1、9-15Features CMOS Design for Very Low Power Output Drivers Directly Drive Both Digits andSegments of Large 8-Digit LED Displays Measures Frequencies from DC to 10MHz; Periodsfrom 0.5s to 10s Stable High Frequency Oscillator uses either 1MHz or10MHz Crystal Both Common Anode and Common Cathode Availa
2、ble Control Signals Available for External SystemsInterfacing Multiplexed BCD OutputsApplications Frequency Counter Period Counter Unit Counter Frequency Ratio Counter Time Interval CounterDescriptionThe ICM7226 is a fully integrated Universal Counter andLED display driver. It combines a high freque
3、ncy oscillator, adecade timebase counter, an 8-decade data counter andlatches, a 7-segment decoder, digit multiplexer and segmentand digit drivers which can directly drive large LED displays.The counter inputs accept a maximum frequency of 10MHzin frequency and unit counter modes and 2MHz in the oth
4、ermodes. Both inputs are digital inputs. In many applications,amplification and level shifting will be required to obtainproper digital signals for these inputs.The ICM7226 can function as a frequency counter, periodcounter, frequency ratio (fA/fB) counter, time interval counteror as a totalizing co
5、unter. The devices require either a10MHz or 1MHz quartz crystal timebase, or if desired anexternal timebase can also be used. For period and timeinterval, the 10MHz timebase gives a 0.1s resolution. Inperiod average and time interval average, the resolution canbe in the nanosecond range. In the freq
6、uency mode, theuser can select accumulation times of 0.01s, 0.1s, 1s and10s. With a 10s accumulation time, the frequency can be dis-played to a resolution of 0.1Hz. There is 0.2s between mea-surements in all ranges. Control signals are provided toenable gating and storing of prescaler data.Leading z
7、ero blanking has been incorporated with frequencydisplay in kHz and time in s. The display is multiplexed at a500Hz rate with a 12.2% duty cycle for each digit. TheICM7226A is designed for common anode displays with typi-cal peak segment currents of 25mA, and the ICM7226B isdesigned for common catho
8、de displays with typical segmentcurrents of 12mA. In the display off mode, both digit driversand segment drivers are turned off, allowing the display tobe used for other functions.Ordering InformationPART NUMBERTEMP.RANGE (oC) PACKAGEPKG.NO.ICM7226AlJL -25 to 85 40 Ld CERDIP F40.6ICM7226BlPL -25 to
9、85 40 Ld PDIP E40.6August 1997ICM7226A,ICM7226B8-Digit, Multi-Function,Frequency Counter/TimerFile Number 3169.1CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.http:/ or 407-727-9207 | Copyright Intersil Corporation 19999-16PinoutsICM7226ACOMMON
10、ANODE (CERDIP)TOP VIEWICM7226BCOMMON CATHODE (PDIP)TOP VIEWNOTE:1. For maximum frequency stability, connect to VDDor VSS.CONTROL INPUTINPUT BFUNCTIONSEG eSEG gSEG aVSSSEG dSEG bSEG cSEG fRST INPUTEXT DP ININPUT ABUF OSC OUTOSC OUTEXT RANGED1D3D5VDDD6D7D8HOLDD2D4STORE131234567891011121415161718192028
11、40393837363534333231302927262524232221 RANGEOSC INNC (NOTE 1)NC (NOTE 1)EXT OSC INRST OUTMEASUREMENT IN PROGRESSBCD 2BCD 1BCD 4BCD 8DPCONTROL INPUTINPUT BFUNCTIOND3D2D4VSSD5D6D7D8RST INPUTEXT DP ININPUT ABUF OSC OUTOSC OUTEXT RANGEDP OUTSEG eSEG dVDDSEG bSEG cSEG fHOLDSEG gSEG aSTORE1312345678910111
12、2141516171819202840393837363534333231302927262524232221 RANGEOSC INNC (NOTE 1)NC (NOTE 1)EXT OSC INRST OUTMEASUREMENT IN PROGRESSBCD 2BCD 1BCD 4BCD 8D1ICM7226A, ICM7226B9-17Functional Block DiagramSTOREAND RESETREFERENCEDIGITDECODEROSC 104ORRANGECONTROLDPDECODERSEGMENTINPUTINPUTFNMAINDRIVERSCOUNTER+
13、103LOGICFFCONTROLLOGICCONTROLLOGICCONTROLLOGICDATA LATCHESOUTPUT MUXMAIN103SELECTCONTROLLOGICLOGICDRIVERSAND LZBFUNCTIONINPUTDCLENCLOVERFLOWSTORE100HzQHOLDINPUTINPUT BSEGMENTOUTPUTSEXTDPINPUTCONTROLINPUTDIGITOUTPUTS(8)(8)38 856478644444444LOGICRANGESELECTLOGIC105EXT RANGEINPUTLOGIC4 4MEAS INPROGRESS
14、OUTPUTRANGEINPUTEXT OSCINPUTOSCINPUTBUF OSCOUTPUTRESETINPUTINPUT AOSCOUTPUTCOUNTERRESETBCDOUTPUTS(4)RESETOUTPUTSTOREOUTPUT8RICM7226A, ICM7226B9-18Absolute Maximum Ratings Thermal InformationMaximum Supply Voltage (VDD- VSS). . . . . . . . . . . . . . . . . . . .6.5VMaximum Digit Output Current. . .
15、. . . . . . . . . . . . . . . . . . . . .400mAMaximum Segment Output Current . . . . . . . . . . . . . . . . . . . . .60mAVoltage On Any Input orOutput Terminal (Note 1) . . . . . . . . . . . . . . VDD+0.3V to VSS-0.3VOperating ConditionsTemperature Range . . . . . . . . . . . . . . . . . . . . . .
16、. . . . -25oC to 85oCThermal Resistance (Typical, Note 2) JA(oC/W) JC(oC/W)CERDIP Package . . . . . . . . . . . . . . . . 45 9PDIP Package . . . . . . . . . . . . . . . . . . . 50 N/AMaximum Junction TemperatureCERDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175oCPDIP
17、Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150oCMaximum Storage Temperature Range . . . . . . . . . .-55oC to 150oCMaximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oCCAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause p
18、ermanent damage to the device. This is a stress only rating and operationof the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.NOTES:1. Destructive latchup may occur if input signals are applied before the power supply i
19、s established or if inputs or outputs are forced tovoltages exceeding VDDor VSSby 0.3V.2. JAis measured with the component mounted on an evaluation PC board in free air.Electrical Specifications VDD= 5.0V, TA= 25oC, Unless Otherwise SpecifiedPARAMETER TEST CONDITIONS MIN TYP MAX UNITSOperating Suppl
20、y Current, IDDDisplay Off, Unused Inputs to VSS-25mASupply Voltage Range (VDD-VSS), VSUPPLY-25oC to 85oC, INPUT A,INPUT B Frequency at fMAX4.75 - 6.0 VMaximum Frequency INPUT A, Pin 40, fA(MAX)-25oC to 85oC4.75V VDD 6.0V, Figure 9Function = Frequency, Ratio,Unit Counter10 14 - MHzFunction = Period,
21、Time Interval 2.5 - - MHzMaximum Frequency INPUT B, Pin 2, fB(MAX)-25oC to 85oC4.75V VDD 6.0V, Figure 102.5 - - MHzMinimum Separation INPUT A to INPUT B,Time Interval Function-25oC to 85oC4.75V VDD 6.0V, Figure 1250 - - nsOscillator Frequency and External Oscillator Frequency,fOSC-25oC to 85oC4.75V
22、VDD 6.0V0.1 - 10 MHzOscillator Transconductance, gMVDD-4.75V, TA= 85oC 2000 - - SMultiplex Frequency, fMUXfOSC= 10MHz - 500 - HzTime Between Measurements fOSC= 10MHz - 200 - msInput Rate of Charge, dVIN/dt Inputs A, B - 15 - mV/sInput Voltages: Pins 2, 19, 33, 39, 40, 35Input Low Voltage, VIL-25oC t
23、o 85oC - - 1.0 VInput High Voltage, VlH3.5 - - VPins 2, 39, 40, Input Leakage, A, B, IILK-20AInput Resistance to VDDPins 19, 33, RINVIN= VDD-1.0V 100 400 - kInput Resistance to VSSPin 31, RINVIN= +1.0V 50 100 - kOutput CurrentLow Output Current, Pins 3, 5-7, 17, 18, 32, 38, IOLVOL= +0.4V 400 - - AHi
24、gh Output Current, Pins 5-7, 17, 18, 32, HOLVOH= +2.4V 100 - - AHigh Output Current, Pins 3, 38, HOLVOH= VDD-0.8V 265 - - AICM7226ASegment Driver: Pins 8-11, 13-16Low Output Current, IOLVO= +1.5V 25 35 - mAHigh Output Current, IOHVO= VDD-1.0V - 100 - AICM7226A, ICM7226B9-19Timing WaveformMultiplex I
25、nputs: Pins 1, 4, 20, 21Input Low Voltage, VIL- - 0.8 VInput High Voltage, VIH2.0 - - VInput Resistance to VSS,RINVIN= +1.0V 50 100 - kDigit Driver: Pins 22-24, 26-30Low Output Current, IOLVO= +1.0V - -0.3 - mAHigh Output Current, IOHVO= VDD-2.0V 150 180 - mAICM7226BSegment Driver: Pins 22-24, 26-30
26、Leakage Current, ILVO= VSS-10AHigh Output Current, IOHVO= VDD-2.0V 10 15 - mAMultiplex Inputs: Pins 1, 4, 20, 21Input Low Voltage, VIL-VDD-2.0 VInput High Voltage, VIHVDD-0.8 - - VInput Resistance to VSS,RINVIN= VDD-1.0V 100 360 - kDigit Driver: Pins 8-11, 13-16Low Output Current, IOLVO= +1.0V 50 75
27、 - mAHigh Output Current, IOHVO= VDD-2.5V - 100 - ANOTES:1. Assumes all leads soldered or welded to PC board and free air flow.2. Typical values are not tested.Electrical Specifications VDD= 5.0V, TA= 25oC, Unless Otherwise Specified (Continued)PARAMETER TEST CONDITIONS MIN TYP MAX UNITSMEASUREMENTI
28、N PROGRESS30ms TO 40msSTORERESETINPUT AINPUT BPRIMING EDGESPRIMINGFUNCTION:TIME INTERVALUPDATE190ms TO 200ms40ms60ms40msMEASUREMENT INTERVAL250ns MINMEASUREDINTERVAL(FIRST)MEASUREDINTERVAL(LAST)UPDATENOTE:1. If range is set to 1 event, first and last measured interval will coincide.FIGURE 1. WAVEFOR
29、MS FOR TIME INTERVAL MEASUREMENT (OTHERS ARE SIMILAR, BUT WITHOUT PRIMING PHASE)ICM7226A, ICM7226B9-20Typical Performance CurvesFIGURE 2. ICM7226B TYPICAL IDIGITvs VOUTFIGURE 3. ICM7226A TYPICAL IDIGvs VDD-VOUTFIGURE 4. ICM7226B TYPICAL ISEGvs VDD-VOUTFIGURE 5. ICM7226A TYPICAL ISEGvs VOUTFIGURE 6.
30、ICM7226B TYPICAL IDIGITvs VOUTFIGURE 7. ICM7226A TYPICAL ISEGvs VOUTVDD= 5.5V20050100001 2 3VOUT(V)IDIGIT(mA)50TA= 25oCVDD= 4.5VVDD= 5.0V85oC-20oC4.5 VDD 6.0V30020010000 123VDD-VOUT(V)IDIG(mA)25oC85oC-20oC4.5 VDD 6.0V3020100123VDD-VOUT(V)ISEG(mA)25oCVDD= 5.5V806040001 2 3VOUT(V)ISEG(mA)20TA= 25oCVDD
31、= 4.5VVDD= 5.0V85oC-20oCVDD= 5.0V2001501000123VOUT(V)IDIGIT(mA)25oC5085oC-20oCVDD= 5.0V8060400123VOUT(V)ISEG(mA)25oC20ICM7226A, ICM7226B9-21DescriptionINPUTS A and BThe signal to be measured is applied to INPUT A infrequency period, unit counter, frequency ratio and timeinterval modes. The other inp
32、ut signal to be measured isapplied to INPUT B in frequency ratio and time interval. fAshould be higher than fBduring frequency ratio.Both inputs are digital inputs with a typical switching thresh-old of 2.0V at VDD= 5.0V and input impedance of 250k.For optimum performance, the peak-to-peak input sig
33、nalshould be at least 50% of the supply voltage and centeredabout the switching voltage. When these inputs are beingdriven from TTL logic, it is desirable to use a pullup resistor.The circuit counts high to low transitions at both inputsNote that the amplitude of the input should not exceed thedevic
34、e supply (above the VDDand below the VSS) by morethan 0.3V, otherwise the device may be damaged.Multiplexed InputsThe FUNCTION, RANGE, CONTROL and EXTERNALDECIMAL POINT inputs are time multiplexed to select thefunction desired. This is achieved by connecting the appro-priate Digit driver output to t
35、he inputs. The function, rangeand control inputs must be stable during the last half of eachdigit output, (typically 125s). The multiplexed inputs areactive high for the common anode lCM7226A and active lowfor the common cathode lCM7226B.Noise on the multiplex inputs can cause improper operation.Thi
36、s is particularly true when the unit counter mode ofoperation is selected, since changes in voltage on the digitdrivers can be capacitively coupled through the LED diodesto the multiplex inputs. For maximum noise immunity, a 10kresistor should be placed in series with the multiplexedinputs as shown
37、in the application circuits.FIGURE 8. fA(MAX), fB(MAX) AS A FUNCTION OF SUPPLYTypical Performance Curves (Continued)fA(MAX) FREQUENCY UNIT COUNTER,FREQUENCY RATIO MODESfA(MAX) fB(MAX) PERIODTIME INTERVAL MODESTA= 25oCVDD-VSS(V)FREQUENCY (MHz)2015105034 5 6INPUT A4.5V0.5V50ns MIN tr= tf= 10nsCOUNTEDT
38、RANSITIONS50ns MINFIGURE 9. WAVEFORM FOR GUARANTEED MINIMUM fA(MAX)FUNCTION = FREQUENCY, FREQUENCY RATIO,UNIT COUNTERINPUT A ORINPUT B4.5V0.5VMEASUREDINTERVAL250nsMINtr= tf= 10s250nsMINFIGURE 10. WAVEFORM FOR GUARANTEED MINIMUM fB(MAX)AND fA(MAX) FOR FUNCTION = PERIOD ANDTIME INTERVALICM7226A, ICM72
39、26B9-22Table 1 shows the functions selected by each digit for theseinputs.Function InputThe six functions that can be selected are: Frequency,Period, Time Interval, Unit Counter, Frequency Ratio andOscillator Frequency.The implementation of different functions is done by routingthe different signals
40、 to two counters, called “Main Counter”and “Reference Counter”. A simplified block diagram of thedevice for functions realization is shown in Figure 11. Table 2shows which signals will be routed to each counter in differ-ent cases. The output of the Main Counter is the informationwhich goes to the d
41、isplay. The Reference Counter divides itsinput to 1, 10, 100 and 1000. One of these outputs will beselected through the range selector and drive the enableinput of the Main Counter. This means that the ReferenceCounter, along with its associated blocks, directs the MainCounter to begin counting and
42、determines the length of thecounting period. Note that Figure 11 does not show the com-plete functional diagram (See the Functional Block Dia-gram). After the end of each counting period, the output ofthe Main Counter will be latched and displayed, then thecounter will be reset and a new measurement
43、 cycle willbegin. Any change in the FUNCTION INPUT will stop thepresent measurement without updating the display and theninitiate a new measurement. This prevents an erroneous firstreading after the FUNCTION INPUT is changed. In allcases, the 1-0 transitions are counted or timed.TABLE 1. MULTIPLEXED
44、 INPUT FUNCTIONSINPUT FUNCTION DIGITFUNCTION INPUTPin 4Frequency D1Period D8Frequency Ratio D2Time Interval D5Unit Counter D4Oscillator Frequency D3RANGE INPUTPin 210.01s/1 Cycle D10.1s/10 Cycles D21s/100 Cycles D310s/1K Cycles D4Enable External Range Input D5CONTROL INPUTPin 1Display Off D4 andHold
45、Display Test D81MHz Select D2External Oscillator Enable D1External Decimal PointEnableD3External DP INPUTPin 20Decimal point is output for same digitthat is connected to this input.TABLE 2. INPUT ROUTINGFUNCTIONMAINCOUNTER COUNTERFrequency (fA) Input A 100Hz (Oscillator 105or 104)Period (tA) Oscilla
46、tor Input ARatio (fA/fB) Input A Input BTime Interval(AB)Oscillator Input AInput BUnit Counter(Count A)Input A Not ApplicableOsc. Freq.(fOSC)Oscillator 100Hz (Oscillator 105or 104)INTERNAL CONTROL100HzINPUT AINPUT BINPUTSELECTORINTERNAL OREXTERNALOSCILLATORINPUT AENABLECLOCKMAIN COUNTERRANGE SELECTO
47、R1101001000INTERNAL CONTROLINTERNAL CONTROLCLOCKINTERNAL CONTROLINPUTSELECTORREFERENCE COUNTERFIGURE 11. SIMPLIFIED BLOCK DIAGRAM OF FUNCTIONS IMPLEMENTATIONICM7226A, ICM7226B9-23Frequency - In this mode input A is counted by the MainCounter for a precise period of time. This time is determinedby th
48、e time base oscillator and the selected range. For the10MHz (or 1MHz) time base, the resolutions are 100Hz,10Hz, 1Hz and 0.1Hz. The decimal point on the display isset for kHz reading.Period - In this mode, the timebase oscillator is counted bythe Main Counter for the duration of 1, 10, 100 or 1000(r
49、ange selected) periods of the signal at input A. A 10MHztimebase gives resolutions of 0.1s to 0.0001s for 1000periods averaging. Note that the maximum input frequencyfor period measurement is 2.5MHz.Frequency Ratio - In this mode, the input A is counted bythe Main Counter for the duration of 1, 10, 100 or 1000(range selected) periods of the signal at input B. The fre-quency at input A should be higher than input B for meaning-ful result. The result in this case is unitless and its resolutioncan go up to 3 digits after dec
