ADC0833 datasheet(13/20 Pages) NSC

13 / 20 page

Functional Description (Continued)

This zener is intended for use as a shunt voltage regulator

to eliminate the need for any additional regulating compo-

nents This is most desirable if the converter is to be re-

motely located from the system power source

Figures 4

and

5 illustrate two useful applications of this on-board ze-

ner when an external transistor can be afforded

An important use of the interconnecting diode between Va

and VCC is shown in Figures 6 and 7 Here this diode is

used as a rectifier to allow the VCC supply for the converter

to be derived from the clock The low current requirements

of the AD (E3 mA) and the relatively high clock frequen-

cies used (typically in the range of 10k-400 kHz) allows us-

ing the small value filter capacitor shown to keep the ripple

on the VCC line to well under

of an LSB The shunt zener

regulator can also be used in this mode This requires a

clock voltage swing which is in excess of VZ A current limit

for the zener is needed either built into the clock generator

or a resistor can be used from the CLK pin to the Va pin

Applications

TLH5607 – 15

TLH5607 – 16

FIGURE 4 Operating with a Temperature

Compensated Reference

TLH5607 – 17

Note 45V s VCC s 63V

FIGURE 6 Generally VCC from the Converter Clock

FIGURE 5 Using the AD as the

System Supply Regulator

TLH5607 – 9

FIGURE 7 Remote SensingClock

and Power on 1 Wire

ADC0833 bảng dữ liệu(PDF) 13 Page - National Semiconductor (TI)