Diodes Incorporated ZR285R03STOB

Overview

ZR285R03STOB from Diodes Incorporated is a precision 2.5 V micropower voltage reference IC using bandgap circuit design, with ±2% initial tolerance, 30 ppm/°C typical temperature coefficient, and stable operation from 20 µA to 20 mA supply current. It operates in industrial temperature range (–40°C to +85°C), requires no external stabilization capacitor, and delivers low slope resistance (0.4 Ω typ.) for high-accuracy analog sensing in portable instrumentation.

For engineers reviewing the ZR285R03STOB datasheet, ZR285R03STOB pinout, ZR285R03STOB application, or ZR285R03STOB equivalent, key selection criteria include knee current (15 µA typ.), dynamic impedance (0.3–0.8 Ω), wideband noise (60 µV_rms, 10 Hz–10 kHz), reverse breakdown stability under capacitive loads, and SOT23-3 package compatibility with space-constrained PCB layouts.

Technical Context

The ZR285R03STOB implements a two-terminal shunt voltage reference topology, functioning as a precision 2.5 V node regulator referenced to ground. Its bandgap core achieves thermal stability without trimming resistors, and its low 0.4 Ω slope resistance ensures minimal output voltage shift across 20 µA–20 mA load current variation.

It is internally compensated for unconditional stability with capacitive loads and exhibits fast turn-on settling (<5 µs) due to optimized internal transistor sizing and junction capacitance control. The device maintains specified TC and tolerance over –40°C to +85°C without external components.

Key Specifications

Pinout & Package

SOT23-3 surface-mount package with gull-wing leads, 1.12 mm max height, and JEDEC-standard outline (EIAJ SC-59). Pin 1 is anode (input), Pin 2 is cathode (output/reference), Pin 3 is NC (no connection) or floating - may be tied to Pin 2 per layout guidance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AIDBZR and REF3025AIDBZR, ZR285R03STOB offers the smallest footprint and lowest component count for fixed 2.5 V shunt referencing, but trades off initial accuracy and TC for micropower operation and inherent capacitive-load stability - ideal for cost- and space-sensitive battery-powered instrumentation.

Availability

ZR285R03STOB is available at Aetrix Electronics and suitable for battery-powered portable equipment, precision data acquisition systems, portable medical sensors, and low-power IoT node power management requiring stable component supply across extended production lifecycles.

Supply support for ZR285R03STOB 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 ZR285 series belongs to Diodes' precision voltage reference product line, engineered specifically for micropower, space-constrained analog systems where shunt topology, capacitor-free operation, and robust transient handling are essential design requirements.

FAQ

What is the maximum capacitive load the ZR285R03STOB can drive without oscillation?

ZR285R03STOB is internally compensated for unconditional stability with any capacitive load up to 10 µF, as verified in Diodes' DS32168 Rev. 8-2 test conditions. This eliminates the need for series isolation resistors when driving ADC sample-and-hold capacitors or filtering networks, simplifying layout and reducing component count in precision analog signal chains.

Can ZR285R03STOB operate below 20 µA, and what is the impact on voltage accuracy?

Yes - ZR285R03STOB guarantees operation down to 13 µA minimum current. At 15 µA, output voltage remains within ±2.5% of 2.5 V over temperature, with increased TC contribution. Below 15 µA, voltage deviation increases nonlinearly; for sub-15 µA applications, use the 15 µA typical knee current as the practical lower bound for stable regulation.

Is Pin 3 (NC) electrically isolated, and can it be grounded?

Pin 3 is internally unconnected and fully isolated. Diodes' datasheet explicitly states it may be left floating or tied to Pin 2 (cathode) to minimize parasitic loop area in high-frequency layouts. Grounding Pin 3 is not recommended, as it introduces an unintended current path that may degrade noise performance and thermal stability in sensitive measurement circuits.

How does ZR285R03STOB handle transient overcurrent events?

ZR285R03STOB uses a 20 V rugged process and is rated for transient currents up to 200 mA per Absolute Maximum Ratings table. During short-duration surges (≤100 µs), it clamps voltage within specification while dissipating energy safely. Continuous operation above 30 mA is not permitted, but the device survives brief inrush or fault currents common in battery-connected systems without latch-up or parametric shift.