package

Package: Thin SOT23-6 (TSOT23-6), 2.9mm × 1.6mm × 1.0mm profile, -40°C to +125°C junction temperature range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX16832ATA+T and TPS61165DRVR, the MIC3289-16YD6-TR uniquely combines true 1-wire control, integrated Schottky, and presettable startup in a TSOT23-6 package - delivering lowest component count and simplest MCU integration for mid-power portable backlighting.

Availability

MIC3289-16YD6-TR is available at Aetrix Electronics and suitable for cell phone backlighting, GPS display illumination, and digital camera LCD power management requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MIC3289-16YD6-TR 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

Micrel Inc. was a U.S.-based semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015. Its legacy LED driver portfolio emphasizes integration, efficiency, and ease of use in portable electronics.

The MIC3289-16YD6-TR belongs to Micrel's white LED driver product line, engineered specifically for space-constrained, battery-powered backlighting applications where minimal external components, ultra-low shutdown current, and intuitive digital dimming are critical design requirements.

FAQ

What is the function of the DC pin on the MIC3289-16YD6-TR?

The DC pin on the MIC3289-16YD6-TR serves as a single-wire digital interface for both LED brightness control and shutdown. It accepts edge-triggered pulses to select among 16 logarithmic dimming levels or enter sub-1µA shutdown mode. Pulse widths are strictly defined: t_SHUTDOWN ≥1260µs for shutdown, t_{MODE_UP} = 100–160µs to switch to Count Up mode, and t_{PROG_HIGH}/t_{PROG_LOW} = 1–32µs for brightness steps. No external pull-up or clock is needed - the MIC3289-16YD6-TR handles all timing internally.

Does the MIC3289-16YD6-TR require an external Schottky diode?

No, the MIC3289-16YD6-TR integrates a Schottky diode internally, eliminating the need for an external rectifier. This integration reduces total component count to just four external parts: input capacitor, output capacitor, power inductor, and current-sense resistor. The internal diode has a typical forward drop of 0.9V at 150mA and leakage <4µA at 30V reverse bias - verified in the MIC3289-16YD6-TR datasheet electrical characteristics table.

What is the maximum number of white LEDs the MIC3289-16YD6-TR can drive?

The MIC3289-16YD6-TR supports up to four series white LEDs when configured with the 16V overvoltage protection option. With typical white LED forward voltage of 3.2V per device, four LEDs require ~12.8V output - well within the 16V OVP clamp. Driving five or six LEDs would exceed this limit and trigger protection; for those configurations, the MIC3289-24YD6 variant (24V OVP) is required. The MIC3289-16YD6-TR's 750mA switch current rating ensures headroom for peak currents during startup and dimming transitions.

How does the MIC3289-16YD6-TR achieve ±5% LED current accuracy?

The MIC3289-16YD6-TR achieves ±5% LED current accuracy through a precision 250mV feedback reference voltage (V_FB = 237–263mV) combined with low-input-bias-current feedback sensing (<450nA). The LED current is set by I_LED = 250mV / R_SENSE, making accuracy dependent primarily on resistor tolerance and temperature coefficient. External resistor selection, layout symmetry, and thermal management of the sense resistor directly impact final accuracy - the MIC3289-16YD6-TR itself contributes minimal error beyond the specified V_FB tolerance band.

Can the MIC3289-16YD6-TR be used with a 2.5V input supply?

Yes, the MIC3289-16YD6-TR operates down to 2.5V input, making it compatible with deeply discharged Li-ion cells and 3-cell alkaline/NiMH batteries. At 2.5V, the device maintains regulation for LED strings requiring ≤10V output (e.g., three 3.2V LEDs), provided the inductor DCR and Schottky losses remain within budget. Startup is guaranteed above the 2.1V UVLO threshold, and efficiency remains >80% across the full 2.5V–6.5V range - confirmed in MIC3289-16YD6-TR typical performance curves.