LTC2378-20 Datasheet, PDF (1/28 Pages) Linear Technology – 20-Bit, 1Msps, Low Power SAR ADC with 0.5ppm INL

Features
n _{1Msps Throughput Rate}
n _{±0.5ppm INL (Typ)}
n _{Guaranteed 20-Bit No Missing Codes}
n _{Low Power: 21mW at 1Msps, 21µW at 1ksps}
n _{104dB SNR (Typ) at fIN = 2kHz}
n _{–125dB THD (Typ) at fIN = 2kHz}
n _{Digital Gain Compression (DGC)}
n _{Guaranteed Operation to 85°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. Patents Pending. Protected by U.S. Patents, including
7705765, 7961132, 8319673.
LTC2378-20
20-Bit, 1Msps, Low Power
SAR ADC with 0.5ppm INL
Description
The LTC^®2378-20 is a low noise, low power, high speed
20-bit successive approximation register (SAR) ADC.
Operating from a 2.5V supply, the LTC2378-20 has a
±V_REF fully differential input range with V_REF ranging from
2.5V to 5.1V. The LTC2378-20 consumes only 21mW and
achieves ±2ppm INL maximum, no missing codes at 20
bits with 104dB SNR.
The LTC2378-20 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 1Msps
throughput with no cycle latency makes the LTC2378-20
ideally suited for a wide variety of high speed applications.
An internal oscillator sets the conversion time, easing exter-
nal timing considerations. The LTC2378-20 automatically
powers down between conversions, leading to reduced
power dissipation that scales with the sampling rate.
The LTC2378-20 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
0V
V_REF
0V
+
10Ω
6800pF
V_DD OV_DD CHAIN
IN⁺
RDL/SDI
SDO
3300pF
LTC2378-20
SCK
–
10Ω
IN^–
6800pF
REF
BUSY
CNV
GND ^REF/DGC
2.5V TO 5.1V
237820 TA01
47µF
(X7R, 1210 SIZE)
SAMPLE CLOCK
V_REF
For more information www.linear.com/LTC2378-20
Integral Nonlinearity vs Output Code
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0
262144 524288 786432 1048576
OUTPUT CODE
237820 TA02
237820f
1