LM1238AAD/NA NOPB National Semiconductor, LM1238AAD/NA NOPB Datasheet
LM1238AAD/NA NOPB
Specifications of LM1238AAD/NA NOPB
Related parts for LM1238AAD/NA NOPB
LM1238AAD/NA NOPB Summary of contents
Page 1
... I C compatible microcontroller interface n Internal OSD generator with 16 sets of color icons Block and Connection Diagram © 2003 National Semiconductor Corporation n OSD override allows OSD messages to be displayed while blanking input video n Internally generated burn-in screen n 4 DAC outputs (8-bit resolution) for bus controlled CRT ...
Page 2
... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage, Pins 15 and 19 Peak Video DC Output Source Current (Any One Amp) Pins 18 Voltage at Any Input Pin ( Thermal Resistance to Ambient (θ ...
Page 3
Video Signal Electrical Characteristics Unless otherwise noted 25˚ numbers refer to the definitions in Table 1. See Note 7 for Min and Max parameters and Note 6 for Typicals. Symbol Parameter A Track Gain Change between ...
Page 4
DAC Output Electrical Characteristics Unless otherwise noted 25˚ for Min and Max parameters and Note 6 for Typicals. DAC parameters apply to all 4 DACs. Symbol Parameter ∆ Variation in voltage of DAC with ...
Page 5
System Interface Signal Characteristics < Note 5: Input from signal generator ns Note 6: Typical specifications are specified at +25˚C and represent the most likely parametric norm. Note 7: Tested limits are guaranteed to ...
Page 6
Typical Performance Characteristics 25˚C unless otherwise specified CC A SYSTEM INTERFACE SIGNALS The Horizontal and Vertical Blanking and the Clamping input signals are important for proper functionality of the LM1238. Both blanking inputs must be ...
Page 7
Typical Performance Characteristics otherwise specified (Continued) FIGURE 7. Red Cathode Response FIGURE 8. ABL Gain Reduction Curve Figure 2 and Figure 3 show the case where the Horizontal and Vertical inputs are logic levels. Figure ...
Page 8
Pin Descriptions and Application Information Pin Pin Name No Flyback 2 V Bypass REF 3 V Current Set REF 4 Analog Ground 5 Blue Video In 6 Red Video In 7 Green Video In 8 PLL Ground 10 ...
Page 9
Pin Descriptions and Application Information Pin Pin Name No. 9 PLL Filter 11 SDA 12 SCL 13 DAC 4 Output 14 DAC 2 Output 15 DAC 3 Output 16 DAC 1 Output 17 Ground Green Output ...
Page 10
Pin Descriptions and Application Information Pin Pin Name No. 22 ABL 23 CLAMP 24 H Flyback www.national.com (Continued) Schematic The Automatic Beam Limiter input is biased to the desired beam current limit by R and normally keeps D the current ...
Page 11
Schematic Diagram FIGURE 9. LM123x-LM246x Demo Board Schematic 11 20038716 www.national.com ...
Page 12
Schematic Diagram FIGURE 10. LM123x-LM246x Demo Board Schematic (continued) www.national.com 12 20038717 ...
Page 13
PCB Layout FIGURE 11. LM123x-LM246x Demo Board Layout 13 20038718 www.national.com ...
Page 14
OSD Operation The LM1238 is designed to enable ultra-low cost OSD op- eration in monitors that usually use a simple button + LED interface instead of OSD. The basic screen is formed by a frame as shown in figure 12 ...
Page 15
OSD Operation (Continued) FIGURE 13. The First 8 Icon Sets (0-7) 15 20038763 www.national.com ...
Page 16
OSD Operation (Continued) www.national.com FIGURE 14. Last 8 Icon Sets (8-15) 16 20038762 ...
Page 17
Microcontroller Interface The microcontroller interfaces to the LM1238 preamp via the compatible interface. The protocol of the interface begins with a Start Pulse followed by a byte comprised of a seven bit Slave Device Address and a ...
Page 18
Microcontroller Interface www.national.com (Continued) 2 FIGURE 16 Compatible Read Sequence 18 20038727 ...
Page 19
LM1238 Address Map Address Range R/W 0x0800h-0x0805h R/W 0x0810h-0x081Fh R/W 2 Pre-Amp Interface I C Registers TABLE 4. LM1238 Pre-Amplifier Interface I Register Address BGAINCTRL 0x0810 GGAINCTRL 0x0811 RGAINCTRL 0x0812 CONTRCTL 0x0813 DAC2CTRL 0x0814 DAC3CTRL 0x0815 DAC1CTRL 0x0816 DAC4CTRL 0x0817 ...
Page 20
Control Register Definitions Bits 7–3 Bar Indicator. These five bits determine the length of the bar indicator on a scale of 0–31. A value of 0 results in no indicator. 31 results in a full scale ...
Page 21
Control Register Definitions Icon Alternate Period Control Register (I Register Name (address): ALT (0x0804h RSV RSV Bits 3–0 Icon Alternate Period. These four bits set the period at which the icon will switch between images, in increments of ...
Page 22
Control Register Definitions 2 Contrast Control Register (I C address 0x0813h) Register Name (address): CONTRCTRL (0x0813h RSV CO Bits 6–0 Contrast Gain Control. These seven bits determine the overall gain of all the three channels. Bit 7 Reserved. ...
Page 23
Control Register Definitions 2 Global Video Control Register (I C address 0x0819h) Register Name (address): GLOBALCTRL (0x0819h D_ID5 D_ID4 Bit 0 Blank Video. When this bit is a one, blank the video output. When this bit is a ...
Page 24
... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...