TS3003

TS3003 Rev. 1.0

Page 9

TS3003 Start-up Time

As the TS3003 is powered up, its FOUT terminal

(and PWMOUT terminal, if enabled) is active once

the applied VDD is higher than 1.55V. Once the

applied VDD is higher than 1.55V, the master

oscillator achieves steady-state operation within 8ms.

Divide the PWMOUT Output Frequency by Two

with the TS3003

Using a single resistor and capacitor, the TS3003 can

be configured to a divide by two circuit as shown in

Figure 2. To achieve a divide by two function with the

TS3003, the pulse width of the PWMOUT output

must be at least a factor of 2 greater than the period

set at FOUT by resistor RSET. The CPWM capacitor

selected must meet this pulse width requirement and

can be calculated using Equation 2. In Figure 3, a

value of 4.32M

Ω for RSET sets the FOUT output

period to 40µs. A CPWM capacitor of 265pF was

chosen, which sets the pulse width of PWMOUT to

approximately 80µs. This is well above the required

minimum pulse width of 40µs.

Using the TS3003 and a Potentiometer to Dim an

LED

The TS3003 can be configured to dim an LED by

modulating the pulse width of the PWMOUT output.

With an RSET= 2M

Ω, the FOUT output frequency is

approximately 51kHz (or 19.5µs period). Refer to

Figure 3. The CPWM capacitor was calculated using

Equation 2 with a pulse width of 15µs. To reduce the

pulse width from 15µs and in turn, dim the LED, a

1M

Ω potentiometer is used. The potentiometer is

connected to the PWM_CNTRL pin in a voltage

divider configuration. The supply voltage of the circuit

is 5V.

.

Figure 2: Configuring the TS3003 into a Divide by

Two Frequency Divider

Figure 3: TS3003 Configured to Dim an LED with a

Potentiometer