TC818

TC818A Auto-Ranging Analog-to-Digital Converter with 3-1/2 Digit Display Features • Auto-Ranging Analog-to-Digital Converter with 3-1/2 Digit Display • Annunciator Outputs Permit Customizing of LCD • Auto-Range Operation for AC and DC Voltage and Resistance Measurements • Two User Selected AC/DC • Current Ranges: 20mA and 200mA • 22 Operating Ranges: 9 DC/AC Voltage • 4 AC/DC Current • 9 Resistance and Low Power Ohms • Display Hold Function • 3-1/2 Digit Resolution in Auto-Range Mode: 1/2000 • Extended Resolution in Manual Range Mode: 1/3000 • Internal AC-to-DC Conversion Op Amp • Triplex LCD Drive for Decimal Points, Digits, • Bar Graphs, and Annunciators • Continuity Detection and Piezoelectric Transducer Driver • Low Drift Internal Reference: 75ppm/°C • 9V Battery Operation: 10mW • Low Battery Detection and LCD Annunciator General Description The TC818A is an integrating analog-to-digital converter (ADC) with a 3-1/2 digit numeric LCD driver, automatic ranging, and single 9V battery operation. The numeric display provides 0.05% resolution and a full set of annunciators that spell out the TC818A's many operating modes. Automatic range selection is provided for both voltage (DC and AC) and ohms (high and low power) measurements. Expensive and bulky mechanical range switches are not required. Five full scale ranges are available, with automatic selection of external volt/ohm attenuators over a 1 to 10,000 range. Two current ranges, 20mA and 200mA, can be manually selected. The auto-range feature can be bypassed, allowing input attenuator selection through a single line input. During Manual mode operation, resolution is extended to 3000 counts full scale. Extended resolution is also available during 2000kΩ and 2000V full scale autorange operation. The extended range operation is indicated by a flashing 1 MSD and by the fully extended bar graph. The TC818A includes an AC-to-DC converter for AC voltage and current measurements. Only external diodes/resistors/capacitors are required. Other features include a Memory mode, low battery detection, display HOLD input, and continuity buzzer driver. The 3-1/2 digit numeric display includes a full set of annunciators. Decimal points are adjusted as automatic or manual range changes occur, and Voltage, Current, and Ohms Operating modes are displayed. Additional annunciators are activated for manual, auto, memory, HOLD, AC, low power ohms, and low battery conditions. The TC818A is available in a surface mounted 64-pin flat package. Combining a numeric display driver, single 9V battery operation, internal range switching, and compact surface mounting, the TC818A is ideal for advanced portable instruments. Device Selection Table Part Number TC818ACBU Package 64-Pin PQFP Operating Temperature Range 0°C to +70°C 2002 Microchip Technology Inc. DS21475B-page 1 © TC818A Package Type 64-Pin PQFP I DC(Ω)/ AC(LOΩ) RVIBUF RANGE RΩBUF DGND HOLD ACVH -MEM ADO VSS 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 NC CAZ 48 NC 47 CI 46 ACVL ADI NC CFI 1 2 3 4 5 6 7 8 9 LCD Segment Drives LCD Backplanes OHM 20mA BUZ XTAL1 XTAL2 RX 45 II 44 VI 43 VR4 VDISP BP1 BP2 TC818A 42 VR5 41 VR2 40 VR3 39 ΩR5 38 ΩR4 37 ΩR3 36 ΩR2 35 ΩR1 34 REFHI 33 CREFH BP3 10 LOΩ/A 11 Ω/V 12 k/m/ HOLD 13 BCP0 14 AGD0 15 FE0 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 FE1 FE2 AC/-/AUTO ANNUNC NC DEINT -MEM/BATT RMREFL AGD1 BCP1 BCP2 BCP3 AGD2 COM © DS21475B-page 2 CREFL VCC 2002 Microchip Technology Inc. © -MEM – HOLD LO W + AC LCD Bias 0.1µF BP1 BP2 BP3 20 19 18 FE1 AGD1 BCP1 10's 16 15 14 FE0 AGD0 BCP0 AUTO kΩ mVA Typical Application Resistance Input 11 12 7 8 9 10 27 50 RX VDISP Ω/V ANNUNC LOΩ/A RMREFL R7/100kΩ 2002 Microchip Technology Inc. 30 5 DEINT XTAL1 XTAL2 VCC VSS DGND 6 28 57 58 V Ω 200mA 3 20mA 200mA V OHM *Not required when Resistor Network is used. (See Applications Section for details.) I 2 63 Ω 20mA 32.768kHz (~ 33kHz) 39pF 9V ΩR5 (÷10,000) 22 21 13 25 26 24 23 k/m/ AC/–/ –MEM/ BCP3 FE2 AGD2 BCP2 HOLD AUTO BATT 100's Display 1000's Annunciators R8/220Ω (PTC) R6/100kΩ 31 0.1 µF 1.6385MΩ 39 ΩR4 (÷1,000) ΩR3 (÷100) Ohms Range Attenuator ΩR2 (÷10) SYNC Backplane Drivers 1's 163.85kΩ 38 Segment and Decimal Point Drive Positive Temperature Coefficient Resistor R3/16.385kΩ 37 Z1 R2/1638.5Ω 36 6.2V R1/163.85Ω 35 ΩR1 (÷1) II Current Input 45 20mA R15 9Ω D3 D4 TC818A 200mA R16 1Ω 200mA DC/AC or Ω/LOΩ RANGE 62 59 R13* 500kΩ Voltage R14/9.9MΩ 44 VR1 (÷1) Input R12/1.111MΩ 41 VR2 (÷10) R11/101kΩ 40 VR3 (÷100) Voltage Range Attenuator -MEM BUZ 61 4 Enable CAZ CI HOLD CFI CREFL CREFH COM REFHI Audio Transducer R10/10kΩ VR4 (÷1,000) VR5 (÷10,000) ADI 52 C1/1µF C2/0.22µF 56 ACVH 42 ADO 53 R21/2.2MΩ 43 R9/1kΩ ACVL RΩBUF RVIBUF 46 54 220 kΩ 55 150 kΩ COM 49 CAZ 0.1µF 47 60 51 32 29 34 163.85mV R22/470kΩ C4/1µF + – D2 R24/10kΩ D1 C5/1µF – + R26/3kΩ R27/2kΩ R23/10kΩ CINT R20 100kΩ 33 CREF 4.7µF R18/24kΩ RΩBUF RVIBUF HOLD C6 0.01µF R19/5kΩ TC818A VCC DS21475B-page 3 TC818A 1.0 ELECTRICAL CHARACTERISTICS *Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings* Supply Voltage ....................................................... 15V Analog Input Voltage ..................................VCC to V SS Reference Input Voltage..............................VCC to V SS Voltage at Pin 43 ................................. Common ±0.7V Power Dissipation ............................................800mW Operating Temperature Range................ 0°C to +70°C Storage Temperature Range .............. -65°C to +150°C TC818A ELECTRICAL SPECIFICATIONS Electrical Characteristics: VA = 9V, TA = +25°C, unless otherwise specified. Symbol Parameter Zero Input Reading Min -0000 -0001 -0000 RE Rollover Error — — — NL IIN EN Linearity Error Input Leakage Current Input Noise AC Frequency Error Open Circuit Voltage for Ohm Measurements Open Circuit Voltage for LO Ohm Measurements VCOM VCTC Analog Common Voltage Common Voltage Temperature Coefficient Display Multiplex Rate VIL Low Logic Input — — — — — — — 2.8 — — — Typ 0000 — 0000 — — — — — 20 ±1 ±5 570 285 3 — 100 — Max +0000 +0001 +0000 ±1 ±3 ±1 ±1 10 — — — 660 350 3.3 50 — 1 Count pA µ VP-P % % mV mV V ppm/°C Hz µA 20mA, AC, I, LOW Ω, HOLD Range, -MEM, OHMs (Relative to DGND, Pin 58) 20mA, AC, I, LOW Ω, HOLD Range, -MEM, OHMs (Relative to DGND, Pin 58) ANNUNC, DEINT: IL = 100µA ANNUNC, DEINT: IL = 100µA VCC to VSSA BW = 0.1 to 10Hz 40 to 500Hz Error 40 to 2000Hz Excludes 200Ω Range Excludes 200Ω Range (VCC - VCOM) Unit Digital Reading Digital Reading Digital Reading Counts Test Conditions 200mV Range without 10MΩ Resistor 200mV Range with 10MΩ Resistor 20mA and 200mA Range 200mV Range without 10MΩ Resistor 200mV Range with 10MΩ Resistor 20mA and 200mA Range Best Case Straight Line Logic 1 Pull-up Current — 25 — V VOL VOH Low Logic Output High Logic Output Buzzer Drive Frequency Low Battery Flag Voltage Operating Supply Current — — — 6.3 — DGND +0.1 VCC - 0.1 4 6.6 0.8 — — — 7 1.5 V V kHz V mA © DS21475B-page 4 2002 Microchip Technology Inc. TC818A 2.0 PIN DESCRIPTIONS PIN FUNCTION TABLE Symbol NC OHM 20mA BUZ No connection. Logic Input. “0” (Digital Ground) for resistance measurement. Logic Input. “0” (Digital Ground) for 20mA full scale current measurement. Buzzer. Audio frequency, 4kHz, output for continuity indication during resistance measurement. A noncontinuous 4kHz signal is output to indicate an input over range during voltage or current measurements. 32.768kHz Crystal Connection. 32.768kHz Crystal Connection. Sets peak LCD drive signal: VP - VDD -VDISP. VDISP may also be used to compensate for temperature variation of LCD crystal threshold voltage. LCD Backplane #1. LCD Backplane #2. LCD Backplane #3. LCD Annunciator segment drive for low ohms resistance measurement and current measurement. LCD Annunciator segment drive for resistance measurement and voltage measurement. LCD Annunciator segment drive for k (“kilo-Ohms”), m (“milliamps” and “millivolts”) and HOLD mode. Description The descriptions of the pins are listed in Table 2-1. TABLE 2-1: Pin Number (64-Pin PQFP) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 XTAL1 XTAL2 VDISP BP1 BP2 BP3 LOΩ/A Ω/V k/m/HOLD BCP0 LCD segment drive for “b,” “c” segments and decimal point of least significant digit (LSD). (One’s digit) AGD0 FE0 NC BCP1 AGD1 FE1 BCP2 AGD2 FE2 BCP3 AC/-/AUTO LCD segment drive for “a,” “g,” “d” segments of LSD. LCD segment drive for “f” and “e” segments of LSD. No connection. LCD segment drive for “b,” “c” segments and decimal point of 2nd LSD. LCD segment drive for “a,” “g,” “d” segments of 2nd LSD. LCD segment drive for “f” and “e” segments of 2nd LSD. LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD (hundred’s digit). LCD segment drive for “a,” “g,” “d” segments of 3rd LSD. LCD segment drive for “f,” “e” segments of 3rd LSD. LCD segment drive for “b,” “c” segments and decimal point of MSD, (thousand’s digit). LCD annunciator segment drive for AC measurements, polarity, and auto-range operation. -MEM/BATT LCD annunciator segment drive for AC for low battery indication and memory (relative measurement). ANNUNC Square wave output at the backplane frequency, synchronized to BP1. ANNUNC can be used to control display annunciators. Connecting an LCD segment to ANNUNC turns it on; connecting it to its backplane turns it off. Positive battery supply connection. Analog circuit ground reference point. Nominally 3V below VCC. De-integrate output. Ratiometric (resistance measurement) reference low voltage. Reference capacitor negative terminal CREF = 0.1µ f. Reference capacitor positive terminal CREF = 0.1µ f. Reference voltage for voltage and current measurement. Nominally 163.85mV. Standard resistor connection for 200Ω full scale. Standard resistor connection for 2000Ω full scale. 28 29 30 31 32 33 34 35 36 VCC COM DEINT RMREFL CREFL CREFH REFHI ΩR1 ΩR2 2002 Microchip Technology Inc. DS21475B-page 5 © TC818A TABLE 2-1: Pin Number (64-Pin PQFP) 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 PIN FUNCTION TABLE (CONTINUED) Symbol ΩR3 ΩR4 ΩR5 VR3 VR2 VR5 VR4 VI II ACVL CI NC CAZ RX CFI ADI ADO RΩBUF RVIBUF ACVH VSS DGND RANGE HOLD -MEM DC(Ω)/ AC(LOΩ) I NC Description Standard resistor connection for 20kΩ full scale range. Standard resistor connection for 200kΩ full scale range. Standard resistor connection for 2000kΩ full scale. Voltage measurement ÷ 100 attenuator. Voltage measurement ÷ 10 attenuator. Voltage measurement ÷ 10,000 attenuator. Voltage measurement ÷ 1000 attenuator. Unknown voltage input ÷ attenuator. Unknown current input. Low output of AC-to-DC converter. Integrator capacitor connection. Nominally 0.1µF. (Must have low dielectric absorption. Polypropylene dielectric suggested.) No connection. Auto-zero capacitor connection. Nominally 0.1µF. Unknown resistance input. Input filter connection. Negative input of internal AC-to-DC operational amplifier. Output of internal AC-to-DC operational amplifier. Active buffer output for resistance measurement. Integration resistor connection. Nominally 220kΩ. Active buffer output for voltage and current measurement. Integration resistor connection. Nominally 15kΩ. Positive output of AC-to-DC converter. Negative supply connection. Connect to negative terminal of 9V battery. Internal logic digital ground. Ground connection for the logic "0" level. Nominally 4.7V below VCC . Input to set manual operation and change ranges. Input to hold display. Connect to DGND to "FREEZE" display. Input to enter Memory Measurement mode for relative measurements. The two LSDs are stored and subtracted from future measurements. Input that selects AC or DC option during voltage/current measurements. For resistance measurements, the ohms or low power (voltage) ohms option can be selected. Input to select measurement. Connect to logic "0" (digital ground) for current measurement. No connection. 3.0 3.1 DETAILED DESCRIPTION Analog-to-Digital Converter (ADC) The TC818A includes an integrating ADC with autoranging resolution of 2000 counts and manual range resolution of 3000 counts. Figure 3-1 shows a simplified schematic of the analog section. In Auto-Ranging mode, internal logic will adjust the input voltage or ohms attenuators so that measurements will always be made in the appropriate range. Measurement ranges, logic control inputs, 3-1/2 digit LCD formatting, and other features are identical to the TC818A auto-ranging A/D converter. However, the TC818A is not pin compatible with, and is not a replacement for, the TC818A. A display annunciator output (ANNUNC) can be used to customize the LCD. ANNUNC is a square wave at the backplane frequency. Connecting an annunciator segment to the ANNUNC driver turns the segment on; connecting the segment to its backplane turns it off. © DS21475B-page 6 2002 Microchip Technology Inc. TC818A FIGURE 3-1: 0.1µF R7/100 kΩ Ohms Input R8/220 Ω (PTC) 0.1µF Ω RX 50 S12 V • 1/1 S21 DE • Ω S24Ω • 1/10k VCC 10k Ω VCC TC818A ANALOG SECTION TC818A R6/100kΩ RMREFL 31 R5/1.638M Ω Ω R5 39 R4/163.85k Ω ΩR4 38 R3/16385 Ω Ω• S25 1/1k Ω• S26 1/100 Ω• S27 1/10 S28 Ω • 1/1 S33 S32 S31 S30 S29 Ω • Ω • Ω • Ω • Ω• 1/1 1/10 1/1001/1k 1/10k VCC W+1 S10 S22 DE • Ω VCC ΩR3 37 ΩR2 36 ΩR1 35 S44 Ω • HI Ω 1.5Ω S43 + Ω • LOΩ 2.8V REF AMP – 1.5 kΩ + – R18/24k Ω Z1 6.2V R2/1638.5Ω R1/163.85Ω R19/5k Ω 29 Analog Cmmon 34 REFHI ≈163.85mV Current Input 20mA R15/9Ω II 45 D3 D4 200mA R16/1Ω Voltage Input R14/9.9 MΩ S22 DE • Ω VI 44 S1 V• V• V• V• 1/10 1/100 1/1 1/10k k S6 S7 S8 S9 S2 S3 S4 S5 AC-to-DC Converter Op Amp + – V•1/1 R13/500kΩ* *Not Required when Resistor Network is Used R12/1.11M Ω VR2 41 R11/101kΩ VR3 40 R10/10kΩ VR4 43 Common R9/1kΩ V•1/10 V•1/100 V•1/1k 33 CREFH S20 DE CREFH 0.1µF 32 CREFL S18 DE VR5 42 V•1/10k S19 DE+ Ω S11 4.7µF D1 D2 53 R22 470 kΩ + ADO Ω+AC S16 DE+ S17 DE51 CFI R24 C3 10kΩ +1µF R23 10kΩ C4 1µF C2 R21 2.2 MΩ ADI 52 S13 INT•( Ω + DC) R20/100kΩ C6 0.01µF R26 3kΩ R27/2kΩ 0.22µF ACVH 56 C1/1µF ACVH 46 S14 INT• Ω •ACΩ + Buffer S38 AZ – Comparator Integrator 49 55 RΩ RVI C BUF BUF AZ 220 0.01µF k Ω 150 Ω CAZ k 47 INT 0.01µF CINT + To Digital Section + S40 INT•Ω•ACΩ S39 S15 AZ – S35 Ω Ω S34Ω 54 RΩBUF S37 Ω INT+ Ω + DC RΩBUF 2002 Microchip Technology Inc. – DS21475B-page 7 © TC818A 3.2 Resistance, Voltage, Current Measurement Selection R8, a positive temperature coefficient resistor, and the 6.2V zener, Z1, provide input voltage protection during ohms measurements. The TC818A is designed to measure voltage, current, and resistance. Auto-ranging is available for resistance and voltage measurements. The OHM (Pin 2) and I (Pin 63) input controls are normally pulled internally to VCC. By tying these pins to DGND (Pin 58), the TC818A is configured internally to measure resistance, voltage, or current. The required signal combinations are shown in Table 3-1. TABLE 3-2: OHMS RANGE LADDER NETWORK Standard Resistance 163.85Ω (R1) 1638.5kΩ (R2) 16,385Ω(R3) 163,85Ω (R4) 1,638,500Ω (R5) Low Power Ohms Mode NO YES YES YES YES Full-Scale Range 200Ω 2000Ω 20kΩ 200kΩ 2,000kΩ TABLE 3-1: TC818A MEASUREMENT SELECTION LOGIC Function Select Pin 0 = Digital Ground 1 = Floating or Tied to VCC OHM (Pin 2) 0 0 1 1 I (Pin 63) 0 1 0 1 3.4 Selected Measurement Ratiometric Resistance Measurements Voltage Resistance Current Voltage Note 1: OHM and I are normally pulled internally high to VCC (Pin 28). This is considered a logic “1”. 2: Logic “0” is the potential at digital ground (Pin 58). The TC818A measures resistance ratiometrically. Accuracy is set by the external standard resistors connected to Pin 35 through 39. A Low Power Ohms mode may be selected on all but the 200Ω full scale range. The Low Power Ohms mode limits the voltage applied to the measured system. This allows accurate “incircuit” measurements when a resistor is shunted by semiconductor junctions. Full auto-ranging is provided. External precision standard resistors are automatically switched to provide the proper range. Figure 3-2 shows a detailed block diagram of the TC818A, configured for ratiometric resistance measurements. During the signal integrate phase, the reference capacitor charges to a voltage inversely proportional to the measured resistance, RX. Figure 3-3 shows that the conversion accuracy relies on the accuracy of the external standard resistors. Normally, the required accuracy of the standard resistances will be dictated by the accuracy specifications of the users end product. Table 3-3 gives the equivalent ohms per count for various full scale ranges to allow users to judge the required resistor for accuracy. 3.3 Resistance Measurements (Ohms and Low Power Ohms) The TC818A can be configured to reliably measure incircuit resistances shunted by semiconductor junctions. The TC818A Low Power Ohms Measurement mode limits the probe open circuit voltage. This prevents semiconductor junctions in the measured system from turning on. In the Resistance Measurement mode, the Ω/LO Ω (Pin 62) input selects the Low Power Ohms Measurement mode. For low power ohms measurements, Ω/LOΩ (Pin 62) is momentarily brought LOW to digital ground potential. The TC818A sets up for a low power ohms measurement, with a maximum open circuit probe voltage of 0.35V above analog common. In the Low Power Ohms mode, an LCD display annunciator, LOΩ, will be activated. On power-up, the Low Power Ohms mode is not active. If the Manual Operating mode has been selected, toggling Ω/LO Ω resets the TC818A back to the AutoRange mode. In Manual mode, the decision to make a normal or low power ohms measurement should be made before selecting the desired range. The low power ohms measurement is not available on the 200Ω full scale range. Open circuit voltage on this range is below 2.8V. The standard resistance values are listed in Table 3-2. TABLE 3-3: Full Scale Range 200k 2k 20k 200k 2M REFERENCE RESISTORS Reference Resistor 163.85 1638.5 16385 163,850 1,638,500 Ω/Count 0.1 1 10 100 1000 © DS21475B-page 8 2002 Microchip Technology Inc. TC818A FIGURE 3-2: RATIOMETRIC RESISTANCE MEASUREMENT FUNCTIONAL DIAGRAM 9V VSS R5/1638500 Ω R4/163850Ω R3/16385 Ω 39 38 37 S29 S30 S31 S32 S33 ÷10k ÷1k ÷100 ÷10 ÷1 VA Ohms Ω • HIΩ Low Ohms Ω • LO VCC REFHI 34 10kΩ 57 VCC 28 + R2/1638.5Ω 36 ~1.5kΩ R18 24kΩ ÷10k ÷1k ÷100 ÷10 ÷1 R1/163.85Ω 35 ~1.5kΩ Voltage Reference + – VCC -2.6V 5kΩ S24 S25 S26 S27 S28 R8 220Ω (PTC) 33 CREF 0.1µF 32 31 R6/100kΩ R7/100kΩ RX Unknown 50 V• S12 1 1 S18 S21 DE S13 INT • ( Ω + DC) DE DE • Ω DE • Ω S20 DE S19 29 S23 ≈ VCC -2.8V DE + Ω Analog Common TC818A Buffer S37 S36 S34 Ω Ω Ω S35 Ω Integrator Comparator RΩBUF 54 55 150kΩ 220kΩ 49 RVIBUF CAZ 0.1µF CINT 0.1µF 47 FIGURE 3-3: RESISTANCE MEASUREMENT ACCURACY SET BY EXTERNAL STANDARD RESISTOR Example: 200kΩ Full Scale Measurement VA =     0.64V for Ohms 0.32V for LO Ohms + VR 163.85k Ω (a ) VR = ------------------------------------------------ x0.64 163.85 + 220 + R X     RS 163.85kΩ CREF 100kΩ (b) VX = RX -------------------------------------------------------------- x0.64 163.85k Ω + 220 Ω + R X (c) “Ramp Up Voltage” = “Ramp Down Voltage” 220Ω VX Unknown RX To Analog Buffer . VX VX . . ----------------xT I = ----------------T DE ( RICI) ( RI C I ) Where: RI = Integrating Resistor, TI = Integrate Time CI = Integrating Capacitor, TDE = De-integrate Time (TDE) (d) RX = 163.85 TI Independent of RI, CI or Internal Voltage Reference 2002 Microchip Technology Inc. DS21475B-page 9 © TC818A 3.5 Voltage Measurement Resistive dividers are automatically changed to provide in range readings for 200mV to 2000V full scale readings (Figure 3-1). The input resistance is set by external resistors R14/R13. The divider leg resistors are R9R12. The divider leg resistors give a 200mV signal VI (Pin 44) for full scale voltages from 200mV to 2000V. For applications which do not require a 10mΩ input impedance, the divider network impedances may be lowered. This will reduce voltage offset errors induced by switch leakage currents. The minimum AC full scale voltage range is 2V. The DC full scale minimum voltage is 200mV. AC current measurements are available on the 20mA and 200mA full scale current ranges. 3.8 Conversion Timing The TC818A analog-to-digital converter uses the conventional dual slope integrating conversion technique, with an added phase that automatically eliminates zero offset errors. The TC818A gives a zero reading with a 0 volt input. The TC818A is designed to operate with a low cost, readily available 32.768kHz crystal. It serves as a timebase oscillator crystal in many digital clocks. (See External Crystal Sources.) The external clock is divided by two. The internal clock frequency is 16.348kHz, giving a clock period of 61.04µsec. The total conversion — auto-zero phase, signal integrate and reference de-integrate — requires 8000 clock periods or 488.3msec. There are approximately two complete conversions per second. The integration time is fixed at 1638.5 clock periods or 100msec. This gives rejection of 50/60Hz AC line noise. The maximum reference de-integrate time, representing a full scale analog input, is 3000 clock periods (183.1msec) during manual extended resolution operation. The 3000 counts are available in Manual mode, extended resolution operation only. In Auto-Ranging mode, the maximum de-integrate time is 2000 clock periods. The 1000 clock periods are added to the autozero phase. An auto-ranging or manual conversion takes 8000 clock periods. After a zero crossing is detected in the Reference De-integrate mode, the autozero phase is entered. Figure 3-4 shows the basic TC818A timing relationships. 3.6 Current Measurement The TC818A measures current only under manual range operation. The two user selectable, full scale ranges are: 20mA and 200mA. Select the current Measurement mode by holding the I input (Pin 63) LOW at digital ground potential. The OHM input (Pin 2) is left floating or tied to the positive supply. Two ranges are possible. The 20mA full scale range is selected by connecting the 20mA input (Pin 3) to digital ground. If left floating, the 200mA full scale range is selected. External current-to-voltage conversion resistors are used at the current input (II input, Pin 45). For 20mA measurements, a 10Ω resistor is used. The 200mA range requires a 1Ω resistor; full scale is 200mV. Printed circuit board trace resistance between analog common and R16 must be minimized. In the 200mA range, for example, a 0.05 trace resistance will cause a 5% current-to-voltage conversion error at II (Pin 45). The extended resolution measurement option operates during current measurements. To minimize rollover error, the potential difference between analog common (COM, Pin 29) and system common must be minimized. 3.7 AC-to-DC Measurements In voltage and current measurements, the TC818A can be configured for AC measurements. An on-chip operational amplifier and external rectifier components perform the AC-to-DC conversion. When power is first applied, the TC818A enters the DC Measurement mode. For AC measurements (current or voltage), AC/DC (Pin 62) is momentarily brought LOW to digital ground potential; the TC818A sets up for AC measurements, and the AC liquid crystal display annunciator activates. Toggling AC/DC LOW again returns the TC818A to DC operation. If the Manual Operating mode has been selected, toggling AC/DC resets the TC818A back to the AutoRange mode. In Manual mode operation, AC or DC should be selected first, then the desired range. © DS21475B-page 10 2002 Microchip Technology Inc. TC818A FIGURE 3-4: BASIC TC818A CONVERSION TIMING Signal INT Phase REF DEINT Phase TC818A Auto-Zero Phase Next Conversion Auto-Zero Cycle Extended Resolution Zero Crossing External Crystal = 32.768kHz Internal Clock Period = tP = 2/32.768 = 61.04µsec Total Conversion Time = tCONV = 8000(tP) = 488.3msec ≈ 2 conv/sec Integration Time = TI = 1638.5(tP) = 100msec Min. Auto-Zero Time 3361.5tP Fixed 1638.5tP tI *Max. 3000tP tDE µ To Input Signal Maximum Reference De-integrate Time = tDE 3000(tP) = 183.1msec (manual extended resolution) = 2000(tP) = 122.1msec (auto-range) Maximum Auto-Zero Time = (8000 - 3000 - 1638.5) (tP) = 205.1msec (manual extended resolution) = (8000 - 3000 - 1638.5) (tP) = 205.1msec (manual extended resolution) tCONV = 8000tP *In Auto-Range Operation, Maximum is 2000tP and minimum Auto-Zero Time is 4361.5tP 3.9 Manual Range Selection FIGURE 3-5: The TC818A voltage and resistance auto-ranging feature can be disabled by momentarily bringing RANGE (Pin 59) to digital ground potential (Pin 58). When the change from auto-to-manual ranging occurs, the first manual range selected is the last range in the AutoRanging mode. The TC818A power-up circuit initially selects autorange operation. Once the manual range option is entered, range changes are made by momentarily grounding the RANGE control input. The TC818A remains in the Manual Range mode until the measurement function (voltage or resistance), or measurement option (AC/DC, Ω/LOΩ) changes. This causes the TC818A to return to auto-ranging operation. The “Auto” LCD annunciator driver is active only in the Auto-Range mode. Figure 3-5 shows typical operation where the manual range selection option is used. Also shown is the extended resolution display format. Also, see Figure 3-6 and Figure 3-7. MANUAL RANGE SELECTION RESISTANCE MEASUREMENTS Manual Range Select Continuity Indicator Output 4kHz Audio Frequency Continuous 4kHz Buzzer Yes Is RX < 19 ? No Is RX > 3000 ? No Is RX > 2000 ? No Display True Reading *Mode also operates when Auto-Ranging Operator is selected and 2MΩ < RX < 2.999MΩ. Yes* Yes Over Range Indicator Display "1" 000 "1" = > Flashing MSD Display Last 3 Digits and Flash MSD Extended Resolution Feature 2002 Microchip Technology Inc. DS21475B-page 11 © TC818A FIGURE 3-6: MANUAL RANGE SELECTION CURRENT MEASUREMENTS FIGURE 3-7: MANUAL RANGE SELECTION VOLTAGE MEASUREMENTS Range Select Noncontinuous Yes Output 4kHz Audio Frequency Over Range Indicator Is IX > 3000 ? No Yes Display "1" 000 "1" = > Flashing MSD Yes Display Last 3 Digits and Flash MSD Range Select Noncontinuous Output 4kHz Audio Frequency Over Range Indicator Is VX > 3000 ? No Is VX > 2000 ? No Display True Reading Yes Display "1" 000 "1" = > Flashing MSD Yes Display Last 3 Digits and Flash MSD Extended Resolution Feature Is IX > 2000 ? No Display True Reading 3.10 Extended Resolution Manual Operation When operated in the Manual Range mode, the TC818A extends resolution by 50% for current, voltage, and resistance measurements. Resolution increases to 3000 counts from 2000 counts. The extended resolution feature operates only in the 2000kΩ and 2000V ranges during auto-range operation. In the Extended Resolution Operating mode, readings above 1999 are displayed with a blinking “1” most significant digit. The blinking “1” should be interpreted as the digit 2. The three least significant digits display data normally. The bar graph LCD will be fully extended. An input over range condition causes the most significant digit (MSD) to blink and sets the three least significant digits (LSDs) to display “000.” The buzzer output is enabled for input voltage and current signals with readings greater than 2000 counts in both manual and auto-range operations. For resistance measurements, the buzzer signal does not indicate an over range condition. The buzzer is used to indicate continuity. Continuity is defined as a resistance reading less than 19 counts. © DS21475B-page 12 2002 Microchip Technology Inc. TC818A 3.11 -MEM Operating Mode Bringing -MEM (Pin 61) momentarily LOW configures the TC818A “-MEM” Operating mode. The -MEM LCD annunciator becomes active. In this Operating mode, subsequent measurements are made relative to the last two digits (≤99) displayed at the time MEM is LOW. This represents 5% of full scale. The last two significant digits are stored and subtracted from all the following input conversions. The following examples clarify operation: The “-MEM” Operating mode can be very useful in resistance measurements when lead length resistance would cause measurement errors. 3.12 Automatic Range Selection Operation When power is first applied, the TC818A enters the auto-range operating state. The Auto-Range mode may be entered from Manual mode by changing the measurement function (resistance or voltage), or by changing the measurement option (AC/DC, Ω/LOΩ). The automatic voltage range selection begins on the most sensitive scale first: 200mV for DC or 2V for AC measurements. The voltage range selection flow chart is shown in Figure 3-8. Internal input protection diodes to VCC (Pin 28) and VSS (Pin 57) clamp the input voltage. The external 10MΩ input resistance (see R14 and R13 of Functional diagram) limits current safely in an over range condition. The voltage range selection is designed to maximize resolution. For input signals less than 9% of full scale (count reading 2000 ? N = N +1 No Yes No Display Voltage (V)X No RX > 2000 K = K +1 N=4 ? Yes Extended Resolution No Display "1" XXX Flash MSD Activate Buzzer Over Range No N = N +1 ? K = K +1 Yes N=4 ? Yes Display "1" XXX Flash MSD Over Range No Display "1" 000 Flash MSD VX > 3000 ? Yes RX > 3000 ? Yes Extended Resolution Display "1" 000 Flash MSD Start: Power-on, Function or Measurement Option Change Start: Power-on, Function or Measurement Option Change © DS21475B-page 14 2002 Microchip Technology Inc. TC818A 3.13 Low Battery Detection Circuit The TC818A contains a low battery detector. When the 9V battery supply has been depleted to a 7V nominal value, the LCD low battery annunciator is activated. The low battery detector is shown in Figure 3-10. The low battery annunciator remains OFF with the battery supply greater than 0.7V. The annunciator is ON before the supply battery has reached 6.3V. The TC818A internally generates two intermediate LCD drive potentials (VH and VL) from a resistive divider (Figure 3-11) between VCC and VDISP. The latter impedance is approximately 150kΩ. This drive method is commonly known as 1/3 bias. With VDISP connected to digital ground, VP ≈ 5.0V. The intermediate levels are needed so that drive signals giving RMS “ON” and “OFF” levels can be generated. Figure 3-12 shows a typical drive signal and the resulting waveforms for “ON” and “OFF” RMS voltage levels across a selected LCD element. FIGURE 3-10: LOW BATTERY DETECTOR Low Battery Detector FIGURE 3-11: VCC R1 VT R3 – R2 VZ ≈ 6.2V R2 = 6.2V VT = 73 R1 + R 2 Comparator + To LCD Annunciator Selection Logic 1/3 BIAS LCD DRIVE VCC TC818A 50k To Triplex Segment Drive Logic VH 50k VL 50k See VDSIP For Proper VP with Resistive Divider VDISP VSS Low Battery Annunciator Displayed for VS < 7V. TC818A 3.14 Triplex Liquid Crystal Display (LCD) Drive The TC818A directly drives a triplexed liquid crystal display (LCD) using 1/3 bias drive. All numeric data, decimal point, polarity and function annunciator drive signals are developed by the TC818A. The LCDs must be driven with an AC signal having zero DC component, for long display life. The liquid crystal polarization is a function of the RMS voltage appearing across the backplane and segment driver. The peak drive signal applied to the LCD is: VCC - VDISP For example, if V DISP is set at a potential 3V below VCC, the peak drive signal is: VP = VCC - VDISP = 3V An “OFF” LCD segment has an RMS voltage of VP/3 across it, or 1 volt. An “ON” segment has a 0.63V P signal across it or 1.92V for V CC -V DISP = 3V. Since the VDISP pin is available, the user may adjust the “ON” and “OFF” LCD levels for various manufacturers’ displays, by changing V P signal across it, or 1.92V for V DISP = 3V. “OFF” segments may become visible at high LCD operating temperatures. A voltage with a -5 to -20mV/°C temperature coefficient can be applied to VDISP to accommodate the liquid crystal temperature operating characteristics, if necessary. VP = VCC - VDISP "OFF" = VP/3 RMS "ON" = 11 VP RMS 33 3.15 Liquid Crystal Displays (LCDs) Most users will design their own custom LCD. However, for prototyping purposes, a standard display is available from Varitronix, Ltd. This prototype display configuration is shown in Figure 3-13 and Table 3-4. Varitronix Ltd. 9/F Liven House, 61-63, King Yip Street Kwun Tong, Hong Kong Tel: (852)3-410286 Fax: (852)34-39555 Part No.: VIM-328-DP USA Office: VL Electronics, Inc. 3171 LOs Feliz Blvd, #303 Los Angeles, CA 90039 Tel: (213) 738-8700 2002 Microchip Technology Inc. DS21475B-page 15 © TC818A FIGURE 3-12: TRIPLEX LCD DRIVE WAVEFORMS TC818A Backplanes Segments 1 2 3 4 5 6 Segments 1 VP VH 2 3 4 5 6 Applied RMS Voltage VP (3V) a (FE – BP1) "ON" BP1 VP VH VL 0 -VL -VH -VP VRMS = 11 V P 33 b (BCP – BP1) "ON" BP2 0 VP VH VL BP3 0 c (BCP – BP2) "ON" Waveforms to Generate d (AGD – BP3) "ON" VP VH VL 0 -VL -VH -VP VP VH VL 0 -VL -VH -VP VP VH VL 0 -VL -VP VP VH VL 0 -VL -VP VP VH VL -VL -VP VP VH VL 0 -VL -VH -VP VRMS = 11 V P 33 VRMS = 11 V P 33 VRMS = 11 V P 33 e (FE – BP2) "OFF" VRMS = VP 3 a f g e c d b BP1 BP3 FE AGD BCP BACKP BP2 LANES f (FE – BP1) "OFF" VRMS = VP 3 g (AGD – BP2) "ON" VRMS = 11 V P 33 © DS21475B-page 16 2002 Microchip Technology Inc. TC818A 3.16 External Crystal FIGURE 3-13: The TC818A is designed to operate with a 32,768Hz crystal. This frequency is internally divided by two to give a 61.04µsec clock period. One conversion takes 8000 clock periods or 488.3msec ( ≈ 2 conversions/ second). Integration time is 1638.5 clock periods or 100msec. The 32kHz quartz crystal is readily available and inexpensive. The 32kHz crystal is commonly used in digital clocks and counters. Several crystal sources exist. A partial listing is: • Statek Corporation 512 N. Main Orange, CA 92668 (714) 639-7810 TWX: 910-593-1355 TELEX: 67-8394 • Fox Electronics 5570 Enterprise Parkway Fort Myers, FL 33905 (941) 693-0099 Contact manufacturer for full specifications. TYPICAL LCD CONFIGURATION, TC818A TRIPLEX -MEM –+ HOLD LO W kΩ mVA AC AUTO TABLE 3-4: PAD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 TYPICAL LCD CONFIGURATION BP1 — X0 X5 X6 X11 X12 X17 X18 X23 X24 X29 X30 X35 X36 — BPI — — BP2 — X1 X4 X7 X10 X13 X16 X19 X22 X25 X28 X31 X34 X37 X40 — BP2 — BP3 SCALE X2 X3 X8 X9 X14 X15 X20 X21 X26 X27 X32 X33 X38 X39 — — BP3 PAD 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 BP1 — — BP1 — — HOLD 4B 4A 4F 3B 3A 3F 2B 2A 2A 1B Z AC BP2 — BP2 — LOW W k 4C 4G 4E 3C 3G 3E 2C 2G 2G 1G -MEM y BP3 BP3 — — A V m — 4D — 3P 3D — 2P 2D 2D 1P — AUTO 2002 Microchip Technology Inc. DS21475B-page 17 © TC818A 3.17 “Buzzer” Drive Signal The BUZ output (Pin 4) will drive a piezo electric audio transducer. The signal is activated to indicate an input over range condition for current and voltage measurements, or continuity during resistance measurements. During a resistance measurement, a reading less than 19 on any full scale range causes a continuous 4kHz signal to be output. This is used as a continuity indication. A voltage or current input measurement over range is indicated by a noncontinuous 4kHz signal at the BUZ output. The LCD most significant digit also flashes and the three least significant digits are set to display zero. The buzzer drive signal for over range is shown in Figure 3-14. The BUZ output is active for any reading over 2000 counts in both manual and auto-range operation. The buzzer is activated during an extended resolution measurement. The BUZ signal swings from V CC (Pin 28) to DGND (Pin 58). The signal is at V CC when not active. The BUZ output is also activated for 15ms whenever a range change is made in auto-range or manual operation. Changing the type of measurement (voltage, current, or resistance), or measurement option (AC/DC, Ω/LO Ω), also activates the buzzer output for 15msec. A range change during a current measurement will not activate the buzzer output. FIGURE 3-14: TC818A TIMING WAVEFORM FOR BUZZER OUTPUT 122ms 122ms VCC Digital Ground 1 Conversion 4kHz Signal 122ms 122ms 610ms 122ms Power-up VIN = 250mV 4000 Noncontinuous Buzzer Signal Indicates Input Over Range Change Range Change Range Change Range Change Input VIN = 3.2V 8000 12000 1000 Clock Pulses INT Integrate TSC818A Signals DEINT AZ 100ms 1638.5 CP 122ms 2000 CP 250CP 250CP 2500CP 250CP 3000CP Auto-Ranging 200mV Range Over Range 4kHz 2V Range In Range 2V Range In Range Manual Range 200mV Range Extended Range 2V Range In Range 4kHz 4kHz 610ms Buzzer Activated due to Previous Conversion Over Range 2V Range Out of Range BUZ (Pin 4) 4kHz 15ms One Cycle of Over Range Buzzer 15ms 15ms Due to Manual Due to Range Change Range Change Buzzer Activated due to Power-up 122ms Buzzer Activated due to Previous Conversion Over Range © DS21475B-page 18 2002 Microchip Technology Inc. TC818A Vendors for piezo electric audio transducers are: • Gulton Industries Piezo Products Division 212 Durham Avenue Metuchen, New Jersey 08840 (201) 548-2800 Typical P/Ns: 102-95NS, 101-FB-00 • Taiyo Yuden (USA) Inc. Arlington Center 714 West Algonquin Road Arlington Heights, Illinois 60005 Typical P/Ns: CB27BB, CB20BB, CB355BB 3.20 3.20.1 Component Selection INTEGRATION RESISTOR SELECTION The TC818A automatically selects one of two external integration resistors. RVIBUF (Pin 55) is selected for voltage and current measurement. RΩBUF (Pin 54) is selected for resistance measurements. 3.20.2 RVIBUF SELECTION (PIN 55) 3.18 Display Decimal Point Selection The TC818A provides a decimal point LCD drive signal. The decimal point position is a function of the selected full scale range, as shown in Table 3-5. In auto-range operation, the TC818A operates with a 200mV maximum full scale potential at VI (Pin 44). Resistive dividers at VR2 (Pin 41), VR3 (Pin 40), VR4 (Pin 43), and VR5 (Pin 42) are automatically switched to maintain the 200V full scale potential. In Manual mode, the Extended Operating mode is activated, giving a 300mV full scale potential at VI (Pin 44). The integrator output swing should be maximized, but saturations must be avoided. The integrator will swing within 0.45V of VCC (Pin 28) and 0.5V of VSS (Pin 57) without saturating. A ±2V swing is suggested. The value of RVIBUF is easily calculated, assuming a worst case extended resolution input signal: Where: VINT = Integrator swing = ±2V tI CI = Integration time = 100msec = Integration capacitor = 0.1µF TABLE 3-5: Full Scale Range DECIMAL POINT SELECTION 1*9 DP3 *9 DP2 OFF OFF ON OFF OFF OFF ON OFF *9 DP1 OFF ON OFF OFF ON ON OFF ON 2000V, 2000kΩ 200V, 200kΩ 20V, 20kΩ 2V, 2kΩ 200V, 200Ω 200mV, 200Ω 20mA 200mA OFF OFF OFF ON OFF OFF OFF OFF VMAX = Maximum input at VI = 300mV EQUATION 3-1: RVIBUF = VMAX(T I) = 150k Ω VINT(CI) 3.19 AC-to-DC Converter Operational Amplifier 3.20.3 The TC818A contains an on-chip operational amplifier that may be connected as a rectifier for AC-to-DC voltage and current measurements. Typical operational amplifier characteristics are: • • • • Slew Rate: 1V/µsec Unity Gain Bandwidth: 0.4MHz Open Loop Gain: 44dB Output Voltage Swing (Load = 10kΩ) ± 1.5V (Referenced to Analog Common) RΩBUF SELECTION (PIN 54) In ratiometric resistance measurements, the signal at RX (Pin 50) is always positive, with respect to analog common. The integrator swings negative. The worst case integrator swing is for the 200Ω range with the manual, extended resolution option. The input voltage, VX (Pin 50) is easily calculated (see Figure 3-15). When the AC measurement option is selected, the input buffer receives an input signal through switch S14, rather than switch S11 (see Figure 3-1). With external circuits, the AC Operating mode can be used to perform other types of functions within the constraints of the internal operational amplifier. External circuits that perform true RMS conversion, or a peak hold function, are typical examples. 2002 Microchip Technology Inc. DS21475B-page 19 © TC818A FIGURE 3-15: VCC = 9V SW33 R Ω CALCULATION (200Ω MANUAL OPERATION) 3.21 Capacitors - CINT, CAZ and C REF RS ≈ 600Ω The integration capacitor, CINT, must have low dielectric absorption. A 0.1µF polypropylene capacitor is suggested. The auto-zero capacitor, CAZ, and reference capacitor, CREF, should be selected for low leakage and dielectric absorption. Polystyrene capacitors are good choices. 3.22 R1 Reference Voltage Adjustment 163.85Ω R2 220Ω VX The TC818A contains a low temperature drift internal voltage reference. The analog common potential (Pin 29) is established by this reference. Maximum drift is a low 75ppm/°C. Analog common is designed to be approximately 2.6V below VCC (Pin 28). A resistive divider (R18/R19, Functional Diagram) sets the TC818A reference input voltage (REFHI, Pin 34) to approximately 163.85mV. With an input voltage near full scale on the 200mV range, R19 is adjusted for the proper reading. R3 300Ω 3.23 Analog Common = VCC – 3V Display Hold Feature Where: VANCOM RS RI RX RS = = = = = Potential at Analog Common ≈ 2.7V 220Ω 163.85Ω 300Ω Internal switch 33 resistance ≈ 600Ω The LCD will not be updated when HOLD (Pin 60) is connected to GND (Pin 58). Conversions are made, but the display is not updated. A HOLD mode LCD annunciator is activated when HOLD is low. The LCD HOLD annunciator is activated through the triplex LCD driver signal at Pin 13. 3.24 Flat Package Socket EQUATION 3-2: RΩBUF = (V CC – VANCOM)RX (RX + RS + R 1 + R8) = 0.63V Sockets suitable for prototype work are available. A USA source is: • Nepenthe Distribution 2471 East Bayshore, Suite 520 Palo Alto, CA 94303 (415) 856-9332 TWX: 910-373-2060 “CBQ” Socket, Part No. IC51-064-042 For a 3.1V integrator swing, the value of RΩBUF is easily calculated: Where: VINT TI CI R XMAX VXMAX = = = = = Integrator swing = 3.1V Integration time = 100msec Integration capacitor = 0.1µF 300Ω 700mV 3.25 Resistive Ladder Networks Resistor attenuator networks for voltage and resistance measurements are available from: • Caddock Electronics 1717 Chicago Avenue Riverside, CA 92507 Tel: (714) 788-1700 TWX: 910-332-6108 EQUATION 3-3: RΩBUF = VXMAX(TI) CI(VINT) = 200kΩ With a low battery voltage of 6.6V, analog common will be approximately 3.6V above the negative supply terminal. With the integrator swinging down from analog common toward the negative supply, a 3.1V swing will set the integrator output to 0.5V above the negative supply. TABLE 3-6: Attenuator Accuracy 0.1% 0.25% 0.25% RESISTIVE LADDER NETWORKS Attenuator Type Voltage Voltage Resistance Caddock Part Number 1776-C441 1776-C44 T1794-204-1 © DS21475B-page 20 2002 Microchip Technology Inc. TC818A 4.0 4.1 PACKAGING INFORMATION Package Marking Information Package marking data not available at this time. 4.2 Taping Form Component Taping Orientation for 64-Pin PQFP Devices User Direction of Feed PIN 1 W P Standard Reel Component Orientation for TR Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 64-Pin PQFP 32 mm 24 mm 250 13 in Note: Drawing does not represent total number of pins. 4.3 Package Dimensions 64-Pin PQFP PIN 1 .018 (0.45) .012 (0.30) .009 (0.23) .005 (0.13) 7° MAX. .041 (1.03) .031 (0.78) .555 (14.10) .547 (13.90) .687 (17.45) .667 (16.95) .031 (0.80) TYP. .555 (14.10) .547 (13.90) .687 (17.45) .667 (16.95) .010 (0.25) TYP. .120 (3.05) .100 (2.55) .130 (3.30) MAX. Dimensions: mm (inches) 2002 Microchip Technology Inc. DS21475B-page 21 © TC818A SALES AND SUPPORT Data Sheets Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following: 1. 2. 3. Your local Microchip sales office The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277 The Microchip Worldwide Site (www.microchip.com) Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. New Customer Notification System Register on our web site (www.microchip.com/cn) to receive the most current information on our products. © DS21475B-page 22 2002 Microchip Technology Inc. TC818A Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical components in life support systems is not authorized except with express written approval by Microchip. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, FilterLab, KEELOQ, microID, MPLAB, PIC, PICmicro, PICMASTER, PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company’s quality system processes and procedures are QS-9000 compliant for its PICmicro ® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001 certified. 2002 Microchip Technology Inc. DS21475B-page 23 © WORLDWIDE SALES AND SERVICE AMERICAS Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com ASIA/PACIFIC Australia Microchip Technology Australia Pty Ltd Suite 22, 41 Rawson Street Epping 2121, NSW Australia Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 Japan Microchip Technology Japan K.K. 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Unit 901-6, Tower 2, Metroplaza 223 Hing Fong Road Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 Italy Microchip Technology SRL Centro Direzionale Colleoni Palazzo Taurus 1 V. Le Colleoni 1 20041 Agrate Brianza Milan, Italy Tel: 39-039-65791-1 Fax: 39-039-6899883 Toronto 6285 Northam Drive, Suite 108 Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 India Microchip Technology Inc. India Liaison Office Divyasree Chambers 1 Floor, Wing A (A3/A4) No. 11, O’Shaugnessey Road Bangalore, 560 025, India Tel: 91-80-2290061 Fax: 91-80-2290062 United Kingdom Arizona Microchip Technology Ltd. 505 Eskdale Road Winnersh Triangle Wokingham Berkshire, England RG41 5TU Tel: 44 118 921 5869 Fax: 44-118 921-5820 03/01/02 © DS21475B-page 24 2002 Microchip Technology Inc. *B57412SD*