LTC1402_15 Datasheet, PDF (1/24 Pages) Linear Technology – Serial 12-Bit, 2.2Msps Sampling ADC with Shutdown

LTC1402
Serial 12-Bit, 2.2Msps
Sampling ADC with Shutdown
FEATURES
s _{Sample Rate: 2.2Msps}
s _{72dB S/(N + D) and –89dB THD at Nyquist}
s _{Power Dissipation: 90mW (Typ)}
s _{80MHz Full Power Bandwidth Sampling}
s _{No Missing Codes over Temperature}
s _{Available in 16-Pin Narrow SSOP Package}
s _{Single Supply 5V or ±5V Operation}
s _{Nap Mode with Instant Wake-Up: 15mW}
s _{Sleep Mode: 10µW}
s _{True Differential Inputs Reject Common Mode Noise}
s _{Input Range (1mV/LSB): 0V to 4.096V or ±2.048V}
s _{Internal Reference Can Be Overdriven Externally}
s _{3-Wire Interface to DSPs and Processors (SPI and}
MICROWIRE^TM Compatible)
U
APPLICATIO S
s Telecommunications
s _{High Speed Data and Signal Acquisition}
s _{Digitally Multiplexed Data Acquisition Systems}
s _{Digital Radio Receivers}
s _{Spectrum Analysis}
s _{Low Power and Battery-Operated Systems}
s _{Handheld or Portable Instruments}
s _{Imaging Systems}
, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corp.
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.
BLOCK DIAGRA
10µF
A_IN+
3
A_IN–
4
5
V_REF
10µF
SAMPLE-
AND-HOLD
4.096V
64k
–
7
GAIN
64k
+
LTC1402
14 V_SS
10µF
–5V OR 0V
1 AV_DD
5V
3V OR 5V
12 DV_DD 11 OV_DD
12-BIT ADC
OUTPUT
BUFFER
10
D_OUT
2.048
REFERENCE
2 AGND1 6 AGND2
TIMING
LOGIC
13 DGND 9 OGND
8
BIP/UNI
16 _CONV
15
SCK
1402 TA01
5 Harmonic THD, 2nd, 3rd and SFDR
vs Input Frequency (Unipolar)
0
THD
–10
SFDR
–20
2ND
–30
3RD
–40 ^{fSAMPLE = 2.22MHz}
–50
–60
–70
–80
–90
–100
–110
–120
10⁴
10⁵
10⁶
INPUT FREQUENCY (Hz)
10⁷
1401 G05
1