Texas Instruments REF1933AIDDCT

Overview

REF1933AIDDCT from Texas Instruments is a dual-output, low-drift, low-power voltage reference IC delivering precise VREF = 3.3 V and VBIAS = 1.65 V (VREF/2) in a SOT23-5 package. It features ±0.1% initial accuracy, 25 ppm/°C max temperature drift over –40°C to 125°C, 6 ppm/°C max VREF–VBIAS tracking over –40°C to 85°C, and ±20 mA output drive capability - enabling high-precision biasing of bipolar ADC inputs in single-supply industrial data acquisition systems.

For engineers reviewing the REF1933AIDDCT datasheet, REF1933AIDDCT pinout, REF1933AIDDCT application, or REF1933AIDDCT equivalent, this page delivers verified specifications, validated pin functions, confirmed dual-output tracking behavior, real-world thermal hysteresis and solder-shift performance data, and two rigorously cross-checked alternative parts for single-supply precision reference design.

Technical Context

The REF1933AIDDCT implements a band-gap core with e-Trim™ post-mold calibration to achieve simultaneous high initial accuracy and low temperature drift on both outputs. Its architecture uses matched resistor dividers (R1/R2 and R3/R4) and independent buffers to generate VREF and VBIAS from the same reference node, ensuring tight tracking.

It operates in active mode when EN ≥ VIN – 0.7 V and enters shutdown (quiescent current ≤5 µA) when EN < 0.7 V, with 10 mV dropout enabling use down to VIN = VREF + 0.02 V. Both outputs source and sink ±20 mA while maintaining 8 ppm/mA load regulation and 3 ppm/V line regulation.

Key Specifications

Pinout & Package

SOT23-5 package (2.90 mm × 1.60 mm body size), surface-mount, moisture-sensitive level 1 (MSL-1), RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF1930AIDDCT, REF1933AIDDCT offers higher VREF for improved SNR in 3.3 V ADC systems; compared with ADR4533BRZ, it integrates VBIAS generation and reduces layout complexity, though with slightly higher drift - making it optimal for cost- and space-constrained industrial DAQ where 25 ppm/°C is sufficient.

Availability

REF1933AIDDCT is available at Aetrix Electronics and suitable for industrial process control, portable data acquisition, motor control feedback, and medical diagnostic equipment requiring stable component supply with guaranteed long-term continuity.

Supply support for REF1933AIDDCT 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 reference solutions.

The REF19xx product line was designed specifically for single-supply systems needing matched dual-reference outputs - targeting high-accuracy current sensing, motor control, and portable instrumentation where board space, power, and thermal stability are critical constraints.

FAQ

What is the exact output voltage specification for REF1933AIDDCT?

The REF1933AIDDCT provides two precisely trimmed outputs: VREF = 3.3 V ±0.1% (max initial error) and VBIAS = 1.65 V (exactly half of VREF, also ±0.1%). Both outputs maintain identical temperature drift (±25 ppm/°C max) and tracking performance (±6 ppm/°C max over –40°C to 85°C), as confirmed in TI's SBOS697A datasheet Section 7.5.

Does REF1933AIDDCT support bidirectional output current?

Yes, REF1933AIDDCT supports ±20 mA output current on both VREF and VBIAS pins - meaning each output can source up to 20 mA or sink up to 20 mA. This capability is explicitly specified in the Electrical Characteristics table (Section 7.5) and enables direct driving of ADC reference inputs, op-amp bias networks, and current-sense amplifier supplies without external buffers.

What is the minimum input voltage required for REF1933AIDDCT to regulate properly?

The minimum input voltage for REF1933AIDDCT is VREF + 0.02 V = 3.32 V under no-load conditions, per Recommended Operating Conditions (Section 7.3). At full 20 mA load, dropout is 10 mV, so VIN must be ≥3.33 V. This ultra-low dropout enables operation from partially discharged Li-ion batteries and low-headroom power rails.

How does the EN pin function on REF1933AIDDCT?

The EN pin is an active-high digital input: REF1933AIDDCT enters active mode when EN ≥ VIN – 0.7 V, and shutdown mode when EN < 0.7 V. In shutdown, outputs go high-impedance and quiescent current drops to ≤5 µA. The EN threshold is not fixed - it scales with VIN - ensuring reliable enable/disable across varying supply voltages.

Is REF1933AIDDCT pin-compatible with other REF19xx variants?

Yes, all REF19xx devices (including REF1925AIDDCT, REF1930AIDDCT, REF1933AIDDCT, and REF1941AIDDCT) share identical SOT23-5 pinout and package dimensions. Pin 1 = VBIAS, Pin 2 = GND, Pin 3 = EN, Pin 4 = VIN, Pin 5 = VREF. This allows drop-in replacement across the family when only VREF/VBIAS voltage levels differ.