Diodes Incorporated PT7M8218B28TAEX

Overview

PT7M8218B28TAEX from Pericom Semiconductor is a 2.8V fixed-output, 300mA low-dropout linear regulator featuring 150mV dropout at 150mA, ±2% initial output accuracy, 75dB PSRR at 1kHz, and 36µA quiescent current. It operates from 1.7V to 5.5V input, supports 0.47µF ceramic output capacitors, and integrates thermal shutdown, current limiting, and auto output discharge - deployed in mobile RF front-ends and portable audio subsystems.

For engineers reviewing the PT7M8218B28TAEX datasheet, PT7M8218B28TAEX pinout, PT7M8218B28TAEX application, or PT7M8218B28TAEX equivalent, key selection criteria include dropout voltage under load, PSRR performance at baseband frequencies, EN pin logic polarity (high-active), output capacitor compatibility with X5R/X7R ceramics, and thermal behavior across –40°C to +85°C ambient.

Technical Context

The PT7M8218B28TAEX uses a P-channel MOSFET pass element controlled by an error amplifier comparing feedback against an internal reference. Its internal phase compensator enables stability with 0.47µF low-ESR ceramic capacitors on both input and output, eliminating need for external compensation networks.

EN pin logic is high-active with V_ENH ≥1.2V and V_ENL ≤0.3V; when disabled, the device engages auto output discharge via a 50Ω internal path. Protection includes foldback current limiting (400mA typical trip) and thermal shutdown at 170°C with 20°C hysteresis.

Key Specifications

Pinout & Package

PT7M8218B28TAEX is packaged in lead-free, RoHS-compliant SOT23-5L (JEDEC MO-178C/AA) - 2.9mm × 1.6mm footprint, 0.95mm pitch, 1.2mm height - optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6206P282MR and RT9193-28GB, PT7M8218B28TAEX uniquely combines high PSRR (75dB), auto-discharge, and high-active EN in a 5-pin SOT23 package - critical for RF-sensitive, sequenced portable systems where noise, startup timing, and reset integrity are co-dependent.

Availability

PT7M8218B28TAEX is available at Aetrix Electronics and suitable for mobile RF front-ends, digital camera ISP supplies, and portable audio codec rails requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for PT7M8218B28TAEX 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

Pericom Semiconductor (now part of Diodes Incorporated) specialized in high-performance analog and mixed-signal ICs for communications, computing, and consumer electronics before its 2016 acquisition.

The PT7M8218 belongs to Pericom's precision LDO family targeting battery-powered portable devices - engineered for ultra-low noise, high PSRR, and minimal external components in space-constrained RF and imaging subsystems.

FAQ

What is the minimum input voltage required to maintain 2.8V output at 300mA?

The datasheet specifies 150mV dropout at 150mA for V_OUT = 2.8V. At full 300mA, typical dropout rises to ~180mV based on load regulation curves. Therefore, minimum input is 2.8V + 0.18V = 2.98V. For guaranteed 300mA operation across temperature and process variation, 3.0V input is recommended.

Can PT7M8218B28TAEX be used with 1µF output capacitors instead of 0.47µF?

Yes - the device remains stable with 1µF X5R/X7R ceramics, though 0.47µF is the minimum validated value. Larger capacitance improves load transient response and reduces output ripple, but adds cost and board area. No recompensation is needed; stability margin increases slightly with higher C_OUT.

Is the NC pin (Pin 4) electrically isolated or internally tied?

Pin 4 is confirmed as no-connect: not bonded to any internal circuitry. The datasheet explicitly states it may be left open or tied to GND. No internal connection exists - tying to GND improves mechanical anchoring and reduces potential antenna effects, but has no electrical impact on regulation or protection functions.

Does PT7M8218B28TAEX support reverse current blocking?

No - the device uses a P-channel MOSFET pass element, which inherently lacks reverse-current blocking capability. If input voltage drops below output (e.g., during hot-swap or battery swap), current can flow backward from V_OUT to VIN through the body diode. External reverse-blocking diode or ideal diode controller is required for such use cases.