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Multimedia ICs Color TV Signal Encoder BH7236AF The BH7236AF converts analog RGB signals into color TV signals in the NTSC and PAL formats. From inputs of analog RGB signals, a composite synch signal, burst pulses and a color carrier, this IC generates a color TV signal, and can be adapted for either NTSC or PAL standards, which are selected externally. When set to PAL, chroma phase is switched for each line. The chroma signals and luminosity signals can be combined into a color TV signal or output separately, making this IC suitable for S pins. There are also pins for analog RGB signal output, and each output pin has its own internal 75 driver. *Applications TV peripherals *Featuresadapted for NTSC and PAL formats. 1) Can be 2) Internal burst timing signal generator with half-H killer. 3) Internal flip-flop for PAL phase switching. 4) Separate Y / C output pins. 5) Analog RGB signal output pins. 6) Internal 75 driver. (outputs color TV signals, luminosity signals, chroma signals and analog RGB signals) 7) Adaptable for color subcarrier pulse input. *Block diagram GND1 1 24 GND2 RIN 2 CLAMP SYNC 75 23 ROUT GIN 3 CLAMP SYNC 75 22 GOUT BIN 4 CLAMP SYNC FILTER MATRIX 75 21 BOUT N. C. PHASE SIFTER 5 75 20 VOUT R-Y MOD. B-Y MOD. SCIN Y/C MIX 6 19 VCC2 F*F BFP BFPOUT BPF NT / PAL DELAY 7 18 N. C. 8 17 YTRAP BFP N. C. SYNC MIX 9 BFP GEN. 75 16 YOUT SYNCIN 10 75 15 COUT SYNCOUT 11 14 N. C. VCC1 12 13 N. C 1 Multimedia ICs BH7236AF *Pin descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Pin name GND1 RIN GIN BIN N. C. SCIN NT / PAL BFPOUT N. C. SYNCIN SYNCOUT VCC1 N. C. N. C. COUT YOUT YTRAP N. C. VCC2 VOUT BOUT GOUT ROUT GND2 Function Ground for all drivers other than the 75 driver. Analog R signal input. Drive at low impedance. Analog G signal input. Drive at low impedance. Analog B signal input. Drive at low impedance. This pin is not connected inside the IC. Color subcarrier input. Input a 3.579545MHz (NTSC) or 4.433619MHz (PAL) sign wave or pulse wave (50% duty). Do not exceed the range of GND-Vcc. Selecting the type of color TV signal output. The high level selects NTSC, the low level PAL. Internally pulled up to 50k. Burst timing output. Burst timing is generated inside the IC when the subcarrier and composite synchronization signal. This pin is not connected inside the IC. Composite synchronization signal input. When the low level is input, the synchronization signal is output to both YOUT and VOUT, and inputs to RIN, GIN and BIN are clamped. This pin is internally pulled up to 100k. Composite synchronization signal output. Power supply pin for all except the 75 driver. This pin is not connected inside the IC. This pin is not connected inside the IC. Chroma signal output. Internal 75 driver. Luminance signal output. Internal 75 driver. Attached luminance trap filter. Attaching a trap filter reduces chroma signal cross-color caused by the luminance signal. Output impedance is approximately 2k. This pin is not connected inside the IC. Power supply pin for the 75 driver. Color TV signal output. Internal 75driver. Analog B signal output. Internal 75 driver. Analog G signal output. Internal 75 driver. Analog R signal output. Internal 75 driver. Ground for the 75 driver. 2 Multimedia ICs BH7236AF *Absolute maximum ratings (Ta = 25C) Parameter Power supply voltage Power dissipation Operating temperature Storage temperature Symbol VCC Pd Topr Tstg Limits 7 550 - 20 ~ + 70 - 55 ~ + 125 Unit V mW C C When mounted on a 50 x 50 x 1.6mm glass epoxy board. Reduced by 5.5mW for each increase in Ta of 1C over 25C. *Recommended operating conditions (Ta = 25C) Parameter Power supply voltage RIN input level GIN input level BIN input level SCIN input level Symbol VCC RI GI BI SC Limits 4.5 ~ 5.5 0 ~ 1.0 0 ~ 1.0 0 ~ 1.0 0.4 ~ 5.0 Unit V VP-P VP-P VP-P VP-P 3 Multimedia ICs BH7236AF *Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 5V, NTSC format) Parameter Supply current Luminance level Luminance level R YOUT VOUT Luminance level G Luminance level B Synchronization level Synchronization / Luminance level ratio R / burst level ratio R phase G / burst level ratio G phase COUT VOUT B / burst level ratio B phase Burst level PAL burst phase ( + ) PAL burst phase ( - ) PAL burst level ratio Carrier leak SYNCOUT, "H" level SYNCOUT, "L" level ROUT output level GOUT output level BOUT output level YOUT DC voltage COUT DC voltage VOUT DC voltage ROUT DC voltage GOUT DC voltage BOUT DC voltage Input volt. SYNCIN, NT / PAL, "H" level Input volt. SYNCIN, NT / PAL, "L" level Input curr. SYNCIN, NT / PAL, "H" level Input curr. SYNCIN, NT / PAL, "L" level Symbol ICC L L (R) L (G) L (B) S RS / L RR / BU R RG / BU G RB / BU B BU BU+ BU- RBU CL -- -- RO GO BO VYO VCO VVO VRO VGO VBO VH VL IH IL Min. -- 0.63 0.19 0.37 0.07 0.27 0.38 2.84 94 2.65 231 2.01 337 0.23 125 215 0.9 -- 3.90 -- 0.63 0.63 0.63 1.30 2.00 1.15 1.40 1.40 1.40 2.2 -- -- -- Typ. 42 0.70 0.21 0.41 0.08 0.30 0.43 3.16 104 2.95 241 2.24 347 0.29 135 225 1.0 -- -- -- 0.70 0.70 0.70 1.70 2.40 1.55 1.80 1.80 1.80 -- -- -- -- Max. 55 0.77 0.23 0.45 0.09 0.33 0.48 3.48 114 3.25 251 2.47 357 0.35 145 235 1.1 35 -- 0.80 0.77 0.77 0.77 2.10 2.80 1.95 2.20 2.20 2.20 -- 0.8 300 200 deg -- deg VP-P deg deg -- mVP-P V V VP-P VP-P VP-P V V V V V V V V A A Input current when applied = 5V Input current when applied = 0V RI = 1.0VP-P GI = 1.0VP-P BI = 1.0VP-P Unit mA VP-P VP-P VP-P VP-P VP-P -- -- deg RI = 1.0VP-P1 GI = 1.0VP-P1 BI = 1.0VP-P1 2 Conditions RI = GI = BI = 1.0VP-P RI = 1.0VP-P1 GI = 1.0VP-P1 BI = 1.0VP-P1 RYO = S / L PAL1 PAL1 PAL1 2 1 Guaranteed performance. 2 Measured with a 3.58MHz BPF. Not designed for radiation resistance. 4 Multimedia ICs BH7236AF *Measurement circuit 1 Analog R signal 2 0.1 Analog G signal 3 0.1 Analog B signal 4 0.1 5 Color subcarrier 6 VCC F*F NT / PAL selector BGPOUT 7 FILTER SYNC CLAMP SYNC PHASE SIFTER MATRIX 75 75 24 CLAMP SYNC CLAMP 75 23 + 220 75 75 75 75 75 75 75 75 VCC ROUT measurement point GOUT measurement point BOUT measurement point VOUT measurement point 75 22 + 220 21 + 220 20 + 220 R - Y MOD. B - Y MOD. Y/C MIX 19 BFP DELAY 8 BFP SYNC MIX BPF 18 N.C. 17 N.C. Composite SYNCH 9 BFP GEN. 75 16 + 220 75 75 75 YOUT measurement point COUT measurement point 10 SYNCOUT measurement point VCC 12 75 15 0.47 75 11 SYNC 14 N.C. 13 N.C. *Circuit operation composite synch input. During low (1) SYNCIN is for input, the synchronization signal is output to YOUT, VOUT and SYNCOUT. This signal also controls the timing of the pedestal clamps of RIN, GIN and BIN. (The pedestal levels of RIN, GIN and BIN are kept constant by charging an attached capacitor.) (2) SCIN is for color subcarrier input. Set input to a pulse wave or sine wave (3.579545MHz for NTSC and 4.433619MHz for PAL). (3) NT / PAL is the NTSC / PAL selector pin, and connects to Vcc when set to NTSC and to GND when set to PAL. Chroma phase is switched for each line when the IC is set to PAL. (4) Using the composite synch and subcarrier inputs, the IC generates a burst flag signal, according to which a burst signal is output to COUT and VOUT. The half-H killer presents the burst signal from being output at the wrong points. (5) PAL chroma phases are also switched at a regular cycle (1H) during vertical synchronization. (6) COUT and YOUT are for output of chroma signals and luminosity signals, respectively. Because the chroma signal and luminosity signals can be output separately, the IC can be adapted for S pins. Each has a 75 driver. (7) VOUT is for color TV signal output, and has an internal 75 driver. (8) ROUT, GOUT and BOUT are for analog RGB signal output, and have an internal 75 driver. 5 Multimedia ICs BH7236AF *Application example (NTSC color TV signal) 1 Analog R input 2 0.1 24 CLAMP SYNC CLAMP SYNC CLAMP SYNC PHASE SIFTER FILTER MATRIX 75 23 ROUT Analog G input 3 0.1 75 22 GOUT Analog B input 4 0.1 N.C. 75 21 BOUT 5 75 20 + 220 75 Color TV signal 6 VCC F*F 7 R - Y MOD. B - Y MOD. BFP Y/C MIX Color subcarrier input VCC 19 DELAY 75 75 BGPOUT 8 BFP SYNC MIX BPF 18 N.C. 17 N.C. 9 BFP GEN. 16 YOUT Composite SYNC input 10 15 COUT SYNCOUT 11 SYNC 12 14 N.C. VCC 13 N.C. *Operation notes at the input terminals should be as (1) Input impedance low as possible as the analog RGB signal is clamped there. (2) The color subcarrier should have a duty of 50%. Duty fluctuation will affect chroma phase. (3) Composite synch and burst flag pulse inputs should conform to their respective standards, as input of an off-standard signal will shift the burst position and cause other problems that may prevent the TV from displaying color images. For input, use the TTL level and an impedance of 8k. *External dimensions (Units: mm) 15.0 0.2 24 7.8 0.3 5.4 0.2 13 0.15 0.1 0.3Min. 0.15 1 12 1.8 0.1 0.11 1.27 0.4 0.1 SOP24 6 |
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