1 standard ics cr timer BA225 / BA225f / ba235 / ba226 / ba226f / ba236 the BA225, BA225f, ba235, ba226, ba226f, and ba236 are monolithic ics having independent monostable multi- vibrator circuits which consume very low current (0.75ma typ.). using external resistors and capacitors, the timing control time can be set within a range from 0.01ms to 100ms. as the BA225, BA225f, and ba235 are triggered at the rising edge of the signal, they have no trigger input differenti- ating circuit and can be used in measuring instruments, control devices, digital data systems and other equipment as sub-compact attachments. the ba226, ba226f, and ba236 are available as falling edge trigger types. block diagram out1 cr1 trigger1 4 gnd 3 2 1 5 6 7 8 v cc out2 cr2 trigger2 o t cr o t cr 1 v cc ot cr v cc v cc gnd 2 out1 3 cr1 4 trigger1 5 gnd 6 trigger2 7 cr2 8 out2 9 v cc o t cr BA225 / BA225f ba226 / ba226f ba235 / ba236 applications delay timers monostable multivibrator (ideal for vcr system con- trollers) pulse generators features 1) as these are edge trigger types (BA225 / ba235: ris- ing edge trigger types, ba226 / ba236: falling edge trigger types), there is no need for an input differenti- ating circuit. 2) the dual type design enables delay timer configura- tion. 3) fewer attachments are required. 4) current dissipation is as low as 0.75ma for each cir- cuit. 5) uniformity in the supply current between high and low output states simplifies the design of the power supply section. 6) wide operating power supply voltage range of 4.0v to 16v. 7) the ba235 and ba236 pin assignments are sym- metrical, allowing reverse insertion. 8) hysteresis in the input results in a high level of noise withstand resistance.
2 standard ics BA225 / BA225f / ba235 / ba226 / ba226f / ba236 absolute maximum ratings (ta = 25?) parameter symbol limits unit power supply voltage v cc 16 v power dissipation BA225 / ba226 ba235 / ba236 BA225f / ba226f pd 800 * 1 950 * 2 450 * 3 mw mw mw operating temperature topr c ?20 ~ + 75 storage temperature tstg c ?55 ~ + 125 * 1 reduced by 8mw for each increase in ta of 1 c over 25 c. * 2 reduced by 9.5mw for each increase in ta of 1 c over 25 c. * 3 reduced by 4.5mw for each increase in ta of 1 c over 25 c. electrical characteristics (unless otherwise noted, ta = 25?, v cc = 5v) ba236 parameter symbol min. typ. max. unit conditions measurement circuit operating power supply voltage 4.0 5.0 16.0 v fig.7 quiescent current i q 1.5 3.0 ma fig.7 timing accuracy t err 10 % fig.7 timing change with power supply t ds 0.5 3.0 % 5v y 16v fig.7 timing change with temperature t ot 200 fig.7 trigger voltage v t 1.0 2.0 3.0 v * 2 fig.7 0.7 1.6 2.5 trigger current i t 70 200 m a fig.7 output low level voltage v ol 0.5 1.0 v fig.7 output high level voltage v oh 3.0 4.0 v fig.7 v cc 1 r = 100k w , c = 0.1 m f * 1 v t = 3.0v (BA225 / ba235) v t = 2.5v (ba226 / ba226f / ba236) ppm / c * 1 one-shot cycle t = 0.5 cr * 2 with input hysteresis (hysteresis width 6 200 to 600mv) i sink = 5ma i source = 5ma electrical characteristic curves 4 3 "h" output "l" output 2 1 0 quiescent current: i o (ma) power supply voltage: v cc (v) 04 12 820 16 fig. 1 quiescent current vs. power supply voltage 2.0 1.0 0 saturation voltage: v ol (v) sink current: i sink (ma) 04 12 820 16 v cc = 5v fig. 3 output voltage (logic 0 side) characteristics 3.2 2.4 v cc = 5v 1.6 0.8 2.8 2.0 1.2 0.4 0 saturation voltage: v cc ? oh (v) source current: i source (ma) 04 12 820 16 fig. 2 output voltage (logic 1 side) characteristics
3 standard ics BA225 / BA225f / ba235 / ba226 / ba226f / ba236 1.010 1.000 c = 0.01 m f r = 100k w 0.990 0.980 1.005 0.995 0.985 0 delay time normalized: td power supply voltage: v cc (v) 04 12 820 16 fig. 4 power supply voltage vs. delay time 10 0.001 capacitance: c ( m f) 1.0 0.1 0.01 timing period: t (ms) 0.01 0.1 10 1100 10k w 100k w 1m w fig. 6 one-shot time characteristics ambient temperature: ta ( c) ?25 0 50 25 75 v cc = 5v c = 0.01 m f r = 100k w 1.010 1.015 1.020 1.000 0.990 0.980 1.005 0.995 0.985 delay time normalized: td fig. 5 temperature vs. delay time measurement circuit v cc cr ma pg BA225 BA225f ba235 gnd s 3 5ma 5ma d.v m a d.v counter out in s 1 s 0 off on v cc s 2 0.1 m f 100k w fig. 7 attached components (1) timing capacitors (pins 2 and 6) connected between these pins and the ground (gnd), this capacitor determines the one-shot period. we rec- ommend using a capacitor with a value greater than 1000pf. the one-shot cycle is determined by t = 1 / 2 c ?r. (2) timing resistor (pins 2 and 6) connected to the power supply line, these resistors determine the one-shot period. the timing capacitor is charged through this resistor. the recommended range for the timing resistor is 10k w to 1m w . (3) power supply capacitor (pin 8) connect a 0.02 m f capacitor between the power supply pin and the ground (gnd) so as to prevent malfunction resulting from a rise in the impedance of the power supply line. (4) load (pins 1 and 7) a load of up to 5ma can be accommodated for both the inflow current and the outflow current.
4 standard ics BA225 / BA225f / ba235 / ba226 / ba226f / ba236 operation notes (1) usage range for voltage the recommended voltage range is 4.0v to 16v. use of these ics at 3.0v or lower voltage may cause the same mode as the input trigger signal to be output at around 2.6v. (2) input trigger the input trigger level is 2.0v. the low level is 1.0v or lower and the high level is 3.0 v or higher. trigger signals of 10ms / v or lower should be used for both the rising and falling edges. (3) time constant determining c ?r the recommended value for the timing capacitor is 1000pf or more and that for the timing resistor is from 10k w to 1m w . the voltage, which is determined by comparison of dis- charge resistance and the timing resistance in the ic, remains on the cr pins. if timing resistance is set at 5k w or less, this voltage will reach threshold level (0.4 v cc ), and operation will come to a halt. also, when timing resistance is set to a low value, voltage remains on the cr pins, which shortens the time constant. if timing resistance is set to 2m w or higher, the ic's inter- nal comparator cannot be driven, which may bring operation to a halt. (4) note that pin connections and pin arrangements on the BA225 / ba226 (ba235f / ba226f) differ from those on the ba235 / ba236. application example figure 8 shows an example of the circuit including these ics, while figure 9 shows the basic operation timing chart. figure 10 shows the basic operation tim- ing chart of the falling edge trigger type ic. when no trigger signal is applied, the output is in the low state and the timing capacitor is in the discharged state. when a trigger signal is applied, its rising edge causes the output to become high and the timing capacitor to be charged. the charging time of this timing capacitor is determined by the time constants of the external timing resistor and the timing capacitor. when the charged voltage reach- es 0.4 v cc , the flip-flop in the ic is reset and the out- put state changes from high to low. at the same time, the timing capacitor is discharged to be ready for the next operation. cr m. m2 0t cr gnd BA225 ba226 BA225f ba226f v cc v cc 1234 0.1 m f c v cc = 5v r 100k w c 8765 0.02 m f v cc out2 out1 100k w r m. m1 0t fig. 8 0.1 m f
5 standard ics BA225 / BA225f / ba235 / ba226 / ba226f / ba236 application examples rising edge trigger trigger input cr pin output t one-shot cycle: t 6 0.5 cr 0.4v cc fig. 9 basic operation timing chart (rising edge trigger) falling edge trigger trigger input cr pin output t one-shot cycle: t 6 0.5 cr 0.4v cc fig. 10 basic operation timing chart (falling edge trigger)
6 standard ics BA225 / BA225f / ba235 / ba226 / ba226f / ba236 external dimensions (units: mm) dip8 sip9 sop8 BA225 / ba226 ba235 / ba236 BA225f / ba226f 2.54 10.5 0.5 3.5 0.5 1 1.2 5.8 0.2 0.6 9 0.3 0.1 0.8 1.3 21.8 0.2 2.8 0.2 0.4 0.1 1.27 0.15 0.3min. 0.15 0.1 0.11 6.2 0.3 4.4 0.2 5.0 0.2 85 4 1 1.5 0.1 0.5 0.1 3.2 0.2 3.4 0.3 85 14 9.3 0.3 6.5 0.3 0.3 0.1 0.51min. 2.54 0 ~ 15 7.62
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