FEATURES
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LTC1402
Serial 12-Bit, 2.2Msps
Sampling ADC with Shutdown
DESCRIPTIO
The LTC
®
1402 is a 12-bit, 2.2Msps sampling A/D con-
verter. This high performance device includes a high dy-
namic range sample-and-hold and a precision reference.
It operates from a single 5V supply or dual
±5V
supplies
and draws only 90mW from 5V.
The versatile differential input offers a unipolar range of
4.096V and a bipolar range of
±2.048V
for dual supply
systems where high performance op amps perform best,
eliminating the need for special translation circuitry.
The high common mode rejection allows users to elimi-
nate ground loops and common mode noise by measuring
signals differentially from the source.
Outstanding AC performance includes 72dB S/(N + D) and
–93dB SFDR at the Nyquist input frequency of 1.1MHz
with dual
±5V
supplies and –84dB SFDR with a single 5V
supply.
The LTC1402 has two power saving modes: Nap and
Sleep. Nap mode consumes only 15mW of power and can
wake up and convert immediately. In Sleep mode, it
typically consumes 10µW of power. Upon power-up from
Sleep mode, a reference ready (REFRDY) signal is avail-
able in the serial data word to indicate that the reference
has settled and the chip is ready to convert.
The 3-wire serial port allows compact and efficient data
transfer to a wide range of microprocessors, microcon-
trollers and DSPs. A digital output driver power supply pin
allows direct connection to 3V or lower logic.
Sample Rate: 2.2Msps
72dB S/(N + D) and –89dB THD at Nyquist
Power Dissipation: 90mW (Typ)
80MHz Full Power Bandwidth Sampling
No Missing Codes over Temperature
Available in 16-Pin Narrow SSOP Package
Single Supply 5V or
±5V
Operation
Nap Mode with Instant Wake-Up: 15mW
Sleep Mode: 10µW
True Differential Inputs Reject Common Mode Noise
Input Range (1mV/LSB): 0V to 4.096V or
±2.048V
Internal Reference Can Be Overdriven Externally
3-Wire Interface to DSPs and Processors (SPI and
MICROWIRE
TM
Compatible)
APPLICATIO S
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Telecommunications
High Speed Data and Signal Acquisition
Digitally Multiplexed Data Acquisition Systems
Digital Radio Receivers
Spectrum Analysis
Low Power and Battery-Operated Systems
Handheld or Portable Instruments
Imaging Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corp.
BLOCK DIAGRA
10µF
A
IN+
A
IN–
V
REF
10µF
3
SAMPLE-
AND-HOLD
5V
1 AV
DD
12 DV
DD
3V OR 5V
11 OV
DD
5 Harmonic THD, 2nd, 3rd and SFDR
vs Input Frequency (Unipolar)
0
–10
–20
THD, SFDR, 2ND 3RD (dB)
12-BIT ADC
4
5
OUTPUT
BUFFER
10
D
OUT
–30
–40
–50
–60
–70
–80
–90
–100
–110
4.096V
64k
–
8
2.048
REFERENCE
2 AGND1
6 AGND2
TIMING
LOGIC
13 DGND
9 OGND
16
15
1402 TA01
GAIN
7
64k
LTC1402
14
+
BIP/UNI
CONV
SCK
V
SS
10µF
–5V OR 0V
–120
10
4
U
W
U
THD
SFDR
2ND
3RD
f
SAMPLE
= 2.22MHz
10
5
10
6
INPUT FREQUENCY (Hz)
10
7
1401 G05
1
LINER [ LINEAR TECHNOLOGY ]
