1 standard ics el driver for portable sets ba3899f the ba3899f is an ic developed for el drive applications. it uses a more compact interface than transformer sys- tems, and is ideal for use in thin sets. applications pagers, electronic notebooks and other portable devices block diagram 8 7 6 1 2 3 5 stby 4 gnd n.c. c1 c2 sw1 sw2 v cc stby osc2 osc1 r sw2 features 1) drive oscillation frequency can be set using external capacitance. 2) equipped with standby control pin. absolute maximum ratings (ta = 25?) parameter power supply voltage power dissipation operating temperature storage temperature v cc pd topr tstg 8.0 450 * ?10 ~ + 60 ?55 ~ + 125 v symbol limits unit mw c c maximum applied voltage v st 8.0 v * reduced by 4.5mw for each increase in ta of 1 c over 25 c. recommended operating conditions (ta = 25?) parameter v cc 1.0 5.0 7.0 v symbol min. typ. max. unit power supply voltage
2 standard ics ba3899f pin descriptions v cc gnd c1 1k v cc gnd c2 200 w v cc gnd sw2 50k 500 w x20 x1 gnd stby 1k 200k 50k v cc gnd sw1 x5 x1 pin no. osc1 oscillator circuit; external capacitor pin osc2 oscillator circuit; external capacitor pin standby control pin (high state: standby cancelled) sw2 switching output pin sw1 switching output pin s when applying resistance, etc. to the stby pin, be careful not to exceed the threshold values. 2 n.c. ? cc input pin 6i v cc 3 i / o c1 4 i / o c2 5i0 stby 7o sw2 8o sw1 1 i gnd pin gnd pin name i / o pin voltage internal equivalent circuit function
3 standard ics ba3899f electrical characteristics (unless otherwise noted, ta = 25?, v cc = 5.0v, c1 = 0.033 m f, c2 = 1500pf) parameter symbol min. typ. supply current i cc ma when used as stand-alone unit 3.0 4.6 6.2 c1 pin oscillation frequency f sw1 hz 75 95 120 c2 pin oscillation frequency f sw2 khz 17 23 29 source current sw1 sw2 standby pin control voltage condition i sw1so m av c1 = 1.0v, v c2 = 0.05v, v sw1 = 0v 100 140 180 sink current i sw1si m av c1 = 0.05v, v c2 = 0.05v, v sw1 = 1.0v ?40 source current i sw2so ma v c1 = 0.05v, v c2 = 0.05v, v sw2 = 0v 3.2 4.4 6.1 pull-down resistance r sw2 w vst = 0.35v, v sw2 = 0.3v 400 500 600 operating v ston v 1.0 non-operating v stoff v 0.3 quiescent current in standby state i q (st) m a 0 2.0 max. unit conditions measurement circuit 2 i sw1 v sw1 f sw1 v cc counter v c1 0.033 f i q v stby 8 v c2 1500pf 1% 1% 1 i sw2 v sw2 f sw2 counter 7 3 4 stby osc2 osc1 r sw2 fig.1 a a a 6 5
4 standard ics ba3899f application example 5 6 7 stby 8 osc2 osc1 fig. 2 r sw2 el 16000pf r1 2k d1 q2 q1 l1 100k v cc = 5v rohm: 1ss376 rohm: 2sc4061kp sw1 sw2 stby r x 300k v cc sanyo: 2sc3645t 1.5mh (toko: d73lc) * gnd n.c. c1 c1 8200pf 10% 2.2 m f c2 1500pf 10% c2 1234 + * because of the characteristics of the el element, continuous application of particularly high dc power supply voltage can short en the lifetime of the element. to avoid this, we recommend inserting a switch in the power supply line.
5 standard ics ba3899f 2 5 stby gnd n.c. c1 c2 sw1 r1 4.7k rohm: 1ss376 d1 el 5000pf sw2 v cc v cc = 1.5v stby osc2 osc1 r sw2 q1 q2 l1 1mh rohm: 2sc4061kp sanyo: 2sc3143k5 ( toko: 43fs ) or ( tdk: nl453232 ) c2 1500pf 10% c1 0.033 f 10% 4 1 3 6 8 7 v stby = 1.5v hi: act fig. 3 2.2 m f +
6 standard ics ba3899f operation notes (1) el drive output as shown in figure 4, the el drive output consists of charging (rise in voltage caused by switching) and dis- charging waveforms. the switching frequency is deter- mined by f sw2 and the charging and discharging timing by f sw1 . (4) q1, q2, and d1 the v o ( max. ) shown in figure 4 is applied to the output v o , so if using any transistor other than that recom- mended, caution is required concerning the pressure withstand value. also, q2 must have characteristics which allow it to keep pace with the switching speed of f sw2 . t 1 t sw1 (f sw1 ) v o (max.) t 2 charge discharge fig.4 (2) setting f sw1 the oscillation frequency is determined by charging and discharging of the external capacitance of the c1 pin. the value for c1 should be set based on the fol- lowing equation. (5) r x (resistor for adjusting light volume) with a configuration like that shown in figure 5, the volume of light can be adjusted. however, r x should be set so that i x satisfies the following condition. c1 = = (3.14e ?6) ( + ) v c1 (v cc = 5v) 1 11 i 1 1 f sw1 i 2 1 f sw1 ix ( = ) < 40 m a vx ?0.2v rx if i x > 40 m a, lsi dispersion, temperature fluctuation, and other elements can cause oscillation of the c2 pin to stop. be sure the above condition is satisfied. the recommended setting range for f sw1 is 40hz to 800hz. however, the v o ( max. ) shown in figure 4 is determined by f sw1 , so caution is required concerning the pressure withstand values of q1, q2, and d1. (3) f sw2 f sw2 is the switching pressure rise frequency, and is determined by the external capacitance of the c2 pin. this value (1500pf) is determined by the inductance value and the q2 transistor capability. when changing this value, the drive capability of q2 must be taken into consideration in order to avoid the possibility of mal- function. 4 c2 1500pf vx rx ix fig.5
7 standard ics ba3899f electrical characteristic curves 0 012345678910 1 2 3 4 5 6 7 c1 = 0.033 m f c2 = 1500pf v st = 5v rx = 8 9 10 quiescent current: i cc (ma) 75 c ?25 c 25 c input voltage: v cc ( v) fig. 6 supply current (when used as stand-alone unit) vs. power supply voltage 10k 1k 100 023 15 4678 oscillation frequency: f sw (hz) c1 = 0.033 m f c2 = 1500pf rx = 75 c f sw1 f sw2 ?25 c 25 c 75 c ?25 c 25 c input voltage: v cc ( v) fig. 7 oscillation frequency of c1 and c2 pins vs. power supply voltage sw1 source current: i swiso ( m a) 0 012345678910 50 100 150 200 250 v c1 = 1.0v v sw1 = 0v 25 c ?25 c 75 c input voltage: v cc ( v) fig. 8 sw1 sink current vs. power supply voltage sw1 sink current: i sw1si (%) input voltage: v cc ( v) 0 012345678910 10 2.0 3.0 1.0 v c1 = 0v v sw1 = 1.0v v st = 5v 25 c ?25 c 75 c fig. 9 sw1 source current vs. power supply voltage 0 012345678910 1 2 3 4 5 6 7 v c1 = 1.0v v sw1 = 0v v st = 5v 8 9 10 sw2 source current: i sw2so (ma) input voltage: v cc ( v) 75 c ?25 c 25 c fig. 10 sw2 source current vs. power supply voltage 0 012345678910 100 200 300 400 500 600 700 v cc = 5v v sw2 = 0.2v v st = 0v 800 900 1000 sw2 pull-down resistance: r sw2 ( w ) input voltage: v cc ( v) 75 c ?25 c 25 c fig. 11 sw2 pull-down resistance vs. power supply voltage
8 standard ics ba3899f external dimensions (units: mm) sop8 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
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