ICL7149 Intersil Corporation, ICL7149 Datasheet
ICL7149
Available stocks
Related parts for ICL7149
ICL7149 Summary of contents
Page 1
... Copyright ICL7139, ICL7149 Description The Intersil ICL7139 and ICL7149 are high performance, low power, auto-ranging digital multimeter lCs. Unlike other autoranging multimeter ICs, the ICL7139 and ICL7149 always display the result of a conversion on the correct range. There is no “range hunting” noticeable in the display. ...
Page 2
... Functional Block Diagram CRYSTAL OSC DIGITAL COMMON POWER SUPPLY SECTION V+ V- COM ICL7139, ICL7149 SWITCHES CONTROL LOGIC BEEPER INCLUDING DRIVER AUTORANGING LOGIC DISPLAY DRIVER COUNTERS AND LATCHES ANALOG SECTION ANALOG SWITCHES, INTEGRATION AND COMPARATOR EXTERNAL RESISTORS AND CAPACITORS 3-34 PIEZO ELECTRIC ...
Page 3
... Noise is defined as the width of the uncertainty window (where the display will flicker) between two adjacent codes. 3. Applies to pins 17-20. 4. Analog Common falls out of regulation when the Low Battery Detect is asserted, however the ICL7139 and ICL7149 will continue to operate correctly with a supply voltage above 7V and below 11V. ...
Page 4
... Integrate Capacitor ( Beeper Output DC/Lo ICL7139, ICL7149 FIRST AUTO ZERO FIRST INTEGRATE FIRST DEINTEGRATE AUTO ZERO SECOND AUTO ZERO SECOND INTEGRATE SECOND DEINTEGRATE AUTO ZERO THIRD AUTO ZERO THIRD INTEGRATE THIRD DEINTEGRATE AUTO ZERO FOURTH AUTO ZERO DESCRIPTION I/O ...
Page 5
... C 1000 clock cycles which is one 60Hz line cycle with a 120kHz oscillator, or one 50Hz line cycle with a 100kHz oscillator. Range 1 Integrate 0 The ICL7139 and ICL7149 perform a full autorange search a for each reading, beginning with range 1. During the range ...
Page 6
... When the count is less than 360, an underrange has occurred, and the ICL7139 and ICL7149 then switch to range 2 - the 40V scale. Range 2 The range 2 measurement begins with an autozero cycle similar to the one that preceded range 1 integration ...
Page 7
... AC Voltage Measurement for ICL7149 The ICL7149 is designed to be used with an optional voltage converter circuit. It will autorange through two voltage ranges (400V and 40V), and the AC annunciator is enabled. A typical averaging converter is shown in Figure 6, while an RMS to DC converter is shown in Figure 7 ...
Page 8
... 20M - 4 ICL7652 0.1 F COM FIGURE 6. AC VOLTAGE MEASUREMENT USING OPTIONAL AVERAGING CIRCUIT 10M V IN 0VAC - 400VAC 50Hz - 1000Hz COM FIGURE 7. AC VOLTAGE MEASUREMENT USING OPTIONAL RMS CONVERTER CIRCUIT ICL7139, ICL7149 1.0 F 100k ICL7652 50k 8 1 0 ...
Page 9
... R During the deintegrate phases, the input voltage is the voltage across the reference resistor R KNOWN1 Continuity Indication When the ICL7139 and ICL7149 are in the LO measurement mode, the continuity circuit of Figure 9 will be active. When the voltage across R is less than approximately X 100mV, the beeper output will be on ...
Page 10
... RMS OFF voltage calculations. Duplex multiplexing is used to minimize the number of connections between the ICL7139 and ICL7149 and the LCD. The LCD has two separate back- planes. Each drive line can drive two individual segments, one referenced to each backplane. The ICL7139 and ICL7149 ...
Page 11
... Display The ICL7139 and ICL7149 use a custom, duplexed drive dis- play with range, polarity, and low battery annunciators. With a 3V peak display voltage, the RMS ON voltage will be 2.37V minimum ...
Page 12
... Reference Voltage Source A voltage divider connected to V+ and Common is the sim- plest source of reference voltage. While minimizing external component count, this approach will provide the same volt- age tempco as the ICL7139 and ICL7149 Common - about o 100PPM improve the tempco, an ICL8069 bandgap reference may be used (see Figure 13) ...
Page 13
... ICL7149. The analog circuitry should be removed or shielded from any 120V AC power inputs, and any AC sources such as LCD drive waveforms. Keeping the analog and INT l Pins; 2) circuit section close to the ICL7139 and ICL7149 will also pins. AZ help keep the area free of any loops, thus reducing magneti- cally coupled interference coming from power transformers, or other sources ...