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±4
±3
±2
±1
0
1
2
3
4
0 200 400 600 800 1000
Reference Droop (LSB)
Time (µs)
C042
Regular Voltage Reference Droop
REF60xx Droop
Bandgap
Voltage
Reference
C
FILT
C
L
R
ESR
R
FILT
Buffer
+
VIN
OUT_S
OUT_F
FILT
VIN
GND_S GND_F
Power Supply
SS
REF60xx
R
LIM
EN
GND
REF
+
V
IN
R
R
R
Power Supply
R
F
R
F
R
C
F
THS4521
AINP
AINN
ADS8881
Copyright © 2016, Texas Instruments Incorporated
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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.
REF6025
,
REF6030
,
REF6033
,
REF6041
,
REF6045
,
REF6050
SBOS708B –MAY 2016–REVISED AUGUST 2016
REF60xx High-Precision Voltage Reference With Integrated ADC Drive Buffer
1
1 Features
1
• Excellent Temperature Drift Performance
– 5 ppm/°C (max) from –40°C to +125°C
• Extremely Low Noise
– Total Noise: 5 µV
RMS
With 47-µF Capacitor
– 1/f Noise (0.1 Hz to 10 Hz): 3 µV
PP
/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 REF60xx variants of REF6000 family
specify a maximum temperature drift of just 5 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)
REF60xx 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
Reference Droop comparison
(1 LSB = 19.07 µV, With ADS8881 at 1 MSPS)
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