Microchip Technology MIC4801YM

Overview

MIC4801YM from Micrel is a single-channel linear white LED (WLED) driver delivering up to 600mA constant current with ±1% typical accuracy, 130mV dropout at 400mA, and Ultra Fast PWM™ dimming support from 200Hz to 500kHz. It operates from 3.0V to 5.5V input and drives high-power LEDs directly from battery voltage-eliminating switching noise and losses in billboards, marquee displays, and instrument panels.

For engineers reviewing the MIC4801YM datasheet, MIC4801YM pinout, MIC4801YM application, or MIC4801YM equivalent, key selection criteria include dropout voltage under load, PWM frequency/duty cycle linearity, RSET-based current programming accuracy, thermal performance in SOIC-8 at TJ = –40°C to +125°C, and EN-pin dual-role functionality for enable and dimming control.

Technical Context

The MIC4801YM implements a precision current mirror architecture referenced to an internal 1.27V RSET voltage, enabling programmable LED current via external resistor with K-factor compensation (0.140kΩ offset). Its linear topology avoids inductive boost or charge-pump switching losses, achieving high efficiency only when VIN–VLED margin exceeds dropout.

Ultra Fast PWM™ dimming operates through the EN pin, supporting logic-level inputs (VIH ≥ 1.2V, VIL ≤ 0.2V) with sub-1% minimum duty cycle at 200Hz and non-linear current response above 20kHz due to propagation delay. Standby-to-on delay is 2µs; shutdown-to-on is 40–60µs; transient rise/fall times are 1µs/0.3µs.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (M), surface-mount, JEDEC MS-012AC compliant, θJA = 98.9°C/W, rated for –40°C to +125°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AL8805W-7 and TPS61165DRVR, the MIC4801YM delivers superior current accuracy (±1% vs. ±4%), zero EMI, and simpler layout-but requires sufficient VIN–VLED margin. It is the optimal choice for single-WLED, noise-critical, space-constrained applications within its voltage window.

Availability

MIC4801YM is available at Aetrix Electronics and suitable for billboard displays, marquee signage, and instrument panel backlighting requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MIC4801YM 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 founded in 1978 and acquired by Microchip Technology in 2015; known for high-performance power management, timing, and interface ICs.

The MIC4801YM belongs to Micrel's linear LED driver product line, engineered specifically for high-accuracy, low-noise, single-channel WLED biasing in commercial signage and instrumentation where EMI and thermal stability are critical.

FAQ

What is the maximum LED current supported by the MIC4801YM?

The MIC4801YM supports a maximum continuous LED current of 600mA. This rating is specified under thermal conditions that maintain junction temperature within –40°C to +125°C, with proper PCB copper area and airflow. At 400mA, the dropout voltage is 130mV typical; current regulation remains accurate (±1% typical) across the full 0–600mA range when configured with appropriate RSET and thermal design. The MIC4801YM does not support peak currents beyond 600mA.

How does the MIC4801YM implement PWM dimming?

The MIC4801YM uses its EN pin for PWM dimming: applying a logic-level PWM signal directly controls LED brightness without external circuitry. It supports frequencies from 200Hz to 500kHz, with linear 1%–100% current control below 20kHz and non-linear response above due to internal propagation delay. A minimum 60µs high pulse is required to wake from sleep mode before dimming begins. The MIC4801YM does not require separate dimming pins or external transistors.

What is the purpose of the RSET pin on the MIC4801YM?

The RSET pin on the MIC4801YM provides access to an internal 1.27V reference voltage used to program LED current via an external resistor to GND. Using the formula ILED (mA) ≈ 4920 × D / (RSET(kΩ) – 0.140), designers set precise average current (e.g., 12.1kΩ yields ~416mA at 100% duty). The RSET pin enables accurate, resistor-based current scaling without trimming or digital interfaces-making the MIC4801YM ideal for cost-sensitive, high-volume display applications.

Can the MIC4801YM operate from a 3.3V supply?

Yes, the MIC4801YM operates from 3.0V to 5.5V, so a 3.3V supply is fully supported. However, usable LED forward voltage is limited by dropout: at 400mA, dropout is 130mV typical, meaning the maximum VLED is ~3.17V. For higher-VLED LEDs (e.g., 3.6V), VIN must be increased to ≥3.73V. Always verify VLED + dropout ≤ VIN across temperature and current extremes. The MIC4801YM's low dropout makes it uniquely viable for 3.3V-powered single-WLED applications where boost drivers would add noise and complexity.

What thermal considerations apply to the MIC4801YM in SOIC-8 package?

The MIC4801YM in SOIC-8 has θJA = 98.9°C/W. Power dissipation is calculated as PLOSS = ILED × VD1, where VD1 is the voltage across the D1 pins (≈ VIN – VLED). At 600mA and 500mV dropout, PLOSS = 0.3W, causing ~29.7°C rise above ambient. To keep TJ ≤ 125°C, ambient must stay ≤ 95°C with standard 2-layer PCB copper. Layout best practices include connecting all four D1 pins, using thermal vias under the exposed pad (if present), and minimizing trace resistance. The MIC4801YM's –40°C to +125°C rating assumes adherence to these thermal guidelines.