1 video ics vcr hi-fi audio signal rec / pb amplifier with flying-erase oscillator BA7745fs the BA7745fs has the recording and playback amplifiers required for hi-fi vcr signal processing, and also con- tains a flying-erase oscillator. the recording system uses a constant-current amplifeir with agc to eliminate the need to adjust the recording current, and ensure stable operation as the head wears. the ic also features rec mute and over rec functions . the playback system has a high-gain preamplifier, a low-offset head switch, a vca and an ep-gain amplifier. the flying-erase oscillator has low 2nd and 3rd harmonic distortion, and when connected to an external driver large out- put current can be obtained. a h / l control system eliminates the need for special power supplies for the recording and playback systems. the ic has low power consumption, and comes in a compact 32-pin ssop-p package that requires little area on the pcb. it will improve the reliability and performance of your designs while reducing external component requirements. applications vcrs features the low-noise playback amplifier has a total gain of 83db (typ.). designed for vhs-bandoperation with low external parts count. it has two built-in circuits for hi-fi vcr operation. 2) the circuit has been designed to suppress head- switching noise. 3) built-in ep / sp gain switching function that boosts the playback gain by 5db. 4) built-in vca for easy playback output adjustment. 5) high-output recording amplifier for audio fm record- ing. 6) constant-current drive provides stable recording characteristics when the load (head impedance) is fluctuating. 7) built-in recording level agc eliminates the need to adjust recording current. 8) built-in low-pass filter limits the input bandwidth of the recording amplifier. 9) built-in over rec recording current amplifier function and rec mute function that stops record- ing output. 10) built-in high-frequency oscillator for use with flying erase function. 11) record / playback switching can be done directly via the system controller, and consumes litlle power. 12) possible to construct a high-performance audio system by pairing this chip with a hi-fi-audio signal processing ic.
2 video ics BA7745fs block diagram 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 rec / pb ctrl rec agc filter rec current sense rec out main gnd pre ac ?fb ch1 pre ac ?fb ch2 pre in ch1 pre gnd pre in ch2 rec + b ch2 v cc rec + b n.c. fe v cc fe out rec + b ch1 rec nf rec mix in over rec ctrl rec mute ctrl v cc vca ctrl n.c. pre out ep / sp ctrl hswpin fe level fe3 fe2 fe1 fe gnd fe ctrl agc p / r p pb / rec pre pre sw ep ch2 ch1 ch2 ch1 r r bf n.c. fe osc fe ctrl n.c. vca rec absolute maximum ratings (ta = 25?) parameter symbol limits unit v cc 7.0 v 12.5 pd 1000 * mw topr ?10 ~ + 70 c tstg ?55 ~ + 125 c pb / rec system fe system power supply voltage power dissipation operating temperature storage temperature * when mounted on a 90mm 50mm 1.6mm glass epoxy board, reduced by 10mw for each increase in ta of 1 c over 25 c.
3 video ics BA7745fs recommended operating conditions (ta = 25?) parameter symbol min. typ. max. unit 4.5 5.0 5.5 v 10.5 11.0 11.5 v v ccs recommended operating voltage pb / rec system fe system electrical characteristics recording system (unless otherwise noted, ta = 25?, v cc = 5v, and f = 1.7mhz) parameter symbol min. typ. max. unit conditions 17pin: h iq (rec) ?690ma i oar 44.7 48.2 51.7 15pin 93.0db m in, 19pin out d i oar 10 13 db d agc < 0.8db, 19pin out cmd 04 50 ?43 db 15pin mixin ( * ), 19pin out (0.4mhz ?1.3mhz) cmd 09 55 ?40 db 15pin mixin ( * ), 19pin out (0.9mhz ?1.3mhz) 2hd 26 47 ?40 db 15pin mixin ( * ), 19pin out (2.6mhz ?1.3mhz) cmd 30 42 ?35 db 15pin mixin ( * ), 19pin out (3.0mhz ?1.3mhz) 2hd 34 45 ?40 db 15pin mixin ( * ), 19pin out (3.4mhz ?1.7mhz) v 14l 0.0 2.2 v 3.5 v i or.ov + 1.4 + 1.9 + 2.4 db v 13l 0.0 2.2 v v 13h 3.5 v i or.mu 45 ?40 db v cc v cc ma p-p v 14h * f = 1.3mhz (89.0db m ) + 1.7mhz (97.0db m ) (mix) 15pin 93.0db m in, 14pin: ? 15pin 93.0db m in, 13pin: ? when 14pin dc, normal rec when 14pin dc, over rec when 13pin dc, mute off when 13pin dc, mute on no signal, pin 12 + pin 29, inflow current recording mode ? quiescent current output current agc level output current agc range cross modulation distortion 0.4mhz component cross modulation distortion 0.9mhz component 2nd-harmonic distortion 2.6mhz component cross modulation distortion 3.0mhz component 2nd-harmonic distortion 3.4mhz component over rec holding voltage over rec holding voltage current emphasis over rec mute holding voltage rec mute holding voltage mute attenuation
4 video ics BA7745fs playback system (unless otherwise noted, ta = 25?, v cc = 5v, and f = 1.5mhz) parameter symbol min. typ. max. unit conditions iq (pb) 19.0 31.0 ma g vp1 80 83 86 db g vp2 80 83 86 db d g vp ?2.0 0 + 2.0 db ct 1 ? 2 40 ?35 db ct 2 ? 1 40 ?35 db f p1 0 2.4 5 db f p2 0 2.4 5 db 17pin: ?? 11pin: 2.0v 23pin, 20.5db m in, 10pin out, 8pin: ? 25pin, 20.5db m in, 10pin out, 8pin: ? 23pin 31.0db m , 25pin 0 in, 23pin 0, 25pin 31.0db m in, 23pin 20.5db m in, 8pin: ? f = 2.2mhz / 1.0mhz, d 10pin out 25pin 20.5db m in, 8pin: ? f = 2.2mhz / 1.0mhz, d 10pin out ? d g vca 40 ?30 db + d g vca + 4 + 6 db v omp 2.0 2.6 v p-p v np1 0.4 1.0 m v rms v np2 0.4 1.0 m v rms v hs2 0.0 2.2 v v hs1 2.8 v cc v d v odc ?20 0 + 20 mv v 17l 0.0 1.0 v v 17h 3.5 v cc v r swp ?10 w v 9l 0.0 2.2 v v 9h 3.5 v cc v g vp. ep 4.0 5.0 6.0 db 8pin: ?? ? ?? d 10pin out 8pin: ?? ? ?? d 10pin out 11pin 2.0v ? 0.8v, d 10pin out 11pin 2.0v ? 3.3v, d 10pin out 23pin, 25pin, 20.5db m in, d 10pin out playback mode ? supply current voltage gain ch1 voltage gain ch2 voltage gain differential ch1 to ch2 crosstalk ch2 to ch1 crosstalk ch1 frequency characteristic ch2 frequency characteristic gain adjustment headroom gain adjustment headroom maximum output voltage ch1 input conversion noise ch2 input conversion noise head switch voltage head switch voltage output dc offset pb holding voltage rec holding voltage head switch-on resistance sp holding voltage ep holding voltage gain emphasis ep inflow current to pin 12 when no signal. pin 23 and 25 in, pin 10 out 3rd-harmonic distortion, when -30db. input conversion for pin 23: 0.01 m f + 10 w at gnd pin 8: ? , pin 10 out. input conversion for pin 25: 0.01 m f + 10 w at gnd pin 8: ?? pin 10 out. pin 8 dc when ch2 operating pin 8 dc when ch1 operating 23, 25pin 0 in, 8pin: ?? ? ?? d 10pin out pin 17 dc for pb mode pin 17 dc for rec mode pin 20 on resistance pin 9 dc for sp mode pin 9 dc for ep mode 23, 25pin 20.5db m in, 9pin: ?? 10pin out design reference values flying erase system (unless otherwise noted, ta = 25?, v cc = 11.0v) parameter symbol min. typ. max. unit conditions 5pin: ? iq (fe) 12.0 ma v 2 5.5 v 2pin dc v 3 5.5 v 3pin dc v 6 1.0 v 6pin dc v 32 4.3 v 32pin dc f 32 8 13 mhz 32pin out u 32 2.8 v p-p 32pin out v 5h 4.0 v cc v 0 0.5 v v 5l 5pin dc, when fe on 5pin dc, when fe off flying erase mode ? supply current pin 2 voltage pin 3 voltage pin 6 voltage pin 32 voltage oscillator frequency range output amplitude range fe on holding voltage fe off holding voltage * the values given above are design values, they are not ratings and are not guaranteed. pin 31 inflow current
5 video ics BA7745fs control mode tables (1) rec / pb control switch between rec and pb using pin 17. control pin mode rec / pb h rec on off on off l pb off on off on rec amp pre amp rec + b sw head sw (p) function 0.01 m 20k 5v 390 0.01 m 100 m 100 m agc p / r p pb / rec pre pre sw ep ch2 ch1 ch2 ch1 r r bf n.c. fe osc fe ctrl n.c. 2.2k vca 0.1 m 68k 12 680 220p 0.1 m 0.01 m 0.01 m 0.1 m 12 m 12 m 100 m 11v bf 100 m 470 0.01 m 560 1k 560 0.22 m 0.1 m 220k 10 10 100p 100p 1k 12pin short fe out pre in ch1 pre in ch2 current sense pb / rec ctrl 0.01 m rec rec mix in overrec ctr l recmute ctrl 1.8k pre out ep / sp ctrl hswpin fe on / off 68p 22k 4.7 m 68p 0.01 m 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 fig. 1 measurement circuit
6 video ics BA7745fs (2) over rec control control for over rec (current emphasis) is done using pin 14. when in over rec mode, the gain setting is recording amplifier agc level + 1.9db. h l 60.0ma p-p 48.2ma p-p over rec over rec mode function rec age level control pin (4) ep / sp control ep / sp control during playback is done using pin 9. when ep is selected, the gain of the playback amplifier is increased by 5db over its normal setting. ep / sp h ep typ. + 5db l sp typ. mode function pre amp gain control pin (3) rec mute control control for rec mute when recording is done using pin 13. rec mute h rec mute off l on rec amp mode control pin function
7 video ics BA7745fs application example 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 120p 120p 1.5k 1.5k 10 fe head 10 8.2k 8.2k 16 15 14 13 0.01 m 20k 5v 390 0.01 m 100 m 100 m 12 11 10 9 8 7 6 5 4 3 2 1 agc p / r p pb / rec pre pre sw ep ch2 ch1 ch2 ch1 r r bf n.c. fe osc fe ctrl n.c. 2.2k vca 0.1 m 68k 12 680 220p 0.1 m 0.01 m 0.01 m 0.1 m 100 m 11v 100 m 470 0.01 m 560 560 0.22 m 0.1 m 220k 560 560 100p audio head 100p 12pin short current sense pb / rec ctrl 0.01 m rec rec mix in overrec ctr l recmute ctrl 1.8k pre out ep / sp ctrl hswpin fe on / off 68p 22k 4.7 m 68p 0.01 m 11v fig. 2
8 video ics BA7745fs external dimensions (units: mm) ssop-p32 0.25 0.1 0.8 13.6 0.2 17 16 0.36 0.1 32 1 0.11 1.9 0.1 5.4 0.2 7.8 0.3 0.3min. 0.15
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