LTC2271 datasheet(13/24 Pages) LINER

13 / 24 page

LTC2387-18

238718fa

For more information www.linear.com/LTC2387-18

TiMing DiagraM

applicaTions inForMaTion

Data Output Timing

tCLKH

tCLKDCO

CLK+

CLK–

DCO+

DCO–

DA+

DA–

tCLKDCO

tCLKD

tCLKL

238718 TD03

DB+

DB–

OVERVIEW

The LTC2387-18 is a low noise, high speed, 18-bit succes-

siveapproximationregister(SAR)ADC.Operatingfrom5V

and 2.5V supplies, the LTC2387-18 has a fully differential

±4.096V input range, making it ideal for applications that

require a wide dynamic range. The LTC2387-18 achieves

±3LSB INL (maximum), no missing codes at 18-bits and

96dB SNR (typical).

The LTC2387-18 includes a precision internal 2.048V

reference, with a guaranteed 0.25% initial accuracy and

a ±20ppm/°C (maximum) temperature coefficient, as well

as an internal reference buffer. The LTC2387-18 also has

a high speed serial LVDS interface that can output one or

two bits at a time. The fast 15Msps throughput with no

pipeline latency makes the LTC2387-18 ideally suited for

a wide variety of high speed applications. The LTC2387-18

dissipates only 125mW at 15Msps and has a power-down

mode to reduce the power consumption to 10μW during

inactive periods.

CONVERTER OPERATION

The LTC2387-18 operates in two phases. During the ac-

quisition phase, the sample capacitors are connected to

the analog input pins IN+ and IN– to sample the differential

analog input voltage. A rising edge on the CNV pin initiates

a conversion. During the conversion phase, the ADC is

sequencedthroughasuccessiveapproximationalgorithm,

comparing the sampled input with binary-weighted frac-

tions of the reference voltage (e.g. VREFBUF/2, VREFBUF/4

… VREFBUF/262144) using a differential comparator. At

the end of conversion, control logic prepares the 18-bit

digital output code for serial transfer.

TRANSFER FUNCTION

The LTC2387-18 digitizes the full-scale voltage of 2×

REFBUF into 218 levels, resulting in an LSB size of

31.25μV with REFBUF = 4.096V. The output data is in

two’s complement format. The ideal transfer function is

shown in Figure 1. The ideal offset binary transfer func-

tion can be obtained from the two’s complement transfer

function by inverting the most significant bit (MSB) of

each output code.

LTC2271 датащи(PDF) 13 Page - Linear Technology

LTC2271 датащи(HTML) 13 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

датащи скачать

ссылки URL