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19-1205; Rev 2; 5/98
8-Bit, Ultra-High-Speed DAC
________________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 50 or 75 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. The MAX5140 is available in a 24-pin PDIP package in the -20C to +85C industrial temperature range.
____________________________Features
o 400Msps Nominal Conversion Rate o RS-343-A Compatible o Complete Video Controls: Sync, Blank, Bright, and Reference White (force high) o ECL Compatible o Single Power Supply o Registered Data and Video Controls o Differential Current Outputs o Stable On-Chip Bandgap Reference o 50 and 75 Output Drive o ESD-Protected Data and Control Inputs
MAX5140
________________________Applications
Raster Graphics High-Resolution Color or Monochrome Displays to 2k x 2k Pixels Medical Electronics: CAT, PET, and MR Imaging Displays CAD/CAE Workstations Solids Modeling General-Purpose, High-Speed Digital-to-Analog Conversion Digital Synthesizers Automated Test Equipment Digital Transmitters/Modulators
Ordering Information
PART MAX5140IPG TEMP. RANGE -20C to +85C PIN-PACKAGE 24 Plastic DIP
Pin Configuration
TOP VIEW
D3 1 D2 2 D1 3 D0 4 VEE 5 CONV 6 CONV 7 FT 8 VCC 9 FH 10 Blank 11 BRT 12 24 D4
Sync, Blank, Bright, Ref - White
Functional Diagram
23 D5 22 D6 21 D7
Video Controls In 4 Video Data In D0 - D3 4 4 4 Out +
Register
Video Data In D4 - D7 (MSBs) 4
Output Current Switches
Out -
MAX5140
20 VEE 19 Out+ 18 Out17 VCC 16 ISet 15 Ref In 14 Ref Out 13 Sync
4 To 15 Decode
Feedthrough Convert 2
ISet Ref In Ref Out
Ref Buffer Bandgap Reference
DIP
________________________________________________________________ Maxim Integrated Products
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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.
8-Bit, Ultra-High-Speed DAC MAX5140
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 .............................................................-20C to +85C Junction..........................................................................+175C Lead Temperature (soldering, 10sec) .............................+300C Storage Temperature Range .............................-60C to +150C
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 Integral Linearity Error Differential Linearity Error Gain Error Gain-Error Tempco Bandgap Tempco Input Capacitance, ISET, Ref Out Compliance Voltage, Positive Output Compliance Voltage, Negative Output Equivalent Output Resistance Output Capacitance Maximum Current, Positive Output Maximum Current, Negative Output Output Offset Current Input Voltage, Logic High Input Voltage, Logic Low Convert Voltage, Common-Mode Range Convert Voltage, Differential Input Current, Logic Low, Data and Controls Input Current, Logic High, Data and Controls Input Current, Convert IIL IIH ICONV ROUT COUT IO+(MAX) IO-(MAX) IOS VIH VIL CREF SYMBOL ILE DLE CONDITIONS 1.0mA < ISET < 1.3mA 1.0mA < ISET < 1.3mA TEST LEVEL VI VI VI V V V VI VI VI V IV IV VI VI VI IV IV VI VI VI -0.5 0.4 35 40 2 -1.0 -1.5 -2.5 1.2 120 120 60 45 -45 0.05 0.5 -1.2 -1.2 20 9 MIN -0.37 -0.95 -0.2 -0.5 -6.5 150 100 5 1.5 1.5 TYP MAX 0.37 0.95 0.2 0.5 6.5 UNITS % Full Scale LSB % Full Scale LSB % Full Scale ppm/C ppm/C pF V V k pF mA mA LSB V V V V A A A
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8-Bit, Ultra-High-Speed DAC
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = ground, VEE = -5.2V 0.3V, CC = 0pF, ISET = 1.105mA, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER Reference Voltage (measured to VCC) Reference Output Current Input Capacitance, Data and Controls Power-Supply Sensitivity Supply Current SYMBOL VREF IREF CIN CONDITIONS TEST LEVEL VI VI V VI VI -120 MIN -1.3 -50 3 20 155 120 220 TYP -1.2 MAX -1.0 UNITS V A pF A/V mA
MAX5140
IEE
AC ELECTRICAL CHARACTERISTICS
(RL = 37.5, CL = 5pF, ISET = 1.105mA, TA = +25C, unless otherwise noted.) PARAMETER Maximum Conversion Rate Rise Time Current-Settling Time, Clocked Mode Clock to Output Delay, Clocked Mode Data to Output Delay, Transparent Mode Glitch Energy Convert Pulse Width Reference Bandwidth Setup Time, Data and Controls Hold Time, Data and Controls Slew Rate Clock Feedthrough tPWH, tPWL -3dB tS tH 20% to 80% G.S. tR tSI tDSC tDST 10% to 90% G.S. To 0.2% G.S. TA = TMIN to TMAX TA = TMIN to TMAX Area = 1/2VT RL = 25 RL = 25 SYMBOL CONDITIONS TEST LEVEL IV IV V III IV III IV V III V III III V III 1.0 0.5 700 -48 1.3 1.25 4 3 2.2 3.2 4 MIN 385 TYP 400 900 600 MAX UNITS Msps ps ns 4 4.5 6 6 ns ns pV-s ns MHz ns ns V/s dB
TEST-LEVEL CODES All electrical characteristics are subject to the following conditions: 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. Unless otherwise noted, all tests are pulsed tests; therefore, Tj = TC = TA.
TEST LEVEL I II III IV V VI
TEST PROCEDURE 100% production tested at the specified temperature. 100% production tested at TA = +25C, 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 = +25C. Parameter is guaranteed over specified temperature range.
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8-Bit, Ultra-High-Speed DAC MAX5140
______________________________________________________________Pin Description
PIN 1, 2, 3 4 5, 20 6 7 8 9, 17 10 11 12 13 14 15 16 18 19 21 22, 23, 24 NAME D3, D2, D1 D0 VEE CONV CONV FT VCC FH Blank BRT Sync Ref Out Ref In ISet OutOut+ D7 D6, D5, D4 Data Bits 3, 2, and 1 Data Bit 0 (LSB) Negative Supply Convert Clock Input Convert-Clock-Input Complement Register Feedthrough Control Positive Supply Data Force-High Control Video Blank Input Video Bright Input Video Sync Input Reference Output Reference Input Reference Current Output Current Negative Output Current Positive Data Bit 7 (MSB) Data Bits 6, 5, and 4 FUNCTION
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.
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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).
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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
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
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 130, which is easily terminated using a 330 resistor to VEE and a 220 resistor to ground. This arrangement gives a Thevenin-equivalent termination of 130 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.
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8-Bit, Ultra-High-Speed DAC MAX5140
VCC
Ref In
Conv
ISet
Conv I Bias VEE
Reference Segment Switch
IBias
IBias
IBias VEE
Data and Controls
V
80 k
VEE
Figure 2. Equivalent Input Circuits--Data, Clock, Controls, and Reference
Output Considerations
The analog outputs are designed to directly drive a doubly terminated 50 or 75 load-transmission system as shown. The MAX5140 output source impedances are high-impedance current sinks. The load impedance (RL) must be 25 or 37.5 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
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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 0.01F and 10F capacitors.
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8-Bit, Ultra-High-Speed DAC
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. increased by 50% for doubly terminated 75 video applications.
MAX5140
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.
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 500 to 1k trimmer. A double 50 load (25) can be driven if I Set is
Figure 3. Reference Buffer and DAC Output Circuit
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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,
MAX5140
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 tS tH
-1.3 V
Data Control Inputs
tDST tDSC
1/2 LSB
OUT OUT + tSI
1/2 LSB
Figure 4. Timing Diagram
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8-Bit, Ultra-High-Speed DAC MAX5140
Table 1. Video-Control Operation (output values for setup: 10IRE, 75 standard load)
SYNC 1 0 0 0 0 0 0 0 BLANK X 1 0 0 0 0 0 0 REF WHITE X X 1 1 0 0 0 0 BRIGHT X X 1 0 0 0 1 1 DATA INPUT X X X X 000... 111... 000... 111... OUT- (mA) 28.57 20.83 0.00 1.95 19.40 1.95 17.44 0.00 OUT- (V) -1.071 -0.781 0.000 -0.073 -0.728 -0.073 -0.654 0.000 OUT- (IRE) -40 0 110 100 7.5 100 17.5 110 DESCRIPTION Sync Level Blank Level Enhanced High Level Normal High Level Normal Low Level Normal High Level Enhanced Low Level Enhanced High Level
IRE 110 100
0 mV -73 mV
Bright Normal High (White)
256 Gray Levels
Video
Normal Low (Black) 7.5 0 -728 mV -781 mV Blank
-40
-1071 mV
Sync
Figure 5. Video-Output Waveform for Standard Load
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8-Bit, Ultra-High-Speed DAC MAX5140
In video applications, the outputs can drive a doubly terminated 50 or 75 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. 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 50A 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.
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
Figure 6. CONV, CONV Switching Levels
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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
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8-Bit, Ultra-High-Speed DAC MAX5140
________________________________________________________Package Information
PDIPW.EPS
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 (c) 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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