TS3001 Datasheet, PDF (7/10 Pages) Touchstone Semiconductor Inc – A 1V/1uA Easy-to-Use Resistor-Tuned Silicon Oscillator/Timer

BLOCK DIAGRAM
TS3001
THEORY OF OPERATION
The TS3001 is a user-programmable oscillator where
the period of the square wave at its FOUT terminal is
generated by an external resistor. The output
frequency is given by:
1
1
FOUT (kHz) =
t_FOUT ( s) k x R _T MΩ
Table 1: FOUT vs R_SET
R_SET (MΩ) FOUT (kHz)
1
110
2.49
44
4.32
25.5
6.81
16
9.76
11
where the scalar k is approximately 9.09E3. With an
R_SET = 4.32MΩ, the output frequency is
approximately 25kHz with a 50% duty cycle. As
design aids, Tables 1 lists TS3001’s typical FOUT for
various standard values for R_SET.
The TS3001 also provides a separate PWM output
signal at its PWMOUT terminal that is anti-phase with
respect to FOUT. In addition, applying a voltage at
the CNTRL both enables the TS3001’s internal PWM
engine as well as adjusting the duty cycle from 12%
to 90%. A dc control voltage equal to 0.03 x VDD
applied to the CNTRL pin enables the PWM engine
to set the duty cycle to 12%. A dc control voltage
equal to 0.27 x VDD increases the duty cycle to 90%
and connecting CNTRL to VDD disables the PWM
engine altogether. Configured for nominal operation
(PWM engine OFF), the supply current of the TS3001
is 1µA; enabling the PWM engine increases the
TS3001 operating supply current as shown in the
electrical specification table.
TS3001DS r1p0
Page 7
RTFDS