MAX122ACAG 데이터 시트보기 (PDF) - Maxim Integrated

부품명

상세내역

일치하는 목록

MAX122ACAG

500ksps, 12-Bit ADCs with Track/Hold and Reference

Maxim Integrated 

MAX120/MAX122

500ksps, 12-Bit ADCs with Track/Hold

and Reference

Figure 14. Power-Supply Grounding

Figure 15. VSS Power-Supply Rejection vs. Frequency

Gain and Offset Adjustment

Figure 17 plots the bipolar input/output transfer func-

tion for the MAX120/MAX122. Code transitions occur

halfway between successive integer LSB values. Output

coding is two’s-complement binary with 1 LSB = 2.44mV

(10V/4096).

In applications where gain (full-scale range) adjustment

is required, Figure 18’s circuit can be used. If both offset

and gain (full-scale range) need adjustment, either of the

circuits in Figures 19 and 20 can be used. Offset should

be adjusted before gain for either of these circuits.

Figure 16. VDD Power-Supply Rejection vs. Frequency

To adjust bipolar offset with Figure 19’s circuit, apply +1/2

LSB (0.61mV) to the noninverting amplifier input and

adjust R4 for output-code flicker between 0000 and 0000

0000 0001. For full scale, apply FS - the output code flick-

ers between 0111 1111 1110 and 0111 1111 1111. There

may be some interaction between these adjustments. The

MAX120/MAX122 transfer function used in conjunction

with Figure 19’s circuit is the same as Figure 17, except

the full-scale range is reduced to 2.5V.

To adjust bipolar offset with Figure 20’s circuit, apply

-1/2 LSB (-1.22mV) at VIN and adjust R5 for output-code

flicker between 0000 0000 0000 and 0000 0000 0001. For

gain adjustment, apply -FS + ½ LSB (-4.9951V) at VIN

and adjust R1 so the output code flickers between 0111

1111 1110 and 0111 1111 1111. As with Figure 20’s circuit,

the offset and gain adjustments may interact. Figure 21

plots the transfer function for Figure 20’s circuit.

Dynamic Performance

High-speed sampling capability and 500ksps throughput

(333ksps for the MAX122) make the MAX120/MAX122

ideal for wideband-signal processing. To support these

and other related applications, fast fourier transform (FFT)

test techniques are used to guarantee the ADC’s dynamic

frequency response, distortion, and noise at the rated

throughput. Specifically, this involves applying a low-

distortion sine wave to the ADC input and recording the

digital conversion results for a specified time. The data is

then analyzed using an FFT algorithm, which determines

its spectral content.

www.maximintegrated.com

Maxim Integrated │  11

Share Link: