Electrical Specifications Subject to Change
LTC2258-12
LTC2257-12/LTC2256-12
12-Bit, 65/40/2 5Msps
Ultralow Power 1.8V ADCs
FEATURES
DESCRIPTION
The LTC®2258-12/LTC2257-12/LTC2256-12 are sam-
pling 12-bit A/D converters designed for digitizing high
frequency, wide dynamic range signals. They are perfect
for demanding communications applications with AC
performancethatincludes71.1dBSNRand85dBspurious
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71.1dB SNR
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88dB SFDR
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Low Power: 79mW/47mW/34mW
Single 1.8V Supply
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CMOS, DDR CMOS or DDR LVDS Outputs
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free dynamic range (SFDR). Ultralow jitter of 0.17ps
Selectable Input Ranges: 1V to 2V
RMS
P-P
P-P
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allows undersampling of IF frequencies with excellent
800MHz Full-Power Bandwidth S/H
noise performance.
Optional Data Output Randomizer
Optional Clock Duty Cycle Stabilizer
Shutdown and Nap Modes
DC specs include 0.3LSB INL (typical), 0.1LSB DNL
(typical) and no missing codes over temperature. The
transition noise is a low 0.3LSB
Serial SPI Port for Configuration
.
RMS
Pin Compatible 14-Bit and 12-Bit Versions
The digital outputs can be either full rate CMOS, double
data rate CMOS, or double data rate LVDS. A separate
output power supply allows the CMOS output swing to
range from 1.2V to 1.8V.
40-Pin (6mm × 6mm) QFN Package
APPLICATIONS
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Communications
The ENC and ENC inputs may be driven differentially
or single-ended with a sine wave, PECL, LVDS, TTL or
CMOS inputs. An optional clock duty cycle stabilizer al-
lows high performance at full speed for a wide range of
clock duty cycles.
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Cellular Base Stations
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Software Defined Radios
Portable Medical Imaging
Multi-Channel Data Acquisition
Nondestructive Testing
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L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
1.8V
2-Tone FFT, fIN = 68MHz and 69MHz
1.2V
TO 1.8V
V
DD
0
OV
DD
–10
–20
–30
–40
–50
–60
–70
D11
+
–
12-BIT
PIPELINED
ADC CORE
CMOS
OR
LVDS
•
•
•
CORRECTION
LOGIC
ANALOG
INPUT
OUTPUT
DRIVERS
INPUT
S/H
D0
OGND
–80
–90
CLOCK/DUTY
CYCLE
CONTROL
–100
–110
–120
225812 TA01a
GND
0
20
10
FREQUENCY (MHz)
30
65MHz
CLOCK
225812 TA01b
225812p
1