Diodes Incorporated APX809-44SRG-7

Overview

APX809-44SRG-7 from Diodes Incorporated is a 3-pin microprocessor reset supervisor IC with active-low push-pull RESET output, precision 4.38 V reset threshold (±0.07 V over temperature), 200 ms typical reset timeout, 30 µA supply current, and guaranteed operation down to VCC = 1 V. It monitors 5 V power rails in embedded controllers and portable systems to prevent erroneous microprocessor startup during brownout.

For engineers reviewing the APX809-44SRG-7 datasheet, APX809-44SRG-7 pinout, APX809-44SRG-7 application, or APX809-44SRG-7 equivalent, key selection criteria include reset threshold accuracy at temperature extremes, push-pull drive capability without external pull-up, low quiescent current for battery operation, and SOT23-3 footprint compatibility with space-constrained PCB layouts.

Technical Context

The APX809-44SRG-7 integrates a precision voltage reference, comparator, and monostable timer in a single SOT23-3 package. Its reset assertion logic triggers when VCC falls below 4.38 V (min 4.29 V, max 4.47 V at −40°C to +85°C) and holds RESET low for ≥240 ms after VCC recovers above threshold.

Designed for direct connection to µP reset inputs, it features push-pull output capable of sinking 3.2 mA at 0.4 V and sourcing 500 µA while maintaining VOH ≥ 0.8×VCC - eliminating need for external pull-up resistors and ensuring deterministic logic states across full 1.1–5.5 V operating range.

Key Specifications

Pinout & Package

SOT23-3 (SR package) with 2.9 mm × 1.3 mm footprint, 0.95 mm height, and thermal resistance θJA = 201°C/W on standard FR-4 PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD2T1G and TPS3808G33DBVR, the APX809-44SRG-7 uniquely combines 5 V-specific 4.38 V threshold accuracy, push-pull drive eliminating external components, and sub-1 V reset validity - making it optimal for cost-sensitive, space-constrained 5 V microcontroller systems requiring deterministic brownout response.

Availability

APX809-44SRG-7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, and smart energy meters requiring stable component supply with long-term lifecycle support and consistent parametric performance.

Supply support for APX809-44SRG-7 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, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The APX809/810 series was designed specifically for cost-effective, space-efficient microprocessor reset supervision in battery-powered and industrial embedded systems - emphasizing precision threshold stability, ultra-low quiescent current, and SOT23-3 integration.

FAQ

What is the minimum VCC required for APX809-44SRG-7 to assert a valid RESET signal?

The APX809-44SRG-7 guarantees RESET remains a valid logic low down to VCC = 1 V. Below 1 V, the output enters high-impedance state; however, most µPs are non-operational below this voltage, so system-level impact is negligible. For applications requiring validity to 0 V, a 100 kΩ pull-down resistor on RESET is recommended.

Does APX809-44SRG-7 require an external capacitor for reset timing?

No. The 200 ms typical reset timeout is generated by an internal monostable circuit - no external timing capacitor or resistor is needed. This eliminates component variation, temperature drift, and PCB area associated with discrete RC networks, improving manufacturing yield and long-term reliability.

Can APX809-44SRG-7 be used with 3.3 V microcontrollers?

Yes, but only if the 3.3 V system uses a 5 V auxiliary rail for supervisor power. The APX809-44SRG-7 is configured for 4.38 V threshold and requires VCC ≥ 1.1 V to operate; it cannot monitor 3.3 V rails directly. For 3.3 V supervision, select APX809-31SRG-7 (3.08 V threshold) instead.

Is APX809-44SRG-7 compatible with lead-free reflow profiles?

Yes. The SR package is fully RoHS-compliant, halogen- and antimony-free, and rated for standard lead-free reflow profiles with peak temperatures up to 260°C. Its SOT23-3 footprint aligns with IPC-7351B density level A, supporting automated placement and reflow without special process adjustments.