LTC1410CG Linear Technology, LTC1410CG Datasheet - Page 8

• Manufacturer Part Number: LTC1410CG
• Description: IC A/D CONV 12BIT SAMPLNG 28SSOP
• Manufacturer: Linear Technology

Specifications of LTC1410CG

• Number Of Bits: 12
• Sampling Rate (per Second): 1.25M
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 230mW
• Voltage Supply Source: Dual ±
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP (0.200", 5.30mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
LTC1410
DYNAMIC PERFORMANCE
The LTC1410 has excellent high speed sampling capabil-
ity. Fast Four Transform (FFT) test 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 algo-
rithm, the ADC’s spectral content can be examined for
frequencies outside the fundamental.
Signal-to-Noise Ratio
The Signal-to-Noise plus Distortion ratio [S/(N + D)] is the
ratio between the RMS amplitude of the fundamental input
frequency to the RMS amplitude of all other frequency
components at the ADC output. The output is band limited
8
Figure 2a. LTC1410 Nonaveraged 4096 Point FFT, 100kHz Input
Figure 2b. LTC1410 Nonaveraged 4096 Point FFT, 600kHz Input
–100
–120
–100
–120
–20
–40
–60
–80
–20
–40
–60
–80
0
0
0
0
f
f
SFDR = 84.7dB
SINAD = 71.7dB
SAMPLE
IN
100
100
= 599.975kHz
U
= 1.25MHz
200
200
FREQUENCY (kHz)
FREQUENCY (kHz)
INFORMATION
U
300
300
f
f
SFDR = 90.1dB
SINAD = 72.4dB
SAMPLE
IN
400
400
= 100.098kHz
W
= 1.25MHz
500
500
1410 F02b
1410 F02a
600
600
U
to frequencies from above DC and below half the sampling
frequency. Figures 2a and 2b shows a typical spectral
content with a 1.25MHz sampling rate for 100kHz and
600kHz inputs. The dynamic performance is excellent for
input frequencies up to the Nyquist limit of 625kHz and
beyond.
Effective Number of Bits
The Effective Number of Bits (ENOBs) is a measurement
of the resolution of an ADC and is directly related to the
S/(N + D) by the equation:
where N is the effective number of bits of resolution and
S/(N + D) is expressed in dB. At the maximum sampling
rate of 1.25MHz the LTC1410 maintains very good ENOBs
up to the Nyquist input frequency of 625kHz and beyond.
Refer to Figure 3.
Total Harmonic Distortion (THD)
Total harmonic distortion is the ratio of the RMS sum of all
harmonics of the input signal to the fundamental itself. The
out-of-band harmonics alias into the frequency band
between DC and half the sampling frequency. THD is
expressed as:
THD
Figure 3. Effective Bits and Signal/(Noise + Distortion)
vs Input Frequency
N = [S/(N + D) – 1.76]
20
12
10
8
6
4
2
0
1k
log
f
SAMPLE
V
10k
= 1.25MHz
INPUT FREQUENCY (Hz)
2
2
V
NYQUIST
3
2
100k
V
1
V
/
4
2
6.02
1M
. . .V
LTC1410 • TA02
n
2
10M
74
68
62
56
50