Diodes Incorporated APX809-31SAG-7

Overview

APX809-31SAG-7 from Diodes Incorporated is a 3-pin microprocessor reset supervisor IC with active-low push-pull RESET output, precision 3.08 V reset threshold (±0.07 V over -40°C to +85°C), 200 ms typical reset timeout, 30 µA supply current, and guaranteed operation down to VCC = 1 V. It monitors 3.3 V digital power rails in embedded controllers and portable systems to prevent erroneous code execution during brownout or power-up.

For engineers reviewing the APX809-31SAG-7 datasheet, APX809-31SAG-7 pinout, APX809-31SAG-7 application, or APX809-31SAG-7 equivalent, key selection criteria include reset threshold accuracy, low-VCC validity, push-pull drive strength, SOT23 footprint compatibility, and RoHS-compliant green packaging.

Technical Context

The APX809-31SAG-7 integrates a precision voltage comparator with internal reference and a monostable timer to generate a clean, glitch-immune reset pulse. Its reset assertion is triggered when VCC falls below 3.08 V and held for ≥240 ms after VCC rises above threshold.

Designed for single-supply monitoring, it operates across 1.1–5.5 V input range, ignores fast transients on VCC, and guarantees correct logic state of RESET output down to VCC = 1 V - enabling reliable reset signaling even during deep brownouts.

Key Specifications

Pinout & Package

SOT23-3 (SA package) surface-mount package with 2.4 mm × 1.3 mm footprint, 0.95 mm height, and lead-free green molding compound compliant with RoHS, halogen-free, and antimony-free standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3T and TPS3808G30DBVR, the APX809-31SAG-7 delivers identical timing and threshold while eliminating external components and offering superior ESD immunity - making it optimal for cost-sensitive industrial PCBs with moderate power constraints.

Availability

APX809-31SAG-7 is available at Aetrix Electronics and suitable for industrial controllers, portable medical devices, and smart energy meters requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for APX809-31SAG-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, engineered specifically for deterministic power-on and brownout reset in space-constrained, cost-sensitive embedded systems with 3.3 V and 5 V rails.

FAQ

What is the minimum VCC required for APX809-31SAG-7 to assert a valid RESET signal?

The APX809-31SAG-7 guarantees correct RESET logic state down to VCC = 1 V. Below 1 V, the output enters high-impedance mode and no longer actively sinks current. This design ensures reset remains asserted through deep brownouts while avoiding false releases during marginal supply conditions.

Does APX809-31SAG-7 require an external capacitor for reset timing?

No. The 200 ms 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 RC networks - simplifying layout and improving long-term reliability.

Can APX809-31SAG-7 be used with a 2.5 V supply rail?

No. The APX809-31SAG-7 is specified for 3.08 V threshold and requires VCC ≥ 1.1 V to operate, but its reset function activates only when VCC crosses 3.08 V. For 2.5 V systems, use APX809-23SAG-7 (2.25 V threshold) or APX809-26SAG-7 (2.63 V threshold) instead.

Is APX809-31SAG-7 pin-compatible with other APX809 variants?

Yes. All APX809 variants (e.g., -23, -26, -29, -31, -40, -44, -46) share identical SOT23-3 pinout (VCC, GND, RESET), same electrical interface, and identical timing characteristics - enabling drop-in voltage-threshold replacement without layout changes.