7493 4-Bit Binary Counter Technical Summary

Overview

The 7493 is a monolithic 4-bit binary counter integrated circuit containing four master-slave flip-flops with additional gating circuitry. This component provides flexible counting capabilities with a divide-by-two counter and a three-stage binary counter that can be configured for different count cycle lengths depending on the specific variant (divide-by-five for the 90A version). The device is designed for high-speed operation with typical count frequencies up to 42 MHz, making it suitable for various digital counting and frequency division applications.

Features

• Four master-slave flip-flops with integrated counting logic
• Configurable as divide-by-two and divide-by-eight counters (or divide-by-five for 90A variant)
• High-speed operation: up to 42 MHz count frequency
• Low power consumption:
  • 90A version: 145 mW typical power dissipation
  • 93A version: 130 mW typical power dissipation
• Standard TTL compatible inputs and outputs
• Asynchronous master reset capability
• Available in multiple package options

Applications

The 7493 counter finds use in numerous digital applications including:

• Frequency division and counting circuits
• Digital clocks and timers
• Industrial control systems
• Event counting applications
• Digital instrumentation
• Sequential logic systems
• Frequency synthesizers
• Pulse generation circuits

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (Vcc): 7V
• Input Voltage: 5.5V
• Operating Free Air Temperature Range:
  • Commercial: 0°C to +70°C
  • Military: -55°C to +125°C
• Storage Temperature Range: -65°C to +150°C

Recommended Operating Conditions

• Supply Voltage (Vcc): 4.75V to 5.25V
• High Level Input Voltage: 2V min
• Low Level Input Voltage: 0.8V max
• Operating Temperature Range: See specific variant datasheet

DC Electrical Characteristics

• High Level Output Voltage: 2.4V min, 3.4V typ
• Low Level Output Voltage: 0.2V max, 0.1V typ
• Input Clamp Voltage: -1.5V max
• High Level Input Current: 40μA max
• Low Level Input Current: -1.6mA max
• Short Circuit Output Current: -18mA to -55mA
• Supply Current (total): 34mA max

AC Electrical Characteristics

• Maximum Clock Frequency: 42MHz
• Propagation Delay Time (clock to output): 16ns typ, 24ns max
• Propagation Delay Time (reset to output): 24ns typ, 36ns max
• Setup Time (data to clock): 20ns min
• Hold Time (data after clock): 0ns min

Package Information

The 7493 is available in multiple package options to suit different application requirements:

Dual-In-Line Package (DIP) Options

• DM5490J: 14-pin ceramic DIP (NS Package Number J14A)
• DM5490W: 14-pin ceramic flatpack (NS Package Number W14B)
• DM7490AN: 14-pin plastic DIP (NS Package Number N14A)
• DM7493AN: 14-pin plastic DIP (NS Package Number N14A)

Package Dimensions

• J14A (Ceramic DIP):
  • Body Length: 19.05mm max
  • Body Width: 6.35mm max
  • Lead Pitch: 2.54mm
• N14A (Plastic DIP):
  • Body Length: 19.30mm max
  • Body Width: 6.60mm max
  • Lead Pitch: 2.54mm
• W14B (Ceramic Flatpack):
  • Body Length: 10.16mm max
  • Body Width: 6.35mm max
  • Lead Pitch: 1.27mm

Functional Description

The 7493 consists of four JK flip-flops internally connected to provide a divide-by-two counter and a divide-by-eight counter. These can be used independently or cascaded to form a divide-by-sixteen counter. The device features asynchronous master reset inputs (MR1 and MR2) that when both are high, reset all flip-flops to zero regardless of the clock input state.

The counting sequence can be modified by appropriate external connections. For example, the 90A variant can be configured for a decade (divide-by-10) counter by connecting the Q0 output to the B input and using the A input as the clock. The reset function is asynchronous and active high, providing immediate clearing of all flip-flops when both MR1 and MR2 are high.

Connection Diagrams

Pin Configuration (14-pin DIP)

• Pin 1: Clock Input B (CP1)
• Pin 2: Master Reset 1 (MR1)
• Pin 3: Master Reset 2 (MR2)
• Pin 4: NC (No Connection)
• Pin 5: Vcc (+5V supply)
• Pin 6: Clock Input A (CP0)
• Pin 7: NC (No Connection)
• Pin 8: Q0 Output
• Pin 9: Q1 Output
• Pin 10: Q2 Output
• Pin 11: Q3 Output
• Pin 12: NC (No Connection)
• Pin 13: NC (No Connection)
• Pin 14: Ground

Design Considerations

When implementing the 7493 in circuit designs, several factors should be considered:

• Power supply decoupling: A 0.1μF ceramic capacitor should be placed close to the Vcc pin
• Unused inputs should be tied to ground or Vcc through appropriate resistors
• The reset inputs should be properly conditioned to prevent accidental resets
• For high-frequency operation, keep clock signal traces short and properly terminated
• Output loading should be considered to maintain proper signal integrity

Reliability Information

The 7493 is designed for reliable operation under normal conditions. Key reliability parameters include:

• ESD Protection: All inputs and outputs protected against electrostatic discharge
• Latch-up Immunity: Designed to withstand 100mA latch-up current
• Burn-in: Military grade devices undergo extended burn-in testing
• Quality Assurance: Devices meet or exceed applicable MIL-STD-883 requirements