AS1544 datasheet(24/29 Pages) AMSCO

24 / 29 page

www.austriamicrosystems.com

Revision 1.00

24 - 29

AS1543/44

Data Sheet - D e t a i l e d D e s c r i p t i o n

The Power vs. Throughput Rate graph in the Typical Operating Characteristics section shows the power vs. through-

put rate when using the auto shutdown mode and auto standby mode with 5V supplies (similar power calculations can

be done at 3V, althought the power is decreased even more when using 3V supplies).

VDRIVE

VDRIVE controls the serial interface voltage. VDRIVE allows easy interface to 3V and 5V processors. For example, if the

AS1543/44 were operated with a VDD of 5V, pin VDRIVE could be powered from a 3V supply. The AS1543/44 has better

dynamic performance with a VDD of 5V while still being able to interface to 3V processors.

Note: VDRIVE must not exceed VDD by more than 0.3V (see Absolute Maximum Ratings on page 4)

External Reference

An external reference source should be connected directly to the pin VREFIN of the AS1543/44. The external reference

voltage can reach from 1V to VDD. The correlation between performance of the AS1543/44 and the reference voltage

is shown in Figure 9 on page 9. However for specified performance the reference voltage has to stay at 2.5V ±1%. The

analog input range depends on VREFIN and the setting of bit RANGE and bit SE/FDN of the control register (see Ana-

log Input Configuration on page 15). Errors in the reference source will result in gain errors in the AS1543/44 transfer

function and will add to the specified full scale errors of the device.

Note: A capacitor of at least 0.1µF should be placed on pin REFIN.

AS1544 数据表(PDF) 24 Page - ams AG