ts3003 demo board page 1 ? 2013 touchstone semiconductor, inc. all rights reserved. features ? 5v supply voltage ? fout /pwmout output period: 40 s (25khz) o rset = 4.32 m ? pwmout output duty cycle : o 75 % for fdiv2:0 = 000 o cpwm = 100p f ? pwmout duty cycle reduction o 1m potentiometer ? fully assembled and tested ? 2in x 2in 2 - layer circuit boar d component list designation qty description c 1 1 100p f 10% capacitor (0805) c2 1 4.7f 10% capacitor (0805) r2 1 10 m 1% (0805) r1 1 4.32 m 1% (0805) pwm_adj 1 1m potentiometer u1 1 ts3003 vdd,f_ out, pwm_ out 3 test points j 1 1 jumper description the ts3003 is a single - supply , second - generation touchstone semi oscillator/timer fully specified to operate at a supply voltage range of 1.55v to 5.25v while consuming less than 2.4 a (max) supply current. requiring only a resistor to set the base output fr equency (or output period) at 25k h z (or 40 s) w ith a 50% duty cycle, the ts3003 timer/oscillator is compact, easy - to - use, and versatile. optimized for ultra - long life, low frequency, battery - powered/portable applications, ts3003 joins the ts3001, ts3002, ts3004, and ts3006 i n touchstones cmos timer family in its nanowatt analog? series of high - performance analog integrated circuits. the ts3003 requires only a n rset = 4.32 m resistor to set the fout /pwmout output period to 40s (25khz) . with an on - board 100p f cpwm capacitor, the duty cycle of pwmout is set at approximately 75 %. further reduction of the duty cycle is available with an on - board 1m potentiometer. the complete circuit is designed at a supply voltage of 5v. the ts3003 is fully specified over the - 40c to +85c temperature range and is available in a low - profile, 10 - pin 3x3 mm tdfn package with an exposed back - side paddle . product datasheet and additional documentation can be found on the factory web site at www.touchstonesemi.com . ordering information order number description ts3003 db ts3003 demo board a 1.55v to 5 .25 v, 1.9 a, 9khz to 300khz silicon timer figure 1 . ts3003 demo board circuit
ts3003 demo board ts3003 db r1p0 page 2 rtfds d escription t he ts3003 requires only an rset = 4.32 m resistor to set the fout/pw mout output period to 40s (25khz) . with an on - board 100p f cpwm capacitor, the duty cycle of p wmout is set at approximately 75 %. further reduction of the duty cycle is available with an on - board 1m potentiometer. the complete circuit is designed at a supply voltage of 5v and it is shown in figure 1 . the ts3003 is a user - programmable oscillator where the period of the square wave at its f out terminal is generated by an external resistor connected to the rset pin. the output period is given by: o t ( ) 1 08 11 s t equation 1. fout frequency calculation with r set = 4.32 m ? , the fout period is approximately 40 s (25khz) with a 50% duty cycle. as design aids, tables 1 lists ts3003 s typical o t frequency for various standard values for r set . the ts3003 also provides a separate pwm output signal at its pwmout terminal that is anti - phase with respect to fout. to adjust the pulse width of the pwmout output, a single capacitor can be placed at the cpwm p in. to determine the capacitance needed for a desired pulse width, the following equation is to be used: cpwm ( ) pulse width ( s ) cpwm cpwm 00 m equation 2. cpwm capacit or calculation where i cpwm and v cpwm is the current supplied and voltage applied to the cpwm capacitor, respectively. the pulse width is determined based on the period of fout and should never be greater than the period at fout. make sure the pwm_cntrl pin is set to at least 400mv when calculating the pulse width of pwmout. note v cpwm is approximately 300mv, which is the rset volta ge. also note that i cpwm is approximately 1 a. quick start procedure required equipment ? ts3003 demo board ? dc power supply ? oscilloscope model agilent dso1014a or equivalent ? two 10x, 15p //10m oscilloscope probes ? potentiometer screwdriver to evaluate the ts3003 silicon timer, the following steps are to be performed: 1) before connecting the dc power supply to the demo board, turn on the power supply, set the dc voltage to 5v, and then turn it off. 2) connect the dc power supply positive terminal to the test point labeled vdd. connect the negative terminal of the dc power supply to the test point labeled gnd. 3) to monitor the f out output signal, connect the signal terminal of an oscilloscope probe to th e test point labeled f out and the ground terminal to the test point labeled gnd. 4) to monitor the pwmout output signal, connect the signal terminal of a second oscilloscope probe to the test point labeled pwm _ out and the ground terminal to the test point lab eled gnd. 5) select two channels on the oscilloscope and set the vertical voltage sca le and the vertical position on each channel to 2 v/div and 0v , respectively. set the horizontal time scale to 5 s/div. the coupling should be dc coupling. turn on the power s upply. the supply current will vary depending on the load on the output . given the default set - up on the board, the fout/pwmout out put period is approximately 40 s. the pwmout duty cycle is set to approximately 75 %. with an output load of r set (m ? ) fout (khz) 0.360 300 1 108 2.49 43.37 4.32 25 6.81 15.86 9.76 11.07 12 9 table 1 : fout vs r set
ts3003 demo board ts3003 db r1p0 page 3 rtfds 15pf on both fout and pwmout outputs due to the oscilloscope probes, the supp ly current should be less than 8 a. 6) if further reduction of the duty cycle of the pwmout output is desired, turn the potentiometer clockwise . if jumper j1 is removed, the pwm_cntrl pin is ti ed to vdd and the potentiometer will not change the pwmout output duty cycle.
ts3003 demo board page 4 touchstone semiconductor, inc. ts3003 db r1p0 630 alder drive, milpitas, ca 95035 rt f ds +1 (408) 215 - 1220 ? www.touchstonesemi.com figure 3 . top layer view #1 figure 4 . top layer view #2 figure 5 . bottom layer (gnd) #2 figure 2 . fout /pwmout period vs r set figure 6 . bottom layer (gnd) #2 r set - m period - s 2 4 40 0 100 period vs r set 0 6 60 80 20 8 10 12 120
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