AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Key Features n General Description l 100µV Resolution l High Impedance Differential Inputs l Differential Reference l Drive LCD (AME7106) or LED (AME7107) Directly l Four New Convenient Features (AME7106A/AME7107A) l Display-Hold l Low-Battery Indication l Integration Status Indication l De-Integration Status Indication n Applications l Digital multimeter l pH meter l Capacitance meter l Thermometer l Digital Panel meter l Photometer n Typical Operating Circuit The AME7106 and AME7107 family are high performance, low power, 3-1/2 digit, dual-slope integrating A/ D converters, with on-chip display drivers. The AME7106 is designed for a single battery operated system, will drive non-multiplexed LCD display directly. The AME7107 is designed for a dual power supply system, will directly drive common anode LED display. These A/D converters are inherently versatile and accurate. They are immune to the high noise environments. The true differential high impedance inputs and differential reference are very useful for making ratiometric measurement, such as resistance, strain gauge and bridge transducers. The built-in auto-zero feature automatically corrects the system offset without any external adjustments. Display-hold, low-battery flag, integration and de-integration status flags are four additional features which are available in the 44-pin package, AME7106ACKW and AME7107ACKW. * For the operating circuit of the reverse-pins version, please refer to pin configuration on page 4 and pin description on page 5 & 6 1 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power n Absolute Maximum Ratings AME7106 Supply Voltage (V+ to V-) Analog Input Voltage (Either inputs) Reference Input Voltage (Either inputs) Clock Input Power Dissipation Operating Temperature Storage Temperature Lead Temperature (Soldering 60 seconds) 12V V+ TO VV+ TO VTest to V+ 800mW 0oC to 70oC -55oC to 150oC 300oC AME7107 Supply Voltage V+ VAnalog Input Voltage (Either inputs) Reference Input Voltage (Either inputs) Clock Input Power Dissipation 6V -6V V+ to VV+ to VGnd to V+ 800mW Operating Temperature 0 C to 70 C Storage Temperature -55 C to 150 C o 300 C Lead Temperature (Soldering 60 seconds) o o o o Static sensitive device. Unused devices must be stored in the conductive material. Protect device from static discharge and static field. Stresses exceed the above Absolute Maximum Ratings may cause permanent damage to the device. Exposure to Absolute Maximum Rating Conditions for extended periods may affect the reliability of the device. 2 AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Ordering Information Part Number Display AME7106CPL LCD AME7106RCPL LCD AME7106ACKW LCD AME7106Y LCD AME7107CPL LED AME7107RCPL LED AME7107ACKW LED AME7107Y LED Marking AME7106CPL YYWW AME7106RCPL YYWW AME7106ACKW YYWW AME7106Y YYWW AME7107CPL YYWW AME7107RCPL YYWW AME7107ACKW YYWW AME7107Y YYWW Package Pin Layout Temp. Range 40 Pin PDIP Normal 0oC to 70oC 40 Pin PDIP Reverse 0oC to 71oC 44 Pin PQFP Normal 0oC to 72oC 44 Pin Dice Normal 0oC to 73oC 40 Pin PDIP Normal 0oC to 74oC 40 Pin PDIP Reverse 0oC to 75oC 44 Pin PQFP Normal 0oC to 76oC 44 Pin Dice Normal 0oC to 77oC 3 AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Electrical Characteristics Unless otherwise noted, AME7106 & AME7107 are specified at TA = 25OC, fclock = 48KHz. Supply voltage = 9V (V+ to V-) Parameter Zero Input Reading Conditions Min Vin = 0V Typ Max 0 Unit Digital Reading Full-Scale = 200.0mV Ratiometric Reading Vin = Vref = 100.0mV Roll-Over Error (Difference in Reading for Equal Positive and Negative 999 999/1000 1000 Digital Reading -1 –0.2 +1 Counts -1 –0.2 +1 Counts -Vin=+Vin ≈200.0mV Reading Near Full-Scale) Linearity (Max. Deviation Full-Scale = 200.0mV From Best Straight Line Fit) Common-Mode Vcm = –1V, Vin =0V 50 µV/V 15 µV Rejection Ratio Full-Scale = 200.0mV Noise (Pk-Pk Value Not Vin = 0V Exceeded 95% of Time) Full-Scale = 200.0mV Leakage Current at Input Vin = 0V 1 10 pA Zero Reading Drift Vin = 0V, 0OC to 70OC 0.2 1 Supply Current Vin = 0V 0.8 1.2 O µV/ C mA 3.0 3.2 V 50 75 ppm/OC (Excluding LED current for 7107) Analog Common Voltage (With respect to V+) Temp. Coeff. of Analog Common (With respect to V+) 25KΩ Between Common and V+ 2.8 25KΩ Between Common and V+ 0OC ≤TA ≤70OC Low Battery Flag V+ to V- 6.3 7.0 7.7 V Test Pin Voltage With respect to V+ 4 5 6 V V+ to V- = 9V 4 5 6 V V+ to V- = 9V 4 5 6 V Segment Sinking Current V+ = 5.0V 5 8.0 mA (Except Segment AB4) Segment Voltage = 3V 10 16 mA (AME7106 only) LCD Segment Drive Voltage (AME7106 only) Backplane Drive Voltage (AME7106 only) (AME7107 only) Segment Sinking Current V+ = 5.0V (Segment AB4) Segment Voltage = 3V (AME7107 only) Notes: 1. Input voltage may exceed the supply voltages provided the input current is limited to ±100µA. 2. Dissipation rating assumes a device is mounted with all leads soldered to printed circuit board. 4 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power n Pin Configurations 5 AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Pin Description 40-pin DIP 40-pin DIP 44-pin PQFP Symbol Pin Number (Reverse) Pin Number 1 (40) 8 V+ 2 (39) 9 D1 3 (38) 10 C1 4 (37) 11 B1 5 (36) 12 A1 6 (35) 13 F1 7 (34) 14 G1 8 (33) 15 E1 9 (32) 16 D2 10 (31) 17 C2 11 (30) 18 B2 12 (29) 19 A2 13 (28) 20 F2 14 (27) 21 E2 15 (26) 22 D3 16 (25) 23 B3 17 (24) 24 F3 18 (23) 25 E3 19 (22) 26 AB4 20 (21) 27 POL 21 (20) 28 BP/ GND 22 (19) 29 G3 23 (18) 30 A3 24 (17) 31 C3 25 (16) 32 G2 ¢w 33 LB 26 (15) 34 V27 (14) 35 INT 28 29 30 31 32 6 (13) (12) (11) (10) (9) 36 37 38 39 40 BUF A/Z INLO INHI COM Description Positive supply voltage Units-digit D-segment driver Units-digit C-segment driver Units-digit B-segment driver Units-digit A-segment driver Units-digit F-segment driver Units-digit G-segment driver Units-digit E-segment driver Tens-digit D-segment driver Tens-digit C-segment driver Tens-digit B-segment driver Tens-digit A-segment driver Tens-digit F-segment driver Tens-digit E-segment driver Hundreds-digit D-segment driver Hundreds-digit B-segment driver Hundreds-digit F-segment driver Hundreds-digit E-segment driver Thousands-digit, B&C segments driver Negative-polarity driver LCD backplane driver (AME7106) Digital ground (AME7107) Hundreds-digit G-segment driver Hundreds-digit A-segment driver Hundreds-digit C-segment driver Tens-digit G-segment driver Low-battery flag segment driver Negative power supply voltage Integrator output. Connection point for integration capacitor. Integrator resistor connection-point. Auto-zero capacitor connection-point Analog-input low Analog-input high Analog-common AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Pin Description (Cont.) 40-pin DIP 40-pin DIP 44-pin PQFP Pin Number (Reverse) Pin Number 33 (8) 41 34 (7) 42 35 (6) 43 36 (5) 44 1 2 37 (4) 3 38 (3) 39 40 (2) (1) 4 5 6 7 Symbol Description CREFCREF+ VREF+ VREFDEEN INTEN TEST Reference capacitor, negative terminal Reference capacitor, positive terminal Analog-reference input, negative terminal Analog-reference input, positive terminal De-integration status flag Integration status flag Display-test pin, When pulled to V+, display should read -1888. See OSC1 Hold pin, Logic 1 holds display See OSC1 Pin OSC1, OSC2, OSC3 make up the oscillator. See Clock section for details OSC3 HOLD OCS2 OCS1 n Function Description 7 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power The A/D conversion has the following three phases: 1. Auto-Zero Phase 2. Integration Phase 3. De-integration Phase linearity errors. Care must be exercised to make sure the integrator output does not saturate. In a typical application, the common mode is eliminated by connecting the INLO to COM, Analog Common. Auto-Zero Phase Differential Reference (VREF+ & VREF-) The INHI and INLO are shorted to analog common internally. The reference capacitor is charged to the reference voltage. A feedback loop is closed around the system to cancel the offset voltage of buffer, integrator and comparator. The converter integrates the differential voltage across the INHI and INLO for a fixed time, 1000 system clocks. The polarity of the signal is determined at the end of this phase. The reference voltage can be generated anywhere within the V+ to V-. Under a large common mode voltage, reference capacitor can gain charge during the de-integration of a positive signal. The reference capacitor will lose charge when de-integrating a negative input signal. The difference in reference voltage for positive or negative input voltages can cause the rollover error. To prevent rollover error from being induced by large common-mode voltages, reference capacitor should be large compared to stray node capacitance. Reference Integration Phase Analog Common (COM) INLO is internally connected to the Analog Common, INHI is connected across the reference capacitor with appropriate polarity determined by the control circuit. The integrator output will then return to zero. The time it takes to return to zero, 1000 X VIN /VREF, is the digital representation of the analog signal. The Analog Common is to set a common mode voltage for the analog signal. The analog common is typically 3.0V below V+, set primary for the battery operated application. Analog common is capable to sink 20 mA. It’s source current is limited to 10 µA. Analog common is therefore easily pulled to a more negative voltage to override the internal reference. When supply voltage is greater than 7V, analog common can be used as reference source with temperature coefficient of typically 50 ppm/OC. The internal heating by the LED display drivers of the AME7107 may degrade the stability of the Analog Common. An external reference is recommended. Signal Integration phase Differential Signal Inputs (INHI & INLO) The AME7106/AME7107 has true differential inputs and accepts input signals within the input common mode voltage range (Vcm). Typical range is from 1V above the V- to 1V below the V+. The integrator output can swing within 0.3 V of V+ or V- without increasing 8 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power n Digital Block Diagrams 9 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Digital Section Digital Ground AME7106 generates an internal digital ground, typically 5V below the V+. The digital ground of AME7107 is supplied externally. Clock Circuit The clock can be generated in either of the following three methods. 1. An external oscillator connected to“OSC1” 2. A crystal between pins” OSC1” and “OOSC2” 3. A R-C oscillator using “OOSC1”, “OOSC2” and “OSC3” Notes: There is no on-chip feedback resister across osc1 and osc2. Systems Timing The oscillator frequency is divided by 4 prior to clocking the internal decade counters. Each conversion takes 4000 counts or 16000 oscillator clock pulses. The timing of each phase are as follows: 10 3-1/2 Digit A/D Converter High Accuracy, Low Power Auto-Zero Phase: 1000 to 3000 Counts Signal Integration Phase: 1000 Counts (Fixed) Reference Integration Phase : 0 to 2000 Counts For signals less than full-The A/D conversion has the following three phases:scale, the unused reference integration time is assigned to the autozero phase. Segment Drivers (AME7106) The backplane frequency is 1/800 of the oscillator clock frequency. For example if the oscillator frequency is 48 KHz (3 conversions per second) the backplane frequency will be 60 Hz. The segment and backplane are at the same frequency with a nominal 5 volt amplitude. The segment is visible (ON) when the segment and the backplane are out of phase, otherwise it is invisible (OFF). The polarity segment is “ON” for negative analog inputs. When the TEST pin on the AME7106 is pulled to V+, all segments are turned “ON”. The display reads -1888. During this mode the LCD segments have a constant DC voltage impressed. DO NOT LEAVE THE DISPLAY IN THIS MODE FOR MORE THAN SEVERAL MINUTES! LCD displays may be destroyed if operated with DC levels for extended periods. AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R Segment Drivers (AME7107) The AME7107 is designed to drive common anode LEDs. All segment drivers are N-channel transistors with a typically 8 mA current driving capability. The 1000’s segment AB4 sinks current from two LED segments, and has a 16 mA driving capability. The polarity indication is “on” when the analog input voltage is negative. Test When the TEST is pulled to V+ all segments and the minus sign will be activated. The TEST pin is tied to the internally generated digital ground through a 500Ω resistor in the AME7106. It is typically 5V lower than V+. TEST pin may be used as the negative power supply for external CMOS logic at the maximum current of 1 mA. 3-1/2 Digit A/D Converter High Accuracy, Low Power Integration Status (INTEN) The INTEN is an output signal of the converter, it is “high” during the signal integration phase. This signal can be used as a status indicator or a control to connect the analog signal to the converter for processing. It is available in 44 pin package. De-integration Status (DEEN) The DEEN is an output signal of the converter, it is “high” during the reference de-integration phase. The period of the DEEN is proportional to the conversion result. Users may calculate the conversion result by counting the number of clock pulse on the OSC3 pin when DEEN is “high”. The conversion result is equal to (N/4) - 1/2 where N is the number of the pulse at the OSC3 pin. It is available in 44 pin package. Data Hold When the Hold pin is connected to V+ the conversion result will not be updated. The conversion is still free running during the hold mode. It is available in 44 pin package. n Component Value Selection recommended for 2.0V full-scale applications. A mylar dielectric capacitor is adequate. Auto-Zero Capacitor (Caz) Reference Capacitor (Cref) The Caz capacitor size has some influence on system noise. A 0.47µF capacitor is recommended for 200 mV full-scale applications. A 0.047µF capacitor is A 0.1µF capacitor is acceptable when “INLO” is tied to analog common. If a large common-mode voltage 11 AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Component Value Selection Auto-Zero Capacitor (Caz) The Caz capacitor size has some influence on system noise. A 0.47µF capacitor is recommended for 200 mV full-scale applications. A 0.047µF capacitor is recommended for 2.0V full-scale applications. A mylar dielectric capacitor is adequate. Reference Capacitor (Cref) A 0.1µF capacitor is acceptable when “INLO” is tied to analog common. If a large common-mode voltage exists and the application requires 200 mV full-scale, increase Cref to 1.0 µF. A mylar dielectric capacitor is adequate. Integrating Capacitor (Cint) Cint should be selected to maximize the integrator output voltage swing without causing output saturation. A ±2V full-scale integrator output swing is recommended if “ANALOG COMMON” is used as signal reference. For 3 readings/second (fosc = 48 KHz) a 0.22 µF value is suggested. If a different oscillator frequency is used, Cint must be changed in inverse proportion to maintain the nominal 2V integrator swing. An exact expression for Cint is: Cint = [(4000)(1/fosc)(Vfs/Rint)] / Vint where: fosc= Oscillator clock frequency Vfs = Full-scale input voltage Rint = Integrating resistor Vint = Desired full-scale integrator output swing Cint must have low dielectric absorption to minimize rollover error. A polypropylene capacitor is recommended. Integrating Resistor (Rint) The input buffer amplifier and integrator both have a class A output stage with 100 µA quiescent current. The integrator and buffer can supply 20 µA drive currents with negligible linearity errors. Rint is chosen to keep the output stage in the linear region. For a 200mV full-scale, it is 47KΩ; 2.0V full-scale requires 470KΩ. Summary of component selection: F u ll s c a le 2 0 0 .0 m V 2 .0 0 0 V C az R in t 0 .4 7 µ F 47 KΩ 0 .0 4 7 µ F 470 KΩ C in t V re f 0 .2 2 µ F 1 0 0 .0 m V 0 .2 2 µ F 1 .0 0 0 V Note: fosc = 48 KHz 12 Oscillator Components R-C Oscillator A 100 KΩ Rosc is recommended for all frequencies. Cosc is selected by using the equation: fosc = 0.45/(RC) For fosc of 48KHz, Cosc is 100pF nominally. To achieve maximum line noise rejection, the signalintegrate period should be a multiple of line period. The optimum oscillator frequencies for 60 Hz and 50 Hz rejection are listed as follows: For 60 Hz rejection: 40KHz, 48KHz, 60KHz etc. For 50 Hz rejection: 40KHz, 50KHz, 66-2/3KHz etc. Reference Voltage Selection A full-scale reading (2000 counts) requires the input signal be twice the reference voltage. F u ll-S c a le V o lta g e V re f 2 0 0 .0 m V 2 .0 0 0 V 1 0 0 .0 m V 1 .0 0 0 V In some applications a scale factor other than unity may exist between a transducer output voltage and the required digital reading. Assume, for example, a pressure transducer output is 600 mV for 2000 Ib/in2. Rather than dividing the input voltage by three the reference voltage should be set to 300 mV. This permits the transducer input to be used directly. The integrator resistor would be 120KΩ. In some temperature and weighting system with variable tare, the offset reading can be generated by connecting the voltage transducer between INHI and COMMON and the variable offset voltage between COMMON and INLO. AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R Power Supplies The AME7107 is designed to work from ±5V supplies. However, if a negative supply is not available, it can be generated from the clock output with two diodes, two capacitors, and an inexpensive IC. The 7660 DC to DC converter may also be used to generate -5V from +5V. Low Battery Flag (LB) The low battery flag is set when the supply voltage (V+ to V-) is lower than seven volts, typical. Once the LB is set, the waveform of the LB will be out of phase with the BP (Back Plane) to turn on a low battery annunciator for AME7106; LB pin will be low (Ground) 3-1/2 Digit A/D Converter High Accuracy, Low Power for AME7107 and is capable to sink 8 mA to turn on a LED indicator. AME7107 Power Dissipation Reduction The AME7107 sinks the LED display current and this generates heat in the IC package. If the internal voltage reference is used, the fluctuating chip temperature can cause the display to change reading. The AME7107 package power dissipation can be reduced by reducing the LED common anode voltage. A typical LED has 1.8 volts across it, at 7mA. When its common anode is connected to +5V, the AME7107 13 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R output is at 3.2V. Maximum power dissipation is 8.1 mA X 3.2 V X 24 segments = 622mW. However, once the AME7107 output voltage is above two volts, the LED current is essentially constant as output voltage increases. Reducing the output voltage by 0.7V, results in 7.7mA of LED current, only a 5 percent reduction. Maximum power dissipation is only 7.7mA X 2.5V X 24 = 462 mW, a reduction of 26%. An output voltage reduction of 1 volt reduces LED current by 10% (7.3mA) power dissipation by 38%. (7.3mA X 2.2V X 24 = 385mW). There are two ways to reduce the power dissipation: either a 5.1 ohm resistor or a 1 Amp diode placed in series with the display (but not in series with the AME7107). The resistor will reduce the AME7107 output voltage, when all 24 segments are “ON”. When segments turn off, the output voltage will increase. The n Typical Applications 14 3-1/2 Digit A/D Converter High Accuracy, Low Power diode, on the other hand, will result in a relatively steady output voltage. In addition to limiting maximum power dissipation, the resistor reduces the change in power dissipation as the display changes. As fewer segments are “ON,” each “ON” output drops more voltage and current. For the best case of six segments (a “111” display) to worst case (a “1888” display) the resistor will change about 230 mW. While a circuit without the resistor will change about 470 mW. Therefore, the resistor will reduce the variation of power dissipation by about 50%. The change in LED brightness caused by the resistor is almost unnoticeable as more segments turn off. If steady display brightness is very important, a diode is recommended. AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power 15 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 16 3-1/2 Digit A/D Converter High Accuracy, Low Power AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 3-1/2 Digit A/D Converter High Accuracy, Low Power 17 AME, Inc. AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R 18 3-1/2 Digit A/D Converter High Accuracy, Low Power AME, Inc. 3-1/2 Digit A/D Converter High Accuracy, Low Power AME7106/AME7106A/AME7106R AME7107/AME7107A/AME7107R n Package Dimension PDIP-40 SYMBOLS A MILLIMETERS MIN MAX 0.150 0.165 INCHES MIN MAX 0.0059 0.0065 A1 B 0.072 (TYP) 0.0028 0.018(TYP) 0.0007 B1 D 0.050(TYP) 0.0020 2.049 2.074 0.0807 0.0817 E1 F e 0.540 0.555 0.0213 0.0219 EB 0.600 0.700 θ 0 o 15 0.600(TYP) 0.0236 0.100(TYP) 0.0039 o 0.0236 0.0276 o 15 0 o 19 www.ame.com.tw E-Mail: [email protected] Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. ã AME, Inc. , February 2002 Document: 1021-DS7106/7107-C U.S. Headquarter Corporate Headquarter Analog Microelectronics, Inc. AME, Inc. 3100 De La Cruz Blvd. Suite 201 Santa Clara, CA. 95054-2046 2F , 189 Kang-Chien Road, Nei-Hu District Taipei 114, Taiwan, R.O.C. Tel : (408) 988-2388 Fax: (408) 988-2489 Tel : 886 2 2627-8687 Fax : 886 2 2659-2989