CD4521BE - 24-Stage CMOS Frequency Divider | Texas Instruments
MPN： CD4521BE ✓ 啟用中CD4521BE 概覽
A frequency divider is a counter IC that converts an input waveform into a lower output frequency according to a defined division ratio. The CD4521BE belongs to the CD4000 CMOS logic family and combines a 24-stage ripple-counter section with oscillator-support circuitry. Its negative-edge counting behavior and asynchronous reset make it useful for digital timing, frequency reduction, and periodic-event generation systems.
The principal operating characteristics are a 24-bit counting capacity, a single counter element, a maximum counting rate of 13 MHz, and a 3 V to 18 V supply range. The Divide-by-2 configuration supports binary frequency division, while the oscillator section can be configured with RC or crystal timing networks according to the manufacturer documentation. Asynchronous reset provides a direct method for returning the counter to a defined state.
The CD4521B family is manufactured in multiple package options, but the CD4521BE ordering code identifies the 16-lead dual-in-line plastic package. A 16-pin PDIP offers a straightforward through-hole footprint and generous lead spacing for hand assembly, prototyping, repair, and educational or industrial control boards where surface-mount assembly is unnecessary.
Typical uses include divide-by-two clock conditioning, waveform division in timing modules, programmable counters, digital clock circuits, industrial control logic, and oscillator-based frequency generation. In a divider circuit, the incoming clock is applied at the timing input and the resulting divided signal is taken from an appropriate counter output. Reset should be controlled so that it remains inactive during normal counting.
The most important design consideration is to preserve the input signal's amplitude and transition timing relative to the supply voltage. Wiring should be kept short, unused inputs should be tied to a defined logic level, and decoupling should be placed close to the supply pins. Because the CD4521BE uses a through-hole package, lead length and assembly workmanship can materially affect clock reliability in high-frequency layouts.
This product page organizes the confirmed ordering information, operating limits, package details, technical FAQ, application guidance, and design considerations into a practical engineering reference. It also separates confirmed manufacturer characteristics from parameters that require direct confirmation in the current datasheet, helping designers evaluate CD4521BE without relying on ambiguous or unsupported substitution data.
直接替換替代品，適用於 CD4521BE — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此產品無可直接替換的替代品。
申請替代品CD4521BE 最大額定值與電氣特性
| Product Type | CMOS 24-stage frequency divider |
| Logic Family | CD4000 CMOS |
| Number of Counter Elements | 1 element |
| Number of Bits per Element | 24 bits |
| Divider Configuration | Divide-by-2 |
| Trigger Type | Negative edge |
| Maximum Count Rate | 13 MHz |
| Reset Type | Asynchronous |
| Minimum Supply Voltage | 3 V |
| Maximum Supply Voltage | 18 V |
| Minimum Operating Temperature | -55°C |
| Maximum Operating Temperature | +125°C |
| 封裝 | 16-lead PDIP |
| 腳位數 | 16 pins |
| Mounting Technology | Through-hole |
| Oscillator Support | RC or crystal oscillator configuration using IN1 |
CD4521BE 16-lead pdip 腳位配置指南
CD4521BE（16-lead pdip 封裝）的腳位配置。 此數位 IC 包含 GPIO、通訊介面（UART、SPI、I2C）與電源腳位。替代腳位功能與配置選項請參閱製造商資料表。對嵌入式系統設計與 PCB 佈局至關重要。
無詳細腳位定義資料： CD4521BE.
請參閱 資料表 以查看完整腳位配置。
典型應用
CD4521BE 適用於 6 應用s: Divide-by-Two Clock Conditioning, Digital Timer and Event Generation, RC or Crystal Oscillator Support, Industrial Control Timing, Waveform Division and Signal Conditioning, Prototyping and Legacy Control Boards.
Divide-by-Two Clock Conditioning
The CD4521BE fits divide-by-two clock conditioning because it combines a 24-stage counter element with negative-edge triggering and a confirmed maximum count rate of 13 MHz. Place the source clock on the timing input and select the appropriate divider output for a halved clock. The asynchronous reset can restore a defined counter state during startup, while the 3 V to 18 V supply range supports conventional CMOS logic rails. Confirm input rise and fall times, operating voltage, and output drive requirements in the manufacturer datasheet before finalizing timing margins.
Digital Timer and Event Generation
A CD4521BE can serve as the counting element in a digital timer or periodic-event generator because its counter contains 24 stages and operates by negative-edge counting. A stable periodic input advances the internal ripple-counter stages, allowing one output to provide a divided or periodic timing reference. Asynchronous reset gives the system a direct initialization path. Design the reset logic to avoid false triggering, and verify the maximum operating frequency at the selected supply voltage and temperature.
RC or Crystal Oscillator Support
The CD4521BE includes oscillator-support circuitry that can use the IN1 configuration for RC or crystal oscillator designs. This makes the device useful as the timing core of a frequency source rather than only as a divider for an externally generated waveform. Select the timing components and oscillator mode from the manufacturer application guidance, maintain short signal paths, and account for component tolerance and temperature drift when the source accuracy is important. The oscillator output can also serve as the divider's timing input.
Industrial Control Timing
The CD4521BE is applicable to industrial control timing because it supports a 3 V to 18 V supply range and an operating temperature range of -55°C to +125°C. The negative-edge counter and asynchronous reset provide predictable control of timing chains, while the 16-lead PDIP package simplifies through-hole assembly and inspection. Use robust reset isolation and clean supply decoupling in industrial equipment, and confirm the manufacturer's qualification and reliability information for the exact environmental requirement.
Waveform Division and Signal Conditioning
The CD4521BE can condition a periodic waveform into a lower-frequency signal because it is configured as a divide-by-two counter with 24 counter stages and negative-edge triggering. This is useful when downstream logic cannot accept the source frequency or when a slower timing reference is required. Check the input amplitude against the supply rail and ensure transition times meet the device's timing requirements. Output fan-out and load capacitance should also be checked against the manufacturer electrical characteristics.
Prototyping and Legacy Control Boards
The CD4521BE is particularly suitable for prototyping and repair of systems that use a 16-pin PDIP footprint. Its through-hole package offers visible joints and a larger assembly tolerance than fine-pitch surface-mount alternatives, while the established CD4521B function supports divide-by-two and longer-count applications. Confirm the exact pinout and connector orientation against the manufacturer package drawing, and avoid installing a small-outline package variant in the same socket because the lead geometry is not interchangeable.
工程參考資料，適用於 CD4521BE — 比較、設計指引及合規資訊。
選型指南
設計說明
Route the timing input and any oscillator-network connections as short as practical, especially when operating near the 13 MHz maximum count rate. Avoid routing the clock path beneath long power or ground paths and minimize stub branches. For a crystal oscillator arrangement, follow the manufacturer connection diagram exactly and keep the oscillator pins away from high-current switching nodes.
Do not substitute CD4521BEG4 or CD4521BNSR for CD4521BE without redesigning the PCB. Those ordering codes use different package configurations from the 16-lead PDIP CD4521BE. Also keep the asynchronous reset inactive during normal counting; a floating or noisy reset line can prematurely clear the counter and create an apparently unstable timing output.
Use a supply within the 3 V to 18 V operating range and place local supply bypassing close to the device. Because CD4521BE is a CMOS logic IC, unused inputs should not be left floating; connect them to a defined valid logic level. Confirm output-current, input-threshold, and timing values at the actual supply voltage and temperature rather than relying only on headline frequency and voltage limits.
合規資訊
The manufacturer product page and ordering information in the referenced sources do not state the requested compliance statuses for the exact CD4521BE ordering code.
