TS2950ACT datasheet(5/6 Pages) TSC

5 / 6 page

TS2950-51 series

5-6

2003/12 rev. B

Application Hints (continued)

Programming The output Voltage

The TS2951/A output voltage is programmable for any

value from it reference voltage of 1.235V and it maximum

rating of 30V. For example for 5 volt needs to

pin-strapped and using the internal voltage divider by

tying pin 1 to 2 and pin 7 to pin 6. Refer to Figure 2, there

are two external resistor required for this programming.

Refer to the below equation for the programming the

output voltage:

Volt=Vref x (1+R1\R2)+IFB * R1

The Vref is 1.235V and IFB is the feedback bias current,

nominally -20nA. The minimum recommended load

current of 1uA forces an upper limit of 1.2MΩon value of

R2, If no load presented the IFB produces error of typically

2% in Vout which maybe eliminated at room temperature

by trimming R1. To improve the accuracy chooses the

value of R2=100K and this reduces the error by 0.17%

and increases the resistor program current by 12uA. The

TS2951/A typically draw 60uA at no load with pin 2

open-circuit, and this value does not look much.

Figure 2. Adjust Voltage

Block Diagram and Typical Applications Circuit

TS2950ACT 数据表(PDF) 5 Page - Taiwan Semiconductor Company, Ltd