CD4521BM - CMOS 24-Stage Frequency Divider | Texas Instruments
N.º da peça: CD4521BM ✗ Fim de vidaCD4521BM Visão geral
A CMOS frequency divider is a type of sequential logic IC that divides an input clock by a fixed binary factor. In the broader semiconductor hierarchy, it belongs to counters and dividers, then logic ICs, and ultimately the wider digital semiconductor category. The CD4521BM is useful when a system needs long division ratios, a generated clock, or a cascaded timing chain without implementing the counter in a microcontroller or discrete flip-flop array. Its oscillator and counter sections provide a dedicated hardware function for timing and sequencing.
The key verified characteristics include a 24-stage ripple-carry counter, 16-pin SOIC packaging, a -55°C to +125°C temperature range, and a 3 V minimum operating voltage as shown in the available cross-reference information. The counter is advanced on the negative transition of IN1, while RESET returns the state to all zeros and disables the oscillator. These characteristics make the device suitable for long-period timers, modulo counters, clock dividers, and low-frequency signal generation. The manufacturer identifies the circuit as a CMOS 24-stage frequency divider in its CD4521B product documentation.
Because the oscillator can be configured with either RC or crystal components, the circuit supports a range of timing approaches. An unused oscillator input must be tied either HIGH or LOW, preventing an undefined input state. RESET provides a deterministic starting condition, and the multiple counter outputs allow different division ratios or timing phases to be observed. This architecture is particularly useful when one input frequency must be converted into several related output frequencies without continuous software intervention.
The CD4521BM is supplied by Texas Instruments in a 16-pin SOIC package. The manufacturer product page provides the CD4521B family data sheet, while distributor records identify the CD4521BM ordering variant, tube packaging, and availability information. Its broad temperature rating supports industrial and instrumentation use, although designers must still verify the complete electrical limits, timing characteristics, and output-drive requirements in the manufacturer data sheet before release.
For oscillator-based designs, calculate the RC or crystal timing network from the manufacturer guidance and keep oscillator traces short and away from noisy switching nodes. For externally clocked designs, ensure that IN1 transitions satisfy the specified negative-edge counting requirement and that unused inputs are tied to defined logic levels. RESET can be used during power sequencing to hold the divider in a known state until the surrounding system is ready.
This product data combines manufacturer-family information, distributor specifications, verified pricing references, cross-reference results, and practical implementation guidance. It also distinguishes genuine same-package substitutes from unspecified or cross-package alternatives so engineers can evaluate replacement decisions without relying on unsupported equivalence claims.
Alternativas drop-in para CD4521BM — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
CD4521BPW
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MC14521BDR2G
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MC14521BDG
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
HEF4521BTD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
CD4521BM Classificações máximas e características elétricas
| Product Type | CMOS 24-stage frequency divider |
| Counter Architecture | 24 ripple-carry binary counter stages |
| Divider Bit Count | 24 bit |
| Logic Family | CD4000 CMOS |
| Counting Edge | Negative transition of IN1 |
| Oscillator Support | RC or crystal oscillator configuration using IN1 |
| Minimum Supply Voltage | 3 V |
| Faixa de temperatura de operação | -55°C to +125°C |
| Package Type | 16-pin SOIC |
| Package Dimensions | 0.154 inch width, 3.90 mm |
| Packaging Type | Tube |
| Tipo de montagem | Surface Mount |
| Status RoHS | Compliant |
| Reset Function | Sets all counter outputs to zero and disables the oscillator |
| Lead Time | 3-7 business days |
Guia de Configuração de Pinos do CD4521BM 0.154 inch width, 3.90 mm
Configuração de pinos para CD4521BM (pacote 0.154 inch width, 3.90 mm). Este CI digital inclui GPIO, interfaces de comunicação (UART, SPI, I2C) e pinos de alimentação. Consulte o datasheet do fabricante para funções alternativas dos pinos e opções de configuração. Essencial para projeto de sistemas embarcados e layout de PCB.
Nenhum dado detalhado de pinagem disponível para CD4521BM.
Consulte a ficha técnica para a configuração completa dos pinos.
Aplicações típicas
CD4521BM é adequado para 6 aplicaçãos: Long-Interval Industrial Timers, Precision Clock Divider Networks, RC-Oscillator Timing Modules, Instrumentation Event Counters, Communication Bit-Rate Reduction, Low-Frequency Signal Generation.
Long-Interval Industrial Timers
The CD4521BM is suitable for long-period industrial timing because its 24 ripple-carry counter stages can divide a periodic input into a substantially longer interval. The counter advances on each negative transition of IN1, allowing a stable reference clock to control a much slower event cadence without repeated software counting. Its verified -55°C to +125°C operating range supports demanding temperature environments. RESET can hold the divider at the all-zero state during initialization, and the SOIC package simplifies assembly on conventional surface-mount control boards.
Recomendado
Precision Clock Divider Networks
The CD4521BM can generate several related clock phases from one periodic input by using the outputs of its 24 ripple-carry stages. This makes it useful in counter, modulo, and clock-distribution networks where reducing frequency is more important than driving a high-speed modern processor clock. A negative-edge counting characteristic provides a defined update behavior, while RESET establishes a known all-zero state. Designers should preserve signal margin at the 3 V minimum supply condition and verify the complete timing limits in the TI data sheet.
Recomendado
RC-Oscillator Timing Modules
The CD4521BM oscillator section supports RC timing, allowing a compact module to generate and divide a local frequency without requiring an external clock source. The oscillator configuration uses IN1 and can support either RC or crystal implementations according to the TI CD4521B documentation. A HIGH on RESET disables the oscillator and clears the counter, which helps establish repeatable startup behavior. If the oscillator is unused, IN1 must be tied HIGH or LOW so that the input never floats.
Recomendado
Instrumentation Event Counters
For instrumentation and measurement systems, the CD4521BM can count periodic sensor or timing events and expose divided states for downstream control. Its 24-stage architecture provides a long count chain, while the RESET input permits the system to synchronize measurements to a defined starting point. The -55°C to +125°C range is useful across industrial and laboratory environments, and the 16-pin SOIC package supports compact assembly. Engineers should ensure that event amplitudes satisfy the input thresholds and that timing jitter is acceptable for the intended measurement resolution.
Recomendado
Communication Bit-Rate Reduction
The CD4521BM can reduce an incoming periodic communication or synchronization signal to a lower internal rate by using its binary counter stages. This application benefits from the dedicated ripple-carry architecture and deterministic negative-edge counting, which avoids dedicating microcontroller instruction cycles to simple division. RESET can inhibit counting until the communication system is ready, and the 16-pin SOIC package is convenient for retrofit boards. The clocking source must have clean transitions and acceptable jitter to prevent stage-to-stage timing errors.
Recomendado
Low-Frequency Signal Generation
A crystal or RC oscillator connected to the CD4521BM can provide a divided low-frequency output for beacon timing, sampling control, or periodic system actions. The internal 24-stage counter converts the oscillator frequency into a much lower divided rate, while multiple stages can support additional related outputs. RESET supplies a deterministic state for startup and test sequencing. Because oscillator accuracy depends on component tolerance, crystal selection, and layout, engineers should follow the manufacturer guidance and validate frequency stability over the intended temperature range.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para CD4521BM — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | CD4521BPW | MC14521BDR2G | MC14521BDG | HEF4521BTD |
|---|---|---|---|---|---|
| Package | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC | 16-pin SOIC |
| Brand | Texas Instruments | Vishay Intertechnology | onsemi | onsemi | Nexperia |
| Function | CMOS 24-stage frequency divider | 24-stage frequency divider | Frequency divider | Frequency divider | Frequency divider |
| Technology Family | CD4000 CMOS | CD4000 | CMOS | CMOS | CMOS |
| Oscillator and Counter Architecture | Oscillator section plus 24 ripple-carry binary counter stages | Frequency-divider and oscillator function | Frequency-divider function | Frequency-divider function | Frequency-divider function |
Principais diferenciais
- Verified direct-replacement evidence (vs MC14521BDR2G)
- Original manufacturer family documentation (vs HEF4521BTD)
- Wide verified temperature rating (vs CD4521BPW)
- Integrated oscillator and counter architecture (vs MC14521BDR2G)
Notas de projeto
Do not leave IN1 floating. The verified TI description states that IN1 must be tied either HIGH or LOW when the internal oscillator is not used. RESET must be driven deliberately because a HIGH clears all counter stages and disables the oscillator. Confirm the logic sequence used by the board so that reset assertion does not unintentionally stop an external clock before the system reaches its normal operating state.
For RC or crystal oscillator use, keep the oscillator section physically compact and separate from high-current switching nodes. Follow the manufacturer oscillator guidance for component placement and grounding. The supplied records do not contain the recommended PCB artwork, track lengths, or grounding values, so those details must be obtained from the official data sheet and reference material rather than inferred from the 16-pin SOIC outline.
Design the supply rail for a minimum operating voltage of 3 V while allowing for ripple and transient margin. Because the verified records do not provide the maximum supply voltage, quiescent current, or output-drive limits, the power design cannot be completed from the supplied snippets alone. Review the TI CD4521B data sheet for absolute maximum ratings, recommended operating conditions, and input levels before selecting bypass capacitance or defining the acceptable supply tolerance.
A matching 16-pin SOIC outline does not by itself establish a safe drop-in substitution. Before replacing CD4521BM with CD4521BPW, MC14521BDR2G, MC14521BDG, or HEF4521BTD, compare the numbered pinout, oscillator configuration, reset behavior, counting edge, propagation delays, supply range, output-drive capability, and absolute maximum ratings using each manufacturer’s current data sheet.
Informações de conformidade
RoHS compliance is explicitly stated in the verified FindMyChip product information. No verified evidence was supplied for REACH, lead-free status, halogen-free status, conflict-minerals compliance, or automotive qualification.
