LTC2412
2-Channel Differential Input
24-Bit No Latency ∆Σ ADC
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DESCRIPTIO
FEATURES
TheLTC®2412isa2-channeldifferentialinputmicropower
24-bit No Latency ∆ΣTM analog-to-digital converter with
anintegratedoscillator.Itprovides2ppmINLand0.16ppm
RMS noise over the entire supply range. The two differen-
tial channels are converted alternately with channel ID
included in the conversion results. It uses delta-sigma
technology and provides single conversion settling of the
digital filter. Through a single pin, the LTC2412 can be
configured for better than 110dB input differential mode
rejection at 50Hz or 60Hz ±2%, or it can be driven by an
external oscillator for a user defined rejection frequency.
The internal oscillator requires no external frequency
setting components.
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2-Channel Differential Input with Automatic
Channel Selection (Ping-Pong)
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Low Supply Current: 200µA, 4µA in Autosleep
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Differential Input and Differential Reference with
GND to VCC Common Mode Range
2ppm INL, No Missing Codes
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2.5ppm Full-Scale Error and 0.1ppm Offset
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0.16ppm Noise, 22.5 Effective Number of Bits
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No Latency: Digital Filter Settles in a Single Cycle and
Each Channel Conversion is Accurate
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Internal Oscillator—No External Components
Required
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110dB Min, 50Hz or 60Hz Notch Filter
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Narrow SSOP-16 Package
The converter accepts any external differential reference
voltage from 0.1V to VCC for flexible ratiometric and
remote sensing measurement configurations. The full-
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Single Supply 2.7V to 5.5V Operation
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APPLICATIO S
scale differential input range is from –0.5VREF to 0.5VREF
.
The reference common mode voltage, VREFCM, and the
input common mode voltage, VINCM, may be indepen-
dently set anywhere within the GND to VCC. The DC
common mode input rejection is better than 140dB.
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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 LTC2412 communicates 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.
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TYPICAL APPLICATIO
Total Unadjusted Error vs Input
1.5
2.7V TO 5.5V
V
CC
1µF
1.0
= INTERNAL OSC/50Hz REJECTION
1
2
4
14
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION
V
F
O
CC
+
+
0.5
0
REF
CH0
LTC2412
5
3
13
12
11
–
T
T
= 90°C
= 25°C
CH0
SCK
SDO
CS
A
A
V
= 5V
CC
–0.5
–1.0
–1.5
+
THERMOCOUPLE
REF = 5V
3-WIRE
SPI INTERFACE
–
–
REF
REF = GND
T
= –45°C
A
6
7
V
V
= 5V
INCM
= GND
+
REF
CH1
CH1
= 2.5V
–
F
O
8, 9, 10, 15, 16
–2.5 –2 –1.5 –1 –0.5
V
0
0.5
1
1.5
2
2.5
GND
2412 TA01
(V)
2412 TA02
IN
2412f
1