TS3001

Page 8

TS3001 Rev. 1.0

APPLICATIONS INFORMATION

Minimizing Power Consumption

To keep the TS3001’s power consumption low,

resistive loads at the FOUT and PWMOUT terminals

increase dc power consumption and therefore should

be as large as possible. Capacitive loads at the

FOUT

and

PWMOUT

terminals

increase

the

TS3001’s transient power consumption and, as well,

should be as small as possible.

One challenge to minimizing the TS3001’s transient

power consumption is the probe capacitance of

oscilloscopes and frequency counter instruments.

Most instruments exhibit an input capacitance of

15pF or more. Unless buffered, the increase in

transient load current can be as much as 400nA.

To minimize capacitive loading, the technique shown

in Figure 1 can be used. In this circuit, the principle of

series-connected capacitors can be used to reduce

the effective capacitive load at the TS3001’s FOUT

and PWMOUT terminals.

probe capacitance is known by simply solving for

1

1

-

1

For

example,

if

the

instrument’s

input

probe

capacitance is 15pF and the desired effective load

capacitance at either or both FOUT and PWMOUT

terminals is to be

be

≤7.5pF.

TS3001 Start-up Time

As the TS3001 is powered up, its FOUT terminal

(and PWMOUT terminal, if enabled) is active once

the applied VDD is higher than 0.9 volt. Once the

applied VDD is higher than 0.9 volt, the master

oscillator achieves steady-state operation within

1.2ms.

Current- and Voltage-Controlled Oscillators

The

TS3001

can

be

configured

into

a

Current-Controlled Oscillator as shown in Figure 2.

With a current source sourcing a current of 223nA to

262nA, FOUT can generate an output signal with a

frequency range of 5.2kHz to 90kHz. In a similar

manner, a Voltage-Controlled Oscillator can be

configured as shown in Figure 3. In this case, a

voltage source sourcing a voltage of 290mV to

341mV

can

generate

an

FOUT

output

signal

frequency range of 5.2kHz to 90kHz as well. It is

recommended to use resistor values with a 1%

tolerance.

Figure 1: Using an External Capacitor in Series with

Probes Reduces Effective Capacitive Load.

Figure 2: Configuring the TS3001 into a

Current-Controlled Oscillator.

Figure 3: Configuring the TS3001 into a

Voltage-Controlled Oscillator.