Microchip Technology MIC2845A-PPYMT-TR

Overview

MIC2845A-PPYMT-TR from Micrel is a 6-channel linear white LED driver with dual low-I_Q LDOs, designed for portable display and keypad backlighting in mobile handsets and digital cameras. It delivers ±1.5% typical current accuracy and channel matching, 40mV dropout at 20mA, 3.0–5.5V input range, and supports Ultra Fast PWM dimming from 200Hz to 500kHz.

For engineers reviewing the MIC2845A-PPYMT-TR datasheet, MIC2845A-PPYMT-TR pinout, MIC2845A-PPYMT-TR application, or MIC2845A-PPYMT-TR equivalent, key selection criteria include linear WLED driver efficiency without boost losses, DAM™-enabled uniform illumination across six LEDs, dual 3.0V LDO outputs with 150mV dropout at 150mA, and thermal shutdown protection in a 2.5mm × 2.5mm Thin MLF® package.

Technical Context

The MIC2845A-PPYMT-TR integrates six independent linear current sources controlled by a master RSET resistor and Dynamic Average Matching™ (DAM™) circuitry that multiplexes four reference currents to maintain ±1.5% matching across all channels under varying PWM duty cycles and temperature. Its Ultra Fast PWM™ interface accepts 200Hz–500kHz signals with sub-1% minimum duty cycle support up to 20kHz.

Two fully independent LDOs each deliver 3.0V output (per ordering code PP), with ±3% output voltage accuracy, 150mV dropout at 150mA, and 35µA ground current in operation. Each LDO features dedicated enable pins (EN1/EN2), thermal shutdown, current limiting, and stability with ≥1µF ceramic output capacitance.

Key Specifications

Pinout & Package

The MIC2845A-PPYMT-TR is housed in a 14-pin 2.5mm × 2.5mm Thin MLF® (MicroLeadFrame) leadless package with exposed thermal pad (EPAD) for enhanced power dissipation. Pin 1 is marked with ▲ on top view.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-channel linear WLED driver applications.

Compared with LM3530TMX/NOPB and TPS61165DRVR, the MIC2845A-PPYMT-TR uniquely combines six linear WLED channels, dual 3.0V LDOs, and Ultra Fast PWM™ in one 2.5mm × 2.5mm package - delivering lower EMI, higher efficiency above 3.0V, and reduced system-level component count for space-constrained portable designs.

Availability

MIC2845A-PPYMT-TR is available at Aetrix Electronics and suitable for mobile handset backlighting, digital camera flash modules, keypad illumination, portable GPS displays, and industrial handheld HMI requiring stable component supply and long-term lifecycle continuity.

Supply support for MIC2845A-PPYMT-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 fabless semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015. It emphasized high-efficiency, low-noise, and thermally robust ICs for portable and industrial applications.

The MIC2845A product line was engineered to replace inefficient boost-based WLED drivers in battery-powered consumer electronics, integrating linear LED control, DAM™ matching, and dual LDOs to minimize board space, EMI, and power loss in compact mobile form factors.

FAQ

What is the maximum LED current per channel for MIC2845A-PPYMT-TR?

The MIC2845A-PPYMT-TR supports up to 20mA per channel at 100% PWM duty cycle when configured with a 20.5kΩ RSET resistor. Peak current scales inversely with RSET value per the formula I_LED(mA) = 410 × D / RSET(kΩ), where D is duty cycle. The device maintains regulation down to 40mV dropout at 20mA, enabling efficient operation directly from Li-ion battery voltage.

Does MIC2845A-PPYMT-TR support true 1% PWM dimming?

Yes, MIC2845A-PPYMT-TR supports <1% minimum duty cycle for PWM dimming at frequencies up to 20kHz, enabled by its Ultra Fast PWM™ architecture. At higher frequencies (20–500kHz), duty cycle linearity degrades due to propagation delay, but average current remains controllable across the full range. This allows flicker-free dimming in handheld UIs without requiring external PWM generators.

How are the LDO outputs configured for MIC2845A-PPYMT-TR?

The MIC2845A-PPYMT-TR is ordered with LDO1 = 3.0V and LDO2 = 3.0V (denoted by "PP" in the part number). Both LDOs deliver ±3% output voltage accuracy over temperature, 150mV dropout at 150mA load, and draw only 35µA ground current in active mode. Each has independent enable pins (EN1/EN2) allowing selective power gating to reduce system standby current.

Can MIC2845A-PPYMT-TR drive more than six LEDs?

Yes - MIC2845A-PPYMT-TR supports parallel operation: connecting D1–D6 together drives a single high-current LED (e.g., camera flash) with up to 6× the per-channel current. With RSET = 1.65kΩ, each channel delivers 250mA, yielding 1.5A total. This configuration retains DAM™-level matching and Ultra Fast PWM™ timing control, making it suitable for torch and flash applications without external FETs.

What thermal considerations apply to MIC2845A-PPYMT-TR in a 2.5mm × 2.5mm Thin MLF® package?

MIC2845A-PPYMT-TR has a junction-to-ambient thermal resistance (θ_JA) of 89°C/W. In high-power configurations (e.g., six 20mA LEDs + dual 150mA LDOs), PCB copper area under the EPAD and proper thermal vias are essential to maintain T_J ≤ 125°C. For example, at 3.6V input and 3.0V LDO outputs with 150mA loads, total power dissipation reaches ~0.435W - limiting max ambient to ~99°C without forced airflow or enhanced heatsinking.