Diodes Incorporated ZRT040GC1TC

Overview

ZRT040GC1TC from Zetex Semiconductors is a precision 4.01 V bandgap voltage reference IC with 1% initial tolerance, 15 ppm/°C max temperature coefficient, and trimmable output via external resistor. It operates from 150 µA to 75 mA, delivers low 50 µV_P-P noise (0.1–10 Hz), and requires no external capacitor in most applications. Used in ADC/DAC biasing, sensor signal conditioning, and power supply feedback loops.

For engineers reviewing the ZRT040GC1TC datasheet, ZRT040GC1TC pinout, ZRT040GC1TC application, or ZRT040GC1TC equivalent, key selection criteria include initial voltage accuracy, TCVR stability over –40°C to +85°C, trim range capability, slope resistance ≤3.0 Ω, and SOT223 thermal performance under 2 W dissipation.

Technical Context

The ZRT040GC1TC implements a monolithic bandgap reference core with integrated trimming node, enabling ±5% output adjustment using a single external potentiometer. Its architecture achieves low 1.1 Ω typical slope resistance and maintains <24 mV total output variation across the C-grade temperature range.

It features inherent thermal compensation without external components, supports direct connection of the trim pin to ground or open-circuit operation, and exhibits stable regulation down to 150 µA knee current-enabling ultra-low-power system monitoring functions.

Key Specifications

Pinout & Package

SOT223 package: 4-pin surface-mount outline with exposed thermal pad (pin 4 floating or tied to pin 2 per datasheet). Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = Trim, Pin 4 = Thermal pad / Anode tie.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDBZR, ZRT040GC1TC offers native 4.01 V output and simpler trim; versus REF43, it trades lower noise and tighter TCVR for 10× lower knee current-making it optimal for low-power industrial sensing where 50 µV_P-P noise is acceptable.

Availability

ZRT040GC1TC is available at Aetrix Electronics and suitable for industrial sensor transmitters, portable medical instrumentation, and programmable logic controller (PLC) analog I/O requiring stable component supply with guaranteed long-term continuity.

Supply support for ZRT040GC1TC 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 (now part of Diodes Incorporated) specialized in high-performance analog and discrete semiconductors, with emphasis on precision, efficiency, and reliability for industrial and automotive markets.

The ZRT series was designed specifically for applications demanding stable, trimmable, low-noise voltage references in compact SOT223 packages-targeting sensor signal conditioning, data acquisition, and power management systems.

FAQ

What is the correct configuration for the trim pin when not in use?

The trim pin (Pin 3) must be left open-circuit when adjustment is not required. Connecting it to ground or V_REF will force the output outside specification. The internal circuitry is designed for high-impedance trim control, and unintended loading degrades accuracy and temperature stability.

Can ZRT040GC1TC replace TL431 in existing designs?

Yes, with circuit modification: TL431 requires external resistors to set 4.01 V, while ZRT040GC1TC provides it natively. However, ZRT040GC1TC lacks the TL431's shunt regulator topology and cannot sink current like a 2-terminal device-its anode must be grounded, cathode used as output.

Does ZRT040GC1TC require a heatsink in 2 W operation?

No heatsink is required at 25°C ambient due to the SOT223 package's 2 W rating, but PCB copper area under the thermal pad (Pin 4) must be ≥100 mm² with ≥4 thermal vias to maintain junction temperature within limits. Derating applies above 25°C per datasheet curve.

How does the 150 µA knee current affect low-power system design?

The 150 µA knee current defines the minimum operating current below which regulation collapses. In sleep-mode circuits, this allows the reference to remain active during microcontroller deep-sleep states where supply current drops to ~200 µA-enabling wake-up signal integrity without re-stabilization delay.