Microchip Technology MIC5158YM

Overview

MIC5158YM from Micrel is a Super LDO™ Regulator Controller designed to drive external N-channel MOSFETs for high-current, ultralow-dropout linear regulation. It supports fixed 5V output or adjustable 1.3V–36V output via two external resistors, features an internal charge pump tripler (17.5V max clamp), 4.5mA typical operating current, and operates across –40°C to +85°C in 14-pin SOIC. It enables constant-current-limited 10A+ supplies in desktop computer power rails.

For engineers reviewing the MIC5158YM datasheet, MIC5158YM pinout, MIC5158YM application, or MIC5158YM equivalent, key selection criteria include gate-drive voltage headroom (VCP ≈ 3×VDD − 3V), 35mV current-limit threshold accuracy, 1.235V bandgap reference tolerance, enable input compatibility with TTL logic, and SOIC-14 thermal resistance (120°C/W).

Technical Context

The MIC5158YM implements a precision error amplifier referenced to a 1.235V bandgap, driving an external N-channel MOSFET gate through a charge-pump-powered output stage. Its internal 160kHz oscillator drives a three-stage voltage tripler (C1+/C1−/C2+/C2−/VCP) to generate gate drive up to 17.5V above VDD, enabling logic-level MOSFET enhancement even at low input voltages like 3.5V.

It integrates an open-collector FLAG output that asserts low when output voltage drops ≥8% below nominal (3% hysteresis), plus an EN input with 2.4V VIH and 0.8V VIL thresholds. Current limiting is implemented via a dedicated comparator monitoring VDD–D voltage drop, with 35mV threshold and no foldback behavior.

Key Specifications

Pinout & Package

Package: 14-pin SOIC (M), 120°C/W θJA, RoHS-compliant (Pb-free per MIC5158YM ordering code).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar regulator controller applications.

Compared with MIC5157BM and LT1581CS#PBF, the MIC5158YM uniquely combines adjustable output capability with integrated charge pump and sub-5mA operating current - making it optimal for compact, low-input-voltage, programmable high-current regulators where board space and supply simplicity are critical.

Availability

MIC5158YM is available at Aetrix Electronics and suitable for desktop computer power supplies, battery charging circuits, SMPS post-regulation, and high-current switching applications requiring stable component supply across industrial and computing product lifecycles.

Supply support for MIC5158YM 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 power management, timing, and interface ICs before its acquisition by Microchip Technology in 2015.

The MIC5158YM belongs to Micrel's Super LDO™ Regulator Controller family, engineered for high-current, ultralow-dropout linear regulation using external N-MOSFETs - targeting demanding applications in computing, industrial power, and battery systems.

FAQ

What output voltage options does the MIC5158YM support?

The MIC5158YM supports two configurations: fixed 5V output (by connecting the 5V FB pin to the EA pin) or adjustable output from 1.3V to 36V (using an external resistor divider from S to EA). It does not support 3.3V or 12V fixed outputs - those are exclusive to the MIC5157. The 1.235V internal bandgap reference enables precise adjustment with standard 1% resistors.

How does the MIC5158YM generate gate drive voltage for the external MOSFET?

The MIC5158YM uses an internal 160kHz charge pump tripler to generate gate drive voltage (VCP), approximated as VCP ≈ 3×(VDD − 1V) and clamped to a maximum of 17.5V above VDD. This eliminates the need for an external gate drive supply. Three external capacitors are required: two 0.1µF pump caps (C1+, C1−, C2+, C2−) and one 1–10µF reservoir cap (VCP to GND).

What is the purpose and accuracy of the FLAG output on the MIC5158YM?

The FLAG output is an open-collector fault indicator that pulls low when the regulated output falls to 92% or less of its nominal value, with 3% hysteresis to prevent oscillation. Its saturation voltage is ≤0.2V at 1mA sink current. This allows direct interfacing with microcontroller GPIOs or supervisor ICs for system-level fault detection and shutdown sequencing in the MIC5158YM design.

Can the MIC5158YM be used without current limiting, and how is it disabled?

Yes - current limiting is optional and disabled by omitting the external sense resistor (RS) between VDD and the D pin. In this configuration, the MIC5158YM operates as a pure voltage regulator controller. When RS is present, the device limits output current by holding VDD–D at 35mV (typical); removing RS disables this function entirely, allowing unrestricted current flow subject only to MOSFET and thermal limits.

What thermal considerations apply to the MIC5158YM in SOIC-14 package?

The MIC5158YM in SOIC-14 (M) package has a junction-to-ambient thermal resistance (θJA) of 120°C/W. At 4.5mA operating current and 12V VDD, power dissipation is ~54mW - resulting in <7°C junction rise above ambient. However, under heavy gate-drive loading (e.g., driving large MOSFETs at high frequency), ensure adequate PCB copper area under the exposed pad (if present) and avoid enclosing the device in thermally restrictive enclosures to maintain reliability within the –40°C to +85°C range.