Texas Instruments REF1933AIDDCR

Overview

REF1933AIDDCR from Texas Instruments is a dual-output, low-drift, low-power voltage reference IC providing precise VREF = 3.3 V and VBIAS = 1.65 V outputs with ±0.1% initial accuracy, 25 ppm/°C max temperature drift (–40°C to 125°C), and 6 ppm/°C max VREF/VBIAS tracking (–40°C to 85°C), used in high-precision ADC biasing and single-supply signal conditioning circuits.

For engineers reviewing the REF1933AIDDCR datasheet, REF1933AIDDCR pinout, REF1933AIDDCR application, or REF1933AIDDCR equivalent, key selection criteria include dual-output tracking performance, SOT23-5 package compatibility, ±20 mA output drive capability, low 360 µA quiescent current, and 10 mV dropout voltage for battery-sensitive designs.

Technical Context

The REF1933AIDDCR implements a band-gap core with e-Trim™ post-mold calibration to achieve matched VREF and VBIAS outputs derived from the same reference node, enabling tight tracking. Its dual-buffer architecture isolates load effects on each output while maintaining identical electrical specifications across both pins.

It operates in active mode when EN ≥ VIN – 0.7 V and enters shutdown (5 µA IQ) when EN < 0.7 V, supporting power-gated precision systems. The device supports capacitive loads up to 10 µF and maintains stability without external compensation.

Key Specifications

Pinout & Package

SOT23-5 package (2.90 mm × 1.60 mm), surface-mount, thermally enhanced plastic body with exposed pad not connected internally.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output voltage reference applications.

Compared with REF1930AIDDCR, REF1933AIDDCR offers higher reference voltage for improved ADC SNR in 3.3 V systems; compared with ADR4533BRZ, it integrates VBIAS generation with superior tracking, eliminating external components and layout sensitivity.

Availability

REF1933AIDDCR is available at Aetrix Electronics and suitable for industrial process control, medical instrumentation, and portable data acquisition systems requiring stable component supply with guaranteed long-term availability and traceable lot-level documentation.

Supply support for REF1933AIDDCR 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

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in precision analog ICs and industrial-grade reliability.

The REF19xx product line was designed specifically for high-accuracy, dual-output voltage referencing in single-supply data acquisition systems, addressing the need for matched VREF/VBIAS generation without external trimming or calibration.

FAQ

What is the maximum load current supported by each output of the REF1933AIDDCR?

The REF1933AIDDCR supports ±20 mA per output (VREF and VBIAS). Both outputs can simultaneously source and sink up to 20 mA while maintaining specified accuracy and regulation. Exceeding this limit risks thermal overload or output voltage deviation beyond datasheet tolerances. The device includes short-circuit protection limiting output current to 50 mA.

Does the REF1933AIDDCR require external capacitors for stability?

No, the REF1933AIDDCR is internally compensated and stable with 0 µF to 10 µF output capacitance. Unlike many references, it does not require a minimum capacitor for phase margin; adding up to 10 µF improves PSRR and transient response without risk of oscillation. Ceramic capacitors are recommended for lowest ESR.

How does the EN pin function on the REF1933AIDDCR?

The EN pin on the REF1933AIDDCR is an active-high enable input. When voltage at EN ≥ VIN – 0.7 V, the device operates in active mode with 360 µA quiescent current. When EN < 0.7 V, it enters shutdown mode, disabling both outputs (high-Z state) and reducing IQ to 5 µA. No pull-up is required; direct MCU GPIO control is sufficient.

What is the significance of VREF/VBIAS tracking specification in the REF1933AIDDCR?

VREF/VBIAS tracking quantifies how closely VBIAS maintains exactly half of VREF across temperature - critical for ratiometric systems where ADC output depends on the ratio of input to reference. REF1933AIDDCR guarantees ≤6 ppm/°C tracking from –40°C to 85°C, meaning the relative error between VREF and 2×VBIAS stays below ±0.5 mV over that range, preserving measurement linearity without software correction.

Can the REF1933AIDDCR operate from a 3.3 V supply?

Yes, the REF1933AIDDCR can operate from a 3.3 V supply, but only at reduced output current. With VIN = 3.3 V, the minimum dropout requirement (VREF + 20 mV = 3.32 V) is not met for full 20 mA sourcing. At 3.3 V input, maximum continuous sourcing is ~12 mA while maintaining regulation. For full ±20 mA capability, VIN ≥ 3.32 V is required.