Linear Technology LTC2430 Manual page 2

FEATURES
Low Supply Current (200µA in Conversion Mode
and 4µA in Autosleep Mode)
Differential Input and Differential Reference
with GND to V Common Mode Range
CC
3ppm INL, No Missing Codes
10ppm Full-Scale Error and 1ppm Offset
0.56ppm Noise, 20.8 ENOBs
No Latency: Digital Filter Settles in a Single Cycle.
Each Conversion Is Accurate, Even After an
Input Step
Single Supply 2.7V to 5.5V Operation
Internal Oscillator—No External Components
Required
110dB Min, 50Hz/60Hz Notch Filter
Pin Compatible with 24-Bit LTC2410/LTC2411
U
APPLICATIO S
Direct Sensor Digitizer
Weight Scales
Direct Temperature Measurement
Gas Analyzers
Strain Gauge Transducers
Instrumentation
Data Acquisition
Industrial Process Control
DVMs and Meters
TYPICAL APPLICATIO S
(V
OUT
V
6
OUT
LT1790
3V TO 5V
1 2
4.7µF
V F
CC O
0.1µF
LTC2431
+
REF
SCK
–
REF
ANALOG INPUT RANGE +
IN SDO
–0.5V TO 0.5V
REF REF
–
IN
CS
GND
+ 0.25V) TO 20V
4
0.1µF
V
CC
= INTERNAL OSC/50Hz REJECTION
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION
3-WIRE
SPI INTERFACE
24301 TA01
LTC2430/LTC2431
20-Bit No Latency ∆Σ
with Differential Input and
Differential Reference
DESCRIPTIO
®
The LTC 2430/LTC2431 are 2.7V to 5.5V micropower
20-bit differential ∆Σ analog-to-digital converters with an
integrated oscillator, 3ppm INL and 0.56ppm RMS noise.
They use delta-sigma technology and provide single cycle
settling time for multiplexed applications. Through a
single pin, the LTC2430/LTC2431 can be configured for
better than 110dB differential mode rejection at 50Hz or
60Hz ±2%, or they can be driven by an external oscillator
for a user-defined rejection frequency. The internal oscil-
lator requires no external frequency setting components.
The converters accept any external differential reference
voltage from 0.1V to V
remote sensing measurement configurations. The full-
scale differential input range is from – 0.5V
The reference common mode voltage, V
input common mode voltage, V
dently set anywhere within GND to V
mode input rejection is better than 120dB.
The LTC2430/LTC2431 communicate through a flexible
3-wire digital interface that is compatible with SPI and
TM
MICROWIRE protocols.
, LTC and LT are registered trademarks of Linear Technology Corporation.
No Latency ∆Σ is a trademark of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
TM
ADCs
for flexible ratiometric and
CC
to 0.5V
REF
, and the
REFCM
, may be indepen-
INCM
. The DC common
CC
Total Unadjusted Error
(V = 5V, V = 5V)
CC REF
5
V = 5V
CC
4 V = 5V
REF
V = V = 2.5V
INCM INCM
3
F = GND
O
2
25°C 85°C
1
0
–1
–45°C
–2
–3
–4
–5
–2.5 –2 –1.5 –1 – 0.5 0 0.5 1 1.5 2 2.5
INPUT VOLTAGE (V)
24301 G01
.
REF
24301f
1