LTC2435_15 Datasheet, PDF (1/42 Pages) Linear Technology – 20-Bit No Latency ADCs with Differential Input and Differential Reference

LTC2435/LTC2435-1
Features
20-Bit No Latency ∆∑™
ADCs with Differential Input and
Differential Reference
Description
n _{2× Speed Up Version of the LTC2430: 15Hz Output}
Rate, 60Hz Notch—LTC2435; 13.75Hz Output Rate,
Simultaneous 50Hz/60Hz Notch—LTC2435-1
n _{Differential Input and Differential Reference with}
GND to V_CC Common Mode Range
n _{3ppm INL, No Missing Codes}
n _{10ppm Gain Error}
n _{0.8ppm Noise}
n _{Single Conversion Settling Time for Multiplexed}
Applications
n _{Internal Oscillator—No External Components Required}
n _{Single Supply 2.7V to 5.5V Operation}
n _{Low Supply Current (200µA,4µA in Auto Sleep)}
n _{20-Bit ADC in Narrow SSOP-16 Package}
(SO-8 Footprint)
Applications
n _{Direct Sensor Digitizer}
n _{Weight Scales}
n _{Direct Temperature Measurement}
n _{Gas Analyzers}
n _{Strain Gage Transducers}
n _{Instrumentation}
n _{Data Acquisition}
n _{Industrial Process Control}
n _{6-Digit DVMs}
The LTC^®2435/LTC2435-1 are 2.7V to 5.5V micropower
20‑bit differential ∆∑ analog to digital converters with
integrated oscillator, 3ppm INL and 0.8ppm RMS noise.
They use delta-sigma technology and provide single
cycle 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%, or it can be driven by an external oscillator
for a user defined rejection frequency. The LTC2435-1
can be configured for better than 87dB input differential
mode rejection over the range of 49Hz to 61.2Hz (50Hz
and 60Hz ±2% simultaneously). The internal oscillator
requires no external frequency setting components.
The converters accept any external differential reference
voltage from 0.1V to V_CC for flexible ratiometric and re-
mote 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 independently set
anywhere within the GND to V_CC range of the LTC2435/
LTC2435-1. The DC common mode input rejection is
better than 120dB.
The LTC2435/LTC2435-1 communicate through a flexible
3-wire digital interface which is compatible with SPI and
MICROWIRE™ protocols.
L, LT, LTC and LTM are registered trademarks and C-Load and No Latency ∆∑ are trademarks
of Linear Technology Corporation. Protected by U.S. Patents including 6140950, 6169506.
Typical Applications
2.7V TO 5.5V
1μF
REFERENCE
VOLTAGE
0.1V TO V_CC
2 _VCC
F_O ¹⁴
LTC2435/
LTC2435-1
3 _REF+
4 _REF–
SCK ¹³
ANALOG INPUT RANGE ⁵ _IN+
–0.5V_REF TO 0.5V_REF
6 _IN–
1, 7, 8, 9, 10, 15, 16 _GND
SDO ¹²
CS ¹¹
V_CC
= INTERNAL OSC/50Hz REJECTION (LTC2435)
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION (LTC2435)
= INTERNAL 50Hz/60Hz REJECTION (LTC2435-1)
3-WIRE
SPI INTERFACE
2435 TA01
Integral Nonlinearity vs Input
10
8
6
4
2
T_A = 25°C
0
T_A = 85°C
–2
T_A = –45°C
–4
–6
F_O = GND
V_CC = 5V
–8 ^VREF ^{= 5V}
V_INCM = V_INCM = 2.5V
–10
–2.5 –1.5 –0.5 0.5 1.5
INPUT VOLTAGE (V)
2.5
2435 TA01b
For more information www.linear.com/LTC2435
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