HI3338 8-Bit, CMOS R2R D/A Converter August 1997 Features Description • CMOS Low Power (Typ). . . . . . . . . . . . . . . . . . . .100mW The HI3338 family are CMOS high speed R2R voltage output digital-to-analog converters. They can operate from a single +5V supply, at video speeds, and can produce “rail-to-rail” output swings. Internal level shifters and a pin for an optional second supply provide for an output range below digital ground. • R2R Output, Segmented for Low “Glitch” • CMOS/TTL Compatible Inputs • Fast Settling (Typ) . . . . . . . . . . . . . . . . . 20ns to 1/2 LSB • Feedthrough Latch for Clocked or Unclocked Use • Accuracy (Typ) . . . . . . . . . . . . . . . . . . . . . . . . . ±0.5 LSB • Data Complement Control • High Update Rate (Typ) . . . . . . . . . . . . . . . . . . . . 50MHz • Unipolar or Bipolar Operation • Linearity (INL): - HI3338KIP . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.75 LSB - HI3338KIB . . . . . . . . . . . . . . . . . . . . . . . . . . ±0.75 LSB Applications The data complement control allows the inversion of input data while the latch enable control provides either feedthrough or latched operation. Both ends of the R2R ladder network are available externally and may be modulated for gain or offset adjustments. In addition, “glitch” energy has been kept very low by segmenting and thermometer encoding of the upper 3 bits. The HI3338 is manufactured to give low dynamic power dissipation, low output capacitance, and inherent latch-up resistance. Ordering Information • TV/Video Display • High Speed Oscilloscope Display PART NUMBER TEMP. RANGE (oC) PACKAGE PKG. NO. • Digital Waveform Generator • Direct Digital Frequency Synthesis • Wireless Communication HI3338KIP -40 to 85 16 Ld PDIP E16.3 HI3338KIB -40 to 85 16 Ld SOIC M16.3 Pinout HI3338 (PDIP, SOIC) TOP VIEW D7 1 16 VDD D6 2 15 LE D5 3 14 COMP D4 4 13 VREF+ D3 5 12 VOUT D2 6 11 VREF - D1 7 10 VEE VSS 8 9 D0 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999 10-1464 File Number 4134.1 HI3338 Functional Diagram 16 13 VDD VREF + 8R 15 LE 8R 12 VOUT 8R 3-BIT TO 7-LINE THERMOMETER ENCODER 14 COMP D7 8R 4R R 1 4R D6 D5 D4 D3 D2 D1 D0 VSS 2 LEVEL SHIFTERS FEEDTHROUGH LATCHES 3 2R 2R 4 5 2R 6 2R R R R R 7 2R 9 8 2R R R 2R 11 VREF 10 R ≅ 160Ω Die Characteristics DIE DIMENSIONS: 2,740µm x 3,310µm x 530 ±50µm METALLIZATION: Type: Al with 0.8% Si Thickness: 11kÅ ±1kÅ GLASSIVATION: Type: 3% PSG Thickness: 13kÅ ±2.6kÅ 10-1465 VEE HI3338 Absolute Maximum Ratings Thermal Information DC Supply-Voltage Range . . . . . . . . . . . . . . . . . . . . . . -0.5V to +8V (VDD - VSS or VDD - VEE , Whichever Is Greater) Input Voltage Range Digital Inputs (LE, COMP D0 - D7) . . . . VSS - 0.5V to VDD + 0.5V Analog Pins (VREF+, VREF -, VOUT) . . . . VDD - 8V to VDD + 0.5V DC Input Current Digital Inputs (LE, COMP, D0 - D7). . . . . . . . . . . . . . . . . . ±20mA Recommended Supply Voltage Range. . . . . . . . . . . . . .4.5V to 7.5V Thermal Resistance (Typical) θJA (oC/W) PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150oC Maximum Storage Temperature Range, TSTG . . . . .-65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oC (SOIC - Lead Tips Only) Operating Conditions Temperature Range (TA) . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Electrical Specifications PARAMETER TA = 25oC, VDD = 5V, VREF+ = 4.608V, VSS = VEE = VREF - = GND, LE clocked at 20MHz, RL ≥ 1MΩ, Unless Otherwise Specified TEST CONDITIONS MIN TYP MAX UNITS 8 - - Bits ACCURACY Resolution Integral Linearity Error See Figure 4 - - ±0.75 LSB Differential Linearity Error See Figure 4 - - ±0.5 LSB Gain Error Input Code = FFHEX , See Figure 3 - - ±0.5 LSB Offset Error Input Code = 00HEX , See Figure 3 - - ±0.25 LSB DIGITAL INPUT TIMING Update Rate To Maintain 1/2 LSB Settling DC 50 - MHz Update Rate VREF - = VEE = -2.5V, VREF+ = +2.5V DC 20 - MHz Set Up Time tSU1 For Low Glitch - -2 - ns Set Up Time tSU2 For Data Store - 8 - ns Hold Time tH For Data Store - 5 - ns Latch Pulse Width tW For Data Store - 5 - ns Latch Pulse Width tW VREF - = VEE = -2.5V, VREF+ = +2.5V - 25 - ns OUTPUT PARAMETERS RL Adjusted for 1VP-P Output Output Delay tD1 From LE Edge - 25 - ns Output Delay tD2 From Data Changing - 22 - ns Rise Time tr 10% to 90% of Output - 4 - ns Settling Time tS 10% to Settling to 1/2 LSB - 20 - ns Output Impedance VREF+ = 6V, VDD = 6V 120 160 200 Ω - 150 - pV-s - 250 - pV-s Glitch Area Glitch Area VREF - = VEE = -2.5V, VREF+ = +2.5V REFERENCE VOLTAGE VREF+ Range (+) Full Scale (Note 1) VREF - + 3 - VDD V VREF - Range (-) Full Scale (Note 1) VEE - VREF+ - 3 V 10-1466 HI3338 Electrical Specifications TA = 25oC, VDD = 5V, VREF+ = 4.608V, VSS = VEE = VREF - = GND, LE clocked at 20MHz, RL ≥ 1MΩ, Unless Otherwise Specified (Continued) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS VREF+ = 6V, VDD = 6V - 40 50 mA LE = Low, D0 - D7 = High - 100 220 µA LE = Low, D0 - D7 = Low - - 100 µA Dynamic IDD or IEE VOUT = 10MHz, 0V to 5V Square Wave - 20 - mA Dynamic IDD or IEE VOUT = 10MHz, ±2.5V Square Wave - 25 - mA VDD Rejection 50kHz Sine Wave Applied - 3 - mV/V VEE Rejection 50kHz Sine Wave Applied - 1 - mV/V VREF+ Input Current SUPPLY VOLTAGE Static IDD or IEE DIGITAL INPUTS D0 - D7, LE, COMP High Level Input Voltage Note 1 2 - - V Low Level Input Voltage Note 1 - - 0.8 V Leakage Current - ±1 ±5 µA Capacitance - 5 - pF - 200 - ppm/oC TEMPERATURE COEFFICIENTS Output Impedance NOTE: 1. Parameter not tested, but guaranteed by design or characterization. Timing Diagrams INPUT DATA LATCH ENABLE INPUT DATA tD1 tSU2 tSU1 tW LATCH ENABLE LATCHED DATA FEEDTHROUGH tD2 tH OUTPUT VOLTAGE LATCHED FIGURE 1. DATA TO LATCH ENABLE TIMING tS tr 1/ LSB 2 90% 10% 1/ LSB 2 FIGURE 2. DATA AND LATCH ENABLE TO OUTPUT TIMING 10-1467 HI3338 Non-clocked operation or changing data while LE is low is not recommended for applications requiring low output “glitch” energy: there is no guarantee of the simultaneous changing of input data or the equal propagation delay of all bits through the converter. Several parameters are given if the converter is to be used in either of these modes: tD2 gives the delay from the input changing to the output changing (10%), while tSU2 and tH give the set up and hold times (referred to LE rising edge) needed to latch data. See Figures 1 and 2. Pin Descriptions PIN NAME DESCRIPTION 1 D7 2 D6 Input 3 D5 Data 4 D4 Bits 5 D3 (High = True) 6 D2 7 D1 8 VSS Digital Ground. 9 D0 Least Significant Bit. Input Data Bit. 10 VEE Analog Ground. There is no need for a square wave LE clock; LE must only meet the minimum tW pulse width for successful latch operation. Generally, output timing (desired accuracy of settling) sets the upper limit of usable clock frequency. 11 VREF - Reference Voltage Negative Input. Output Structure 12 VOUT Analog Output. 13 VREF+ Reference Voltage Positive Input. The latches feed data to a row of high current CMOS drivers, which in turn feed a modified R2R ladder network. 14 COMP Data Complement Control input. Active High. 15 LE 16 VDD Most Significant Bit. Clocked operation is needed for low “glitch” energy use. Data must meet the given tSU1 set up time to the LE falling edge, and the tH hold time from the LE rising edge. The delay to the output changing, tD1 , is now referred to the LE falling edge. Latch Enable Input. Active Low. Digital Power Supply, +5V. Digital Signal Path The digital inputs (LE, COMP, and D0 - D7) are of TTL compatible HCT High Speed CMOS design: the loading is essentially capacitive and the logic threshold is typically 1.5V. The 8 data bits, D0 (weighted 20) through D7 (weighted 27), are applied to Exclusive OR gates (see Functional Diagram). The COMP (data complement) control provides the second input to the gates: if COMP is high, the data bits will be inverted as they pass through. The input data and the LE (latch enable) signals are next applied to a level shifter. The inputs, operating between the levels of VDD and VSS , are shifted to operate between VDD and VEE . VEE optionally at ground or at a negative voltage, will be discussed under bipolar operation. All further logic elements except the output drivers operate from the VDD and VEE supplies. The upper 3 bits of data, D5 through D7, are input to a 3-to-7 line bar graph encoder. The encoder outputs and D0 through D4 are applied to a feedthrough latch, which is controlled by LE (latch enable). Latch Operation Data is fed from input to output while LE is low: LE should be tied low for non-clocked operation. The “N” channel (pull down) transistor of each driver plus the bottom “2R” resistor are returned to VREF - this is the (-) full-scale reference. The “P” channel (pull up) transistor of each driver is returned to VREF+, the (+) full-scale reference. In unipolar operation, VREF- would typically be returned to analog ground, but may be raised above ground (see specifications). There is substantial code dependent current that flows from VREF+ to VREF - (see VREF+ input current in specifications), so VREF - should have a low impedance path to ground. In bipolar operation, VREF - would be returned to a negative voltage (the maximum voltage rating to VDD must be observed). VEE , which supplies the gate potential for the output drivers, must be returned to a point at least as negative as VREF -. Note that the maximum clocking speed decreases when the bipolar mode is used. Static Characteristics The ideal 8-bit D/A would have an output equal to VREF with an input code of 00HEX (zero scale output), and an output equal to 255/256 of VREF+ (referred to VREF -) with an input code of FFHEX (full scale output). The difference between the ideal and actual values of these two parameters are the OFFSET and GAIN errors, respectively; see Figure 3. If the code into an 8-bit D/A is changed by 1 count, the output should change by 1/255 (full-scale output-zero scale output). A deviation from this step size is a differential linearity error, see Figure 4. Note that the error is expressed in fractions of the ideal step size (usually called an LSB). Also note that if the (-) differential linearity error is less (in 10-1468 HI3338 absolute numbers) than 1 LSB, the device is monotonic. (The output will always increase for increasing code or decrease for decreasing code). If the code into an 8-bit D/A is at any value, say “N”, the output voltage should be N/255 of the full-scale output (referred to the zero-scale output). Any deviation from that output is an integral linearity error, usually expressed in LSBs. See Figure 4. OUTPUT VOLTAGE AS A FRACTION OF VREF+ - VREF - Note that OFFSET and GAIN errors do not affect integral linearity, as the linearity is referenced to actual zero and full scale outputs, not ideal. Absolute accuracy would have to also take these errors into account. GAIN ERROR (SHOWN -) 255/256 = IDEAL TRANSFER CURVE = ACTUAL TRANSFER CURVE 254/256 OFFSET ERROR (SHOWN +) 1/256 The settling time of the A/D is mainly a function of the output resistance (approximately 160Ω in parallel with the load resistance) and the load plus internal chip capacitance. Both “glitch” energy and settling time measurements require very good circuit and probe grounding: a probe tip connector such as Tektronix part number 131-0258-00 is recommended. 0 01 “Glitch” energy is defined as a spurious voltage that occurs as the output is changed from one voltage to another. In a binary input converter, it is usually highest at the most significant bit transition (7FHEX to 80HEX for an 8-bit device), and can be measured by displaying the output as the input code alternates around that point. The “glitch” energy is the area between the actual output display and an ideal one LSB step voltage (subtracting negative area from positive), at either the positive or negative-going step. It is usually expressed in pV-s. For the purpose of comparison to other converters, the output should be resistively divided to 1V full scale. Figure 5 shows a typical hook-up for checking “glitch” energy or settling time. 2/256 00 Keeping the full-scale range (VREF+ - VREF -) as high as possible gives the best linearity and lowest “glitch” energy (referred to 1V). This provides the best “P” and “N” channel gate drives (hence saturation resistance) and propagation delays. The VREF+ (and VREF - if bipolar) terminal should be well bypassed as near the chip as possible. The HI3338 uses a modified R2R ladder, where the 3 most significant bits drive a bar graph decoder and 7 equally weighted resistors. This makes the “glitch” energy at each 1/8 scale transition (1FHEX to 20HEX , 3FHEX to 40HEX , etc.) essentially equal, and far less than the MSB transition would otherwise display. 253/256 3/256 Dynamic Characteristics 02 03 FD FE FF INPUT CODE IN HEXADECIMAL (COMP = LOW) FIGURE 3. D/A OFFSET AND GAIN ERROR TABLE 1. OUTPUT VOLTAGE vs INPUT CODE AND VREF OUTPUT VOLTAGE STRAIGHT LINE FROM “0” SCALE TO FULL SCALE VOLTAGE = IDEAL TRANSFER CURVE = ACTUAL TRANSFER CURVE • • • B C A = IDEAL STEP SIZE (1/255 OF FULL SCALE -“0” SCALE VOLTAGE) B - A = +DIFFERENTIAL LINEARITY ERROR C - A = -DIFFERENTIAL LINEARITY ERROR 100000012 = 81HEX 2.5800 100000002 = 80HEX 2.5600 011111112 = 7FHEX 2.5400 2.5195 2.5000 2.4805 2.3220 0.0200 0.0195 2.3040 0.0000 0.0000 2.2860 - 0.0200 -0.0195 0.0195 0.0000 0.0180 0.0000 • • • INPUT CODE FIGURE 4. D/A INTEGRAL AND DIFFERENTIAL LINEARITY ERROR 5.12V 5.00V 4.608V 2.56V 2.50V 0 0 0 -2.56V -2.50V 0.0200V 0.0195V 0.0180V 0.0200V 0.0195V Input Code 111111112 = FFHEX 5.1000V 4.9805V 4.5900V 2.5400V 2.4805V 111111102 = FEHEX 5.0800 4.9610 4.5720 2.5200 2.4610 INTEGRAL LINEARITY ERROR (SHOWN -) A 0 00 VREF+ VREF STEP SIZE 000000012 = 01HEX 000000002 = 00HEX 10-1469 0.0200 0.0000 -2.5400 -2.4805 -2.5600 -2.5000 HI3338 HI3338 +5V 15 LE CLOCK +2.5V -2.5V 1-7, 9 D0 - D7 8 DATA BITS VOUT 16 +5V VREF+ VDD R1 12 REMOTE VOUT 13 + 14 8 R3 PROBE TIP OR BNC CONNECTOR + VREF - COMP VEE VSS R2 11 10 + DIGITAL GROUND ANALOG GROUND FUNCTION CONNECTOR R1 R2 R3 VOUT(P-P) Probe Tip 82Ω 62Ω N/C 1V Oscilloscope Display Match 93Ω Cable BNC 75 160 93 1V Match 75Ω Cable BNC 18 130 75 1V Match 50Ω Cable BNC Short 75 50 0.79V NOTES: 1. VOUT(P-P) is approximate, and will vary as ROUT of D/A varies. 2. All drawn capacitors are 0.1µF multilayer ceramic/4.7µF tantalum. 3. Dashed connections are for unipolar operation. Solid connection are for bipolar operation. FIGURE 5. HI3338 DYNAMIC TEST CIRCUIT +6V 4.7µF TAN + HI3338 15 CLOCK VOUT 12 1-7, 9 8 DATA BITS 16 + 4.7µF TAN 0.1µF CER. 14 8 VDD +3.00V AT 25mA VREF+ COMP VREF VSS 5pF 7, 8 D0 - D7 +5V 0.1µF CER. UP TO 5 OUTPUT LINES FOR R = 75Ω, 3 LINES FOR R = 50Ω LE 0.1µF CER. 13 392Ω 1% 14 3 R 9 VOUT1 11 + 6 CA3450 R VOUT = ± 1.5VPEAK 11 VEE 10 + 4.7µF TAN 4, 5, 12, 13 10kΩ 1kΩ 392Ω 1% 0.1µF CER. + NOTES: 1. Both VREF+ pin and 392Ω resistor should be bypassed within 1/ inch. 4 VOUTN R ADJUST OFFSET -6V 4.7µF TAN 2. Keep nodal capacitance at CA3450 pin 3 as low as possible. 3. VOUT Range = ±3V at CA3450. FIGURE 6. HI3338 AND CA3450 FOR DRIVING MULTIPLE COAXIAL LINES 10-1470 R HI3338 Applications Operating and Handling Considerations The output of the HI3338 can be resistively divided to match a doubly terminated 50Ω or 75Ω line, although peak-to-peak swings of less than 1V may result. The output magnitude will also vary with the converter's output impedance. Figure 5 shows such an application. Note that because of the HCT input structure, the HI3338 could be operated up to +7.5V VDD and VREF+ supplies and still accept 0V to 5V CMOS input voltages. HANDLING If larger voltage swings or better accuracy is desired, a high speed output buffer, such as the HA-5033, HA-2542, or CA3450, can be employed. Figure 6 shows a typical application, with the output capable of driving ±2V into multiple 50Ω terminated lines. All inputs and outputs of CMOS devices have a network for electrostatic protection during handling. Recommended handling practices for CMOS devices are described in AN6525. “Guide to Better Handling and Operation of CMOS Integrated Circuits.” OPERATING Operating Voltage During operation near the maximum supply voltage limit, care should be taken to avoid or suppress power supply turn-on and turn-off transients, power supply ripple, or ground noise; any of these conditions must not cause the absolute maximum ratings to be exceeded. Input Signals To prevent damage to the input protection circuit, input signals should never be greater than VDD nor less than VSS . Input currents must not exceed 20mA even when the power supply is off. Unused Inputs A connection must be provided at every input terminal. All unused input terminals must be connected to either VCC or GND, whichever is appropriate. All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see web site http://www.intersil.com 10-1471