ver.1 njm2512 a - 1 - 47 f ac-coupling capacitor low voltage video driver with lpf q general description q package outline the NJM2512A is a low voltage video amplifier featuring small ac-coupling capacitor. the njrc original technology ?asc(advanced sag correction)? realizes 47 f ac-coupling capacitor which enables to downsize mounting space. no worrying about beat noise caused by charge-pump circuit, and over-current caused by circuit short out than capacitor-less video driver. the NJM2512A is suitable for any video application. njm2512: gain=6db NJM2512A : gain=12db q features o operating voltage 3.0 to 5.5v o ac-coupling capacitor 47f o 6db amplifier o 75 ? driver o internal lpf 0dbtyp.at 4.5mhz -33dbtyp.at 19mhz o power-save circuit o bipolar technology o package outline tvsp8 q pin connection q block diagram NJM2512Arb1 1 2 3 4 8 7 6 5 1: ssigv 2: vsag 3: srefv 4: vin 5: gnd 6: power save 7: vout 8: v + ps vin vout 75 ? drv clamp 4.5mhz lpf 12db vsag ssigv 0.1f + 47f 75 ? 75 ? srefv vcc gnd asc
ver.1 NJM2512A - 2 - q absolute maximum ratings (ta=25 c) parameter symbol ratings unit supply voltage v + 7.0 v power dissipation p d 580(note1) mw operating temperature range topr -40 to +85 c storage temperature range tstg -40 to +150 c (note1) at on a board of eia/je dec specification. (114.3 x 76.2 x 1.6mm two layers, fr-4) q reccomended operating conditions (ta=25 c) parameter symbol test condition min. typ. max. unit operating voltage vopr 3.0 - 5.5 v q electrical chracteristcs ( v + =3.3v, rl=150 ? ,ta=25 c) parameter symbol test condition min. typ. max. unit supply current i cc no signal - 10 15 ma supply current at power save mode isave power save mode - 20 50 a maximum output level vom vin=100k hz,sin-signal, thd=1%, 2.2 - - vp-p voltage gain gv vin=1mhz, 1.0vp-p sin-signal 11.5 12.0 12.5 db gf4.5m vin=4.5mhz/1mhz, 1.0vpp sin-signal -0.6 -0.1 +0.4 db low pass filter characteristic gf19 m vin=19mhz/1mhz, 1.0vpp sin-signal - -33 -23 db differential gain dg vin=1.0vp-p 10step video signal - 0.5 - % differential phase dp vin=1.0v p-p 10step video signal - 0.5 - deg s/n ratio sn 100khz to 6mhz, vin=1.0vp-p 100% white video signal, r l =75 ? - 60 - db sw voltage high level vthh active 1.8 - v + v sw voltage low level vthl non-active 0 - 0.3 v sw sink current high level ithh v=5v - - 300 a sw sink current low level ithl v=0.3v - - 5 a q control terminal parameter status mode h power save: off active mode l power save: on non-active mode (mute) power save open power save: off non-active mode (mute)
ver.1 njm2512 a - 3 - q test circuit 68k ? 1f 68k ? 0.1f 0.1f 75 ? 0.1f + 47f v+ + 47f 75 ? 75 ? 1 2 3 4 8 7 6 5 v+ ssigv vout vsag ps srefv gnd vin
ver.1 NJM2512A - 4 - q application circuit1 q application circuit2(2-line drive) q application note njm2512 ahas possibilities that decrease in the capacita nce in low-frequency band when the ceramic capacitor is used(pin7). it is a possibility that the sag is generated when the ceramic capacitor decreases capacity. please verify it in consideration of the capacity drop of the ceramic capacitor. 68k ? 1f 68k ? 0.1f 0.1f 75 ? 0.1f + 47f v+ + 47f 75 ? 1 2 3 4 8 7 6 5 v+ ssigv vout vsag ps srefv gnd vin 75 ? 36k ? 1u 36k ? 0.1u 0.1u 75 ? 0.1u + 47u vcc + 47u 1 2 3 4 8 7 6 5 vcc ssigv vout vsag ps srefv gnd vin 75 ?
ver.1 njm2512 a - 5 - ? clamp circuit 1. operation of sync-tip-clamp input circuit will be explained. sync-tip clamp circuit (below the clamp circuit) operates to keep a sync tip of the minimum potential of the video signal. clamp circuit is a ci rcuit of the capacitor charging and discharging of the external input cin. it is charged to the capacitor to the ex ternal input cin at sync tip of the video signal. therefore, the potential of the sync tip is fixed. and it is discharged charge by capacito r cin at period other than the video si gnal sync tip. this is due to a small discharge current to the ic. in this way, this clamp circuit is fixed sync tip of vi deo signal to a constant potential from charging of cin and discharging of cin at every one horizontal period of the video signal. the minute current be discharged an electrical charge fr om the input capacitor at the period other than the sync tip of video signals. decrease of voltage on dischar ge is dependent on the size of the input capacitor cin. if you decrease the value of the input capacitor, will ca use distortion, called the h sag. therefore, the input capacitor recommend on more than 0.1uf. < clamp circuit > a. cin is large b. cin is small (h sag experience) < waveform of input terminal > 2. input impedance the input impedance of the clamp circuit is different at the capacitor discharge period and the charge period. the input impedance of the charging period is a few k ? . on the other hand, the input impedance of the discharge period is several m ? . because is a small discharge-current through to the ic. thus the input impedance will vary depending on the operating state of the clamp circuit. 3. impedance of signal source source impedance to the input terminal, please lower than 200 ? . a high source impedance, the signal may be distorted. if so, please to connect a buffer for impedance conversion. cin vin clamp circuit charge curren t diccharge curren t signal input charge period discharge period clamp potential charge period clamp potential charge period discharge period charge period
ver.1 NJM2512A - 6 - [caution] the specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. the application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights.
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