Diodes Incorporated APX803S-26SA-7

Overview

APX803S-26SA-7 from Diodes Incorporated is a 3-pin microprocessor reset supervisor IC with open-drain active-low RESET output, precision 2.63 V reset threshold (±0.04 V), 240 ms minimum reset timeout, 10 µA typical supply current, and guaranteed operation down to VCC = 1 V. It monitors 3.3 V digital systems in embedded controllers and portable equipment.

For engineers reviewing the APX803S-26SA-7 datasheet, APX803S-26SA-7 pinout, APX803S-26SA-7 application, or APX803S-26SA-7 equivalent, key selection criteria include reset threshold accuracy, timeout duration, open-drain drive capability, low-voltage validity (VCC ≥ 1 V), and SOT23-3 SA package compatibility with space-constrained PCB layouts.

Technical Context

The APX803S-26SA-7 implements a precision bandgap-based voltage comparator with 30 ppm/°C tempco and internal timer circuitry that asserts RESET low for ≥240 ms after VCC rises above 2.63 V. Its open-drain output requires an external pull-up resistor and supports bidirectional reset interfaces with microcontrollers like the Motorola 68HC11.

It rejects fast VCC transients via controlled dVCC/dt immunity (100 V/µs) and maintains valid logic state across –40°C to +85°C ambient. The device draws only 10 µA at 3.3 V and remains functional down to 1 V supply, enabling reliable brownout detection in battery-powered systems.

Key Specifications

Pinout & Package

APX803S-26SA-7 is housed in a RoHS-compliant, lead-free SOT23-3 (SA) package measuring 2.90 mm × 1.30 mm × 1.00 mm (L × W × H), with gull-wing leads and standard JEDEC MO-178 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with APX809S-26SA-7, the APX803S-26SA-7 enables shared reset buses and bidirectional interfaces; compared with MAX809TRD29+T, it delivers tighter threshold matching for 3.3 V systems and longer timeout for robust initialization under slow-ramp conditions.

Availability

APX803S-26SA-7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, smart energy meters, and automotive body control modules requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for APX803S-26SA-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' precision voltage supervisor product line, engineered specifically for cost-sensitive, space-constrained microprocessor reset applications demanding low quiescent current and guaranteed brownout detection down to 1 V.

FAQ

What is the exact reset threshold voltage for APX803S-26SA-7, and how tightly is it specified?

The APX803S-26SA-7 has a nominal reset threshold of 2.63 V, with a guaranteed range of 2.59 V to 2.67 V at +25°C and ±0.04 V tolerance maintained over –40°C to +85°C. This 30 ppm/°C tempco ensures minimal drift across industrial temperature extremes, eliminating need for external trimming in 3.3 V systems.

Does APX803S-26SA-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. A 4.7 kΩ to 10 kΩ resistor to the monitored VCC rail (or another compatible supply) is recommended. No internal pull-up exists; omission results in undefined logic state and failure to assert reset properly.

Can APX803S-26SA-7 operate reliably when VCC drops below 2.0 V?

Yes - the device guarantees valid RESET output down to VCC = 1.0 V. Below 1.0 V, the output becomes high-impedance and ceases sinking current, but this aligns with most µP operation limits. At 1.2 V, RESET remains asserted with full sink capability (≤0.3 V at 1.2 mA).

How does the 240 ms reset timeout behave during repeated brownout events?

The internal timer resets to zero each time VCC falls below the 2.63 V threshold. If VCC dips repeatedly - e.g., oscillating near threshold - RESET stays low continuously until VCC remains ≥1.02×VTH for ≥240 ms. This prevents false releases during noisy or unstable supply conditions.