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LTC1274_15 Datasheet, PDF (1/20 Pages) Linear Technology – 12-Bit, 10mW, 100ksps ADCs with 1A Shutdown | |||
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LTC1274/LTC1277
12-Bit, 10mW, 100ksps
ADCs with 1µA Shutdown
FEATURES
â Low Power Dissipation: 10mW
â Sample Rate: 100ksps
â Samples Inputs Beyond Nyquist, 72dB S/(N + D)
and 82dB THD at fIN = 100kHz
â Single Supply 5V or ±5V Operation
â Power Shutdown to 1µA in Sleep Mode
â 180µA Nap Mode (LTC1277) with Instant Wake-Up
â Internal Reference Can Be Overdriven
â Internal Synchronized Clock
â 0V to 4.096V or ±2.048V Input Ranges (1mV/LSB)
â 24-Lead SO Package
APPLICATI S
â Battery-Powered Portable Systems
â High Speed Data Acquisition for PCs
â Digital Signal Processing
â Multiplexed Data Acquisition Systems
â Audio and Telecom Processing
â Spectrum Analysis
DESCRIPTIO
The LTC®1274/LTC1277 are 8µs sampling 12-bit A/D
converters which draw only 2mA (typ) from single 5V or
±5V supplies. These easy-to-use devices come complete
with a 2µs sample-and-hold, a precision reference and an
internally trimmed clock. Unipolar and bipolar conversion
modes add to the flexibility of the ADCs.
Two power-down modes are available in the LTC1277. In
Nap mode, the LTC1277 draws only 180µA and the instant
wake-up from Nap mode allows the LTC1277 to be pow-
ered down even during brief inactive periods. In Sleep
mode only 1µA will be drawn. A REFRDY signal is used to
show the ADC is ready to sample after waking up from
Sleep mode. The LTC1274 also provides the Sleep mode
and REFRDY signal.
The A/D converters convert 0V to 4.096V unipolar inputs
from a single 5V supply or ±2.048V bipolar inputs from
±5V supplies.
The LTC1274 has a single-ended input and a 12-bit
parallel data format. The LTC1277 offers a differential
input and a 2-byte read format. The bipolar mode is
formatted as 2âs complement for the LTC1274 and offset
binary for the LTC1277.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATI
Single 5V Supply, 10mW, 100kHz, 12-Bit ADC
LTC1277
2.42V
VREF OUTPUT
ANALOG 1
DIFFERENTIAL INPUTS 2
(0V TO 4.096V) 3
+
4
10µF
0.1µF 5
6
7
8
9
10
8-BIT 11
PARALLEL
BUS
12
AIN+
AINâ
VREF
AGND
REFRDY
SLEEP
NAP
D7
D6
D5
D4
DGND
24
VDD 23
VSS 22
BUSY
21
CS
20
RD
19
CONVST
18
HBEN
17
VLOGIC 16
D0/8
15
D1/9
14
D2/10
13
D3/11
+
10µF
µP
CONTROL
LINES
5V
0.1µF
OPTIONAL 3V SUPPLY
TO INTERFACE WITH 3V
PROCESSOR
LTC1274/77 ⢠TA01
Supply Current vs Sample Rate with
Sleep and Nap Modes
10000
CREF = 4.7µF
WITHOUT SLEEP OR NAP
1000
NAP MODE
100
10
1
0.1
NAP = REFRDY
(SLEEP MODE)
NAP = 5V
(SLEEP MODE)
1 10 100 1k 10k 100k
SAMPLE RATE (Hz)
LTC1274/77 ⢠TA02
1
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