Diodes Incorporated APX803S05-31SA-7

Overview

APX803S05-31SA-7 from Diodes Incorporated is a 3-pin SOT23 open-drain microprocessor reset supervisor IC designed for 3.08 V ±0.05 V supply monitoring in embedded digital systems. It asserts an active-low RESET signal during power-up, brownout, or voltage sag below threshold and maintains it for 50 ms (typ.) after VCC recovers. Its 10 µA supply current, guaranteed operation down to VCC = 1 V, and immunity to fast transients make it suitable for portable and battery-powered microcontroller applications.

For engineers reviewing the APX803S05-31SA-7 datasheet, APX803S05-31SA-7 pinout, APX803S05-31SA-7 application, or APX803S05-31SA-7 equivalent, key selection criteria include reset threshold accuracy (3.04–3.13 V), timeout duration (20–70 ms), open-drain output compatibility with bidirectional µP reset pins, and low-voltage validity (VCC ≥ 1 V).

Technical Context

The APX803S05-31SA-7 implements a precision bandgap-based voltage comparator with internal hysteresis to detect VCC drops below 3.08 V (25°C), triggering an open-drain RESET output. Its internal timer initiates only after VCC rises above threshold, enforcing a fixed 50 ms (typ.) reset hold time independent of supply ramp rate.

Designed for robustness in noisy environments, the device rejects transients via dVCC/dt immunity up to 100 V/µs and guarantees logic-correct RESET state across –40°C to +85°C. The output remains functional down to VCC = 1 V, with leakage <1 µA when high and VOL ≤ 0.4 V at 3.5 mA sink.

Key Specifications

Pinout & Package

APX803S05-31SA-7 is housed in a RoHS-compliant SOT23-3 (SA) package with gull-wing leads, 2.4 mm × 1.3 mm footprint, and 0.915 mm height. Thermal resistance θJA is 232°C/W, supporting operation up to +85°C ambient without heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809SEUR+T and TPS3808G33DBVR, the APX803S05-31SA-7 offers optimal balance of fixed 50 ms timing, open-drain flexibility, and 10 µA consumption-making it ideal for cost-sensitive, space-constrained portable and industrial controllers where deterministic, short-duration reset is critical.

Availability

APX803S05-31SA-7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, and smart energy meters requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for APX803S05-31SA-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 APX803S series belongs to Diodes' supervisory IC product line, engineered specifically for low-cost, low-power microprocessor reset functions in space-constrained embedded systems operating across extended temperature ranges.

FAQ

What is the exact reset threshold voltage for APX803S05-31SA-7 at 25°C?

The reset threshold is specified as 3.04 V (min), 3.08 V (typ.), and 3.13 V (max) at +25°C per DS39161 Rev. 2–2, Table 1. This 3.08 V nominal value targets 3.3 V supply rails with ±3% tolerance, ensuring reset assertion before µP operational failure.

Does APX803S05-31SA-7 require an external pull-up resistor on the RESET pin?

Yes - the RESET pin is open-drain active-low and must be pulled up externally to a valid logic-high voltage (e.g., VCC or another supply). Typical values range from 10 kΩ to 100 kΩ; lower values improve noise immunity but increase static current.

Can APX803S05-31SA-7 operate reliably below 1.0 V VCC?

No - the device guarantees correct RESET logic state only down to VCC = 1.0 V. Below this, the output becomes high-impedance and cannot sink current; most µPs are non-functional below 1.0 V, so this limitation aligns with system-level power collapse behavior.

How does the 50 ms reset timeout differ from the 240 ms variant in the APX803S family?

The APX803S05-31SA-7 delivers a 50 ms (typ.) timeout versus 240 ms (typ.) for standard APX803S-31SA-7. This shorter duration reduces boot latency in applications like portable instruments where rapid wake-up after brownout is essential, without compromising µP initialization stability.