Diodes Incorporated APX803S-40SA-7

Overview

APX803S-40SA-7 from Diodes Incorporated is a 3-pin SOT23 microprocessor reset supervisor IC with 4.00 V ±0.06 V precision reset threshold, open-drain active-low RESET output, 240 ms minimum reset timeout, 10 µA typical supply current, and guaranteed operation down to VCC = 1.0 V. It monitors 5.0 V digital systems during power-up, brownout, and supply glitches to ensure reliable µP initialization in embedded controllers and portable equipment.

For engineers reviewing the APX803S-40SA-7 datasheet, APX803S-40SA-7 pinout, APX803S-40SA-7 application, or APX803S-40SA-7 equivalent, key selection criteria include reset threshold accuracy (±2.5%), temperature coefficient (30 ppm/°C), open-drain drive capability (1.2 mA sink at 0.3 V), fixed 240 ms timeout, and SOT23-SA package compatibility with space-constrained PCB layouts.

Technical Context

The APX803S-40SA-7 integrates a precision voltage comparator with hysteresis and an internal timer to generate a deterministic reset pulse. Its comparator ignores fast transients on VCC (dVCC/dt ≤ 100 V/µs) and maintains valid logic state for VCC ≥ 1.0 V.

The device asserts RESET low when VCC falls below 3.94–4.06 V and holds it active for ≥140 ms (typ. 240 ms) after VCC rises above threshold. The open-drain output requires an external pull-up resistor and supports level-shifting across supply domains.

Key Specifications

Pinout & Package

SOT23-3 (SA package): ultra-compact surface-mount plastic package with 2.4 mm × 1.3 mm footprint, 0.915 mm height, and thermal resistance θJA = 232 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with APX803S-40SA-7, the APX809S-40SA-7 simplifies BOM by removing the pull-up resistor, while the MAX809SEUR+T offers superior ultra-low-power performance but requires PCB revision due to non-identical pin assignment and different reset output architecture.

Availability

APX803S-40SA-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 APX803S-40SA-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 devices for industrial, computing, and consumer markets.

The APX803S series belongs to Diodes' microprocessor supervisory product line, engineered specifically for cost-sensitive, space-constrained applications requiring precise voltage monitoring and deterministic reset timing without external components.

FAQ

What is the exact reset threshold voltage for APX803S-40SA-7?

The APX803S-40SA-7 has a guaranteed reset threshold of 3.94 V (min), 4.00 V (typ), and 4.06 V (max) at +25°C, with ±2.5% total tolerance including temperature drift up to 30 ppm/°C across –40°C to +85°C.

Can APX803S-40SA-7 drive a 10 kΩ pull-up resistor to 5.0 V?

Yes - the open-drain RESET output sinks ≥1.2 mA at VOL ≤ 0.3 V when VCC ≥ VTH – 0.2 V, supporting standard 10 kΩ pull-ups to 5.0 V with <0.3 V logic low and full noise margin for CMOS inputs.

Does APX803S-40SA-7 require an external capacitor for timing?

No - the 240 ms reset timeout is generated by an internal precision timer; no external RC network or capacitor is needed, reducing BOM count and improving reliability versus discrete reset circuits.

Is APX803S-40SA-7 compatible with bidirectional µP reset pins?

Yes - its open-drain output allows direct connection to bidirectional reset pins (e.g., Motorola 68HC11) using a single pull-up resistor, enabling either the supervisor or µP to assert reset without contention or level-shifting circuitry.