Diodes Incorporated APX803S-44SR-7

Overview

APX803S-44SR-7 from Diodes Incorporated is a 3-pin SOT23 open-drain microprocessor reset supervisor IC designed for 4.38 V ±0.07 V supply monitoring. It asserts an active-low RESET signal during power-up, brownout, or VCC drop below threshold, with guaranteed reset validity down to VCC = 1 V and a typical timeout of 240 ms. Used in portable controllers and embedded systems requiring reliable power-on initialization.

For engineers reviewing the APX803S-44SR-7 datasheet, APX803S-44SR-7 pinout, APX803S-44SR-7 application, or APX803S-44SR-7 equivalent, key selection criteria include reset threshold accuracy (4.31–4.45 V), open-drain output compatibility with bidirectional µP reset pins, low 10 µA supply current, and SOT23-SR package footprint alignment with space-constrained PCB layouts.

Technical Context

The APX803S-44SR-7 integrates a precision voltage comparator with internal hysteresis and a fixed-delay timer. Its reset assertion logic responds to VCC falling below 4.38 V (typ.) and holds RESET low for ≥140 ms after VCC rises above threshold, with typical timeout at 240 ms.

Designed for single-supply monitoring, it features open-drain output with guaranteed sink capability up to 3.5 mA at VCC ≥ VTH −0.2 V and leakage <1 µA when high. The comparator ignores fast transients and remains functional down to VCC = 1 V, ensuring deterministic reset behavior across temperature (−40°C to +85°C).

Key Specifications

Pinout & Package

APX803S-44SR-7 is housed in a RoHS-compliant SOT23-3 (SR variant) package with gull-wing leads, 2.9 mm × 1.3 mm footprint, and 0.95 mm height. Pin 1 = GND, Pin 2 = VCC, Pin 3 = RESET (open-drain active-low).

Key Features

Applications

Equivalent & Alternatives

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

Compared with APX803S-44SR-7, the APX809S-44SA-7 offers push-pull drive for simpler routing but sacrifices bus-sharing flexibility, while the MAX809TRD2T provides pin compatibility at the cost of reduced threshold accuracy and higher quiescent current-making APX803S-44SR-7 optimal for low-power, multi-device reset networks.

Availability

APX803S-44SR-7 is available at Aetrix Electronics and suitable for industrial controllers, portable medical instrumentation, and smart energy metering requiring stable component supply with guaranteed long-term continuity.

Supply support for APX803S-44SR-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 and consumer markets.

The APX803S series belongs to Diodes' µP supervisory product line, engineered specifically for cost-sensitive, space-constrained embedded systems needing precise, low-power reset functionality without external components.

FAQ

What is the exact reset threshold voltage for APX803S-44SR-7?

The APX803S-44SR-7 has a guaranteed reset threshold range of 4.31 V to 4.45 V at +25°C, with a typical value of 4.38 V. This specification is fully characterized across −40°C to +85°C ambient temperature and includes a maximum tempco of 30 ppm/°C, ensuring stable operation in industrial environments without recalibration.

Can APX803S-44SR-7 drive multiple microcontrollers on a shared reset bus?

Yes-the open-drain RESET output allows direct wired-OR connection with other open-drain reset sources (e.g., watchdog timers or manual reset buttons) using a single pull-up resistor. This configuration ensures any device can assert reset independently, making it ideal for multi-IC systems requiring coordinated initialization or fault recovery.

Does APX803S-44SR-7 remain functional when VCC drops below 1.0 V?

No-while the device guarantees correct RESET logic state down to VCC = 1.0 V, its internal circuitry ceases operation below that level. At VCC < 1.0 V, the RESET pin becomes high-impedance and no longer sinks current; however, this aligns with µP inactivity at such low voltages, eliminating risk of undefined reset states in real-world systems.

How does the APX803S-44SR-7 handle fast voltage transients on VCC?

The internal reset comparator incorporates built-in noise immunity to reject transients ≤100 ns duration, per the dVCC/dt rating of 100 V/µs. This prevents false resets caused by switching noise or ESD-induced spikes, ensuring reset assertion occurs only during sustained supply droops that genuinely threaten µP stability.