Datasheet

ELECTRICAL CHARACTERISTICS
ADS7279
ADS7280
www.ti.com ............................................................................................................................................................... SBAS436A – MAY 2008 – REVISED JUNE 2009
At T
A
= – 40 ° C to +85 ° C, +VA = 2.7V to 3.6V, +VBD = 1.65V to 1.5x(+VA), V
REF
= 2.5V, f
SAMPLE
= 1MHz for 3V ≤ +VA ≤ 3.6V,
and f
SAMPLE
= 900kHz for 3V < +VA ≤ 2.7V using external clock, unless otherwise noted.
ADS7279, ADS7280
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG INPUT
FSR Full-scale input voltage
(1)
+IN – ( – IN) or (+INx – COM) 0 V
REF
V
+IN, +IN0, +IN1 AGND – 0.2 +VA + 0.2
Absolute input voltage V
– IN or COM AGND – 0.2 AGND + 0.2
Input capacitance 45 pF
No ongoing conversion,
Input leakage current 50 nA
dc Input
At dc 108
Input channel isolation, ADS7280
dB
only
V
IN
= ± 1.25V
PP
at 50kHz 101
SYSTEM PERFORMANCE
Resolution 14 Bits
No missing codes 14 Bits
Integral
INL – 1 ± 0.4 1 LSB
(2)
linearity
DNL Differential linearity – 1 ± 0.4 1 LSB
(2)
Offset
E
O
– 0.8 ± 0.05 0.8 mV
error
(3)
Offset error drift FSR = 2.5V ± 0.1 ppm/ ° C
E
G
Gain error – 0.25 ± 0.06 0.25 %FSR
Gain error drift ± 0.5 ppm/ ° C
At dc 70
CMRR Common-mode rejection ratio dB
V
IN
= 0.4V
PP
at 1MHz 50
Noise 33 µ V
RMS
PSRR Power-supply rejection ratio At FFFFh output code
(3)
78 dB
SAMPLING DYNAMICS
t
CONV
Conversion time 18 CCLK
t
SAMPLE1
Manual trigger 3
Acquisition time CCLK
t
SAMPLE2
Auto trigger 3
2.7V ≤ +VA < 3.0V 0.9
Throughput rate MHz
3.0V ≤ +VA < 3.64V 1
Aperture delay 5 ns
Aperture jitter 10 ps
Step response 100 ns
Overvoltage recovery 100 ns
(1) Ideal input span; does not include gain or offset error.
(2) LSB means least significant bit.
(3) Measured relative to an ideal full-scale input [(+IN) – ( – IN)] of 2.5V when +VA = 3V.
Copyright © 2008 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 5
Product Folder Link(s): ADS7279 ADS7280