Diodes Incorporated APX803S05-40SA-7

Overview

APX803S05-40SA-7 from Diodes Incorporated is a 3-pin SOT23 microprocessor reset supervisor IC with 4.00 V ±0.06 V precision reset threshold, 50 ms (typ.) active-low open-drain reset timeout, and guaranteed operation down to VCC = 1.0 V. It monitors 5.0 V supply rails in embedded microcontroller systems and asserts RESET during power-up, brownout, or voltage glitch events. Used in portable instrumentation and industrial controllers requiring low-current supervision.

For engineers reviewing the APX803S05-40SA-7 datasheet, APX803S05-40SA-7 pinout, APX803S05-40SA-7 application, or APX803S05-40SA-7 equivalent, key selection criteria include reset threshold accuracy (±2.5%), open-drain drive capability (1.2 mA sink at 0.3 V), temperature-stable timing (±30 ppm/°C tempco), and compatibility with bidirectional µP reset pins.

Technical Context

The APX803S05-40SA-7 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 4.00 V, triggering an internal monostable timer that holds RESET low for 50 ms (typ.) after VCC recovers. Its open-drain output interfaces directly with CMOS or TTL reset inputs via external pull-up.

Designed for single-supply monitoring, it draws only 10 µA (typ.) at 3.3 V and maintains valid logic state (RESET = low) across –40°C to +85°C ambient, with reset threshold drift limited to 30 ppm/°C. The device ignores fast transients (dVCC/dt ≤ 100 V/µs) and remains functional down to VCC = 1.0 V.

Key Specifications

Pinout & Package

APX803S05-40SA-7 is housed in a RoHS-compliant, halogen-free SOT23-3 (SA) package with 2.4 mm × 1.3 mm footprint and 0.915 mm height. Thermal resistance θJA = 232°C/W enables operation at full rating without heatsinking in standard PCB layouts.

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, APX803S05-40SA-7 uniquely combines fixed 4.00 V threshold, 50 ms timeout, open-drain output, and sub-15 µA ICC in SOT23-enabling drop-in replacement where precise brownout response and bus-sharing capability are required.

Availability

APX803S05-40SA-7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for APX803S05-40SA-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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.

The APX803S series belongs to Diodes' power management supervisory product line, engineered specifically for cost-sensitive, high-reliability microprocessor reset applications in industrial, computing, and portable equipment.

FAQ

What is the minimum VCC required for APX803S05-40SA-7 to assert a valid RESET signal?

The device guarantees RESET remains low for VCC ≥ 1.0 V. Below 1.0 V, the output enters high-impedance state and cannot sink current. This aligns with typical µP operation thresholds, as most microcontrollers cease functioning below 1.2 V, making the 1.0 V guarantee sufficient for deterministic reset behavior during brownout recovery.

Can APX803S05-40SA-7 interface directly with a µP that has a bidirectional reset pin?

Yes-the open-drain RESET output allows direct connection to bidirectional reset pins (e.g., Motorola 68HC11) using a single external pull-up resistor. Either the APX803S or the µP can pull the line low to initiate system reset, enabling coordinated hardware/software reset sequences without additional logic.

How does the 50 ms reset timeout improve system reliability compared to longer timeouts like 240 ms?

A 50 ms timeout balances robustness against excessive boot delays: it exceeds typical µP oscillator start-up (10–20 ms) and PLL lock times while avoiding unnecessary hold periods that delay application execution. This is optimal for responsive systems like portable instruments where user-perceived latency matters.

Is APX803S05-40SA-7 compatible with 3.3 V logic systems despite its 4.00 V threshold?

Yes-the 4.00 V threshold supervises a 5.0 V supply rail, not the logic voltage. Its RESET output is open-drain and referenced to the host µP's VCC (e.g., 3.3 V), so it interfaces seamlessly with 3.3 V logic when pulled up to that domain. The device itself operates from the monitored 5.0 V rail.