LTC2383CMS-16#PBF Linear Technology, LTC2383CMS-16#PBF Datasheet - Page 13

• Manufacturer Part Number: LTC2383CMS-16#PBF
• Description: IC, ADC, 16BIT, 1MSPS, Serial-SPI, MSOP16
• Manufacturer: Linear Technology

Specifications of LTC2383CMS-16#PBF

• Resolution (bits): 16bit
• Sampling Rate: 1MSPS
• Input Channel Type: Differential
• Data Interface: Serial, SPI
• Supply Voltage Range - Analog: 2.375V To 2.625V
• Supply Current: 5.2mA
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
Table 2. SNR, THD vs R
ADC REFERENCE
The LTC2383-16 requires an external reference to define its
input range. A low noise, low temperature drift reference
is critical to achieving the full datasheet performance
of the ADC. Linear Technology offers a portfolio of high
performance references designed to meet the needs of
many applications. With its small size, low power and high
accuracy, the LTC6652-2.5 is particularly well suited for
use with the LTC2383-16. The LTC6652-2.5 offers 0.05%
(max) initial accuracy and 5ppm/°C (max) temperature
coefficient for high precision applications. The LTC6652-2.5
is fully specified over the H-grade temperature range and
complements the extended temperature operation of the
LTC2383-16 up to 125°C. We recommend bypassing the
LTC6652-2.5 with a 47μF ceramic capacitor (X5R, 0805
size) close to the REF pin. All performance curves shown
in this datasheet were obtained using the LTC6652-2.5.
The REF pin of the LTC2383-16 draws charge (Q
from the 47μF bypass capacitor during each conversion
cycle. The reference replenishes this charge with a DC
current, I
REF pin, I
code. If the LTC2383-16 is used to continuously sample
a signal at a constant rate, the LTC6652-2.5 will keep the
deviation of the reference voltage over the entire code
span to less than 0.5LSBs.
100k
(Ω)
10k
50k
R
IN
CNV
REF
1.24k
6.19k
12.4k
REF
(Ω)
R1
, depends on the sampling rate and output
= Q
PERIOD
CONV
IDLE
1.24k
6.19k
12.4k
(Ω)
R2
IN
/t
for ±10V Single-Ended Input Signal.
CYC
100k
. The DC current draw of the
(Ω)
10k
50k
R3
5.49k
1.1k
(Ω)
11k
R4
Figure 8. CNV Waveform Showing Burst Sampling
SNR
(dB)
92
91
91
THD
(dB)
CONV
–96
–96
–96
)
When idling, the REF pin on the LTC2383-16 draws only a
small leakage current (< 1μA). In applications where a burst
of samples is taken after idling for long periods as shown
in Figure 8, I
a maximum of 910μA at 1Msps. This step in DC current
draw triggers a transient response in the reference that
must be considered since any deviation in the reference
output voltage will affect the accuracy of the output code. In
applications where the transient response of the reference
is important, the fast settling LTC6655-2.5 reference
is recommended. Inserting a 1Ω resistor between the
47μF bypass capacitor and reference output as shown in
Figure 9 helps to improve the transient settling time and
minimize the reference voltage deviation.
DYNAMIC PERFORMANCE
Fast Fourier Transform (FFT) techniques are used to test
the ADC’s frequency response, distortion and noise at the
rated throughput. By applying a low distortion sine wave
and analyzing the digital output using an FFT algorithm, the
ADC’s spectral content can be examined for frequencies
outside the fundamental. The LTC2383-16 provides
guaranteed tested limits for both AC distortion and noise
measurements.
Figure 9. LTC6655-2.5 Driving REF of LTC2381-16
LTC6655-2.5
PERIOD
IDLE
REF
quickly goes from approximately 0μA to
V
V
OUT_S
OUT_F
1Ω
47μF
LTC2383-16
LTC2383-16
238316 F08
238316 F09
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