Diodes Incorporated APX809-40SRG-7

Overview

APX809-40SRG-7 from Diodes Incorporated is a 3-pin microprocessor reset supervisor IC with active-low push-pull RESET output, 4.00 V ±0.07 V precision reset threshold, 200 ms typical reset timeout, and guaranteed operation down to VCC = 1 V. It monitors 5 V or 3.3 V power rails in embedded controllers and portable systems to prevent erroneous code execution during brownout or power-up.

For engineers reviewing the APX809-40SRG-7 datasheet, APX809-40SRG-7 pinout, APX809-40SRG-7 application, or APX809-40SRG-7 equivalent, key selection criteria include reset threshold accuracy (±0.07 V at 4.00 V), low 30 µA supply current, SOT23-3 package compatibility, and guaranteed valid reset assertion across -40°C to +85°C ambient.

Technical Context

The APX809-40SRG-7 implements a precision voltage comparator with internal reference and fixed-delay timer to generate a clean, glitch-immune reset pulse. Its reset threshold is trimmed to 4.00 V (min 3.93 V, max 4.08 V) over temperature, with tempco ≤30 ppm/°C.

It features a push-pull output stage that actively drives RESET low during fault conditions and high after timeout - no external pull-up required. The device remains functional and asserts valid logic states for VCC ≥1 V, and ignores fast transients on VCC via built-in noise immunity.

Key Specifications

Pinout & Package

SOT23-3 (SR package) - surface-mount, 2.9 mm × 1.3 mm × 1.0 mm body, gull-wing leads, RoHS-compliant "Green" molding compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3-T and TPS3808G33DBVR, the APX809-40SRG-7 delivers tighter threshold tolerance (±0.07 V vs ±2%), eliminates external components, and provides stronger noise-immune reset drive - making it optimal for cost-sensitive, space-constrained 5 V embedded designs.

Availability

APX809-40SRG-7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, and network edge routers requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for APX809-40SRG-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 series belongs to Diodes' microprocessor supervisory product line, designed specifically for cost-effective, zero-component power-on reset and brownout detection in resource-constrained embedded systems.

FAQ

What is the minimum VCC voltage at which APX809-40SRG-7 guarantees valid RESET assertion?

The APX809-40SRG-7 guarantees correct logic state on the RESET pin for VCC ≥1 V. Below 1 V, the output becomes high-impedance; however, most microprocessors are non-functional below this voltage, so system-level behavior remains predictable. No external pull-down is required unless VCC <1 V operation is explicitly needed.

Does APX809-40SRG-7 require an external capacitor for reset timing?

No. The APX809-40SRG-7 integrates a precision internal timer that generates a fixed 200 ms typical reset timeout after VCC rises above the 4.00 V threshold. This eliminates the need for external timing capacitors, reducing BOM count, PCB area, and calibration risk.

Can APX809-40SRG-7 be used with a 3.3 V supply rail?

Yes - the device operates from 1.1 V to 5.5 V and is commonly used with 3.3 V rails. However, its 4.00 V reset threshold means it will assert reset only when the 3.3 V rail exceeds specification (i.e., during overvoltage). For 3.3 V brownout detection, select APX809-31SRG-7 (3.08 V threshold) instead.

Is APX809-40SRG-7 pin-compatible with other APX809 variants?

Yes - all APX809 variants (e.g., -23SRG-7, -31SRG-7, -40SRG-7) share identical SOT23-3 pinout (VCC, GND, RESET), same footprint, and identical electrical interface. Only the reset threshold differs; no layout or schematic changes are needed when selecting alternate thresholds.