ADC0804CN

INTEGRATED CIRCUITS ADC0803/0804 CMOS 8-bit A/D converters Product data Supersedes data of 2001 Aug 03 2002 Oct 17 Philips Semiconductors Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 DESCRIPTION The ADC0803 family is a series of three CMOS 8-bit successive approximation A/D converters using a resistive ladder and capacitive array together with an auto-zero comparator. These converters are designed to operate with microprocessor-controlled buses using a minimum of external circuitry. The 3-State output data lines can be connected directly to the data bus. The differential analog voltage input allows for increased common-mode rejection and provides a means to adjust the zero-scale offset. Additionally, the voltage reference input provides a means of encoding small analog voltages to the full 8 bits of resolution. PIN CONFIGURATION D, N PACKAGES CS 1 RD 2 WR 3 CLK IN 4 20 VCC 19 CLK R 18 D0 17 D1 16 D2 15 D3 14 D4 13 D5 12 D6 11 D7 TOP VIEW INTR 5 VIN(+) 6 VIN(–) 7 A GND 8 FEATURES VREF/2 9 D GND 10 • Compatible with most microprocessors • Differential inputs • 3-State outputs • Logic levels TTL and MOS compatible • Can be used with internal or external clock • Analog input range 0 V to VCC • Single 5 V supply • Guaranteed specification with 1 MHz clock SL00016 Figure 1. Pin configuration APPLICATIONS • Transducer-to-microprocessor interface • Digital thermometer • Digitally-controlled thermostat • Microprocessor-based monitoring and control systems ORDERING INFORMATION DESCRIPTION 20-pin plastic small outline (SO) package 20-pin plastic small outline (SO) package 20-pin plastic dual in-line package (DIP) 20-pin plastic dual in-line package (DIP) TEMPERATURE RANGE 0 to 70 °C –40 to 85 °C 0 to 70 °C –40 to +85 °C ORDER CODE ADC0803CD, ADC0804CD ADC0803LCD, ADC0804LCD ADC0803CN, ADC0804CN ADC0803LCN, ADC0804LCN TOPSIDE MARKING ADC0803-1CD, ADC0804-1CD ADC0803-1LCD, ADC0804-1LCD ADC0803-1CN, ADC0804-1CN ADC0803-1LCN, ADC0804-1LCN DWG # SOT163-1 SOT163-1 SOT146-1 SOT146-1 ABSOLUTE MAXIMUM RATINGS SYMBOL VCC Supply voltage Logic control input voltages All other input voltages Tamb Operating temperature range ADC0803LCD/ADC0804LCD ADC0803LCN/ADC0804LCN ADC0803CD/ADC0804CD ADC0803CN/ADC0804CN Storage temperature Lead soldering temperature (10 seconds) Maximum power N package D package dissipation1 Tamb = 25 °C (still air) 1690 1390 mW mW PARAMETER CONDITIONS RATING 6.5 –0.3 to +16 –0.3 to (VCC +0.3) –40 to +85 –40 to +85 0 to +70 0 to +70 –65 to +150 230 UNIT V V V °C °C °C °C °C °C Tstg Tsld PD NOTE: 1. Derate above 25 °C, at the following rates: N package at 13.5 mW/°C; D package at 11.1 mW/°C. 2002 Oct 17 2 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 BLOCK DIAGRAM VIN (+) 6 VIN (–) 7 M + – + 9 VREF/2 LADDER AND DECODER 8 A GND AUTO ZERO COMPARATOR – VCC 20 D7 (MSB) (11) D6 D5 D4 D3 D2 D1 D0 (LSB) (12) (13) (14) (15) (16) (17) (18) OUTPUT LATCHES SAR 10 D GND LE OE 3 WR 8–BIT SHIFT REGISTER CLOCK 1 CS S INTR FF R 2 RD Q 5 INTR 4 CLK IN 19 CLK R SL00017 Figure 2. Block diagram 2002 Oct 17 3 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 DC ELECTRICAL CHARACTERISTICS VCC = 5.0 V, fCLK = 1 MHz, Tmin ≤ Tamb ≤ Tmax, unless otherwise specified. LIMITS SYMBOL PARAMETER ADC0803 relative accuracy error (adjusted) ADC0804 relative accuracy error (unadjusted) RIN VREF/2 input resistance3 Analog input voltage range3 Over analog input voltage range VCC = 5V ±10%1 VCC = 5.25 VDC VCC = 4.75 VDC VIN = 5 VDC VIN = 0 VDC –1 0.005 –0.005 2.0 DC common-mode error Power supply sensitivity Control inputs VIH VIL IIH IIL VT+ VT– VH VOL VOH VOL Logical “1” input voltage Logical “0” input voltage Logical “1” input current Logical “0” input current 15 0.8 1 VDC VDC µADC µADC 3.5 2.1 2.0 0.4 2.4 VDC VDC VDC VDC VDC TEST CONDITIONS CONDITIONS Full-Scale adjusted VREF/2 = 2.500 VDC VCC = 0 V2 400 –0.05 1/16 1/16 680 VCC+0.05 1/8 Min Typ Max 0.50 1 UNIT LSB LSB Ω V LSB LSB Clock in and clock R Clock in positive-going threshold voltage Clock in negative-going threshold voltage Clock in hysteresis (VT+)–(VT–) Logical “0” clock R output voltage Logical “1” clock R output voltage IOL = 360 µA, VCC = 4.75 VDC IOH = –360 µA, VCC = 4.75 VDC 2.7 1.5 0.6 3.1 1.8 1.3 Data output and INTR Logical “0” output voltage Data outputs INTR outputs VO OH IOZL IOZH ISC ISC ICC Logical “1” output voltage 1” output voltage 3-State output leakage 3-State output leakage +Output short-circuit current –Output short-circuit current Power supply current IOL = 1.6 mA, VCC = 4.75 VDC IOL = 1.0 mA, VCC = 4.75 VDC IOH = –360 µA, VCC = 4.75 VDC IOH = –10 µA, VCC = 4.75 VDC VOUT = 0 VDC, CS = logical “1” VOUT = 5 VDC, CS = logical “1” VOUT = 0 V, Tamb = 25 °C VOUT = VCC, Tamb = 25 °C fCLK = 1 MHz, VREF/2 = OPEN, CS = Logical “1”, Tamb = 25 °C 4.5 9.0 12 30 3.0 3.5 2.4 4.5 –3 3 VDC C µADC µADC mADC mADC mA 0.4 0.4 VDC VDC NOTES: 1. Analog inputs must remain within the range: –0.05 ≤ VIN ≤ VCC + 0.05 V. 2. See typical performance characteristics for input resistance at VCC = 5 V. 3. VREF/2 and VIN must be applied after the VCC has been turned on to prevent the possibility of latching. 2002 Oct 17 4 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 AC ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER Conversion time fCLK Clock frequency1 Clock duty cycle1 CR tW(WR)L tACC t1H, t0H tW1, tR1 CIN Free-running conversion rate Start pulse width Access time 3-State control INTR delay Logic input=capacitance Output Output INTR RD RD WD or RD CS = 0, fCLK = 1 MHz INTR tied to WR CS = 0 CS = 0, CL = 100 pF CL = 10 pF, RL = 10 kΩ See 3-State test circuit 30 75 70 100 5 5 100 100 150 7.5 7.5 TO FROM TEST CONDITIONS CONDITIONS fCLK = 1 MHz1 LIMITS Min 66 0.1 40 1.0 Typ Max 73 3.0 60 13690 UNIT µs MHz % conv/s ns ns ns ns pF pF COUT 3-State output capacitance NOTE: 1. Accuracy is guaranteed at fCLK = 1 MHz. Accuracy may degrade at higher clock frequencies. FUNCTIONAL DESCRIPTION These devices operate on the Successive Approximation principle. Analog switches are closed sequentially by successive approximation logic until the input to the auto-zero comparator [ VIN(+)–VIN(–) ] matches the voltage from the decoder. After all bits are tested and determined, the 8-bit binary code corresponding to the input voltage is transferred to an output latch. Conversion begins with the arrival of a pulse at the WR input if the CS input is low. On the High-to-Low transition of the signal at the WR or the CS input, the SAR is initialized, the shift register is reset, and the INTR output is set high. The A/D will remain in the reset state as long as the CS and WR inputs remain low. Conversion will start from one to eight clock periods after one or both of these inputs makes a Low-to-High transition. After the conversion is complete, the INTR pin will make a High-to-Low transition. This can be used to interrupt a processor, or otherwise signal the availability of a new conversion result. A read (RD) operation (with CS low) will clear the INTR line and enable the output latches. The device may be run in the free-running mode as described later. A conversion in progress can be interrupted by issuing another start command. ANALOG OPERATION Analog Input Current The analog comparisons are performed by a capacitive charge summing circuit. The input capacitor is switched between VIN(+)4 and VIN(–), while reference capacitors are switched between taps on the reference voltage divider string. The net charge corresponds to the weighted difference between the input and the most recent total value set by the successive approximation register. The internal switching action causes displacement currents to flow at the analog inputs. The voltage on the on-chip capacitance is switched through the analog differential input voltage, resulting in proportional currents entering the VIN(+) input and leaving the VIN(–) input. These transient currents occur at the leading edge of the internal clock pulses. They decay rapidly so do not inherently cause errors as the on-chip comparator is strobed at the end of the clock period. Input Bypass Capacitors and Source Resistance Bypass capacitors at the input will average the charges mentioned above, causing a DC and an AC current to flow through the output resistance of the analog signal sources. This charge pumping action is worse for continuous conversions with the VIN(+) input at full scale. This current can be a few microamps, so bypass capacitors should NOT be used at the analog inputs of the VREF/2 input for high resistance sources (> 1 kΩ). If input bypass capacitors are desired for noise filtering and a high source resistance is desired to minimize capacitor size, detrimental effects of the voltage drop across the input resistance can be eliminated by adjusting the full scale with both the input resistance and the input bypass capacitor in place. This is possible because the magnitude of the input current is a precise linear function of the differential voltage. Digital Control Inputs The digital control inputs (CS, WR, RD) are compatible with standard TTL logic voltage levels. The required signals at these inputs correspond to Chip Select, START Conversion, and Output Enable control signals, respectively. They are active-Low for easy interface to microprocessor and microcontroller control buses. For applications not using microprocessors, the CS input (Pin 1) can be grounded and the A/D START function is achieved by a negative-going pulse to the WR input (Pin 3). The Output Enable function is achieved by a logic low signal at the RD input (Pin 2), which may be grounded to constantly have the latest conversion present at the output. 2002 Oct 17 5 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 Large values of source resistance where an input bypass capacitor is not used will not cause errors as the input currents settle out prior to the comparison time. If a low pass filter is required in the system, use a low valued series resistor (< 1 kΩ) for a passive RC section or add an op amp active filter (low pass). For applications with source resistances at or below 1 kΩ, a 0.1 µF bypass capacitor at the inputs will prevent pickup due to series lead inductance or a long wire. A 100 Ω series resistor can be used to isolate this capacitor (both the resistor and capacitor should be placed out of the feedback loop) from the output of the op amp, if used. Reference Voltage Span Adjust Note that the Pin 9 (VREF/2) voltage is either 1/2 the voltage applied to the VCC supply pin, or is equal to the voltage which is externally forced at the VREF/2 pin. In addition to allowing for flexible references and full span voltages, this also allows for a ratiometric voltage reference. The internal gain of the VREF/2 input is 2, making the full-scale differential input voltage twice the voltage at Pin 9. For example, a dynamic voltage range of the analog input voltage that extends from 0 to 4 V gives a span of 4 V (4–0), so the VREF/2 voltage can be made equal to 2 V (half of the 4 V span) and full scale output would correspond to 4 V at the input. On the other hand, if the dynamic input voltage had a range of 0.5 to 3.5 V, the span or dynamic input range is 3 V (3.5–0.5). To encode this 3 V span with 0.5 V yielding a code of zero, the minimum expected input (0.5 V, in this case) is applied to the VIN(–) pin to account for the offset, and the VREF/2 pin is set to 1/2 the 3 V span, or 1.5 V. The A/D converter will now encode the VIN(+) signal between 0.5 and 3.5 V with 0.5 V at the input corresponding to a code of zero and 3.5 V at the input producing a full scale output code. The full 8 bits of resolution are thus applied over this reduced input voltage range. The required connections are shown in Figure 7. Analog Differential Voltage Inputs and Common-Mode Rejection These A/D converters have additional flexibility due to the analog differential voltage input. The VIN(–) input (Pin 7) can be used to subtract a fixed voltage from the input reading (tare correction). This is also useful in a 4/20 mA current loop conversion. Common-mode noise can also be reduced by the use of the differential input. The time interval between sampling VIN(+) and VIN(–) is 4.5 clock periods. The maximum error due to this time difference is given by: V(max) = (VP) (2fCM) (4.5/fCLK), where: V = error voltage due to sampling delay VP = peak value of common-mode voltage fCM = common mode frequency For example, with a 60 Hz common-mode frequency, fcm, and a 1 MHz A/D clock, fCLK, keeping this error to 1/4 LSB (about 5 mV) would allow a common-mode voltage, VP, which is given by: VP + or VP + (5 x 10 *3) (10 4) + 2.95V (6.28) (60) (4.5) [V(max) (f CLK) (2f CM)(4.5) Operating Mode These converters can be operated in two modes: 1) absolute mode 2) ratiometric mode In absolute mode applications, both the initial accuracy and the temperature stability of the reference voltage are important factors in the accuracy of the conversion. For VREF/2 voltages of 2.5 V, initial errors of ±10 mV will cause conversion errors of ±1 LSB due to the gain of 2 at the VREF/2 input. In reduced span applications, the initial value and stability of the VREF/2 input voltage become even more important as the same error is a larger percentage of the VREF/2 nominal value. See Figure 8. In ratiometric converter applications, the magnitude of the reference voltage is a factor in both the output of the source transducer and the output of the A/D converter, and, therefore, cancels out in the final digital code. See Figure 9. Generally, the reference voltage will require an initial adjustment. Errors due to an improper reference voltage value appear as full-scale errors in the A/D transfer function. The allowed range of analog input voltages usually places more severe restrictions on input common-mode voltage levels than this, however. An analog input span less than the full 5 V capability of the device, together with a relatively large zero offset, can be easily handled by use of the differential input. (See Reference Voltage Span Adjust). ERRORS AND INPUT SPAN ADJUSTMENTS There are many sources of error in any data converter, some of which can be adjusted out. Inherent errors, such as relative accuracy, cannot be eliminated, but such errors as full-scale and zero scale offset errors can be eliminated quite easily. See Figure 7. Noise and Stray Pickup The leads of the analog inputs (Pins 6 and 7) should be kept as short as possible to minimize input noise coupling and stray signal pick-up. Both EMI and undesired digital signal coupling to these inputs can cause system errors. The source resistance for these inputs should generally be below 5 kΩ to help avoid undesired noise pickup. Input bypass capacitors at the analog inputs can create errors as described previously. Full scale adjustment with any input bypass capacitors in place will eliminate these errors. Zero Scale Error Zero scale error of an A/D is the difference of potential between the ideal 1/2 LSB value (9.8 mV for VREF/2=2.500 V) and that input voltage which just causes an output transition from code 0000 0000 to a code of 0000 0001. If the minimum input value is not ground potential, a zero offset can be made. The converter can be made to output a digital code of 0000 0000 for the minimum expected input voltage by biasing the VIN(–) input to that minimum value expected at the VIN(–) input to that minimum value expected at the VIN(+) input. This uses the differential mode of the converter. Any offset adjustment should be done prior to full scale adjustment. Reference Voltage For application flexibility, these A/D converters have been designed to accommodate fixed reference voltages of 5V to Pin 20 or 2.5 V to Pin 9, or an adjusted reference voltage at Pin 9. The reference can be set by forcing it at VREF/2 input, or can be determined by the supply voltage (Pin 20). Figure 6 indicates how this is accomplished. 2002 Oct 17 6 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 Full Scale Adjustment Full scale gain is adjusted by applying any desired offset voltage to VIN(–), then applying the VIN(+) a voltage that is 1-1/2 LSB less than the desired analog full-scale voltage range and then adjusting the magnitude of VREF/2 input voltage (or the VCC supply if there is no VREF/2 input connection) for a digital output code which just changes from 1111 1110 to 1111 1111. The ideal VIN(+) voltage for this full-scale adjustment is given by: V IN()) + V IN(*) * 1.5 x where: VMAX = high end of analog input range (ground referenced) VMIN = low end (zero offset) of analog input (ground referenced) V MAX * V MIN 255 DRIVING THE DATA BUS This CMOS A/D converter, like MOS microprocessors and memories, will require a bus driver when the total capacitance of the data bus gets large. Other circuitry tied to the data bus will add to the total capacitive loading, even in the high impedance mode. There are alternatives in handling this problem. The capacitive loading of the data bus slows down the response time, although DC specifications are still met. For systems with a relatively low CPU clock frequency, more time is available in which to establish proper logic levels on the bus, allowing higher capacitive loads to be driven (see Typical Performance Characteristics). At higher CPU clock frequencies, time can be extended for I/O reads (and/or writes) by inserting wait states (8880) or using clock-extending circuits (6800, 8035). Finally, if time is critical and capacitive loading is high, external bus drivers must be used. These can be 3-State buffers (low power Schottky is recommended, such as the N74LS240 series) or special higher current drive products designed as bus drivers. High current bipolar bus drivers with PNP inputs are recommended as the PNP input offers low loading of the A/D output, allowing better response time. CLOCKING OPTION The clock signal for these A/Ds can be derived from external sources, such as a system clock, or self-clocking can be accomplished by adding an external resistor and capacitor, as shown in Figure 11. Heavy capacitive or DC loading of the CLK R pin should be avoided as this will disturb normal converter operation. Loads less than 50pF are allowed. This permits driving up to seven A/D converter CLK IN pins of this family from a single CLK R pin of one converter. For larger loading of the clock line, a CMOS or low power TTL buffer or PNP input logic should be used to minimize the loading on the CLK R pin. POWER SUPPLIES Noise spikes on the VCC line can cause conversion errors as the internal comparator will respond to them. A low inductance filter capacitor should be used close to the converter VCC pin and values of 1 µF or greater are recommended. A separate 5 V regulator for the converter (and other 5 V linear circuitry) will greatly reduce digital noise on the VCC supply and the attendant problems. Restart During a Conversion A conversion in process can be halted and a new conversion began by bringing the CS and WR inputs low and allowing at least one of them to go high again. The output data latch is not updated if the conversion in progress is not completed; the data from the previously completed conversion will remain in the output data latches until a subsequent conversion is completed. WIRING AND LAYOUT PRECAUTIONS Digital wire-wrap sockets and connections are not satisfactory for breadboarding this (or any) A/D converter. Sockets on PC boards can be used. All logic signal wires and leads should be grouped or kept as far as possible from the analog signal leads. Single wire analog input leads may pick up undesired hum and noise, requiring the use of shielded leads to the analog inputs in many applications. A single-point analog ground separate from the logic or digital ground points should be used. The power supply bypass capacitor and the self-clocking capacitor, if used, should be returned to digital ground. Any VREF/2 bypass capacitor, analog input filter capacitors, and any input shielding should be returned to the analog ground point. Proper grounding will minimize zero-scale errors which are present in every code. Zero-scale errors can usually be traced to improper board layout and wiring. Continuous Conversion To provide continuous conversion of input data, the CS and RD inputs are grounded and INTR output is tied to the WR input. This INTR/WR connection should be momentarily forced to a logic low upon power-up to insure circuit operation. See Figure 10 for one way to accomplish this. 2002 Oct 17 7 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 APPLICATIONS Microprocessor Interfacing This family of A/D converters was designed for easy microprocessor interfacing. These converters can be memory mapped with appropriate memory address decoding for CS (read) input. The active-Low write pulse from the processor is then connected to the WR input of the A/D converter, while the processor active-Low read pulse is fed to the converter RD input to read the converted data. If the clock signal is derived from the microprocessor system clock, the designer/programmer should be sure that there is no attempt to read the converter until 74 converter clock pulses after the start pulse goes high. Alternatively, the INTR pin may be used to interrupt the processor to cause reading of the converted data. Of course, the converter can be connected and addressed as a peripheral (in I/O space), as shown in Figure 12. A bus driver should be used as a buffer to the A/D output in large microprocessor systems where the data leaves the PC board and/or must drive capacitive loads in excess of 100 pF. See Figure 14. Interfacing the SCN8048 microcomputer family is pretty simple, as shown in Figure 13. Since the SCN8048 family has 24 I/O lines, one of these (shown here as bit 0 or port 1) can be used as the chip select signal to the converter, eliminating the need for an address decoder. The RD and WR signals are generated by reading from and writing to a dummy address. the NE5521 data sheet for a complete description of the operation of that part. Circuit Adjustment To adjust the full scale and zero scale of the A/D, determine the range of voltages that the transducer interface output will take on. Set the LVDT core for null and set the Zero Scale Scale Adjust Potentiometer for a digital output from the A/D of 1000 000. Set the LVDT core for maximum voltage from the interface and set the Full Scale Adjust potentiometer so the A/D output is just barely 1111 1111. A Digital Thermostat Circuit Description The schematic of a Digital Thermostat is shown in Figure 16. The A/D digitizes the output of the LM35, a temperature transducer IC with an output of 10 mV per °C. With VREF/2 set for 2.56 V, this 10 mV corresponds to 1/2 LSB and the circuit resolution is 2 °C. Reducing VREF/2 to 1.28 yields a resolution of 1 °C. Of course, the lower VREF/2 is, the more sensitive the A/D will be to noise. The desired temperature is set by holding either of the set buttons closed. The SCC80C451 programming could cause the desired (set) temperature to be displayed while either button is depressed and for a short time after it is released. At other times the ambient temperature could be displayed. The set temperature is stored in an SCN8051 internal register. The A/D conversion is started by writing anything at all to the A/D with port pin P10 set high. The desired temperature is compared with the digitized actual temperature, and the heater is turned on or off by clearing setting port pin P12. If desired, another port pin could be used to turn on or off an air conditioner. The display drivers are NE587s if common anode LED displays are used. Of course, it is possible to interface to LCD displays as well. Digitizing a Transducer Interface Output Circuit Description Figure 15 shows an example of digitizing transducer interface output voltage. In this case, the transducer interface is the NE5521, an LVDT (Linear Variable Differential Transformer) Signal Conditioner. The diode at the A/D input is used to insure that the input to the A/D does not go excessively beyond the supply voltage of the A/D. See 2002 Oct 17 8 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 TYPICAL PERFORMANCE CHARACTERISTICS Power Supply Current vs Temperature 3.2 POWER SUPPLY CURRENT (mA) 3.0 2.8 2.6 2.4 5.0 V 2.2 2.0 1.8 –50 –25 0 25 50 75 100 125 AMBIENT TEMPERATURE (°C) 4.5 V fCLK = 1 MHz CS = H CLOCK FRQ (MHz) 10.0 8.0 6.0 4.0 2.0 1.0 0.8 0.6 0.4 0.2 MIN. 0.1 10 20 40 60 80100 200 400 600 1000 CLOCK CAP (pF) TYP. –3 –4 –5 0 1 2 3 4 5 APPLIED VREF/2 (V) Clock Frequency vs Clock Capacitor 5 4 3 2 (mA) MAX. 1 0 –1 –2 Input Current vs Applied Voltage at VREF/2 Pin VCC = 5.0 V Tamb = 25 oC 5.5 V f REF/2 Logic Input Threshold Voltage vs Supply Voltage 4.5 CLK–IN THRESHOLD VOLTAGE (V) 1.70 –55 °C 4.0 3.5 3.0 2.5 2.0 1.5 CLK–IN Threshold Voltage vs Supply Voltage –55 °C ≤ Tamb ≤ 125 °C OUTPUT CURRENT (mA) 18 Output Current vs Temperature VCC = 5.0 V 16 14 12 10 VO = 0.4 V 8 6 –50 VO = 2.5 V LOGIC INPUT (V) 1.60 +25 °C +125 °C VT+ 1.50 VT 1.40 1.30 4.50 4.75 5.00 5.25 5.50 1.0 4.50 4.75 5.00 5.25 5.50 –25 0 25 50 75 100 125 VCC SUPPLY VOLTAGE (V) VCC SUPPLY VOLTAGE (V) AMBIENT TEMPERATURE (oC) Full Scale Error vs Conversion Time 4 VCC = 5.0 V VREF/2 = 2.5 V 3 ERROR (LSB) DEALY (ns) 350 300 250 200 150 100 1 50 0 0 20 40 60 80 100 120 CONVERSION TIME (µs) 0 0 Delay From RD Falling Edge to Data Valid vs Load Capacitance VCC = 5.0 V Tamb = 25 oC 2 200 400 600 800 1000 LOAD CAPACITANCE (pF) SL00018 Figure 3. Typical Performance Characteristics 2002 Oct 17 9 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 3-STATE TEST CIRCUITS AND WAVEFORMS (ADC0801-1) 20ns VCC VCC RD CS CL 10 pF DATA OUTPUT 10 kΩ RD GND VOH DATA OUTPUT GND tr 90% 50% 10% t1H 90% RD CS CL VCC VCC VCC RD 10 kΩ DATA OUTPUT 10 pF GND VOH DATA OUTPUT GND tr 90% 50% 10% t0H 10% t1H tOH SL00019 Figure 4. 3-State Test Circuits and Waveforms (ADC0801-1) TIMING DIAGRAMS (All timing is measured from the 50% voltage points) START CONVERSION CS WR tWI tW(WR)L ”BUSY” ACTUAL INTERNAL STATUS OF THE CONVERTER INTR (LAST DATA WAS NOT READ) INT ASSERTED 1/2 TCLK ”NOT BUSY” (LAST DATA WAS READ) 1 TO 8 X 1/fCLK INTERNAL TC DATA IS VALID IN OUTPUT LATCHES INTR INTR RESET CS tRI RD NOTE DATA OUTPUTS tACC t1H, t0H THREE–STATE Output Enable and Reset INTR NOTE: Read strobe must occur 8 clock periods (8/fCLK) after assertion of interrupt to guarantee reset of INTR. SL00020 Figure 5. Timing Diagrams 2002 Oct 17 10 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 VCC 20 VREF (5V) VREF R VREF/2 9 FS OFFSET ADJUST DIGITAL CIRCUITS ZS OFFSET ADJUST – + 330 Ω 0.1 µF TO VREF/2 R ANALOG CIRCUITS TO VIN(–) SL00022 Figure 7. Offsetting the Zero Scale and Adjusting the Input Range (Span) 8 10 NOTE: The VREF/2 voltage is either 1/2 the VCC voltage or is that which is forced at Pin 9. SL00021 Figure 6. Internal Reference Design +5V +5V VCC VIN(+) A/D VREF/2 VIN(–) VOLTAGE REFERENCE VREF/2 VIN(–) 2 kΩ + +5V VCC VIN(+) 10 µF A/D 2 kΩ VREF/2 100 Ω + 10 µF 2 kΩ 2 kΩ a. Fixed Reference b. Fixed Reference Derived from VCC c. Optional Full Scale Adjustment SL00023 Figure 8. Absolute Mode of Operation 2002 Oct 17 11 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 VCC VIN(+) TRANSDUCER A/D VCC + 10µF 2 kΩ VIN(–) VREF/2 FULL SCALE OPTIONAL 100 Ω 2 kΩ SL00024 Figure 9. Ratiometric Mode of Operation with Optional Full Scale Adjustment 10k +5 V CS RD WR 10 kΩ 2.7 kΩ CLK IN INTR 10 kΩ 47 µF TO 100 µF VIN(+) VIN(–) 56 pF A GND VREF/2 1 2 3 4 5 6 7 8 9 A/D 20 VCC 19 CLK R 18 D0 17 D1 16 D2 15 D3 14 D4 13 D5 12 D6 11 D7 DB1 DB2 DB3 DB4 DB5 DB6 DB7 DB0 +5 V D GND 10 SL00025 Figure 10. Connection for Continuous Conversion INT CLK R 19 R CLK IN 4 I/O WR I/O RD CLK C fCLK = 1/1.7 R C R = 10 kΩ CS RD WR CLK IN INTR ANALOG INPUTS 56 pF 1 2 3 4 5 10 kΩ 20 VCC 19 CLK R 18 D0 17 D1 16 D2 A/D 15 D3 DB3 14 D4 13 D5 12 D6 11 D7 DB5 DB6 DB7 DB4 DB1 DB2 DB0 +5 V A/D SL00026 Figure 11. Self-Clocking the Converter VIN(+) 6 VIN(–) 7 A GND 8 VREF/2 9 D GND 10 ADDRESS DECODE LOGIC SL00027 Figure 12. Interfacing to 8080A Microprocessor 2002 Oct 17 12 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 +5 V 18 D0 17 D1 16 D2 VCC 40 1 2 3 4 5 6 P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 D0 18 D1 17 D2 16 D3 15 D4 14 D5 13 D6 12 D7 11 VCC 20 19 CLK R 10 kΩ 4 CLK IN 56 pF A/D 6 A/D 15 D3 14 D4 13 D5 12 D6 11 D7 8–BIT BUFFER N74LS241 N74LS244 N74LS541 DATA BUS SCN8051 OR SCN80C51 7 8 OE VIN(+) VREF/2 ANALOG INPUTS SL00029 17 RD 16 WR 12 INTO 39 P0.0 RD 2 WR 3 INTR CS 5 1 7 Figure 14. Buffering the A/D Output to Drive High Capacitance Loads and for Driving Off-Board Loads 12 A GND 11 D GND SL00028 Figure 13. SCN8051 Interfacing +5 V Ct 18 kΩ 4.7 kΩ 1.5 kΩ 820 Ω NE5521 LVDT 1 µF 4.7 kΩ 0.47 µF 22 kΩ +5 V IN4148 VCC VIN(+) 3.3 kΩ A/D 2 kΩ VIN(–) VREF/2 470 Ω 2 kΩ FULL SCALE ADJUST 100 Ω 2 kΩ SL00030 Figure 15. Digitizing a Transducer Interface Output 2002 Oct 17 13 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 6 2 1 1/4 HEF4071 7 3 RBI 5 NE587 7 8 RBO 4 10 kΩ 6 2 1 1/4 HEF4071 7 3 RBI 5 NE587 7 8 10 kΩ LOWER P15 RAISE P16 13 14 18 17 16 15 14 13 DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 D0 18 D1 17 D2 16 D3 15 D4 14 D5 13 D6 12 D7 11 A/D 4 10 kΩ CLK IN 56 pF 8 10 6 27 RD WR INT P10 RD 2 WR INTR CS 3 5 1 D GND 10 8 6 VIN(+) 7 VIN(–) A GND LM35 19 CLK R 20 VCC + 10 µF +5 V SCC80C51 12 11 +V 2N3906 29 P12 20 GND 1N4148 TO HEATER SL00031 Figure 16. Digital Thermostat 2002 Oct 17 14 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 SO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1 2002 Oct 17 15 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 DIP20: plastic dual in-line package; 20 leads (300 mil) SOT146-1 2002 Oct 17 16 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 REVISION HISTORY Rev _3 Date 20021017 Description Product data; third version; supersedes data of 2001 Aug 03. Engineering Change Notice 853–0034 28949 (date: 20020916). Modifications: • Add “Topside Marking” column to Ordering Information table. _2 20010803 Product data; second version (9397 750 08926). Engineering Change Notice 853–0034 26832 (date: 20010803). _1 19940831 Product data; initial version. Engineering Change Notice 853–0034 13721 (date: 19940831). 2002 Oct 17 17 Philips Semiconductors Product data CMOS 8-bit A/D converters ADC0803/0804 Data sheet status Level I Data sheet status [1] Objective data Product status [2] [3] Development Definitions This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). II Preliminary data Qualification III Product data Production [1] Please consult the most recently issued data sheet before initiating or completing a design. [2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com. [3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status. Definitions Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Disclaimers Life support — These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes — Philips Semiconductors reserves the right to make changes in the products—including circuits, standard cells, and/or software—described or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Contact information For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825 © Koninklijke Philips Electronics N.V. 2002 All rights reserved. Printed in U.S.A. Date of release: 10-02 For sales offices addresses send e-mail to: sales.addresses@www.semiconductors.philips.com. Document order number: 9397 750 10538 Philips Semiconductors 2002 Oct 17 18