LTC2376-18_15 Datasheet, PDF (1/24 Pages) Linear Technology – 18-Bit, 250ksps, Low Power SAR ADC with 102dB SNR

FEATURES
n _{250ksps Throughput Rate}
n _{±1.75LSB INL (Max)}
n _{Guaranteed 18-Bit No Missing Codes}
n _{Low Power: 3.4mW at 250ksps, 3.4μW at 250sps}
n _{102dB SNR (Typ) at fIN = 2kHz}
n _{–126dB 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
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LTC2376-18
18-Bit, 250ksps, Low Power
SAR ADC with 102dB SNR
DESCRIPTION
The LTC^®2376-18 is a low noise, low power, high speed
18-bit successive approximation register (SAR) ADC.
Operating from a 2.5V supply, the LTC2376-18 has a
±V_REF fully differential input range with V_REF ranging from
2.5V to 5.1V. The LTC2376-18 consumes only 3.4mW and
achieves ±1.75LSB INL maximum, no missing codes at
18 bits with 102dB SNR.
The LTC2376-18 has a high speed SPI-compatible se-
rial interface that supports 1.8V, 2.5V, 3.3V and 5V logic
while also featuring a daisy-chain mode. The fast 250ksps
throughput with no cycle latency makes the LTC2376-18
ideally suited for a wide variety of high speed applications.
An internal oscillator sets the conversion time, easing exter-
nal timing considerations. The LTC2376-18 automatically
powers down between conversions, leading to reduced
power dissipation that scales with the sampling rate.
The LTC2376-18 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
6800pF
V_DD OV_DD CHAIN
IN⁺
RDL/SDI
0V
SDO
V_REF
0V
3300pF
LTC2376-18
SCK
–
20Ω
IN^–
6800pF
REF
BUSY
CNV
GND ^REF/DGC
2.5V TO 5.1V
237618 TA01
47μF
(X5R, 0805 SIZE)
SAMPLE CLOCK
V_REF
32k Point FFT f_S = 250ksps, f_IN = 2kHz
0
SNR = 102.3dB
–20
THD = –126dB
SINAD = 102.2dB
–40
SFDR = 127dB
–60
–80
–100
–120
–140
–160
–180
0
25
50
75 100 125
FREQUENCY (kHz)
237618 TA02
237618f
1