LTC2379-18_15 Datasheet, PDF (1/26 Pages) Linear Technology – 18-Bit, 1.6Msps, Low Power SAR ADC with 101.2dB SNR

FEATURES
n _{1.6Msps Throughput Rate}
n _{±2LSB INL (Max)}
n _{Guaranteed 18-Bit No Missing Codes}
n _{Low Power: 18mW at 1.6Msps, 18μW at 1.6ksps}
n _{101.2dB SNR (typ) at fIN = 2kHz}
n _{–120dB THD (typ) at fIN = 2kHz}
n _{Digital Gain Compression (DGC)}
n _{Guaranteed Operation to 125°C}
n _{2.5V Supply}
n _{Fully Differential Input Range ±VREF}
n _{VREF Input Range from 2.5V to 5.1V}
n _{No Pipeline Delay, No Cycle Latency}
n _{1.8V to 5V I/O Voltages}
n _{SPI-Compatible Serial I/O with Daisy-Chain Mode}
n _{Internal Conversion Clock}
n _{16-Lead MSOP and 4mm × 3mm DFN Packages}
APPLICATIONS
n _{Medical Imaging}
n _{High Speed Data Acquisition}
n _{Portable or Compact Instrumentation}
n _{Industrial Process Control}
n _{Low Power Battery-Operated Instrumentation}
n _ATE
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
SoftSpan is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents including 7705765.
LTC2379-18
18-Bit, 1.6Msps, Low Power
SAR ADC with 101.2dB SNR
DESCRIPTION
The LTC^®2379-18 is a low noise, low power, high speed
18-bit successive approximation register (SAR) ADC.
Operating from a 2.5V supply, the LTC2379-18 has a
±V_REF fully differential input range with V_REF ranging from
2.5V to 5.1V. The LTC2379-18 consumes only 18mW and
achieves ±2LSB INL maximum, no missing codes at 18 bits
with 101.2dB SNR.
The LTC2379-18 has a high speed SPI-compatible serial
interface that supports 1.8V, 2.5V, 3.3V and 5V logic while
also featuring a daisy-chain mode. The fast 1.6Msps
throughput with no cycle latency makes the LTC2379-18
ideally suited for a wide variety of high speed applications.
An internal oscillator sets the conversion time, easing exter-
nal timing considerations. The LTC2379-18 automatically
powers down between conversions, leading to reduced
power dissipation that scales with the sampling rate.
The LTC2379-18 features a unique digital gain compres-
sion (DGC) function, which eliminates the driver amplifier’s
negative supply while preserving the full resolution of the
ADC. When enabled, the ADC performs a digital scaling
function that maps zero-scale code from 0V to 0.1 • V_REF
and full-scale code from V_REF to 0.9 • V_REF. For a typical
reference voltage of 5V, the full-scale input range is now
0.5V to 4.5V, which provides adequate headroom for
powering the driving amplifier from a single 5.5V supply.
TYPICAL APPLICATION
2.5V 1.8V TO 5V
10μF
0.1μF
V_REF
+
20Ω
3300pF
V_DD OV_DD CHAIN
IN⁺
RDL/SDI
0V
SDO
V_REF
0V
3300pF
LTC2379-18
SCK
–
20Ω
IN^–
3300pF
REF
BUSY
CNV
GND ^REF/DGC
SAMPLE CLOCK
V_REF
2.5V TO 5.1V
237918 TA01
47μF
(X5R, 0805 SIZE)
32k Point FFT f_S = 1.6Msps, f_IN = 2kHz
0
SNR = 101.2dB
–20
THD = –120dB
SINAD = 101.1dB
–40
SFDR = 121dB
–60
–80
–100
–120
–140
–160
–180
0
100 200 300 400 500 600 700 800
FREQUENCY (kHz)
237918 TA02
237918fa
1