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| Ordering number : EN5680 CMOS IC LC7455A, 7455M Closed Caption Signal Extraction IC Overview The LC7455A/M extracts the closed caption signal superimposed on a video signal during the vertical return period and, under the control of a clock signal provided by the decoder IC, transfers that signal to the IC (usually a microcontroller) that decodes the closed caption data. The LC7455A/M supports four operating modes. Modes 1 and 2 can be used for XDS. In these modes, the LC7455A/M, in combination with the decoder IC (microcontroller), extracts the caption signal superimposed on field 2 and uses it for NTSC VCR functions such as the automatic time and date setting function. In modes 3 and 4, the LC7455A/M, in combination with the decoder IC (microcontroller), extracts the caption signal superimposed on fields 1 and 2 and uses it for NTSC TV applications (mode 3) or PAL TV applications (mode 4). Package Dimensions unit: mm 3006B-DIP16 [LC7455A] Functions * Low power dissipation achieved by fabrication in a CMOS process. * Stable caption signal extraction achieved by a built-in peak hold circuit and the use of digital technology. * Operating supply voltage: 5 V 10% * Package LC7455A: 16-pin DIP LC7455M: 18-pin MFP unit: mm 3095-MFP18 [LC7455M] SANYO: DIP16 SANYO: MFP18 SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN D3097HA(OT) No. 5680-1/13 LC7455A, 7455M Pin Assignments Top view Pin Functions Pin No. Pin VSS1 TEST LN21 O/E/CFOUT HS/CFIN CPDT SCKIN CE VDD1 MOD0 CVIN VCOR MOD1 VDD2 VSS2 CP DIP16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 MFP18 1 2 3 4 5 6 7 8 11 12 13 14 15 16 17 18 Ground Test pin. Must be left open during normal operation. Line 21H pulse output (even field) Field discrimination pulse output Sync separator Hsync pulse output Ceramic oscillator output Ceramic oscillator input Line 21H pulse output (both fields) Line 22H pulse output (both fields) Mode 1 Mode2 Pin function Mode3 Mode4 Field discrimination pulse output Hsync pulse input Caption data output (n-channel open-drain output) Caption data transfer clock input Chip select input Power supply Leave open Composite video input Connection for an external resistor to control the built-in VCO oscillator frequency Leave open Power supply Ground Connection for the filter used by the built-in PLL Short to the power supply Short to the power supply Leave open Short to the power supply Note: VDD1 and VSS1 are the power supply for the digital block, and VDD2 and VSS2 are the power supply for the analog block. Use a circuit similar to the one shown below to minimize mutual interference due to noise from these blocks. Power supply No. 5680-2/13 LC7455A, 7455M System Block Diagram Pedestal clamp PLL reference clock mode 2 mode 3, 4 mode 1 Data peak hold (Data slice) Hsync peak hold (Hsync slice) Output control Divided-by32 circuit Oscillator circuit (Mode 2) (Mode 2) Data output buffer (Modes 1, 3, 4) Operation in the Different Modes Pin MOD1 Open MOD0 Open Mode 1 VCR * Even field line 21 data extraction The internal PLL is operated with the horizontal synchronizing signal separated from the composite video signal as the reference. * Even field line 21 data extraction An external 508 kHz ceramic oscillator is used, and the internal PLL is operated with that oscillator output divided by 32 as the reference. * Odd and even field line 21 data extraction The internal PLL is operated with the Hsync signal applied from fly back as the reference. * Odd and even field line 22 data extraction The internal PLL is operated with the Hsync signal applied from the fly back circuit as the reference. Mode Application equipment Operation Open VDD Mode 2 VCR VDD VDD Open VDD Mode 3 Mode 4 NTSC-TV PAL-TV Note: The data extraction operations in modes 1 and 2 are identical. However, while mode 1 can operate without problem for normal "on air" signals, it may be difficult for the PLL to lock with signals such as scrambled CATV signals. No. 5680-3/13 LC7455A, 7455M Specifications Absolute Maximum Ratings at Ta = 25C, VSS = 0 V Parameter Maximum supply voltage Input voltage Output voltage Allowable power dissipation Operating temperature Storage temperature Symbol VDD max VI VO Pd max Topr Tstg Conditions VDD1, VDD2: VDD1 = VDD2 HS/CFIN, CVIN, SCKIN, CE LN21, CPDT, O/E/CFOUT, HS/CFIN LC7455A LC7455M Ratings -0.3 to +7.0 -0.3 to VDD +0.3 -0.3 to VDD +0.3 300 150 -30 to +70 -55 to +150 Unit V V V mW mW C C Note: VSS1 and VSS2 must be at the same potential. VDD1 and VDD2 must be at the same potential. Allowable Operating Ranges at Ta = -30 to +70C, VSS = 0 V Parameter Operating supply voltage Input high-level voltage Input low-level voltage CVIN input amplitude HS input frequency range Symbol VDD VIH VIL Conditions VDD1, VDD2 : VDD1 = VDD2 HS/CFIN, SCKIN, CE; VDD = 4.5 to 5.5 V HS/CFIN, SCKIN, CE; VDD = 4.5 to 5.5 V Ratings min 4.5 0.75 VDD VSS 1Vp-p - 3dB 15.23 15.13 503 1Vp-p 15.73 15.63 508 typ max 5.5 VDD 0.25VDD 1Vp-p + 3 dB 16.23 16.13 513 Unit V V V V kHz kHz kHz CVIN : SYNC-WHITE = 1.0 V; CVSYNC VDD = 4.5 to 5.5 V fH HS/CFIN : VDD = 4.5 V For mode 3 For mode 4 HS/CFIN, O/E/CFOUT; For mode 2, see Figure 1. VDD = 4.5 to 5.5 V HS/CFIN, O/E/CFOUT; For mode 2, see Figure 2. VDD = 4.5 to 5.5 V Oscillator frequency range*1 FmCF Oscillator stabilization time*2 tmsCF 0.5 5 ms Note: 1. See Table 1 for more information on the oscillator frequency. 2. The oscillator stabilization time is the time required until the oscillator is stable after the power-supply voltage is applied. See figure 2. Electrical Characteristics at Ta = -30 to +70C, VSS = 0 V. Parameter Input high-level current Input low-level current Output high-level voltage Output low-level voltage Input clamping voltage Input clamping current Output clamping current Current drain Symbol IIH IIL VOH VOL VCLMP IIC IOC IDD Conditions HS/CFIN, SCKIN, CE : VIN = VDD; VDD = 4.5 to 5.5 V HS/CFIN, SCKIN, CE : VIN = VSS; VDD = 4.5 to 5.5 V LN21, O/E/CFOUT, HS/CFIN; IOH = -4 mA ; VDD = 4.5 to 5.5 V LN21, CPDT, O/E/CFOUT, HS/CFIN : IOL = 10 mA; VDD = 4.5 to 5.5 V CVIN ; VDD = 5.0 V CVIN : CVIN = 3 V ; VDD = 5.0 V CVIN : CVIN = 2 V ; VDD = 5.0 V VDD1, VDD2 ; VDD = 4.5 to 5.5 V 2.3 5 -120 2.5 10 -70 6 -1 Ratings min typ max 1 Unit A A VDD - 1.2 1 2.7 18 -30 15 V V V A A mA Serial Output Characteristics at Ta = -30 to +70C, VSS = 0 V, VDD = 4.5 to 5.5 V Parameter [Serial clock] Input clock period Input clock low-level pulse width Input clock high-level pulse width Setup time [Serial output] Output delay time tCKO Stipulated with respect to the falling edge of SCKIN. A 1-k external pull-up resistor is connected. See Figure 3. 0.5 s tCKCY tCKL tCKH tICK SCKIN : See Figure 3. SCKIN : See Figure 3. SCKIN : See Figure 3. SCKIN : Stipulated with respect to the falling edge of CE. 1 0.5 0.5 1 s s s s Symbol Conditions Ratings min typ max Unit No. 5680-4/13 LC7455A, 7455M Table 1 Ceramic Oscillator Guaranteed Constants Oscillator type 508-kHz ceramic oscillator Manufacturer Murata Mfg. Co., Ltd. Oscillator element CSB 508E C1 150 pF C2 150 pF Note: Capacitors with K tolerance (10%) and SL characteristics must be used for C1 and C2. * Since this circuit is influenced by the length of the circuit pattern, components related to oscillator functioning must be mounted as close together as possible so that pattern lines do not become longer than is absolutely necessary. * The characteristics are not guaranteed if an oscillator element other than the one listed above is used. Figure 1 Ceramic Oscillator Power supply Operating VDD lower limit Figure 2 Oscillator Stabilization Time Figure 3 Serial Output Test Conditions No. 5680-5/13 O/E and LN21 Output Timing (Modes 1, 2, and 3) Odd field Line no. (modes 1, 3) LC7455A, 7455M This pulse is only output in mode 3. Even field Line no. (modes 1, 3) This pulse is only output in modes 1, 2, and 3. No. 5680-6/13 Notes: O/E is output in modes 1 and 3. In mode 2 it functions as the ceramic oscillator output pin. LN21 is output for even fields in modes 1 and 2, and for both fields in mode 3. O/E and LN21 Output Timing (Mode 4) First field Line no. LC7455A, 7455M Second field Line no. No. 5680-7/13 Caption Data Transfer from the LC7455A/M to the Decoder IC (microcontroller): Method 1 (This is the basic technique.) ( In modes 1 and 2, pulses are output on line 21 of even fields. In mode 3, pulses are output on line 21 of both fields. In mode 4, pulses are output on line 22 of both fields. ) LC7455A, 7455M (Caption data is transferred to the data output buffer.) (The decoder IC (microprocessor) sets CE from high to low after detecting a falling edge on LN21.) High impedance The previous data is output. (Sixteen bits of caption data is output LSB first in synchronization with falling edges on SCKIN.) No. 5680-8/13 Notes: Applications that extract closed caption text data in mode 3 (NTSC TV) or mode 4 (PAL TV) must check the level of the O/E/CFOUT pin when an LN21 falling edge is detected to determine whether odd field or even field data is being acquired. Caption Data Transfer from the LC7455A/M to the Decoder IC (microcontroller): Method 2 (For applications that cannot provide an input port on the decoder IC (microcontroller) to detect LN21 falling edges.) Within a single frame (modes 1 and 2) LC7455A, 7455M 16 bits transfered 16 bits of data all of which are zeros. In modes 1 and 2, since data is output to the output buffer once every frame (in the even field), the decoder IC (microcontroller) must perform a transfer control operation at least twice every frame (about 32 ms). When the second control operation is performed in a given frame, the CPDT output for that second operation will be 16 bits of zeros. This allows the microprocessor to recognize that the data for the next frame has not yet been transferred to the output buffer. Notes: When CE remains low, the hardware will not transfer the data to the output buffer. Thus applications must restore CE from low to high after each data transfer to the decoder IC (microcontroller) operation has completed. This transfer technique (method 2) cannot be used in modes 3 and 4. No. 5680-9/13 LC7455A, 7455M Sample Application Circuits (mode 1) MFP18 DIP16 No. 5680-10/13 LC7455A, 7455M Sample Application Circuits (mode 2) MFP18 DIP16 No. 5680-11/13 LC7455A, 7455M Sample Application Circuits (mode 3) MFP18 Hsync signal DIP16 Hsync signal No. 5680-12/13 LC7455A, 7455M Sample Application Circuits (mode 4) MFP18 Hsync signal DIP16 Hsync signal s No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. s Anyone purchasing any products described or contained herein for an above-mentioned use shall: Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. s Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of December, 1997. Specifications and information herein are subject to change without notice. No. 5680-13/13 |
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