18-Bit 1.6Msps SAR ADC 101dB SNR

18-Bit 1.6Msps SAR ADC
101dB SNR
Up to 5V
IN+
0V
2.5V
2.5V to 5V
VDD
VREF
LTC2379-18
Up to 5V
IN–
SPI
I/O
GND
0V
Unrivaled Performance at Only 18mW
The LTC®2379-18 leads a pin-compatible family of no-latency SAR ADCs featuring unrivaled 101dB SNR at 18-bits and 96dB SNR
at 16-bits from 250ksps to 2Msps. Explicit Busy and Chain pins, along with a user-friendly SPI interface, simplify digital timing. A
unique digital gain compression feature eliminates the need for a negative ADC driver supply while preserving the full resolution of
the ADC, dramatically lowering the total power consumption of the signal chain.
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Features
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1.6Msps Throughput Rate
101.2dB SNR (Typ) at fIN = 2kHz
±2LSB INL (Max), ±0.9LSB DNL (Max)
120dB THD (Typ) at fIN = 2kHz
Low Power: 18mW at 1.6Msps, 18μW at 1.6ksps
Power Down Mode: 2.25µW
Fully Differential Input Range ±VREF
Digital Gain Compression Eliminates Negative Rails
–40°C to 125°C Guaranteed Temperature Range
16-pin MSOP and 4mm × 3mm DFN Packages
–40
AMPLITUDE (dBFS)
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fS = 1.6Msps
fIN = 2kHz
SNR = 101.2dB
THD = –119.7dB
–20
–60
–80
–100
–120
–140
–160
–180
0
100 200 300 400 500 600 700 800
FREQUENCY (kHz)
Complete 18-Bit/16-Bit Pin-Compatible SAR ADC Family
250ksps
500ksps
1Msps
1.6Msps
18-Bit
101dB SNR
2376-18
2377-18
2378-18
2379-18
16-Bit
96dB SNR
2376-16
2377-16
2378-16
6.75mW
13.5mW
Power
Consumption
3.4mW
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.
2Msps
2380-16
18mW
19mW
Digital Gain Compression
ANALOG INPUT
DIGITAL OUTPUT
5V
4.5V
+FS = 011…111
ALL 262,144 CODES!
0.5V
0V
–FS = 100…000
REFERENCE = 5V
The LTC2379-18 family offers an innovative Digital Gain Compression (DGC) feature 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 • VREF and full-scale code from VREF to 0.9 • VREF, allowing the amplifier to operate from a single
positive supply. The elimination of the negative supply dramatically reduces the total power consumption of the signal chain and
reduces component count while simplifying the design.
VIN
6V
LTC6655-5
VOUT_S
5V
VCM
LT6350
V+
4.5V
3
4
8
OUT1
IN+
+
10V
0V
–10V
REF
VDD
LTC2379-18
–
1
2.5V
0.5V
2
–
+
VCM
5
V–
6
IN–
OUT2
4.5V
REF/DGC
0.5V
LTC6655 Voltage Reference
Features
Low Noise: 0.25ppmP-P (0.1Hz to 10Hz)
1.25µVP-P for the LTC6655-5
Low Drift: 2ppm/°C Max
High Accuracy: ±0.025% Max
Sinks and Sources Current: ±5mA
Fully Specified from –40°C to 125°C
Available Output Voltages: 1.25V, 2.048V, 2.5V, 3V, 3.3V,
4.096V, 5V
Available in an 8-Lead MSOP Package
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The LTC®6655 is an ultra-stable very low noise voltage reference, with only 1.25µVP-P noise (0.1Hz to 10Hz), temperature drift less
than 2ppm/°C, and initial voltage accuracy within ±0.025%. It can be powered from as little as 500mV above the output voltage,
up to a maximum supply voltage of 13.2V. A shutdown mode allows the power consumption to be reduced to less than 20µA. The
combination of extreme precision and high temperature operating range make the LTC6655 an ideal voltage reference for the most
demanding automotive, industrial and instrumentation applications.
www.linear.com/2379 n 1-800-4-LINEAR
1111C
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