Diodes Incorporated ZRA124F01TA

Overview

ZRA124F01TA from Zetex Semiconductors is a precision micropower 1.24 V bandgap voltage reference IC in SOT23-3 package, designed for low-current biasing of analog signal chains. It delivers 1% initial tolerance, 30 ppm/°C typical temperature coefficient, and operates stably from 50 µA to 5 mA without external capacitor-enabling use in battery-powered instrumentation and portable measurement systems.

For engineers reviewing the ZRA124F01TA datasheet, ZRA124F01TA pinout, ZRA124F01TA application, or ZRA124F01TA equivalent, key selection criteria include micropower operation down to 50 µA, capacitor-free stability, transient response under 10 µs, SOT23-3 footprint constraints, and industrial temperature range compliance (-40°C to +85°C).

Technical Context

The ZRA124F01TA implements a two-terminal shunt voltage reference topology with internal bandgap core, delivering fixed 1.24 V output via reverse-biased junction regulation. Its slope resistance of 0.65 Ω and dynamic impedance of ≤1 Ω at 1 mA enable tight load regulation across capacitive and resistive loads.

It functions as a passive, current-sink reference requiring an external series resistor for biasing. The device achieves stable regulation without output capacitance and maintains performance up to 25 mA absolute maximum forward current, with transient recovery settling within 10 µs after load step changes.

Key Specifications

Pinout & Package

SOT23-3 package with gull-wing leads; body dimensions 2.9 mm × 1.3 mm × 1.0 mm; thermal pad not present; JEDEC MO-178 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AIDBVR and REF191GSZ-REEL, the ZRA124F01TA uniquely combines fixed 1.24 V, 1% tolerance, 50 µA operation, and SOT23-3 size-making it optimal for space- and power-constrained shunt reference roles where simplicity and long battery life are primary.

Availability

ZRA124F01TA is available at Aetrix Electronics and suitable for battery-powered instrumentation, portable test equipment, and precision analog front ends requiring stable component supply with consistent parametric performance across production lots.

Supply support for ZRA124F01TA 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

Zetex Semiconductors plc was a UK-based analog and discrete semiconductor manufacturer, acquired by Diodes Incorporated in 2008; legacy Zetex products maintain industrial qualification and long-term supply commitment.

The ZRA124 series belongs to Zetex's precision micropower reference product line, engineered specifically for low-current, capacitor-free operation in portable and battery-critical measurement systems.

FAQ

What is the recommended external series resistor value for ZRA124F01TA at 3.3 V supply?

At 3.3 V supply, a 2.2 kΩ resistor sets nominal operating current at ~0.94 mA-well within the 50 µA to 5 mA recommended range. This provides margin against supply variation while maintaining low power dissipation (≈2.1 mW in the resistor) and ensuring stable regulation under load transients.

Can ZRA124F01TA drive a 100 pF capacitive load directly?

Yes-the ZRA124F01TA is explicitly characterized as stable with capacitive loads and requires no external compensation. Data sheet confirms stable operation up to at least 100 pF, making it suitable for driving ADC sample-and-hold inputs and op-amp reference pins without added series resistance or isolation.

Is Pin 3 (NC) required to be grounded or left floating?

Pin 3 is internally unconnected and may be left floating. However, Zetex recommends tying it to Pin 2 (cathode) in production layouts to minimize parasitic coupling and improve noise immunity-no electrical penalty results, and it simplifies routing in dense PCBs.

How does ZRA124F01TA behave during cold-start at -40°C?

At -40°C, the device achieves full regulation within <15 µs and maintains 1.24 V ±1.5% output accuracy. Its bandgap design ensures monotonic startup behavior with no oscillation or hysteresis, verified across temperature cycling tests per Zetex Issue 3 specification report.