Microchip Technology MIC5265-1.5YD5

Overview

MIC5265-1.5YD5 from Micrel is a 150mA low-dropout linear regulator with fixed 1.5V output, designed for noise-sensitive RF and portable digital systems powered by single-cell Li-ion or 3.3V/5V rails. It features 210mV dropout at full load, 57µV_rms output noise, 60dB PSRR at 1kHz, and active shutdown with zero off-mode current.

For engineers reviewing the MIC5265-1.5YD5 datasheet, MIC5265-1.5YD5 pinout, MIC5265-1.5YD5 application, or MIC5265-1.5YD5 equivalent, key selection criteria include low-noise power delivery for RF synthesizers, fast transient response for digital core switching, ceramic capacitor compatibility, and thermal performance in Thin SOT-23-5 footprint constrained designs.

Technical Context

The MIC5265-1.5YD5 integrates a CMOS-based error amplifier, reference bypass path, and active N-channel discharge MOSFET on the output. Its architecture enables stable regulation with 1µF ceramic output capacitors and supports fast load transients (5µs recovery) while maintaining <2% output voltage deviation.

It operates across 2.7V–5.5V input range with enable-controlled startup/shutdown, where EN logic high (≥1.6V) activates regulation and logic low (≤0.2V) forces shutdown and active output discharge via internal 500Ω discharge path.

Key Specifications

Pinout & Package

Package: Pb-free Thin SOT-23-5 (M5), 2.9mm × 1.6mm × 1.1mm body height, 235°C/W junction-to-ambient thermal resistance on minimum footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-1502E/MB and XC6206P152MR-G, the MIC5265-1.5YD5 uniquely combines RF-grade noise performance, active output discharge, and enable control in the same Thin SOT-23-5 package-making it the only option among the three qualified for cellular transceiver and GPS receiver power rails.

Availability

MIC5265-1.5YD5 is available at Aetrix Electronics and suitable for cellular telephones, GPS receivers, and portable medical sensor nodes requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MIC5265-1.5YD5 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.

The MIC5265 family was developed for cost-sensitive, space-constrained portable electronics requiring high PSRR, low noise, and fast transient response-particularly targeting RF front-end and digital baseband power domains.

FAQ

What is the maximum input voltage rating for the MIC5265-1.5YD5?

The MIC5265-1.5YD5 has an absolute maximum input voltage rating of +7V, but its specified operating input range is +2.7V to +5.5V. Exceeding 5.5V may cause permanent damage or unpredictable behavior. For reliable operation in single-cell Li-ion applications, the 2.7V–5.5V range ensures compatibility with battery voltages from fully charged (4.2V) to deeply discharged (2.7V), while maintaining regulation at the 1.5V output.

Does the MIC5265-1.5YD5 require an external bypass capacitor, and what value is recommended?

Yes, the MIC5265-1.5YD5 includes a dedicated BYP pin to reduce output noise by bypassing the internal reference. A 0.01µF ceramic capacitor connected from BYP to GND is recommended for RF applications to achieve the specified 57µV_rms noise and maximize PSRR. Larger values up to 1.0µF further improve noise suppression but slightly increase turn-on time; the device's quick-start circuit mitigates this delay effectively.

How does the active shutdown feature of the MIC5265-1.5YD5 function during disable?

When the EN pin is driven low, the MIC5265-1.5YD5 enters zero-current shutdown and activates an internal N-channel MOSFET between OUT and GND. This 500Ω discharge path rapidly depletes the output capacitor voltage, preventing residual energy from powering downstream circuitry-a critical requirement for proper power sequencing in cellular and GPS modules. The discharge occurs independently of load conditions and is confirmed in the functional characteristics section of the datasheet.

Can the MIC5265-1.5YD5 operate stably with zero load current?

Yes, the MIC5265-1.5YD5 maintains regulation and stability with no load-unlike many LDOs that require minimum load for loop stability. This capability is explicitly documented in the Applications Information section and is essential for applications such as RAM keep-alive circuits, real-time clocks, or sensor biasing in ultra-low-power sleep modes where load current drops to near-zero between measurement cycles.

What thermal derating applies to the MIC5265-1.5YD5 in a standard Thin SOT-23-5 layout?

In a minimum-footprint PCB layout, the MIC5265-1.5YD5 has a junction-to-ambient thermal resistance (θ_JA) of 235°C/W. At 150mA load with a 5.0V input and 1.5V output, power dissipation is ~0.525W, limiting maximum ambient temperature to ~47°C before thermal shutdown (T_J(max) = 125°C). To extend thermal headroom, increase copper area around the pad or use thermal vias-Micrel specifies θ_JA = 145°C/W with 1"² copper cladding.