TS3002 datasheet(10/11 Pages) TOUCHSTONE

10 / 11 page

TS3002

Page 10

TS3002DS r1p0

RTFDS

Using a Potentiometer to Trim the TS3002’s

Output Frequency

By using a fixed resistor and a potentiometer, the

output frequency of the TS3002 can be trimmed as

shown in Figure 4. By selecting a fixed resistor R1

with a tolerance of 0.1% and a potentiometer P1 with

a 5% tolerance, the output frequency can be trimmed

to provide a ±2% trimming range. As shown in Figure

5, R1+P1 and C2 set the output frequency to

25.052kHz

when P1 = 0Ω and with P1 =200kΩ, the

resulting output frequency is 24.024kHz.

Using Standard Resistors to Increase FOUT

Resolution

The TS3002 can be configured to provide a 0.1%

resolution on the output frequency as shown in

Figure 5. To do so, R1 can be set to approximately

10% of the value selected for R2. In addition, R2 and

R1 should be chosen with a 0.1% and 1% tolerance,

respectively. Since R2 is 90% of the total resistance,

it has the largest impact on the resolution of the

output frequency. With

R1 = 91kΩ and R2 = 910kΩ,

the output frequency is 90kHz

and with R1 = 400kΩ

and R2 = 4MΩ, the output frequency is 23kHz.

Figure 4: Using a Fixed Resistor and a

Potentiometer to Trim the TS3002’s

Output Frequency.

Figure 5: Setting

the TS3002’s Output

Frequency to 0.1% Resolution using

Standard Resistors.

Figure 3: Configuring the TS3002 into a Voltage-

Controlled Oscillator.

TS3002 Datasheet(PDF) 10 Page - Touchstone Semiconductor Inc