Texas Instruments REF6133IDGKT

Overview

REF6133IDGKT from Texas Instruments is a high-precision, 3.3 V voltage reference IC with integrated ADC drive buffer, ±0.05% initial accuracy, 8 ppm/°C max temperature drift over –40°C to +125°C, and <50 mΩ output impedance (DC–200 kHz), designed to directly drive the REF pin of SAR and delta-sigma ADCs such as ADS8881 in precision data acquisition systems.

For engineers reviewing the REF6133IDGKT datasheet, REF6133IDGKT pinout, REF6133IDGKT application, or REF6133IDGKT equivalent, this page delivers verified specifications, real-world droop performance at 18-bit resolution, buffer-enabled first-sample precision, and validated compatibility with ADS88xx and ADS127xx ADC families - critical for burst-mode DAQ, test equipment, and medical instrumentation design.

Technical Context

The REF6133IDGKT integrates a bandgap voltage reference core with a low-output-impedance buffer stage optimized for dynamic capacitive loads. Its architecture eliminates external buffering while preserving linearity and noise performance when driving switched-capacitor REF inputs during ADC conversion cycles.

It supports programmable short-circuit current via the SS pin, uses dual ground pins (GND_F/GND_S) for force-sense separation, and requires ≥1 µF CFILT capacitance on the FILT pin for stability - enabling precise regulation under transient load conditions typical in high-speed sampling.

Key Specifications

Pinout & Package

REF6133IDGKT is housed in an 8-pin VSSOP package (3.00 mm × 3.00 mm body size), optimized for thermal performance and PCB space efficiency in high-density analog signal chains.

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF6133IDGKT, REF6130IDGKT offers identical performance at 3.0 V for lower-voltage ADCs, while REF6141IDGKT provides binary-aligned 4.096 V output with matched drift and accuracy - both share the same VSSOP-8 footprint and buffer architecture, simplifying voltage-scaling upgrades without redesign.

Availability

REF6133IDGKT is available at Aetrix Electronics and suitable for precision data acquisition systems, automated test equipment, and medical instrumentation requiring stable component supply, long-term calibration integrity, and guaranteed first-sample accuracy in burst-mode sampling.

Supply support for REF6133IDGKT 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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision voltage references and data converter interfaces.

The REF61xx family was engineered specifically to solve dynamic REF pin loading challenges in high-resolution SAR and delta-sigma ADCs - delivering integrated buffering, ultra-low drift, and guaranteed 18-bit first-sample accuracy without external components.

FAQ

What is the output voltage tolerance and temperature coefficient of REF6133IDGKT?

The REF6133IDGKT has an initial output voltage tolerance of ±0.05% and a maximum temperature coefficient of 8 ppm/°C over –40°C to +125°C. These values apply to both the reference core and integrated buffer combined, ensuring end-to-end accuracy without additional calibration. The 3.3 V nominal output is laser-trimmed at wafer level and verified across temperature extremes per SBOS747B specification limits.

How does REF6133IDGKT achieve first-sample 18-bit precision with ADS8881?

REF6133IDGKT achieves first-sample 18-bit precision by combining a low-output-impedance buffer (<50 mΩ up to 200 kHz) with optimized transient response, limiting reference droop to <1 LSB (19.07 µV) at 1 MSPS with ADS8881. This is validated in Figure 32–34 of the datasheet using actual ADC code analysis - not simulation - confirming sub-LSB settling during the critical first conversion cycle.

Can REF6133IDGKT drive multiple ADCs simultaneously?

Yes, REF6133IDGKT can drive multiple ADCs if total load remains within its ±4 mA output current capability and capacitive load stays within 10–47 µF per the datasheet. For example, it can concurrently drive two ADS8881 REF pins (each drawing ~1–2 mA peak during switching) provided proper PCB layout isolates ground paths and CFILT is correctly placed. Exceeding 47 µF CL risks instability.

What is the purpose of separate GND_F and GND_S pins on REF6133IDGKT?

The GND_F (force ground) and GND_S (sense ground) pins implement a Kelvin connection to isolate high-current return paths from precision feedback sensing. GND_F carries buffer output current, while GND_S returns only the reference core and sense circuitry - preventing IR drop and noise from degrading output voltage accuracy. This separation is critical for maintaining ±0.05% accuracy in noisy industrial environments.

Does REF6133IDGKT require an external filter capacitor on the FILT pin?

Yes, REF6133IDGKT requires a minimum 1 µF capacitor between the FILT pin and GND_F for loop stability and noise reduction. The datasheet specifies CFILT ≥1 µF ceramic (X7R or better); typical designs use 2.2 µF. Omitting or undersizing this capacitor causes oscillation and increased output noise - confirmed in Section 8.1 and Figure 16 of SBOS747B.