NXP HEF4520BP Dual Binary Counter: Datasheet, Pinout, and Application Circuit Guide
The NXP HEF4520BP is a monolithic integrated circuit housed in a standard 16-pin DIP package, providing two identical, internally independent 4-stage binary counters. As part of the HEF4000 family, it is built with standard CMOS technology, offering low power dissipation and a wide operating voltage range, making it suitable for a vast array of digital counting applications.
Datasheet Overview and Key Specifications
The HEF4520BP is a dual binary ripple counter, with each counter featuring a clock input (CP), an asynchronous active-high reset input (MR), and four parallel outputs (Q0 through Q3). The state of the counter advances on the positive-going (rising) edge of the clock pulse.
Key absolute maximum ratings and operational specifications include:
Supply Voltage Range (VDD): -0.5 V to +18 V
Recommended Operating Voltage: 3 V to 15 V
Input Voltage Range: -0.5 V to VDD +0.5 V
Low Power Consumption: Typically 10 nA at 5V (static)
High Noise Immunity: Approximately 45% of VDD
Operating Temperature Range: -40 °C to +85 °C
Its wide voltage compatibility allows it to interface seamlessly with both TTL and CMOS logic families, given appropriate pull-up resistors when used with TTL.
Pinout Configuration
Understanding the pinout is crucial for correct circuit design. The 16-pin assignment is as follows:
Pin 1 (CP0): Clock Input for Counter 1
Pin 2 (MR0): Master Reset for Counter 1 (Active HIGH)
Pin 3 (Q00): Output 0 (LSB) for Counter 1
Pin 4 (Q10): Output 1 for Counter 1
Pin 5 (Q20): Output 2 for Counter 1
Pin 6 (Q30): Output 3 (MSB) for Counter 1
Pin 7 (Enable0): Enable Input for Counter 1 (Often tied to VSS if not used)
Pin 8 (VSS): Ground (0V)
Pin 9 (Enable1): Enable Input for Counter 2
Pin 10 (Q31): Output 3 (MSB) for Counter 2
Pin 11 (Q21): Output 2 for Counter 2
Pin 12 (Q11): Output 1 for Counter 2
Pin 13 (Q01): Output 0 (LSB) for Counter 2
Pin 14 (MR1): Master Reset for Counter 2 (Active HIGH)
Pin 15 (CP1): Clock Input for Counter 2
Pin 16 (VDD): Positive Supply Voltage
Application Circuit Guide: A Simple Frequency Divider
A fundamental application of the HEF4520BP is as a frequency divider or divide-by-n counter. Here is a guide to creating a divide-by-16 circuit using a single section of the dual counter.
1. Power Connections: Connect Pin 16 (VDD) to the positive supply rail (e.g., +5V) and Pin 8 (VSS) to ground.
2. Clock Input: Apply the input clock signal to Pin 1 (CP0). The enable input (Pin 7) must be held HIGH for the counter to increment; connect it directly to VDD.
3. Reset Management: To ensure normal operation, the master reset input (Pin 2, MR0) must be held LOW. Connect it to ground (VSS). A momentary HIGH pulse on this pin will reset all outputs (Q0-Q3) to LOW.
4. Output: The four binary outputs (Pins 3, 4, 5, and 6) represent the count from 0 to 15. The Q3 output (Pin 6) serves as the divided clock signal, toggling once for every 16 input clock pulses, effectively dividing the input frequency by 16.
For higher division ratios, the two internal counters can be cascaded. The output of the first counter (e.g., Q3 on Pin 6) can be connected to the clock input of the second counter (Pin 15). This creates a single divide-by-256 counter, as the total division ratio becomes 16 (from the first counter) multiplied by 16 (from the second counter).
The NXP HEF4520BP stands as a versatile and robust solution for digital counting tasks. Its dual counter design offers excellent functional integration, while its CMOS foundation ensures low-power operation across a wide voltage spectrum. From simple frequency division and event counting to forming more complex sequencers and timers, the HEF4520BP remains a reliable and fundamental component in the electronics designer's toolkit.
Keywords:
1. Binary Ripple Counter
2. CMOS Technology
3. Frequency Divider
4. Pinout Configuration
5. Dual Counter IC
