LTC2435/LTC2435-1
20-Bit No Latency ∆ΣTM
ADCs with Differential Input and
Differential Reference
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DESCRIPTIO
FEATURES
The LTC®2435/2435-1 are 2.7V to 5.5V micropower
20-bit differential ∆Σ analog to digital converters with
integrated oscillator, 3ppm INL and 0.8ppm RMS noise.
Theyusedelta-sigmatechnologyandprovidesinglecycle
settling time for multiplexed applications. Through a
single pin, the LTC2435 can be configured for better than
110dB input differential mode rejection at 50Hz or 60Hz
±2%, oritcanbedrivenbyanexternaloscillatorforauser
defined rejection frequency. The LTC2435-1 can be con-
figured for better than 87dB input differential mode rejec-
tion over the range of 49Hz to 61.2Hz (50Hz and 60Hz
±2% simultaneously). The internal oscillator requires no
external frequency setting components.
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2× Speed Up Version of the LTC2430: 15Hz Output
Rate, 60Hz Notch—LTC2435; 13.75Hz Output Rate,
Simultaneous 50Hz/60Hz Notch—LTC2435-1
Differential Input and Differential Reference with
GND to VCC Common Mode Range
3ppm INL, No Missing Codes
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10ppm Gain Error
0.8ppm Noise
Single Conversion Settling Time for Multiplexed
Applications
Internal Oscillator—No External Components
Required
Single Supply 2.7V to 5.5V Operation
Low Supply Current (200µA,4µA in Auto Sleep)
20-Bit ADC in Narrow SSOP-16 Package
(SO-8 Footprint)
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The converters accept any external differential reference
voltage from 0.1V to VCC for flexible ratiometric and
remote sensing measurement configurations. The full-
scale differential input range is from –0.5VREF to 0.5VREF
.
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The reference common mode voltage, VREFCM, and the
input common mode voltage, VINCM, may be indepen-
dently set anywhere within the GND to VCC range of the
LTC2435/LTC2435-1. The DC common mode input rejec-
tion is better than 120dB.
APPLICATIO S
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Direct Sensor Digitizer
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Weight Scales
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Direct Temperature Measurement
Gas Analyzers
Strain Gage Transducers
Instrumentation
Data Acquisition
Industrial Process Control
6-Digit DVMs
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The LTC2435/LTC2435-1 communicate through a flexible
3-wire digital interface which is compatible with SPI and
MICROWIRETM 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.
Protected by U.S. Patents including 6140950, 6169506.
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Integral Nonlinearity vs Input
TYPICAL APPLICATIO S
10
8
6
2.7V TO 5.5V
V
CC
1µF
4
2
= INTERNAL OSC/50Hz REJECTION (LTC2435)
2
14
T
T
= 25°C
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION (LTC2435)
= INTERNAL 50Hz/60Hz REJECTION (LTC2435-1)
A
V
F
CC
LTC2435/
O
T
= 85°C
A
0
LTC2435-1
–2
–4
–6
–8
–10
3
4
= –45°C
+
A
13
REFERENCE
VOLTAGE
REF
REF
SCK
–
0.1V TO V
F
= GND
CC
O
3-WIRE
SPI INTERFACE
V
V
V
= 5V
CC
REF
INCM
5
6
12
11
+
ANALOG INPUT RANGE
= 5V
= V
IN
SDO
CS
–0.5V
TO 0.5V
= 2.5V
–0.5
REF
REF
INCM
–
IN
1, 7, 8, 9, 10, 15, 16
–2.5
–1.5
0.5
1.5
2.5
GND
2435 TA01
INPUT VOLTAGE (V)
2435 G04
24351fa
1