19-1205; Rev 2; 5/98 8-Bit, Ultra-High-Speed DAC ____________________________Features ♦ 400Msps Nominal Conversion Rate The MAX5140 is available in a 24-pin PDIP package in the -20°C to +85°C industrial temperature range. ________________________Applications ♦ RS-343-A Compatible ♦ Complete Video Controls: Sync, Blank, Bright, and Reference White (force high) ♦ ECL Compatible ♦ Single Power Supply ♦ Registered Data and Video Controls ♦ Differential Current Outputs ♦ Stable On-Chip Bandgap Reference ♦ 50Ω and 75Ω Output Drive Raster Graphics High-Resolution Color or Monochrome Displays to 2k x 2k Pixels ♦ ESD-Protected Data and Control Inputs Medical Electronics: CAT, PET, and MR Imaging Displays CAD/CAE Workstations Ordering Information Solids Modeling General-Purpose, High-Speed Digital-to-Analog Conversion PART MAX5140IPG TEMP. RANGE PIN-PACKAGE -20°C to +85°C 24 Plastic DIP Digital Synthesizers Automated Test Equipment Digital Transmitters/Modulators Functional Diagram Pin Configuration TOP VIEW D3 1 24 D4 D2 2 23 D5 D1 3 22 D6 D0 4 21 D7 Sync, Blank, Bright, Ref - White VEE 5 MAX5140 20 VEE CONV 6 19 Out+ CONV 7 18 Out- FT 8 17 VCC VCC 9 16 ISet Video Controls In 4 4 Video Data In D0 - D3 4 4 Register Video Data In D4 - D7 (MSBs) 4 4 To 15 Decode Out + Output Current Switches Out - Feedthrough Convert FH 10 15 Ref In Blank 11 14 Ref Out BRT 12 2 ISet Ref In Ref Out Ref Buffer Bandgap Reference 13 Sync DIP ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468. MAX5140 ________________General Description The MAX5140 is a monolithic, 8-bit digital-to-analog converter (DAC) capable of accepting video data at 400Msps. Complete with video controls (sync, blank, reference white (force high), and bright), the MAX5140 directly drives doubly terminated 50Ω or 75Ω loads to standard composite video levels. Standard setup level is 7.5IRE. The MAX5140 includes an internal precision bandgap reference that can drive two other MAX5140s in an RGB graphics system. MAX5140 8-Bit, Ultra-High-Speed DAC ABSOLUTE MAXIMUM RATINGS Supply Voltage VEE (measured to VCC)..........................................-7.0V to 0.5V Input Voltages CONV, Data, and Controls (measured to VCC)........VEE to 0.5V Ref+ (measured to VCC) ..........................................VEE to 0.5V Ref- (measured to VCC)............................................VEE to 0.5V Operating Temperature Ranges Ambient .............................................................-20°C to +85°C Junction..........................................................................+175°C Lead Temperature (soldering, 10sec) .............................+300°C Storage Temperature Range .............................-60°C to +150°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS (VCC = ground, VEE = -5.2V ±0.3V, CC = 0pF, ISET = 1.105mA, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS TEST LEVEL Integral Linearity Error ILE 1.0mA < ISET < 1.3mA VI Differential Linearity Error DLE 1.0mA < ISET < 1.3mA VI MIN TYP -0.37 -0.95 -0.2 -0.5 -6.5 MAX UNITS 0.37 0.95 0.2 0.5 6.5 % Full Scale LSB % Full Scale LSB % Full Scale Gain Error VI Gain-Error Tempco V 150 ppm/°C Bandgap Tempco V 100 ppm/°C V 5 pF Input Capacitance, ISET, Ref Out CREF Compliance Voltage, Positive Output VI -1.2 1.5 V Compliance Voltage, Negative Output VI -1.2 1.5 V 20 Equivalent Output Resistance ROUT VI Output Capacitance COUT V Maximum Current, Positive Output IO+(MAX) IV 45 mA Maximum Current, Negative Output IO-(MAX) IV -45 mA Output Offset Current IOS VI Input Voltage, Logic High VIH VI Input Voltage, Logic Low VIL VI kΩ 9 0.05 pF 0.5 -1.0 LSB V -1.5 V Convert Voltage, Common-Mode Range IV -0.5 -2.5 V Convert Voltage, Differential IV 0.4 1.2 V Input Current, Logic Low, Data and Controls IIL VI 35 120 µA Input Current, Logic High, Data and Controls IIH VI 40 120 µA ICONV VI 2 60 µA Input Current, Convert 2 _______________________________________________________________________________________ 8-Bit, Ultra-High-Speed DAC MAX5140 DC ELECTRICAL CHARACTERISTICS (continued) (VCC = ground, VEE = -5.2V ±0.3V, CC = 0pF, ISET = 1.105mA, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS TEST LEVEL MIN TYP MAX UNITS -1.2 -1.0 V Reference Voltage (measured to VCC) VREF VI -1.3 Reference Output Current IREF VI -50 Input Capacitance, Data and Controls CIN V IEE VI VI Power-Supply Sensitivity Supply Current µA 3 -120 pF 20 155 120 220 µA/V mA AC ELECTRICAL CHARACTERISTICS (RL = 37.5Ω, CL = 5pF, ISET = 1.105mA, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS Maximum Conversion Rate Rise Time tR 10% to 90% G.S. Current-Settling Time, Clocked Mode tSI To 0.2% G.S. Clock to Output Delay, Clocked Mode tDSC TA = TMIN to TMAX Data to Output Delay, Transparent Mode tDST TA = TMIN to TMAX Glitch Energy RL = 25Ω RL = 25Ω TEST LEVEL MIN TYP IV 385 400 IV 4 3 2.2 V 3.2 UNITS Msps 900 600 III IV III IV V Area = 1/2VT MAX ps ns 4 4.5 6 6 4 ns ns pV-s Convert Pulse Width tPWH, tPWL III Reference Bandwidth -3dB V Setup Time, Data and Controls tS III 1.0 ns Hold Time, Data and Controls tH III 0.5 ns Slew Rate Clock Feedthrough 20% to 80% G.S. V III TEST-LEVEL CODES All electrical characteristics are subject to the following conditions: TEST LEVEL I II All parameters having min/max specifications are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality Assurance inspection. Any blank section in the data column indicates that the specification is not tested at the specified condition. III IV V VI 1.3 ns 1.25 MHz 700 -48 V/µs dB TEST PROCEDURE 100% production tested at the specified temperature. 100% production tested at TA = +25°C, and sampletested at the specified temperatures. QA sample tested at only the specified temperatures. Parameter is guaranteed (but not tested) by design and characterization data. Parameter is a typical value for reference. 100% production tested at TA = +25°C. Parameter is guaranteed over specified temperature range. Unless otherwise noted, all tests are pulsed tests; therefore, Tj = TC = TA. _______________________________________________________________________________________ 3 MAX5140 8-Bit, Ultra-High-Speed DAC ______________________________________________________________Pin Description PIN NAME FUNCTION 1, 2, 3 D3, D2, D1 4 D0 Data Bit 0 (LSB) 5, 20 VEE Negative Supply 6 CONV Convert Clock Input 7 CONV Convert-Clock-Input Complement 8 FT 9, 17 VCC Positive Supply 10 FH Data Force-High Control 11 Blank Video Blank Input 12 BRT Video Bright Input 13 Sync Video Sync Input 14 Ref Out Reference Output 15 Ref In 16 ISet Reference Current 18 Out- Output Current Negative 19 Out+ Output Current Positive 21 D7 22, 23, 24 D6, D5, D4 Data Bits 3, 2, and 1 Register Feedthrough Control Reference Input Data Bit 7 (MSB) Data Bits 6, 5, and 4 Detailed Description The MAX5140 is an ultra-high-speed video digital-toanalog converter (DAC) capable of up to 400Msps conversion rates. This high speed makes the device suitable for driving 2048 x 2048 pixel displays at 60Hz to 90Hz update rates. In addition, the MAX5140 includes an internal bandgap reference, which may be used to drive two other MAX5140s, if desired. The MAX5140 has ECL logic-level-compatible video control and data inputs. The complementary analog output currents produced by the devices are proportional to the product of the digital control and data inputs in conjunction with the analog reference current. The MAX5140 is segmented so that the input data’s four MSBs are separated into a parallel thermometer code. From here, fifteen identical current sinks are driven to fabricate sixteen coarse output levels. The remaining four LSBs drive four binary-weighted current switches. 4 MSB currents are then summed with the LSBs that contribute one-sixteenth of full-scale to provide the 256 distinct analog output levels. The video-control inputs drive weighted current sinks, which are added to the output current to produce composite video-output levels. These controls (sync, blank, reference white (force high), and bright) are required in video applications. A feature that similar video DACs do not have is feedthrough control. The feedthrough pin (FT) allows registered or unregistered operation of the video control and data inputs. In registered mode, the composite functions are latched to the pixel data to prevent screenedge distortions (generally found on unregistered video DACs). _______________________________________________________________________________________ 8-Bit, Ultra-High-Speed DAC MAX5140 *An external reference can be used, or the Ref Out reference can drive three MAX5140s. Figure 1. Typical Interface Circuit Applications Information General Figure 1 shows a typical interface circuit using the MAX5140 in a color-raster application. The MAX5140 requires few external components and is extremely easy to use. The MAX5140’s ultra-high operating speeds require good circuit layout, supply decoupling, and proper transmission-line design. For best performance, note the following considerations. Input Considerations reduce ringing, crosstalk, and reflections. Maxim recommends that stripline or microstrip techniques be used for all ECL interfaces. A convenient and commonly used microstrip impedance is about 130Ω, which is easily terminated using a 330Ω resistor to VEE and a 220Ω resistor to ground. This arrangement gives a Thevenin-equivalent termination of 130Ω to -2V without the need for a -2V supply. Standard single in-line package (SIP) 220/330 resistor networks are available for this purpose. Figure 2 shows equivalent input circuits. Video-input data and controls can be directly connected to the MAX5140. Note that all ECL inputs are terminated as closely to the device as possible to _______________________________________________________________________________________ 5 MAX5140 8-Bit, Ultra-High-Speed DAC VCC Ref In Conv ISet Reference Segment Switch Conv I Bias VEE IBias IBias IBias VEE Data and Controls V 80 kΩ VEE Figure 2. Equivalent Input Circuits—Data, Clock, Controls, and Reference Output Considerations The analog outputs are designed to directly drive a doubly terminated 50Ω or 75Ω load-transmission system as shown. The MAX5140 output source impedances are high-impedance current sinks. The load impedance (RL) must be 25Ω or 37.5Ω to attain standard RS-343-A video levels. Any deviation from this impedance affects the resulting video output levels proportionally. As with the data interface, it is important that all analog transmission lines have matched impedance throughout, including connectors and transitions between printed wiring and coaxial cable. The combination of matched source-termination resistor RS and 6 load terminator RL minimizes reflections of both forward and reverse traveling waves in the analog transmission system. Power Considerations The MAX5140 has two analog power-supply pins and operates from a standard -5.2V single supply. Proper supply bypassing augments the MAX5140’s inherent supply-noise-rejection characteristics. As shown in Figure 1, each supply pin should be bypassed as close to the device as possible with 0.01µF and 10µF capacitors. _______________________________________________________________________________________ 8-Bit, Ultra-High-Speed DAC Reference Considerations The MAX5140 has two reference inputs (Ref In and ISet) and one reference output (Ref Out). The input pins are connected to the inverting and noninverting inputs of an internal amplifier that serves as a reference buffer. The buffer amplifier’s output is the reference for the current sinks. The amplifier feedback loop is connected around one of the current sinks to achieve better accuracy. (See Figure 3.) Since the analog output currents are proportional to the digital input data and ISet, full-scale output can be adjusted by varying the reference current. ISet is controlled through the MAX5140’s I Set input. Figure 1 shows the method and the necessary equations for setting ISet. The MAX5140 can use an external negativevoltage reference. The external reference must be stable to achieve a satisfactory output, and Ref In should be driven through a resistor to minimize offsets caused by bias current. To change the full-scale output, vary the value for ISet with the 500Ω to 1kΩ trimmer. A double 50Ω load (25Ω) can be driven if I Set is increased by 50% for doubly terminated 75Ω video applications. Data Inputs and Video Controls The MAX5140 has standard, single-ended data inputs. The inputs are registered to produce the lowest differential data-propagation delay (skew) to minimize glitching. Also, four video-control inputs generate composite video outputs: sync, blank, bright, and reference white (force high). Feedthrough control is also provided. All of the controls and data inputs are ECL compatible. In addition, all have internal pulldown resistors to leave them at a logic low so the pins are inactive when not used. This is useful if the devices are applied as standard DACs without the need for video controls, or if fewer than eight bits are used. The MAX5140 is usually configured in synchronous mode. In this mode, the controls and data are synchronized to prevent pixel dropout. This reduces screenedge distortions and provides the lowest output noise while maintaining the highest conversion rate. With the FT control open (low), each rising edge of the convert clock (CONV) latches decoded data and control values into a D-type internal register. The switched-current sinks convert the registered data into the appropriate analog output. When FT is tied high, the control inputs and data are not registered. The analog output asynchronously tracks the input data and video controls. Feedthrough itself is asynchronous and is usually used as a DC control. Figure 3. Reference Buffer and DAC Output Circuit _______________________________________________________________________________________ 7 MAX5140 This device also has two analog ground pins (VCC). Tie both ground pins to the analog ground plane. All power and ground pins must be connected in any application. If a +5V power source is required, the VCC ground pins become the positive supply pins, while the V EE supply pins become the ground pins. The relative polarities of the other input and output voltages must be maintained. MAX5140 8-Bit, Ultra-High-Speed DAC To be registered synchronously, control and data inputs must be present at the input pins for a specific setup time (t s ) before and a specific hold time (t H ) after CONV’s rising edge. Setup and hold times are not important in asynchronous mode. The minimum pulse widths high (tPWH) and low (tPWL), as well as settling time, become the limiting factors (Figure 4). The video controls produce the output levels needed for horizontal blanking, frame synchronization, etc., to be compatible with video-system standards as described in RS-343-A. Table 1 shows the videocontrol effects on the analog output. Internal logic governs blank, sync, and force high so that they override the data inputs as needed in video applications. Sync overrides both the data and other controls to produce full negative video output (Figure 5). Reference-white, video-level output is provided by force high, which drives the internal digital data to fullscale output (100IRE units). Bright gives an additional 10% of full-scale value to the output level. This function can be used in graphic displays for highlighting menus, cursors, or warning messages. If the devices are used in nonvideo applications, the video controls can be left open. Convert Clock For best performance, the clock should be differentially ECL driven by using CONV and CONV (Figure 6). Driving the clock in this manner minimizes clock noise and power-supply/output intermodulation. The clock’s rising edge synchronizes the data and control inputs to the MAX5140. Since CONV determines the actual switching threshold of CONV, the clock can be driven single-ended by connecting a bias voltage to CONV. This bias voltage sets the converter clock’s switching threshold. Analog Outputs The MAX5140 has two analog outputs that are highimpedance, complementary current sinks. The outputs vary in proportion to the input data, controls, and reference-current values so that the full-scale output can be changed by setting ISet. tPWH CONV -1.3 V CONV tPWL tH tS -1.3 V Data Control Inputs tDST 1/2 LSB tDSC OUT OUT + AAAAAAAAA AAAAAAAA AAAA tSI 1/2 LSB Figure 4. Timing Diagram 8 _______________________________________________________________________________________ 8-Bit, Ultra-High-Speed DAC SYNC BLANK REF WHITE BRIGHT DATA INPUT OUT- (mA) OUT- (V) OUT- (IRE) 1 X X X X 28.57 -1.071 -40 Sync Level 0 1 X X X 20.83 -0.781 0 Blank Level 0 0 1 1 X 0.00 0.000 110 Enhanced High Level 0 0 1 0 X 1.95 -0.073 100 Normal High Level 0 0 0 0 000... 19.40 -0.728 7.5 Normal Low Level 0 0 0 0 111... 1.95 -0.073 100 Normal High Level 0 0 0 1 000... 17.44 -0.654 17.5 Enhanced Low Level 0 0 0 1 111... 0.00 0.000 110 Enhanced High Level IRE 110 100 0 mV -73 mV DESCRIPTION Bright Normal High (White) Video 256 Gray Levels Normal Low (Black) 7.5 0 -728 mV -781 mV -40 -1071 mV Blank Sync Figure 5. Video-Output Waveform for Standard Load _______________________________________________________________________________________ 9 MAX5140 Table 1. Video-Control Operation (output values for setup: 10IRE, 75Ω standard load) MAX5140 8-Bit, Ultra-High-Speed DAC In video applications, the outputs can drive a doubly terminated 50Ω or 75Ω load to standard video levels. In the standard configuration shown in Figure 7, the output voltage is the product of the output current and load impedance and is between 0V and -1.07V. Out(Figure 5) provides a video output waveform with the Sync pulse bottom at -1.07V. Out+ is inverted with Sync up. Typical RGB Graphics System In an RGB graphics system, the color displayed is determined by the combined intensities of the red, green, and blue (RGB) DAC outputs. A change in gain or offset in any of the RGB outputs affects the apparent hue displayed on the CRT screen. Thus, it is very important that the DAC’s outputs track each other over a wide range of operating conditions. Since the DAC output is proportional to the product of the reference and digital input code, use a common reference to drive all three DACs in an RGB system to minimize RGB DAC-to-DAC mismatch and improve TC tracking. The MAX5140 contains an internal precision-bandgap reference that completely eliminates the need for an external reference. The reference can supply up to 50µA to an external load, such as two other DAC reference inputs. The circuits shown in Figure 8 show how a single MAX5140 can be used as a master reference in a system with multiple DACs (such as RGB). The other DACs are simply slaved from the MAX5140’s reference output. Figure 6. CONV, CONV Switching Levels 10 ______________________________________________________________________________________ 8-Bit, Ultra-High-Speed DAC MAX5140 a) MAX5140 b) Figure 7. Standard Load (a) and Test Load (b) MAX5140 (MASTER) MAX5140 (SLAVE) MAX5140 (SLAVE) Figure 8. Typical RGB Graphics System ______________________________________________________________________________________ 11 ________________________________________________________Package Information PDIPW.EPS MAX5140 8-Bit, Ultra-High-Speed DAC Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.