Diodes Incorporated APX803S-29SR-7

Overview

APX803S-29SR-7 from Diodes Incorporated is a 3-pin SOT23 open-drain microprocessor reset supervisor IC with 2.93V ±0.04V precision reset threshold, 240ms minimum reset timeout, 10µA typical supply current, and guaranteed reset validity down to VCC = 1V. It monitors 3.3V/3.0V digital power rails in embedded controllers and portable systems to prevent erroneous microprocessor startup during brownout or power-up transients.

For engineers reviewing the APX803S-29SR-7 datasheet, APX803S-29SR-7 pinout, APX803S-29SR-7 application, or APX803S-29SR-7 equivalent, key selection criteria include reset threshold accuracy over temperature (±30 ppm/°C), open-drain output compatibility with bidirectional µP reset pins, fixed 240ms timeout timing, low-voltage operation margin (1V min VCC), and SOT23-SR package footprint alignment with PCB layout constraints.

Technical Context

The APX803S-29SR-7 implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below 2.93V and assert an active-low open-drain RESET signal. Its internal timer initiates only after VCC rises above threshold and holds RESET low for ≥240ms - independent of VCC slew rate or noise.

No external components are required: the device operates with direct VCC connection, uses no capacitors for timing, and guarantees correct logic state at VCC ≥1V. Its ESD protection (3kV HBM) and thermal resistance (θJA = 232°C/W) support industrial ambient operation from –40°C to +85°C.

Key Specifications

Pinout & Package

APX803S-29SR-7 is housed in a RoHS-compliant SOT23-3 (SR variant) package with gull-wing leads, 1.3mm body width, and 2.9mm length per Diodes Incorporated package outline SOT23. The SR pinout differs from SA: Pin 1 = GND, Pin 2 = RESET, Pin 3 = VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with APX809S-29SA-7, the APX803S-29SR-7's open-drain output enables flexible reset bus architecture, while versus MAX809TRD29+T, its longer 240ms timeout and lower 10µA supply current improve reliability in battery-critical and multi-device systems.

Availability

APX803S-29SR-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 availability, and RoHS-compliant sourcing.

Supply support for APX803S-29SR-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' precision voltage supervisor product line, engineered specifically for deterministic reset behavior in resource-constrained embedded systems where low quiescent current and guaranteed sub-1V operation are essential.

FAQ

What is the exact reset threshold voltage for APX803S-29SR-7 and how does it vary with temperature?

The APX803S-29SR-7 has a nominal reset threshold of 2.93V at +25°C, with a guaranteed range of 2.89V to 2.97V. Over the full operating temperature range (–40°C to +85°C), the threshold drift is limited to ±30 ppm/°C, resulting in total variation under ±1.5% - verified in production testing and documented in DS39161 Rev. 2-2 Table 1.

Can APX803S-29SR-7 drive a reset line shared among multiple microcontrollers?

Yes - its open-drain RESET output supports wired-OR configuration. Multiple APX803S-29SR-7 units (or other open-drain reset sources) can share a single reset bus with one pull-up resistor. This enables coordinated reset assertion across heterogeneous supply domains, as confirmed in the "Interfacing to µP with Bidirectional RESET Pins" section of the datasheet.

Does APX803S-29SR-7 require an external capacitor for timing or filtering?

No external capacitor is required. The 240ms reset timeout is internally generated and factory-trimmed. While a 100nF bypass capacitor on VCC is recommended for noise immunity (per Typical Applications Circuit), it is not part of the timing function - the device remains fully functional without it, unlike RC-based discrete supervisors.

What is the minimum VCC voltage at which APX803S-29SR-7 guarantees correct RESET logic state?

The device guarantees valid RESET output (logic low when asserted, high-impedance when released) down to VCC = 1.0V, as specified in Absolute Maximum Ratings and Electrical Characteristics tables. Below 1V, RESET becomes high-impedance - a design feature enabling graceful failure mode during deep brownout, not a limitation.