Diodes Incorporated APX824-31W5G-7

Overview

APX824-31W5G-7 from Diodes Incorporated is a fixed-threshold processor supervisory circuit with active-high reset output, 3.08 V negative-going supply voltage detection (V_TH-), 200 ms typical power-on reset delay (t_d), and integrated watchdog timer (t_tout = 1.6 s typ). It operates across 1.1–5.5 V supply range, draws 30 μA typical supply current, and is rated for -40°C to +85°C ambient operation in SOT25 package. Used for reliable power-up initialization and fault recovery in microcontroller-based industrial control systems.

For engineers reviewing the APX824-31W5G-7 datasheet, APX824-31W5G-7 pinout, APX824-31W5G-7 application, or APX824-31W5G-7 equivalent, key selection criteria include its 3.08 V threshold accuracy, active-high RESET output, watchdog timeout tolerance, SOT25 footprint compatibility, and absence of manual reset input-critical for space-constrained embedded designs requiring deterministic reset timing without external components.

Technical Context

The APX824-31W5G-7 implements a precision bandgap-based voltage reference to monitor V_CC against a factory-trimmed 3.08 V threshold (V_TH-) with ±50 mV hysteresis. Its internal 200 ms reset delay timer activates only after V_CC exceeds V_TH-, ensuring stable power rail establishment before releasing reset.

Watchdog supervision uses edge-triggered WDI input: any positive or negative transition resets the 1.6 s timeout counter; failure to retrigger asserts active-high RESET. Unlike APX823/APX825A, it omits MR input-simplifying layout but removing user-initiated reset capability.

Key Specifications

Pinout & Package

SOT25 package: 5-pin, small-outline transistor outline with gull-wing leads, 3.0 mm × 1.6 mm body, 1.1 mm height, RoHS-compliant matte tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with APX824-31W5G-7, the -30 variant offers earlier reset activation for marginal 3.0 V supplies, while the -33 variant raises the threshold to suppress noise-induced resets on clean 3.3 V rails-both retain identical timing, package, and active-high output behavior.

Availability

APX824-31W5G-7 is available at Aetrix Electronics and suitable for industrial automation, wireless sensor networks, and embedded HMI applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for APX824-31W5G-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 automotive markets.

The APX82x series belongs to Diodes' processor supervisory product line, engineered specifically for deterministic power-on reset, supply voltage monitoring, and watchdog supervision in resource-constrained embedded systems.

FAQ

What is the function of the NC pin (Pin 5) on APX824-31W5G-7?

Pin 5 is a no-connect terminal with no internal connection. It must remain unconnected or tied to GND per Diodes' recommended PCB layout to avoid parasitic coupling. Unlike APX825A's SOT26 package, this SOT25 variant does not repurpose Pin 5 for MR functionality-confirming its true NC status in the device mask set.

Can the watchdog timer be disabled without modifying the PCB?

Yes-the watchdog is automatically disabled when the WDI pin is left unconnected (open-circuit). No pull-up or pull-down is required. This behavior is guaranteed by internal weak pull-down on WDI, verified in the Electrical Characteristics table under I_IL(AV) and confirmed in the Functional Block Diagram.

Does APX824-31W5G-7 support operation at 2.5 V supply?

No-it requires V_CC ≥ 1.1 V to assert RESET initially, but its 3.08 V threshold means reliable supervision begins only above ~3.0 V. At 2.5 V, V_CC remains below V_TH-, holding RESET active indefinitely. Use APX823-26W5G-7 (2.63 V threshold) for 2.5 V systems.

How does temperature affect the 3.08 V threshold accuracy?

V_TH- drifts ±5 mV over -40°C to +85°C, as shown in the "RESET Threshold Voltage vs. Temperature" plot (DS31323 Rev. 5-2, p.8). The typical value remains 3.08 V at 25°C, with worst-case deviation bounded by ±0.05 V-within specification for 3.3 V ±10% systems.