Document
Features
n 71.1dB SNR n 88dB SFDR n Low Power: 79mW/47mW/34mW n Single 1.8V Supply n CMOS, DDR CMOS or DDR LVDS Outputs n Selectable Input Ranges: 1VP-P to 2VP-P n 800MHz Full-Power Bandwidth S/H n Optional Data Output Randomizer n Optional Clock Duty Cycle Stabilizer n Shutdown and Nap Modes n Serial SPI Port for Configuration n Pin Compatible 14-Bit and 12-Bit Versions n 40-Pin (6mm × 6mm) QFN Package
Applications
n Communications n Cellular Base Stations n Software Defined Radios n Portable Medical Imaging n Multi-Channel Data Acquisition n Nondestructive Testing
LTC2258-12 LTC2257-12/LTC2256-12
12-Bit, 65/40/25Msps Ultralow Power 1.8V ADCs
Description
The LTC®2258-12/LTC2257-12/LTC2256-12 are sampling 12-bit A/D converters designed for digitizing high frequency, wide dynamic range signals. They are perfect for demanding communications applications with AC performance that includes 71.1dB SNR and 88dB spurious free dynamic range (SFDR). Ultralow jitter of 0.17psRMS allows undersampling of IF frequencies with excellent noise performance.
DC specs include ±0.3LSB INL (typical), ±0.1LSB DNL (typical) and no missing codes over temperature. The transition noise is a low 0.3LSBRMS.
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.
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 allows high performance at full speed for a wide range of clock duty cycles.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
1.8V VDD
ANALOG INPUT
+
INPUT S/H
–
12-BIT PIPELINED ADC CORE
CORRECTION LOGIC
CLOCK/DUTY CYCLE
CONTROL
65MHz
GND
CLOCK
OUTPUT DRIVERS
1.2V TO 1.8V
OVDD
D11 • CMOS • OR • LVDS D0
OGND
225812 TA01a
For more information www.linear.com/LTC2258-12
AMPLITUDE (dBFS)
LTC2258-12 2-Tone FFT, fIN = 68MHz and 69MHz
0 –10 –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 –120
0
10
20
30
FREQUENCY (MHz)
225812 TA01b
225812fd
1
LTC2258-12 LTC2257-12/LTC2256-12
Absolute Maximum Ratings (Notes 1, 2)
Supply Voltages (VDD, OVDD)........................ –0.3V to 2V Analog Input Voltage (AIN+, AIN–, PAR/SER, SENSE) (Note 3)........... –0.3V to (VDD + 0.2V) Digital Input Voltage (ENC+, ENC–, CS,
SDI, SCK) (Note 4)..................................... –0.3V to 3.9V
SDO (Note 4).............................................. –0.3V to 3.9V
Digital Output Voltage................. –0.3V to (OVDD + 0.3V) Operating Temperature Range:
LTC2258C, LTC2257C, LTC2256C............. 0°C to 70°C
LTC2258I, LTC2257I, LTC2256I............–40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Pin Configurations
FULL-RATE CMOS OUTPUT MODE TOP VIEW
DOUBLE DATA RA.