Description
LM1246 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs November 2003 LM1246 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs General Description The LM1246 pre-amp is an integrated CMOS CRT preamp. It has an I2C compatible interface which allows control of all the parameters necessary to directly setup and adjust the gain and contrast in the CRT display. Brightness and bias can be controlled through the DAC outputs, which are well matched to the LM2479 and LM2480 integrated bias clamp ICs. The LM1246 preamp is also designed to be compatible with the LM246x high gain driver family. Black level clamping of the video signal is carried out directly on the AC coupled input signal into the high impedance preamplifier input, thus eliminating the need for additional clamp capacitors. Horizontal and vertical blanking of the outputs is provided. Vertical blanking is optional and its duration is register programmable. The IC is packaged in an industry standard 24-lead DIP molded plastic package. n n n n n n n n n OSD Window Fade In/Fade Out OSD Half Tone Transparency Video Data dectection for Auto Centering & Sizing OSD override allows OSD messages to override video and the use of burn-in screens with no video output. 4 DAC outputs (8-bit resolution) for bus controlled CRT bias and brightness Spot killer which blanks the video outputs when VCC falls below the specified threshold Suitable for use with discrete or integrated clamp, with software configurable brightness mixer 4-Bit Programmable start position for internal Horizontal Blanking Horizontal blanking and OSD synchronization directly from deflection signals. The blanking can be disabled, if desired. Vertical blanking and OSD synchronization directly from deflection signals. The blanking width is register programmable and can be disabled, if desired. Power Saving Mode with 65% power reduction Matched to LM246x driver and LM2479/80 bias IC’s n Features n Fully addressable 512 Character OSD, simiilar in features to the LM1237/LM1247, with selectable 2 byte character addressing or LM1247 bank select modes n Internal 512 character OSD ROM usable as either (a) 384 2-color plus 128 4-color characters, (b) 640 2-color characters, or (c) some combination in between n Internal 512 character RAM, which can be displayed as one single or two independent windows n Enhanced I2C compatible microcontroller interface to allow versatile Page RAM access n n Applications n Low end 15" and 17" bus controlled monitors with OSD n 1024x768 displays up to 85 Hz requiring OSD capability n Very low cost systems with LM246x driver © 2003 National Semiconductor Corporation DS200685 www.national.com LM1246 Internal Block Diagram 20068501 FIGURE 1. Order Number LM1246AAA/NA See NS Package Number N24D www.national.com 2 LM1246 Absolute Maximum Ratings 3) (Notes 1, Thermal Resistance to Case (θJC) Junction Temperature (TJ) ESD Susceptibility (Note 4) ESD Machine Model (Note 13) Storage Temperature Lead Temperature (Soldering, 10 sec.) 32˚C/W 150˚C 3.0 kV 350V −65˚C to +150˚C 265˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage VCC, Pins 10 and 18 Peak Video DC Output Source Current (Any One Amp) Pins 19, 20 or 21 Voltage at Any Input Pin (VIN) Video Inputs (pk-pk) Thermal Resistance to Ambient (θJA) Power Dissipation (PD) (Above 25˚C Derate Based on θJA and TJ) 6.0V 1.5 mA 0.0 ≤ VIN ≤ 1.2V 51˚C/W VCC +0.5 ≥ VIN ≥ −0.5V Operating Ratings (Note 2) Temperature Range Supply Voltage VCC Video Inputs (pk-pk) 0˚C to +70˚C 4.75V ≤ VCC ≤ 5.25V 0.0V ≤ VIN ≤ 1.0V 2.4W Video Signal Electrical Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, VIN = 0.70 VP-P, VABL = VCC, CL = 8 pF, Video Outputs = 2.0 VP-P. Setting numbers refer to the definitions in Table 1. Test Settings. See (Note 7) for Min and Max parameters and (Note 6) for Typicals. Symbol IS IS-PS VO BLK VO BLK STEP VO Max LE Parameter Supply Current Supply Current, Power Save Mode Active Video Black Level Output Voltage Active Video Black Level Step Size Maximum Video Output Voltage Linearity Error Conditions Test Setting 1, both supplies, no output loading. See (Note 8). Test Setting 1, both supplies, no output loading. See (Note 8). Test Setting 4, no AC input signal, DC offset (register 0x8438 set to 0xd5). Test Setting 4, no AC input signal. Test Setting 3, Video in = 0.70 VP-P Test Setting 4, staircase input signal (see Table 9. Page RAM Format (9-bit mode)). (Note 5), 10% to 90%, Test Setting 4, AC input signal. (Note 5), Test Setting 4, AC input signal. (Note 5), 90% to 10%, Test Setting 4, AC input signal. (Note 5), Test Setting 4, AC input signal. (Note 5), Test Setting 4, AC input signal. (Note 14), Test Setting 8. (Note 14), Test Setting 8. Test Setting 8, AC input signal. Test Setting 5, AC input signal. Test Setting 2, AC input signal. Test Setting 6, AC input signal. Test Setting 7, AC input signal. Test Setting 3, AC input signal. Tracking when changing from Test Setting 8 to Test Setting 5. See (Note 11). 3 Min Typ 200 70 1.2 100 Max 250 95 Units mA mA VDC mVDC V % 4.0 4.3 5 tr OSR tf OSF BW VSEP 10 kHz VSEP 10 MHz AV Max AV C-50% AV Min/AV Max AV G-50% AV G-Min AV Match AV Track Video Rise Time Rising Edge Overshoot Video Fall Time Falling Edge Overshoot Channel Bandwidth (−3 dB) Video Amplifier 10 kHz Isolation Video Amplifier 10 MHz Isolation Maximum Voltage Gain Contrast Attenuation @ 50% Maximum Contrast Attenuation (dB) Gain Attenuation @ 50% Maximum Gain Attenuation Maximum Gain Match between Channels Gain Change between Channels 3.1 2 2.9 2 150 −60 −50 3.8 4.1 −5.2 −20 −4.0 −11 ns % ns % MHz dB dB V/V dB dB dB dB dB ± 0.5 ± 0.5 dB www.national.com LM1246 Video Signal Electrical Characteristics Symbol VidThreshold VABL TH VABL Range AV 3.5/AV Max AV 2.0/AV Max IABL Active IABL Max VABL Max AV ABL Track Parameter Video Threshold ABL Control Range Upper Limit ABL Gain Reduction Range ABL Gain Reduction at 3.5V ABL Gain Reduction at 2.0V ABL Input Bias Current during ABL (Continued) Unless otherwise noted: TA = 25˚C, VCC = +5.0V, VIN = 0.70 VP-P, VABL = VCC, CL = 8 pF, Video Outputs = 2.0 VP-P. Setting numbers refer to the definitions in Table 1. Test Settings. See (Note 7) for Min and Max parameters and (Note 6) for Typicals. Conditions Normal Operation (Note 12), Test Setting 4, AC input signal. (Note 12), Test Setting 4, AC input signal. (Note 12), Test Setting 4, AC input signal. VABL = 3.5V (Note 12), Test Setting 4, AC input signal. VABL = 2.0V (Note 12), Test Setting 4, AC input signal. VABL = VABL MIN GAIN Min Typ 80 4.8 2.8 −2 −12 10 1.0 VCC + 0.1 Max Units mV V V dB dB µA mA V ABL Input Current Sink Capability (Note 12), Test Setting 4, AC input signal. Maximum ABL Input Voltage during Clamping ABL Gain Tracking Error (Note 12), Test Setting 4, AC input signal. IABL = IABL MAX Table 9. Page RAM Format (9-bit mode), Test Setting 4, 0.7 VP-P input signal, ABL voltage set to 4.5V and 2.5V. Test Setting 4. 20 4.5 % RIP Minimum Input Resistance (pins 5, 6, 7) MΩ OSD Electrical Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V. See (Note 7) for Min and Max parameters and (Note 6) for Typicals. Symbol VOSDHIGH max VOSDHIGH 10 VOSDHIGH 01 VOSDHIGH 00 ∆VOSD (Black) Parameter Maximum OSD Level with OSD Contrast 11 Maximum OSD Level with OSD Contrast 10 Maximum OSD Level with OSD Contrast 01 Maximum OSD Level with OSD Contrast 00 Conditions Palette Set at 111, OSD Contrast = 11, RGB Gain = 96, DC Offset = 4 Palette Set at 111, OSD Contrast = 10, RGB Gain = 96, DC Offset = 4 Palette Set at 111, OSD Contrast = 01, RGB Gain = 96, DC Offset = 4 Palette Set at 111, OSD Contrast = 00, RGB Gain = 96, DC Offset = 4 Min Typ 3.85 3.27 2.70 1.97 Max Units V V V V Difference between OSD Black Register 08=0x18, Input Video = Level and Video Black Level (same Black, Same Channel, Test Setting channel) 8 Difference between OSD Black Level and Video Black Level between Channels Output Match between Channels Register 08=0x18, Input Video = Black, Same Channel, Test Setting 8 Palette Set at 111, OSD Contrast = 11, Maximum difference between R, G and B Palette Set at 111, OSD Contrast = 10, Test Setting 4 20 mV ∆VBL,OSD-Video (Ch to Ch) ∆VOSD (White) 20 mV 3 % ∆VOSD/VVideo (White) Matching of OSD to Video peak to peak amplitude ratios between channels, normalized to the smallest ratio. 3 % VOSD-out (Track) Output Variation between Channels OSD contrast varied from max to min 3 % www.national.com 4 LM1246 DAC Output Electrical Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, VIN = 0.7V, VABL = VCC, CL = 8 pF, Video Outputs = 2.0 VP-P. See (Note 7) for Min and Max parameters and (Note 6) for Typicals. DAC parameters apply to all 4 DACs. Symbol VMin DAC VMax DAC Mode 00 VMax DAC Mode 01 ∆VMax DAC (Temp) ∆VMax DAC (VCC) Linearity Monotonicity IMAX Parameter Min Output Voltage of DAC Max Output Voltage of DAC Max Output Voltage of DAC in DCF Mode 01 DAC Output Voltage Variation with Temperature DAC Output Voltage Variation with VCC Linearity of DAC over its Range Monotonicity of the DAC Excluding Dead Zones Max Load Current −1.0 Conditions Register Value = 0x00 Register Value = 0xFF, DCF[1:0] = 00b Register Value = 0xFF, DCF[1:0] = 01b 0 < T < 70˚C ambient VCC varied from 4.75V to 5.25V, DAC register set to mid-range (0x7F) 3.7 1.85 Min Typ 0.5 4.2 2.35 Max 0.7 Units V V V mV/˚C mV % LSB 1.0 mA ± 0.5 50 5 ± 0.5 System Interface Signal Characteristics Unless otherwise noted: TA = 25˚C, VCC = +5.0V, VIN = 0.7V, VABL = VCC, CL = 8 pF, Video Outputs = 2.0 VP-P. See (Note 7) for Min and Max parameters and (Note 6) for Typicals. DAC

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LM1246NA

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