Microchip Technology MIC2845A-PGYMT-TR

Overview

MIC2845A-PGYMT-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-PGYMT-TR datasheet, MIC2845A-PGYMT-TR pinout, MIC2845A-PGYMT-TR application, or MIC2845A-PGYMT-TR equivalent, this page provides verified functional context, validated pin roles, confirmed LDO output voltages (3.0V/1.8V), thermal performance data, and real-world dimming behavior across duty cycles and frequencies.

Technical Context

The MIC2845A-PGYMT-TR integrates six independent linear current sources controlled by a single RSET resistor and an Ultra Fast PWM™ interface on the END pin, enabling precise dimming down to 1% duty cycle at ≤20kHz and supporting up to 500kHz with calibrated non-linear response. Its DAM™ architecture dynamically multiplexes four current references to maintain ±1.5% matching across all channels under varying thermal and load conditions.

Two independently enabled LDOs deliver fixed 3.0V (LDO1) and 1.8V (LDO2) outputs with ±3% accuracy, 150mV dropout at 150mA, and 35µA ground current. Each LDO stabilizes with only 1µF ceramic output capacitance and includes thermal shutdown and current limiting-fully decoupled from LED driver operation.

Key Specifications

Pinout & Package

The MIC2845A-PGYMT-TR is housed in a 14-pin 2.5mm × 2.5mm Thin MLF® leadless package with exposed thermal pad (EPAD) for enhanced heat dissipation. Junction temperature range is –40°C to +125°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3639A and MAX16827, the MIC2845A-PGYMT-TR uniquely combines fixed 3.0V/1.8V LDOs, ±1.5% matching, and 40mV dropout in a 2.5mm × 2.5mm footprint-making it optimal for space-constrained mobile consumer devices requiring integrated power and lighting control.

Availability

MIC2845A-PGYMT-TR is available at Aetrix Electronics and suitable for mobile handset backlighting, digital camera flash circuits, and portable media player UI lighting requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MIC2845A-PGYMT-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 analog and mixed-signal semiconductor company specializing in power management, timing, and interface ICs before its acquisition by Microchip Technology in 2015.

The MIC2845A-PGYMT-TR belongs to Micrel's high-efficiency linear WLED driver product line, engineered specifically for battery-powered mobile devices demanding ultra-low noise, precise current matching, and integrated auxiliary power regulation.

FAQ

What is the exact LDO output voltage configuration for MIC2845A-PGYMT-TR?

The MIC2845A-PGYMT-TR has factory-configured LDO outputs: LDO1 delivers a fixed 3.0V, and LDO2 delivers a fixed 1.8V. These values are defined by the "PG" ordering code in the part number and are trimmed during manufacturing-no external feedback resistors are required. Both outputs maintain ±3% accuracy over temperature and load, with 150mV dropout at 150mA. This configuration is confirmed in the official Micrel ordering information table and functional description section of the MIC2845A datasheet.

How does the MIC2845A-PGYMT-TR achieve ±1.5% LED current matching?

The MIC2845A-PGYMT-TR achieves ±1.5% typical LED current matching through its proprietary Dynamic Average Matching™ (DAM™) architecture, which dynamically multiplexes four internal current references across the six output channels. This technique compensates for process, voltage, and temperature variations in real time-ensuring uniform brightness across all six LEDs regardless of dimming level or ambient conditions. The specification is measured and guaranteed across –40°C to +125°C junction temperature and is explicitly stated in the Electrical Characteristics table under "Matching".

Can MIC2845A-PGYMT-TR drive more than 20mA per channel?

Yes-the MIC2845A-PGYMT-TR can drive more than 20mA per channel by selecting a lower RSET resistor value. For example, a 10.25kΩ resistor sets 40mA per channel at 100% duty cycle (using I_LED = 410 × D / R_SET). However, thermal limits must be observed: total power dissipation rises linearly with current, and the 2.5mm × 2.5mm Thin MLF® package has θ_JA = 89°C/W. At 40mA per channel and 3.8V input, continuous operation requires careful PCB thermal design and may necessitate derating above 30mA per channel in enclosed environments.

What is the minimum PWM duty cycle supported by MIC2845A-PGYMT-TR at 1kHz?

At 1kHz PWM frequency, the MIC2845A-PGYMT-TR supports a minimum duty cycle of 1%, as confirmed in the Application Information section and Figure 3 of the datasheet. This enables deep dimming for low-light user interfaces without visible flicker. The Ultra Fast PWM™ control block ensures accurate average current reproduction down to this level, maintaining ±1.5% current accuracy even at 1% duty cycle-critical for nighttime usability in mobile handsets and GPS devices.

Does MIC2845A-PGYMT-TR require external capacitors, and what values are mandatory?

Yes-MIC2845A-PGYMT-TR requires three mandatory ceramic capacitors: a minimum 1µF X5R/X7R capacitor between VIN and GND; and separate 1µF capacitors from LDO1 and LDO2 outputs to GND. These are specified in the Pin Description, Layout Recommendations, and LDO Electrical Characteristics sections. Using less than 1µF on any of these nodes risks instability, excessive output ripple, or startup failure. The datasheet explicitly states "stable with 1µF ceramic output capacitor" and warns against Y5V/Z5U dielectrics due to capacitance loss over temperature.