LTC2412_15 Datasheet, PDF (1/36 Pages) Linear Technology – 2-Channel Differential Input 24-Bit No Latency ADC

LTC2412
2-Channel Differential Input
24-Bit No Latency ∆Σ ADC
FEATURES
s _{2-Channel Differential Input with Automatic}
Channel Selection (Ping-Pong)
s _{Low Supply Current: 200µA, 4µA in Autosleep}
s _{Differential Input and Differential Reference with}
GND to V_CC Common Mode Range
s _{2ppm INL, No Missing Codes}
s _{2.5ppm Full-Scale Error and 0.1ppm Offset}
s _{0.16ppm Noise, 22.5 Effective Number of Bits}
s _{No Latency: Digital Filter Settles in a Single Cycle and}
Each Channel Conversion is Accurate
s _{Internal Oscillator—No External Components}
Required
s _{110dB Min, 50Hz or 60Hz Notch Filter}
s _{Narrow SSOP-16 Package}
s _{Single Supply 2.7V to 5.5V Operation}
U
APPLICATIO S
s _{Direct Sensor Digitizer}
s _{Weight Scales}
s _{Direct Temperature Measurement}
s _{Gas Analyzers}
s _{Strain-Gage Transducers}
s _{Instrumentation}
s _{Data Acquisition}
s _{Industrial Process Control}
s _{6-Digit DVMs}
DESCRIPTIO
The LTC^®2412 is a 2-channel differential input micropower
24-bit No Latency ∆Σ^TM analog-to-digital converter with
an integrated oscillator. It provides 2ppm INL and 0.16ppm
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.
The converter accepts any external differential reference
voltage from 0.1V to V_CC for flexible ratiometric and
remote sensing measurement configurations. The full-
scale differential input range is from – 0.5V_REF to 0.5V_REF.
The reference common mode voltage, V_REFCM, and the
input common mode voltage, V_INCM, may be indepen-
dently set anywhere within the GND to V_CC. The DC
common mode input rejection is better than 140dB.
The LTC2412 communicates through a flexible 3-wire
digital interface which is compatible with SPI and
MICROWIRE^TM 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.
TYPICAL APPLICATIO
THERMOCOUPLE
2.7V TO 5.5V
1µF
1
V_CC
2 _REF+
4 _CH0+
14
F_O
LTC2412
5 _CH0–
SCK ¹³
3 _REF–
6 _CH1+
7 _CH1–
8, 9, 10, 15, 16
GND
12
SDO
11
CS
2412 TA01
V_CC
= INTERNAL OSC/50Hz REJECTION
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION
3-WIRE
SPI INTERFACE
Total Unadjusted Error vs Input
1.5
1.0
0.5
0
–0.5 ^VRC_E^C_F+^==55VV
REF^– = GND
–1.0 ^VREF ^{= 5V}
V_INCM = 2.5V
F_O = GND
–1.5
–2.5 –2 –1.5 –1 –0.5 0
T_A = 90°C
T_A = 25°C
T_A = –45°C
0.5 1 1.5 2 2.5
V_IN (V)
2412 TA02
2412f
1