Monday, October 15, 2018

ICM7217 Presettable Up-Down Counter

The ICM7217 is a four digit, presettable up/down counter with an onboard presettable register continuously compared to the counter. The ICM7217 is intended for use in hard-wired applications where thumbwheel switches are used for loading data, and simple SPDT switches are used for chip control.

ICM7217 Presettable Up-Down Counter

This circuit provides multiplexed 7 segment LED display outputs, with common anode or common cathode configurations available. Digit and segment drivers are provided to directly drive displays of up to 0.8 inch character height (common anode) at a 25% duty cycle.

ICM7217 Presettable Up-Down Counter

The frequency of the onboard multiplex oscillator may be controlled with a single capacitor, or the oscillator may be allowed to free run. Leading zeros can be blanked. The data appearing at the 7 segment and BCD outputs is latched; the content of the counter is transferred into the latches under external control by means of the Store pin.

Multiplexed Presettable Timer with ICM7217
  • Four Decade, Presettable Up-Down Counter with Parallel Zero Detect
  • Settable Register with Contents Continuously Compared to Counter
  • Directly Drives Multiplexed 7 Segment Common Anode or Common Cathode LED Displays
  • On-Board Multiplex Scan Oscillator
  • Schmitt Trigger On Count Input
  • TTL Compatible BCD I/O Port, Carry/Borrow, Equal, and Zero Outputs
  • Display Blank Control for Lower Power Operation; Quiescent Power Dissipation <5mW
  • All Terminals Fully Protected Against Static Discharge
  • Single 5V Supply Operation

Three Point Preset Counter

delabs Notes-

This is another Intersil Masterpiece in days when using uP was complex and uC was not available.A 8085 could be used but with many supporting chips and it consumed power. This was a CMOS innovation low on power and just one ASIC had the fexibility for many digital operations.A ThumbWheel and Display Interface completed a Gadget.

Tuesday, October 02, 2018

LM336-2.5 - Voltage Reference Diode

The LM136-2.5/LM236-2.5 and LM336-2.5 integrated circuits are precision 2.5V shunt regulator diodes. These monolithic IC voltage references operate as a low-temperature-coefficient 2.5V zener with 0.2 dynamic impedance. A third terminal on the LM136-2.5 allows the reference voltage and temperature coefficient to be trimmed easily.

LM336-2.5 - Voltage Reference Diode

The series is useful as precision 2.5-V low-voltage references (VZ) for digital voltmeters, power supplies, or operational-amplifier circuitry. The 2.5-V voltage reference makes it convenient to obtain a stable reference from 5-V logic supplies.

LM336-2.5 - Voltage Reference Diode

Features
  • Low temperature coefficient
  • Wide operating current of 400 µA to 10 mA
  • 0.2 dynamic impedance
  • ±1% initial tolerance available
  • Guaranteed temperature stability
  • Easily trimmed for minimum temperature drift
  • Fast turn-on
(This was used by me in the manufacture of Indicators and Controllers and was used in place of ICL8609  as that was not in supply)

Related Resources -

ETX, modification of electronic circuit - By changing the 2,5 Volt reference diode from a fixed LM385 to an adjustable LM336 of 2,5 V, The DC motor voltage and therefore the motor speed can be adjusted.

Precision Op-Amp Current Source - In this circuit we tackle the error indicated in the earlier Current Source. The LM336-2.5V eliminates the tiny error of the regulated supply and resistors. Thereby increasing Precision to a higher degree.

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