ADS-119MM Ver la hoja de datos (PDF) - DATEL Data Acquisition products

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componentes Descripción

Fabricante

ADS-119MM

12-Bit, 10MHz, Low-Power Sampling A/D Converters

DATEL Data Acquisition products  

START

CONVERT

N

50ns typ.

ADS-119

12-Bit, 10MHz, Low-Power Sampling A/D Converters

N+1

INTERNAL S/H

INTERNAL EOC

DATA

VALID

10ns typ.

Hold

65ns typ.

Acquisition Time

30ns min.

35ns typ.

37ns max.

15ns typ.

20ns typ.

Conversion Time

Hold

72ns min.

80ns typ.

83ns max.

35ns typ.

40ns typ.

±5ns

60ns typ.

40ns typ.

±5ns

10ns typ.

DATA

DATA N-1 VALID

INVALID DATA

55ns typ.

Scale is approximately 5ns per division.

45ns typ.

INVALID DATA

Figure 2. ADS-119 Timing Diagram

DATA N VALID

INVALID DATA

CALIBRATION PROCEDURE

(Refer to Figures 3 and 4, Table 1)

Any offset and/or gain calibration procedures should not be implemented

ntil devices are fully warmed up. To avoid interaction, offset must be

adjusted before gain. The ranges of adjustment for the circuits in Figure

3 and 4 are guaranteed to compensate for the ADS-119's initial accuracy

errors and may not be able to compensate for additional system errors.

A/D converters are calibrated by positioning their digital outputs exactly

on the transition point between two adjacent digital output codes. This can

be accomplished by connecting LED's to the digital outputs and adjusting

until certain LED's "flicker" equally between on and off. Other approaches

employ digital comparators or microcontrollers to detect when the outputs

change from one code to the next.

Offset adjusting for the ADS-119 is normally accomplished at the point

where the MSB is a 1 and all other output bits are 0's and the LSB just

changes from a 0 to a 1. This digital output transition ideally occurs when

the applied analog input is +½ LSB (+366μV).

Gain adjusting is accomplished when all bits are 1's and the LSB just

changes from a 1 to a 0. This transition ideally occurs when the analog

input is at +full scale minus 1 ½ LSB's (+1.4989V).

Zero/Offset Adjust Procedure

1. Apply a train of pulses to the START CONVERT input (pin 16) so the con-

verter is continuously converting.

2. Apply +366μV to the ANALOG INPUT (pin 19).

3. Adjust the offset potentiometer until the output bits are 1000 0000 0000

and the LSB flickers between 0 and 1.

Gain Adjust Procedure

1. Apply +1.4989V to the ANALOG INPUT (pin 19).

2. Adjust the gain potentiometer until all output bits are 1's and the LSB

flickers between 1 and 0.

3. To confirm proper operation of the device, vary the input signal to obtain

the output coding listed in Table 1.

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

26 Jun 2015 MDA_ADS-119.C02 Page 4 of 10

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