intech , ADVANCED DESCRIPTION The Intech RGB DAC 3800 is a hybrid circuit containing three complete video speed digital-to-analog con- verters. The device makes an ideal interface between the computer output signals and the CRT in an RGB type computer graphics terminal. The DACs have 8-BITs of resolution, providing a color palette of 16.7 million possible display colors. The DAGs are very high speed and have update rates of up to 40 MHz. The data inputs have data latches and their outputs provide a clean video signal which does not require additional deglitching circuits. The outputs will drive a 75 ohm load and will provide the composite sync and blanking levels required for CRT vertical and horizontal retrace operations. All three DACs and latches are packaged in a single, cost effective, dual-in-line package requiring less than 1.7 square inches of PC Board area. , INTECH INC/ MICROCIRCUITS 45 pe Bf sazsaze OOOL2e84 4 i D ANALOG STROBE | 3 VIDEO DACs ~ COMPOSITE SYNC and RED DATA IN See (Ro-R7) & T-51-09-05 RGB DAC 3800 CMOS, TRIPLE, 8-BIT 40 MHz, VIDEO DAC FEATURES CMOS CIRCUITRY IDEAL FOR COLOR GRAPHICS e UPDATE RATES TO 40 MHz 75 OHM VIDEO OUTPUTS BLANKING OUTPUT SIGNALS INPUT DATA LATCHES | e TTL, CMOS COMPATIBLE INPUTS e 40 PIN DIP PACKAGE RED VIDEO DAC { VIDEO _| out | | RED 10% BRIGHT REF RED BLOCK DIAGRAM GRN DATA IN : (Go-G7 | SYNC ADJ VIDEO DAC }- VIDEO | | C___. GRN 10% BRIGHT REF GRN BLU DATA IN (Bo-B7| BLU VIDEO DAC _}- VIDEO _OUT | | - Bi 10% BRIGHT REF BLU RGB BLANK + __}INTECH INC/ MICROCIRCULTS &5 Def) ysesoz2 ooo1ss o B 5-51-09-05 SPECIFICATIONS (Typical @ + 25C, +5V and 75@ load unless otherwise stated) RESOLUTION 8 BITs DYNAMIC CHARACTERISTICS a Settling Time (to 1 LSB) 10 ns PALLETTE 16.7 million Update Rate (min) 40 MHz Rise Time 5ns (each channel) DATA INPUTS Voltage Range 0 to 1.04 Compatibility TTL, CMOS Current BmA Coding BIN Short Circuit Current 17mA Impedance (+ 0.5%) 75Q CONTROL INPUTS Compliance + 1.5V STROBE Compatibility ~ TTL, CMOS VIDEO OUTPUT LEVEL 0 to 0.06375 V Set-up Time (min) 8 ns BLANKING OUTPUT LEVEL Hold Time Ons (Referred to Black Level) +5% 53 mV Propagation (max) 20 ns SYNC OUTPUT LEVEL COMPOSITE BLANKING, SYNC (Referred to Blanking Level) 280 mV Compatibility TTL, GMOS Settling Time 10 ns 10% BRIGHT LEVEL +70 mV Set-up Time (max) 10 ns Propagation (max 20 ns ACCURACY pag (max) (each channel) POWER REQUIREMENTS Channel to Channel Gain Difference +1LSB Voltage +45 to +5.5V Absolute Accuracy +1.6 LSB Current 100 mA typ Differential Linearity +1LSB 140 mA max Offset +1.0 mV Offset Tempco +10 ppm/C TEMPERATURE RANGE 0 to +70C* Gain Tempco + 200 ppm/C : Linearity Tempco + 100 ppm/C *_55C to + 125C Ranges Available PSRR +0.2%/% COMPOSITE VIDEO WAVEFORMS GREEN OUTPUT (SYNC ENABLED and 10% BRIGHT OFF*) vouts RED & BLUE OUTPUT to See # 1.04V Max 10% BRIGHT LEVEL* (OR GRN OUT with NO SYNC, TTT ey TT REF WHITE (all bits on) 10% BRIGHT OFF*) ea ewe me me Me ei ew eK Me nme +0.761V Max 10% BRIGHT LEVEL* +07 . Qo OS +0.691V REF WHITE (all blis on) = awe +0.333V AEF BLACK (all bits off) +0.280V BLANKING LEVEL > 1 +0.2 +0.2 peel -- - 4 pt +0.053v REF BLACK (all bits off) +0.0V SYNC LEVEL +00 +0.0 BLANKING LEVEL { t | +04 ' { I ' | t SYNC ~< wee >| SIGNAL Le An active 10% BRIGHT signal on any channel will cause the output level of that channel to go 70 mV more positive regardless of the status of other input signals or output level. The maximum 10% Bright ievels shown are with all bits on and the 10% Bright input on. dINTECH INC/ MICROCIRCUITS 45 PIN DESCRIPTIONS STROBE This Input is used to clock the input data into the latches. It operates on normal TTL logic levels and is active on the transition from logic 1 to logic 0. DATA (Ro-R7, Go-G7, Bo-B7) These pins are the digital data inputs to the latches for the DACs in each channel (Red, Green, Blue). They oper- ate on normal TTL logic levels and the coding is binary. The input data is transferred to the DACs when the strobe makes a logic 1 to logic 0 transition. RGB BLANK A logic 0 sets the registers to all 0s (Ref Black) and drives the output to a level 53mV more negative than the Reference Black level. This signal has priority over the data inputs and is used to shut off the beam for the darkest display possible. Blanking is synchronous with strobe. SYNC ADJ This input should be left open to enable the 280 mV sync level feature of the Green Output. If this feature is not desired this input should be connected to ground, This is not a digital input. SYNC When enabled (Sync Adj. open) a logic 0 on this input activates the sync function which sets the inputs to the DACs, on all three channels, to all 0s, thereby driving thelr outputs to Reference Black. In addition it drives the output on the green channel to a level 280 mV more negative than the reference black level. When combined with an active blanking signal the output of all three channels will be driven to 0.0 volts, as shown in the Composite Video Waveforms. VIDEO OUTPUTS These are the outputs of the DACs In each channel. They control the CRT display color and brightness in an RGB type color graphics sytem. A separate output is provided for each gun (red, green, and blue) in the CRT. Each of the output waveforms contain the video signals plus a composite blanking level in accordance with the Composite Video Waveforms. In addition the Green Output wil! supply a composite sync signal which is us- ed to trigger the retrace cycles in the CRTs beam sweep circuitry. The DAC outputs have been designed to provide a clean signal, free from excessive switching spikes, and no additional deglitching circuitry is required. Its output circuitry will develop a full output across a 75 ohm load which is sufficient to drive the inputs of most CRT video amplifiers directly. Buazso?2 OOOeaL 1 7251-09-05 REF RED, GRN, BLU These inputs provide a convenient way to force the out- put of the DACs to go to their Ref-White level. A logic Q at these inputs will override the digital data inputs and cause the output to go to its full-scale value. Any one of seven colors, of full intensity, may be gen- erated by using combinations of these inputs. A logic QO at all inputs simultaneously will generate white pixels at full intensity. These inputs are asynchronous and, for the best results, should be synchronized with the STROBE signal then latched externally. RED, GRN, BLU 10% BRIGHT These inputs provide a convenient way to add 10% to the DACs output. A logic 0 at these inputs will increase the DACs output by 70 mV, thus facilitating word and cursor highlighting. TIMING DIAGRAM ON 50% (TYP) STROBE | TIME SET-UP REGISTER | OUTPUT [PROPAGATION DELAY SYNC OR BLANKING REGISTER l \ OUTPUT |+Propacarion>| DELAYINTECH INC/ MICROCIRCUITS 85 ve uB25072 OoOOea? 3 qT, T-51-09-05 MECHANICAL OUTLINE PIN DESIGNATION 0.015 DOT AT PIN 1 Gan _ fp f : Bo t. 40. +5V 0.600 0.790 - B, 2 39, DIG GND (15.24) (20.07) Bg 3. 38. REF BLUE By 4 37. 10% BLU BRIGHT By 5. 36. BLU OUT " = Bs 6. 35. STROBE Be 7. 34. SYNC 0.095 By 8. 33. RGB BLANK (2.41) 0.130 (3.30) . G 2% 32. REF GRN B 2.1400 | Gi 10. 31. SYNC ADJ ~ (53.34) - G2 11. 30. 10% GRN BRIGHT G3 12. 29. GRN OUT G, 13, 28. ANA GND 0.025 Gs 14. 27, REF RED ots (0.64) Ge 15. 26. 10% RED BRIGHT (3.84) | I | G, 16. 25. RED OUT Ro 17. 24 Ry Ri 18. 23. Re Ro 19. 22. Rs k- 0.100 -. Rg 20. 21, Ra _ (0.46) tt . | e (48.26) 0.100 | (2.54) The information in this data sheet has been carefully checked and is believed to be accurate, however, no 2-8601 lIntech 1986 responsibility is assumed for possible errors. The specifications are subject to change without notice. imtech | 2270 MARTIN AVENUE, SANTA CLARA, CALIFORNIA 95050-2781 A D V A N C E D A N A L O G TELEPHONE (408) 988-4930 : TWX 910-338-2213