Diodes Incorporated PT7M7809MTEX

Overview

PT7M7809MTEX from Diodes Incorporated is a precision μP supervisor IC with 4.38V reset threshold, 200ms reset pulse width, push-pull active-low RESET output, and guaranteed operation down to VCC = 1.0V. It monitors power supply integrity during power-up, brownout, and power-down in embedded microprocessor systems, providing reliable reset assertion for industrial controllers and network edge devices.

For engineers reviewing the PT7M7809MTEX datasheet, PT7M7809MTEX pinout, PT7M7809MTEX application, or PT7M7809MTEX equivalent, key selection criteria include reset threshold accuracy (±2.5% over –40°C to +85°C), manual-reset compatibility, SOT23-3 package footprint, and absence of watchdog or manual-reset inputs-making it suitable for cost-sensitive, single-supply monitoring where only voltage supervision is required.

Technical Context

The PT7M7809MTEX implements a precision bandgap-based voltage reference and comparator to detect VCC falling below 4.38V (VRN), asserting RESET low until VCC rises above VRN + hysteresis and remains stable for 200ms. Its internal timer ensures deterministic reset timing independent of external RC components.

No watchdog or manual-reset circuitry is integrated-this variant is functionally simplified versus PT7M7811/7823 families. The push-pull RESET driver delivers VOL ≤ 0.4V at 3.2mA sink current and supports direct interfacing with standard CMOS microcontroller reset inputs without pull-up resistors.

Key Specifications

Pinout & Package

SOT23-3 surface-mount package (3-pin, 1.3mm × 2.9mm footprint) with gull-wing leads; compatible with standard reflow profiles and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervision applications.

Compared with MAX809SEUR+T and TPS3809K33DBVR, PT7M7809MTEX uniquely combines 4.38V threshold accuracy, 1.0V operational floor, and sub-15µA quiescent current-making it optimal for legacy 5V industrial designs requiring extended brownout coverage without added complexity.

Availability

PT7M7809MTEX is available at Aetrix Electronics and suitable for industrial PLC controllers, network edge routers, and embedded security gateways requiring stable component supply across multi-year production cycles.

Supply support for PT7M7809MTEX 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and Malaysia.

The PT7M78xx family targets high-reliability power-supply monitoring in microprocessor systems, emphasizing precision threshold accuracy, wide VCC operating range, and minimal external component count for embedded control applications.

FAQ

Does PT7M7809MTEX support manual reset functionality?

No. PT7M7809MTEX lacks MR (manual reset) input pin and internal pull-up resistor-unlike PT7M7811 or PT7M7824 variants. It provides only voltage-monitoring reset triggered by VCC crossing the 4.38V threshold. Manual reset must be implemented externally using a separate push-button switch and logic gate if required.

What is the minimum VCC required for RESET output validity?

RESET output is guaranteed valid down to VCC = 1.0V, with VOL ≤ 0.4V at 3.2mA sink current when VCC ≥ 4.5V. Below 1.0V, the device ceases operation and RESET state is undefined-this specification ensures reliable reset assertion during deep brownout recovery phases.

Can PT7M7809MTEX be used with a 3.3V microcontroller?

Yes, but only for monitoring a 5V supply rail. Its 4.38V threshold is designed for 5V systems. To supervise a 3.3V rail, use PT7M7803 (2.63V) or PT7M7809 variants with lower thresholds (e.g., PT7M7809T = 3.08V). Direct connection to a 3.3V MCU's nRST pin is safe since RESET is push-pull and compatible with 3.3V logic levels.

Is there a watchdog timer in PT7M7809MTEX?

No. PT7M7809MTEX contains no watchdog input (WDI) or associated timing circuitry. It is a dedicated voltage supervisor only. Watchdog functionality is present only in PT7M7811, PT7M7823, PT7M7824, and PT7M7825 variants, which include WDI pins and 1.6s timeout periods.