LTC2360HS6 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LTC2360HS6

100ksps/250ksps/500ksps, 12-Bit Serial ADCs in TSOT-23

Linear Technology 

LTC2360/LTC2361/LTC2362

APPLICATIONS INFORMATION

DC PERFORMANCE

The noise of an ADC can be evaluated in two ways: sig-

nal-to-noise ratio (SNR) in the frequency domain and

histogram in the time domain. The LTC2360/LTC2361/

LTC2362 excel in both. Figure 5 demonstrates that the

LTC2360/LTC2361/LTC2362 have an SNR of over 73dB.

The noise in the time domain histogram is the transition

noise associated with a 12-bit resolution ADC which can

be measured with a fixed DC signal applied to the input of

the ADC. The resulting output codes are collected over a

large number of conversions. The shape of the distribu-

tion of codes will give an indication of the magnitude of

the transition noise. In Figure 4, the distribution of output

codes is shown for a DC input that has been digitized

16384 times. The distribution is Gaussian and the RMS

code transition is about 0.32LSB. This corresponds to a

noise level of 73dB relative to a full scale of 3V.

DYNAMIC PERFORMANCE

The LTC2360/LTC2361/LTC2362 have excellent high speed

sampling capability. Fast fourier transform (FFT) test

techniques are used to test the ADCs’ 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 ADCs’ spectral content can

be examined for frequencies outside the fundamental.

Figures 5 and 6 show typical LTC2361 and LTC2362 FFT

plots respectively.

10000

VDD = 3V

8000

6000

4000

2000

0

2045 2046 2047 2048 2049 2050

CODE

236012 F04

Figure 4. Histogram for 16384 Conversions

0

VDD = 3V

–20

fSMPL = 250ksps

fIN = 124kHz

SINAD = 73dB

–40 THD = –84dB

–60

–80

–100

–120

–140

0

25

50

75 100 125

INPUT FREQUENCY (kHz)

236012 F05

Figure 5. LTC2361 FFT Plot

0

VDD = 3V

–20

fSMPL = 500ksps

fIN = 248kHz

SINAD = 73dB

–40 THD = –81dB

–60

–80

–100

–120

–140

0

50 100 150 200 250

INPUT FREQUENCY (kHz)

236012 F06

Figure 6. LTC2362 FFT Plot

236012fa

11

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