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REF6125, REF6130, REF6133, REF6141, REF6145, REF6150
SBOS747B – MAY 2016 – REVISED AUGUST 2016
REF61xx High-Precision Voltage Reference With Integrated ADC Drive Buffer
1 Features
•1 Excellent Temperature Drift Performance – 8 ppm/°C (max) from –40°C to +125°C
• Extremely Low Noise – Total Noise: 5 µVRMS With 47-µF Capacitor – 1/f Noise (0.1 Hz to 10 Hz): 3 µVPP/V
• Integrated ADC Drive Buffer – Low Output Impedance: < 50 mΩ (0-200 kHz) – First Sample Precise to 18 Bits With ADS8881 – Enables Burst-Mode DAQ Systems
• Low Supply Current: 820 μA • Low Shutdown Current: 1 µA • High Initial Accuracy: ±0.05% • Very-Low Noise and Distortion
– SNR: 100.5 dB, THD: –125 dB (ADS8881) – SNR: 106 dB, THD: –120 dB (ADS127L01) • Output Current Drive: ±4 mA • Programmable Short-Circuit Current • Verified to Drive REF Pin of ADS88xx family of SAR ADCs and ADS127xx family of Wideband ΔΣ ADCs
2 Applications
• ATE Testers and Oscilloscopes • Test and Measurement Equipment • Analog Input Modules for PLCs • Medical Equipment • Precision Data Acquisition Systems
3 Description
The REF6000 family of voltage references have an integrated low output impedance buffer that enable the user to directly drive the REF pin of precision data converters, while preserving linearity, distortion, and noise performance. Most precision SAR and Delta-Sigma ADCs, switch binary-weighted capacitors onto the REF pin during the conversion process. In order to support this dynamic load the output of the voltage reference must be buffered with a low-output impedance (high-bandwidth) buffer. The REF6000 family devices are well suited, but not limited, to drive the REF pin of the ADS88xx family of SAR ADCs, and ADS127xx family of delta-sigma ADCs, as well as other digital-to-analog converters (DACs).
The REF6000 family of voltage references are able to maintain an output voltage within 1LSB (18-bit) with minimal droop, even during the first conversion while driving the REF pin of the ADS8881. This feature is useful in burst-mode, event-triggered, equivalent-time sampling, and variable-sampling-rate data-acquisition systems. The REF61xx variants of REF6000 family specify a maximum temperature drift of just 8 ppm/°C and initial accuracy of 0.05% for both the voltage reference and the low output impedance buffer combined. For various temperature drift options in REF6000 family, see the Device Comparison Table.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
REF61xx
VSSOP (8)
3.00 mm x 3.00 mm
(1) For all available packages, see the package option addendum at the end of the data sheet.
Typical Application
Power Supply VIN REF61xx
EN Bandgap Voltage
Reference
RFILT
RLIM SS
VIN
Buffer
+
OUT_S OUT_F
GND_S
FILT
GND_F
CFILT
RESR CL
R VIN
R
R Power Supply
+ THS4521
R
RF CF
RF
AINP AINN
GND REF ADS8881
Copyright © 2016, Texas Instruments Incorporated
Reference Droop comparison (1 LSB = 19.07 µV, With ADS8881 at 1 MSPS)
4
3 Regular Voltage Reference Droop
Reference Droop (LSB)
2
1
0
±1 REF61xx Droop
±2
±3
±4 0
200 400 600 800 1000
Time (µs)
C04
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
REF6125, REF6130, REF6133, REF6141, REF6145, REF6150
SBOS747B – MAY 2016 – REVISED AUGUST 2016
www.ti.com
Table of Contents
1 Features .................................................................. 1 2 Applications ........................................................... 1 3 Description ............................................................. 1 4 Revision History..................................................... 2 5 Device Comparison Table..................................... 3 6 Pin Configuration and Functions ......................... 3 7 Specifications......................................................... 4
7.1 Absolute Maximum Ratings ...................................... 4 7.2 ESD Ratings.............................................................. 4 7.3 Recommended Operating Conditions....................... 4 7.4 Thermal Information .................................................. 4 7.5 Electrical Characteristics.......................................... 5 7.6 Typical Characteristics .............................................. 7 8 Parameter Measurement Information ................ 14 8.1 Solder Heat Shift..................................................... 14 8.2 Thermal Hysteresis ................................................. 15 8.3 Reference Droop Measurements ............................ 16 8.4 1/f Noise Performance ............................................ 18 9 Detailed Description ............................................ 19 9.1 Overview ...............