Diodes Incorporated ZRC400A03STOA

Overview

ZRC400A03STOA from Diodes Incorporated is a precision 4.096 V bandgap voltage reference IC with ±3% initial tolerance, 30 ppm/°C typical temperature coefficient, and 0.4 Ω typical slope resistance. It operates from 23 µA to 5 mA without external stabilization capacitors and delivers stable output under capacitive loads-ideal for low-power portable instrumentation and battery-powered metering systems.

For engineers reviewing the ZRC400A03STOA datasheet, ZRC400A03STOA pinout, ZRC400A03STOA application, or ZRC400A03STOA equivalent, key selection criteria include knee current (18 µA typ), transient settling time (<10 µs), TC performance across –40°C to +85°C, and compatibility with SOT23-3 package layout constraints.

Technical Context

The ZRC400A03STOA implements a two-terminal shunt reference architecture using a curvature-compensated bandgap core, enabling stable reverse breakdown operation without series pass elements. Its design supports direct connection between input and load, with regulation maintained across 23 µA–5 mA operating current and up to 200 mA transient surge capability.

It exhibits low dynamic impedance (0.3 Ω typ at 1 mA, 100 Hz), wideband noise of 90 µV_rms (10 Hz–10 kHz), and monotonic slope resistance behavior from 0.1 mA to 10 mA-critical for high-accuracy ADC biasing and sensor excitation circuits where load regulation and noise floor directly impact measurement fidelity.

Key Specifications

Pinout & Package

Package: SOT23-3 (suffix 'F'), with pin 1 floating or connected to pin 2 per ordering matrix. Device functions as a two-terminal shunt reference; pin 1 and pin 2 are anode/cathode pair, pin 3 is NC (no internal connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt voltage reference applications.

Compared with TL431ACDBVR and REF3040AIDBVR, ZRC400A03STOA offers the lowest knee current and zero-capacitor operation-making it uniquely suited for space- and energy-constrained shunt reference roles where simplicity and microamp-level startup are mandatory.

Availability

ZRC400A03STOA is available at Aetrix Electronics and suitable for battery-powered portable meters, industrial process transmitters, and smart energy meter reference subsystems requiring stable component supply with guaranteed long-term continuity.

Supply support for ZRC400A03STOA 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, cost-optimized components for industrial, computing, and consumer markets.

The ZRC400 series belongs to Diodes' precision voltage reference product line, engineered specifically for low-power, space-constrained applications demanding stable 4.096 V reference points without external passive components.

FAQ

What is the minimum operating current for stable regulation?

The ZRC400A03STOA achieves stable regulation at 18 µA typical knee current, with guaranteed operation starting at 23 µA across –40°C to +85°C. Below 23 µA, output voltage may deviate beyond ±3% tolerance, especially at temperature extremes. Designers should verify regulation margin using the device's reverse current vs. voltage curve at worst-case ambient.

Can it drive a 1 nF capacitive load directly?

Yes-the ZRC400A03STOA is explicitly characterized as stable with capacitive loads and requires no external compensation. Test data confirms stability with ≥1 nF loads under all specified operating conditions, including full temperature range and 23 µA–5 mA current. Layout best practice remains local 100 nF ceramic decoupling near the cathode pin.

Is pin 3 internally connected?

No-pin 3 in the SOT23-3 package (ZRC400A03STOA) is not bonded and has no internal connection. The datasheet specifies it as "NC" (no connect). It must remain unconnected unless required for mechanical mounting; tying it to ground or any other net introduces no functional benefit and risks unintended parasitic coupling.

How does its noise performance compare to bandgap references with external filtering?

At 90 µV_rms (10 Hz–10 kHz), ZRC400A03STOA's noise is inherently low for a shunt reference without external filtering. Adding a 1 µF ceramic capacitor reduces broadband noise by ~30%, but degrades transient response. For applications needing <50 µV_rms, a low-noise LDO post-regulator (e.g., AP2112) is recommended instead of RC filtering, preserving speed and regulation integrity.