ADC0809CCN

ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 ADC0808/ADC0809 8-Bit μP Compatible A/D Converters with 8-Channel Multiplexer Check for Samples: ADC0808-N, ADC0809-N FEATURES DESCRIPTION • • The ADC0808, ADC0809 data acquisition component is a monolithic CMOS device with an 8-bit analog-todigital converter, 8-channel multiplexer and microprocessor compatible control logic. The 8-bit A/D converter uses successive approximation as the conversion technique. The converter features a high impedance chopper stabilized comparator, a 256R voltage divider with analog switch tree and a successive approximation register. The 8-channel multiplexer can directly access any of 8-single-ended analog signals. 1 2 • • • • • • Easy Interface to All Microprocessors Operates Ratiometrically or with 5 VDC or Analog Span Adjusted Voltage Reference No Zero or Full-Scale Adjust Required 8-Channel Multiplexer with Address Logic 0V to VCC Input Range Outputs meet TTL Voltage Level Specifications ADC0808 Equivalent to MM74C949 ADC0809 Equivalent to MM74C949-1 KEY SPECIFICATIONS • • • • • Resolution: 8 Bits Total Unadjusted Error: ±½ LSB and ±1 LSB Single Supply: 5 VDC Low Power: 15 mW Conversion Time: 100 μs The device eliminates the need for external zero and full-scale adjustments. Easy interfacing to microprocessors is provided by the latched and decoded multiplexer address inputs and latched TTL TRI-STATE outputs. The design of the ADC0808, ADC0809 has been optimized by incorporating the most desirable aspects of several A/D conversion techniques. The ADC0808, ADC0809 offers high speed, high accuracy, minimal temperature dependence, excellent long-term accuracy and repeatability, and consumes minimal power. These features make this device ideally suited to applications from process and machine control to consumer and automotive applications. For 16channel multiplexer with common output (sample/hold port) see ADC0816 data sheet. (See AN-247 (Literature Number SNOA595) for more information.) Block Diagram Connection Diagrams 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 1999–2013, Texas Instruments Incorporated ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 Figure 1. PDIP Package See Package N0028E www.ti.com Figure 2. PLCC Package See Package FN0028A These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) (3) Supply Voltage (VCC) (4) 6.5V −0.3V to (VCC+0.3V) Voltage at Any Pin Except Control Inputs −0.3V to +15V Voltage at Control Inputs (START, OE, CLOCK, ALE, ADD A, ADD B, ADD C) −65°C to +150°C Storage Temperature Range Package Dissipation at TA=25°C 875 mW Lead Temp. (Soldering, 10 seconds) PDIP Package (plastic) PLCC Package ESD Susceptibility (1) (2) (3) (4) (5) 260°C Vapor Phase (60 seconds) 215°C Infrared (15 seconds) 220°C (5) 400V Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its specified operating conditions. All voltages are measured with respect to GND, unless otherwise specified. If Military/Aerospace specified devices are required, please contact the TI Sales Office/Distributors for availability and specifications. A Zener diode exists, internally, from VCC to GND and has a typical breakdown voltage of 7 VDC. Human body model, 100 pF discharged through a 1.5 kΩ resistor. Operating Conditions (1) (2) TMIN≤TA≤TMAX Temperature Range −40°C≤TA≤+85°C Range of VCC (1) (2) 4.5 VDC to 6.0 VDC Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its specified operating conditions. All voltages are measured with respect to GND, unless otherwise specified. Electrical Characteristics – Converter Specifications Converter Specifications: VCC=5 VDC=VREF+, VREF(−)=GND, TMIN≤TA≤TMAX and fCLK=640 kHz unless otherwise stated. Symbol Parameter ADC0808 Total Unadjusted Error (1) (1) 2 Conditions Min Typ Max Units 25°C ±½ LSB TMIN to TMAX ±¾ LSB Total unadjusted error includes offset, full-scale, linearity, and multiplexer errors. See Figure 5. None of these A/Ds requires a zero or full-scale adjust. However, if an all zero code is desired for an analog input other than 0.0V, or if a narrow full-scale span exists (for example: 0.5V to 4.5V full-scale) the reference voltages can be adjusted to achieve this. See Figure 15. Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 Electrical Characteristics – Converter Specifications (continued) Converter Specifications: VCC=5 VDC=VREF+, VREF(−)=GND, TMIN≤TA≤TMAX and fCLK=640 kHz unless otherwise stated. Symbol Parameter Conditions ADC0809 Total Unadjusted Error (1) VREF(+) Max Units 0°C to 70°C ±1 LSB TMIN to TMAX ±1¼ LSB VCC + 0.1 VDC VCC VCC + 0.1 V (VCC/2) − 0.1 VCC/2 (VCC/2) + 0.1 V −0.1 0 −2 ±0.5 Input Resistance From Ref(+) to Ref(−) Analog Input Voltage Range See Voltage, Top of Ladder Measured at Ref(+) (2) V(+) or V(−) Voltage, Center of Ladder VREF(−) Voltage, Bottom of Ladder IIN fc=640 kHz, Typ 1.0 2.5 GND − 0.1 Measured at Ref(−) Comparator Input Current (2) Min (3) kΩ V μA 2 Two on-chip diodes are tied to each analog input which will forward conduct for analog input voltages one diode drop below ground or one diode drop greater than the VCCn supply. The spec allows 100 mV forward bias of either diode. This means that as long as the analog VIN does not exceed the supply voltage by more than 100 mV, the output code will be correct. To achieve an absolute 0VDC to 5VDC input voltage range will therefore require a minimum supply voltage of 4.900 VDC over temperature variations, initial tolerance and loading. Comparator input current is a bias current into or out of the chopper stabilized comparator. The bias current varies directly with clock frequency and has little temperature dependence (Figure 8). See ANALOG COMPARATOR INPUTS (3) Electrical Characteristics – Digital Levels and DC Specifications Digital Levels and DC Specifications: ADC0808CCN, ADC0808CCV, ADC0809CCN and ADC0809CCV, 4.75≤VCC≤5.25V, −40°C≤TA≤+85°C unless otherwise noted Symbol Parameter Conditions Min Typ Max Units 10 200 nA 1.0 μA ANALOG MULTIPLEXER VCC=5V, VIN=5V, IOFF(+) OFF Channel Leakage Current TA=25°C TMIN to TMAX VCC=5V, VIN=0, IOFF(−) OFF Channel Leakage Current TA=25°C −200 −10 TMIN to TMAX −1.0 μA (VCC − 1.5) V nA CONTROL INPUTS VIN(1) Logical “1” Input Voltage VIN(0) Logical “0” Input Voltage IIN(1) Logical “1” Input Current (The Control Inputs) VIN=15V IIN(0) Logical “0” Input Current (The Control Inputs) VIN=0 ICC Supply Current fCLK=640 kHz 1.5 V 1.0 μA −1.0 μA 0.3 3.0 mA DATA OUTPUTS AND EOC (INTERRUPT) VOUT(1) Logical “1” Output Voltage VCC = 4.75V IOUT = −360µA IOUT = −10µA VOUT(0) Logical “0” Output Voltage IO=1.6 mA 0.45 VOUT(0) Logical “0” Output Voltage EOC IO=1.2 mA 0.45 V 3 μA IOUT 2.4 4.5 V V VO=5V TRI-STATE Output Current −3 VO=0 V μA Electrical Characteristics – Timing Specifications Timing Specifications VCC=VREF(+)=5V, VREF(−)=GND, tr=tf=20 ns and TA=25°C unless otherwise noted. Symbol tSTCLK Parameter Conditions Start Time Delay from Clock (Figure 7) Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N MIn 300 Typ Max Units 900 ns Submit Documentation Feedback 3 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com Electrical Characteristics – Timing Specifications (continued) Timing Specifications VCC=VREF(+)=5V, VREF(−)=GND, tr=tf=20 ns and TA=25°C unless otherwise noted. Symbol Parameter Conditions MIn Typ Max Units tWS Minimum Start Pulse Width (Figure 7) 100 200 ns tWALE Minimum ALE Pulse Width (Figure 7) 100 200 ns ts Minimum Address Set-Up Time (Figure 7) 25 50 ns tH Minimum Address Hold Time (Figure 7) 25 50 ns tD Analog MUX Delay Time From ALE RS=0Ω (Figure 7) 1 2.5 μs tH1, tH0 OE Control to Q Logic State CL=50 pF, RL=10k (Figure 10) 125 250 ns t1H, t0H OE Control to Hi-Z CL=10 pF, RL=10k (Figure 10) 125 250 ns tc Conversion Time fc Clock Frequency tEOC EOC Delay Time (Figure 7) CIN Input Capacitance At Control Inputs COUT TRI-STATE Output Capacitance At TRI-STATE Outputs (1) 4 fc=640 kHz, (Figure 7) (1) 90 100 116 μs 10 640 1280 kHz 8 + 2 μS Clock Periods 10 15 pF 10 15 pF 0 The outputs of the data register are updated one clock cycle before the rising edge of EOC. Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 Functional Description MULTIPLEXER The device contains an 8-channel single-ended analog signal multiplexer. A particular input channel is selected by using the address decoder. Table 1 shows the input states for the address lines to select any channel. The address is latched into the decoder on the low-to-high transition of the address latch enable signal. Table 1. Analog Channel Selection ADDRESS LINE SELECTED ANALOG CHANNEL C B IN0 L L L IN1 L L H IN2 L H L IN3 L H H IN4 H L L IN5 H L H IN6 H H L IN7 H H H A CONVERTER CHARACTERISTICS The Converter The heart of this single chip data acquisition system is its 8-bit analog-to-digital converter. The converter is designed to give fast, accurate, and repeatable conversions over a wide range of temperatures. The converter is partitioned into 3 major sections: the 256R ladder network, the successive approximation register, and the comparator. The converter's digital outputs are positive true. The 256R ladder network approach (Figure 3) was chosen over the conventional R/2R ladder because of its inherent monotonicity, which ensures no missing digital codes. Monotonicity is particularly important in closed loop feedback control systems. A non-monotonic relationship can cause oscillations that will be catastrophic for the system. Additionally, the 256R network does not cause load variations on the reference voltage. The bottom resistor and the top resistor of the ladder network in Figure 3 are not the same value as the remainder of the network. The difference in these resistors causes the output characteristic to be symmetrical with the zero and full-scale points of the transfer curve. The first output transition occurs when the analog signal has reached +½ LSB and succeeding output transitions occur every 1 LSB later up to full-scale. The successive approximation register (SAR) performs 8 iterations to approximate the input voltage. For any SAR type converter, n-iterations are required for an n-bit converter. Figure 4 shows a typical example of a 3-bit converter. In the ADC0808, ADC0809, the approximation technique is extended to 8 bits using the 256R network. The A/D converter's successive approximation register (SAR) is reset on the positive edge of the start conversion start pulse. The conversion is begun on the falling edge of the start conversion pulse. A conversion in process will be interrupted by receipt of a new start conversion pulse. Continuous conversion may be accomplished by tying the end-of-conversion (EOC) output to the SC input. If used in this mode, an external start conversion pulse should be applied after power up. End-of-conversion will go low between 0 and 8 clock pulses after the rising edge of start conversion. The most important section of the A/D converter is the comparator. It is this section which is responsible for the ultimate accuracy of the entire converter. It is also the comparator drift which has the greatest influence on the repeatability of the device. A chopper-stabilized comparator provides the most effective method of satisfying all the converter requirements. The chopper-stabilized comparator converts the DC input signal into an AC signal. This signal is then fed through a high gain AC amplifier and has the DC level restored. This technique limits the drift component of the amplifier since the drift is a DC component which is not passed by the AC amplifier. This makes the entire A/D converter extremely insensitive to temperature, long term drift and input offset errors. Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N Submit Documentation Feedback 5 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com Figure 6 shows a typical error curve for the ADC0808. Figure 3. Resistor Ladder and Switch Tree Figure 4. 3-Bit A/D Transfer Curve Figure 5. 3-Bit A/D Absolute Accuracy Curve Figure 6. Typical Error Curve 6 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 Timing Diagram Figure 7. Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N Submit Documentation Feedback 7 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics Comparator IIN vs VIN (VCC=VREF=5V) Figure 8. Multiplexer RON vs VIN (VCC=VREF=5V) Figure 9. 8 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 TRI-STATE Test Circuits and Timing Diagrams t1H, tH1 t0H, tH0 t1H, CL = 10 pF t0H, CL = 10 pF tH1, CL = 50 pF tH0, CL = 50 pF tr tr 90% 50% 10% 90% 50% 10% tH1 tH0 50% 50% Figure 10. TRI-STATE Test Circuits and Timing Diagrams Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N Submit Documentation Feedback 9 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com APPLICATIONS INFORMATION OPERATION RATIOMETRIC CONVERSION The ADC0808, ADC0809 is designed as a complete Data Acquisition System (DAS) for ratiometric conversion systems. In ratiometric systems, the physical variable being measured is expressed as a percentage of full-scale which is not necessarily related to an absolute standard. The voltage input to the ADC0808 is expressed by the equation • • • • • • VIN= Input voltage into the ADC0808 Vfs= Full-scale voltage VZ= Zero voltage DX= Data point being measured DMAX= Maximum data limit DMIN= Minimum data limit (1) A good example of a ratiometric transducer is a potentiometer used as a position sensor. The position of the wiper is directly proportional to the output voltage which is a ratio of the full-scale voltage across it. Since the data is represented as a proportion of full-scale, reference requirements are greatly reduced, eliminating a large source of error and cost for many applications. A major advantage of the ADC0808, ADC0809 is that the input voltage range is equal to the supply range so the transducers can be connected directly across the supply and their outputs connected directly into the multiplexer inputs, (Figure 11). Ratiometric transducers such as potentiometers, strain gauges, thermistor bridges, pressure transducers, etc., are suitable for measuring proportional relationships; however, many types of measurements must be referred to an absolute standard such as voltage or current. This means a system reference must be used which relates the full-scale voltage to the standard volt. For example, if VCC=VREF=5.12V, then the full-scale range is divided into 256 standard steps. The smallest standard step is 1 LSB which is then 20 mV. RESISTOR LADDER LIMITATIONS The voltages from the resistor ladder are compared to the selected into 8 times in a conversion. These voltages are coupled to the comparator via an analog switch tree which is referenced to the supply. The voltages at the top, center and bottom of the ladder must be controlled to maintain proper operation. The top of the ladder, Ref(+), should not be more positive than the supply, and the bottom of the ladder, Ref(−), should not be more negative than ground. The center of the ladder voltage must also be near the center of the supply because the analog switch tree changes from N-channel switches to P-channel switches. These limitations are automatically satisfied in ratiometric systems and can be easily met in ground referenced systems. Figure 12 shows a ground referenced system with a separate supply and reference. In this system, the supply must be trimmed to match the reference voltage. For instance, if a 5.12V is used, the supply should be adjusted to the same voltage within 0.1V. Figure 11. Ratiometric Conversion System 10 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 The ADC0808 needs less than a milliamp of supply current so developing the supply from the reference is readily accomplished. In Figure 13 a ground referenced system is shown which generates the supply from the reference. The buffer shown can be an op amp of sufficient drive to supply the milliamp of supply current and the desired bus drive, or if a capacitive bus is driven by the outputs a large capacitor will supply the transient supply current as seen in Figure 14. The LM301 is overcompensated to insure stability when loaded by the 10 μF output capacitor. The top and bottom ladder voltages cannot exceed VCC and ground, respectively, but they can be symmetrically less than VCC and greater than ground. The center of the ladder voltage should always be near the center of the supply. The sensitivity of the converter can be increased, (i.e., size of the LSB steps decreased) by using a symmetrical reference system. In Figure 15, a 2.5V reference is symmetrically centered about VCC/2 since the same current flows in identical resistors. This system with a 2.5V reference allows the LSB bit to be half the size of a 5V reference system. Figure 12. Ground Referenced Conversion System Using Trimmed Supply Figure 13. Ground Referenced Conversion System with Reference Generating VCC Supply Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N Submit Documentation Feedback 11 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com Figure 14. Typical Reference and Supply Circuit RA=RB *Ratiometric transducers Figure 15. Symmetrically Centered Reference CONVERTER EQUATIONS The transition between adjacent codes N and N+1 is given by: (2) The center of an output code N is given by: (3) The output code N for an arbitrary input are the integers within the range: Where: • • • • • 12 VIN=Voltage at comparator input VREF(+)=Voltage at Ref(+) VREF(−)=Voltage at Ref(−) VTUE=Total unadjusted error voltage (typically VREF(+)÷512) Submit Documentation Feedback (4) Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N ADC0808-N, ADC0809-N www.ti.com SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 ANALOG COMPARATOR INPUTS The dynamic comparator input current is caused by the periodic switching of on-chip stray capacitances. These are connected alternately to the output of the resistor ladder/switch tree network and to the comparator input as part of the operation of the chopper stabilized comparator. The average value of the comparator input current varies directly with clock frequency and with VIN as shown in Figure 8. If no filter capacitors are used at the analog inputs and the signal source impedances are low, the comparator input current should not introduce converter errors, as the transient created by the capacitance discharge will die out before the comparator output is strobed. If input filter capacitors are desired for noise reduction and signal conditioning they will tend to average out the dynamic comparator input current. It will then take on the characteristics of a DC bias current whose effect can be predicted conventionally. Typical Application *Address latches needed for 8085 and SC/MP interfacing the ADC0808 to a microprocessor Table 2. Microprocessor Interface Table PROCESSOR READ WRITE INTERRUPT (COMMENT) 8080 MEMR MEMW INTR (Thru RST Circuit) 8085 RD WR INTR (Thru RST Circuit) Z-80 RD WR INT (Thru RST Circuit, Mode 0) SC/MP NRDS NWDS SA (Thru Sense A) 6800 VMA•φ2•R/W VMA•φ•R/W IRQA or IRQB (Thru PIA) Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N Submit Documentation Feedback 13 ADC0808-N, ADC0809-N SNAS535H – OCTOBER 1999 – REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision G (March 2013) to Revision H • 14 Page Changed layout of National Data Sheet to TI format .......................................................................................................... 13 Submit Documentation Feedback Copyright © 1999–2013, Texas Instruments Incorporated Product Folder Links: ADC0808-N ADC0809-N PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) ADC0808CCV/NOPB ACTIVE PLCC FN 28 35 RoHS & Green SN Level-2A-245C-4 WEEK -40 to 85 ADC0808 CCV ADC0808CCVX/NOPB ACTIVE PLCC FN 28 750 RoHS & Green SN Level-2A-245C-4 WEEK -40 to 85 ADC0808 CCV ADC0809CCV/NOPB ACTIVE PLCC FN 28 35 RoHS & Green SN Level-2A-245C-4 WEEK -40 to 85 ADC0809 CCV ADC0809CCVX/NOPB ACTIVE PLCC FN 28 750 RoHS & Green SN Level-2A-245C-4 WEEK -40 to 85 ADC0809 CCV (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of