LTC2404/LTC2408
4-/8-Channel 24-Bit µPower
No Latency ∆ΣTM ADCs
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FEATURES
DESCRIPTIO
The LTC®2404/LTC2408 are 4-/8-channel 2.7V to 5.5V
micropower 24-bit A/D converters with an integrated
oscillator, 4ppm INL and 0.3ppm RMS noise. They use
delta-sigma technology and provide single cycle digital
filter settling time (no latency delay) for multiplexed
applications. The first conversion after the channel is
changedisalwaysvalid.ThroughasinglepintheLTC2404/
LTC2408 can be configured for better than 110dB rejec-
tion at 50Hz or 60Hz ±2%, or can be driven by an external
oscillator for a user defined rejection frequency in the
range 1Hz to 120Hz. The internal oscillator requires no
external frequency setting components.
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Pin Compatible 4-/8-Channel 24-Bit ADCs
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Single Conversion Digital Filter Settling Time
Simplifies Multiplexing
4ppm INL, No Missing Codes
4ppm Full-Scale Error
0.5ppm Offset
0.3ppm Noise
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Internal Oscillator—No External Components
Required
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110dB Min, 50Hz/60Hz Notch Filter
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Reference Input Voltage: 0.1V to VCC
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Live Zero—Extended Input Range Accommodates
12.5% Overrange and Underrange
Single Supply 2.7V to 5.5V Operation
The converters accept any external reference voltage from
0.1VtoVCC. Withtheirextendedinputconversionrangeof
–12.5% VREF to 112.5% VREF the LTC2404/LTC2408
smoothly resolve the offset and overrange problems of
preceding sensors or signal conditioning circuits.
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Low Supply Current (200µA) and Auto Shutdown
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APPLICATIO S
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Weight Scales
The LTC2404/LTC2408 communicate through a flexible
4-wire digital interface which is compatible with SPI and
MICROWIRETM protocols.
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Direct Temperature Measurement
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Gas Analyzers
Strain Gauge Transducers
Instrumentation
Data Acquisition
Industrial Process Control
6-Digit DVMs
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, LTC and LT are registered trademarks of Linear Technology Corporation.
No Latency ∆Σ is a trademark of Linear Technology Corporation.
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MICROWIRE is a trademark of National Semiconductor Corporation.
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TYPICAL APPLICATIO
Total Unadjusted Error vs Output Code
0.1V TO V
2.7V TO 5.5V
CC
10
V
V
= 5V
= 5V
DD
REF
= 25°C
8
6
7
4
3
2, 8
V
CC
1µF
T
A
O
V
MUXOUT
ADCIN
REF
F
= LOW
SERIAL DATA LINK
9
CH0
4
MICROWIRE AND
SPI COMPATABLE
23
20
19
25
21
24
10 CH1
11 CH2
12 CH3
13 CH4*
14 CH5*
15 CH6*
17 CH7*
CSADC
CSMUX
SCK
2
0
ANALOG
INPUTS
24-BIT
∆Σ ADC
4-/8-CHANNEL
MUX
–2
–4
–6
–8
–10
MPU
CLK
–0.12V
TO
REF
1.12V
D
REF
IN
SDO
V
CC
LTC2404/LTC2408
GND
= INTERNAL OSC/50Hz REJECTION
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION
26
F
O
0
8,338,608
OUTPUT CODE (DECIMAL)
16,777,215
2404/08 TA01
1, 5, 6, 16, 18, 22, 27, 28
*THESE PINS ARE NO CONNECTS ON THE LTC2404
2404/08 TA02
1