CD4520BD - 4-Bit Binary Up Counter | Harris Corporation
料号： CD4520BD ✓ 量产中CD4520BD 概述
A binary counter is a sequential digital-logic component that advances its output state whenever an active clock edge occurs. The CD4520BD belongs to the CMOS counter family, which is part of the broader logic IC hierarchy: counter → digital counter → sequential logic → logic IC → integrated circuit. Each 4-bit section can represent 16 binary states and may also be configured for divide-by-two operation according to the manufacturer documentation.
Key verified characteristics include a 3 V to 18 V supply range, an 8 MHz maximum frequency, 80 ns timing, and positive-edge clock triggering. The bidirectional output capability allows the counter state to be observed from either the Q or complementary Q output. These features make the IC useful when a design requires repeatable binary sequencing, frequency division, timing generation, or event counting.
The CD4520BD is implemented as a CMOS logic device, providing a practical combination of low power consumption and wide supply-voltage operation. Its operating range permits use in 5 V and higher-voltage logic systems where additional input or output voltage range is useful. The 16-pin SOIC package also supports conventional surface-mount assembly rather than requiring a through-hole footprint.
Typical uses include divide-by-two clock conditioning, programmable digital timers, sequence generators, phase-delay counters, and general-purpose binary event-counting circuits. Two counter sections in one package can reduce board area when a design needs more than one independent counting channel and the required clock and reset arrangements match the device architecture.
Designers should verify clock-edge behavior, reset polarity, output-drive requirements, and unused-input states against the manufacturer datasheet before layout. The 80 ns timing and 8 MHz frequency figures establish the device’s logic-speed context, but external signal fan-out, propagation delay, wiring, and supply level remain important when defining a complete operating point.
This page consolidates the verified manufacturer and distributor information for CD4520BD, provides practical application guidance, records the available 3 V to 18 V and 8 MHz operating limits, and distinguishes verified drop-in evidence from substitute parts that could not be confirmed as pin-compatible.
直接替换替代料： CD4520BD ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
该产品暂无直接替换替代料。
请求替代料CD4520BD 最大额定值与电气特性
| Counter Type | Binary counter |
| Number of Counter Elements | 2 elements |
| Counter Width | 4 bits |
| Count Direction | Up |
| Logic Family | CMOS |
| Supply Voltage Range | 3 V to 18 V |
| Maximum Operating Frequency | 8 MHz |
| Propagation Delay | 80 ns |
| Clock Edge | Positive edge triggered |
| Reset Type | Asynchronous reset |
| 输出类型 | Bidirectional |
| 封装 | 16-SOIC |
| Package Width | 3.90 mm |
| 安装类型 | Surface mount |
| RoHS 状态 | Compliant |
CD4520BD 3.90 mm 引脚配置指南
CD4520BD（3.90 mm 封装）的引脚配置。 该数字 IC 包含 GPIO、通信接口（UART、SPI、I2C）和电源引脚。请参阅制造商数据手册以了解复用引脚功能和配置选项。对嵌入式系统设计和 PCB 布局至关重要。
暂无详细引脚数据： CD4520BD.
请参阅 数据手册 以查看完整引脚配置。
典型应用
CD4520BD 适用于 6 应用s: Digital Event Counter, Divide-by-Two Clock Conditioning, Programmable Sequence Generator, Industrial Control Timing, Frequency Divider and Modulo Control, Instrumentation and Measurement Logic.
Digital Event Counter
The CD4520BD suits a digital event-counter circuit because it provides two 4-bit binary up-counter sections, accepts positive-edge clocking, and supports operation from 3 V to 18 V. Each counting section can advance when a qualifying event pulse reaches its clock input, allowing a controller to observe a binary count representing 0 through 15 states. The 8 MHz maximum operating frequency provides substantial timing margin for many digital event sources. One section may count events while the other performs an auxiliary task if its clock and reset behavior is suitable. Design the input drive so every pulse meets the manufacturer’s voltage and transition requirements, and account for the 80 ns timing figure when calculating worst-case path delay. The 16-SOIC package supports compact surface-mount implementation, while two counter elements in one package can reduce board-space requirements compared with two separate single-counter packages.
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Divide-by-Two Clock Conditioning
CD4520BD is appropriate for a divide-by-two clock-conditioning stage when a clean, stable binary division is required. A 4-bit up-counter can be configured for divide-by-two behavior, and its positive-edge triggering provides a predictable state transition when the relevant clock input is driven by a clean waveform. The verified 8 MHz maximum operating frequency supports counting applications well above common low-speed control-clock rates, while the 3 V to 18 V supply range offers compatibility with both 5 V and higher-voltage CMOS systems. In a clock tree, this function can reduce a source frequency before it enters another timing domain. The designer should still verify the exact output transition timing, reset release sequence, and load capacitance in the manufacturer datasheet. Signal integrity matters because input overshoot, ringing, or slow edges can shift the effective switching point and make the divider output less predictable.
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Programmable Sequence Generator
The two independent 4-bit sections in CD4520BD can form the basis of a programmable binary sequence generator when one section supplies timing and another represents the sequence state. The verified 3 V to 18 V operating range permits implementation within 5 V or higher-voltage control systems, while the 8 MHz maximum frequency gives designers room for several divider or decode stages around the counter. The counter outputs can be decoded externally to produce discrete control steps, timing intervals, or address-like sequences. Using both sections in a coordinated design saves one package and can simplify board partitioning, although their shared supply and package routing still require careful layout. The main design checks are reset-state behavior, valid decode combinations, output timing, and whether the counter clock jitter is acceptable for the resulting sequence. A datasheet review is required before using a counter output as a safety-critical or timing-critical control signal.
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Industrial Control Timing
CD4520BD can support industrial control timing and sequencing where the surrounding system operates from a compatible CMOS rail and requires a compact 4-bit counting element. Its positive-edge-triggered operation permits timing references to advance on a controlled clock edge, and the 80 ns timing value provides a concrete basis for evaluating propagation paths. The 16-SOIC package makes the device suitable for automated surface-mount assembly and reduces the footprint relative to two discrete counter packages. For industrial equipment, engineers should verify the exact operating-temperature grade, supply tolerance, noise margins, and output-drive capability because those values were not available in the supplied source snippets. Inputs and outputs entering or leaving the counter should include appropriate protection, grounding, and filtering according to the machine’s electrical environment. Use the counter for supervisory sequencing rather than a primary safety function unless the complete design has been independently validated.
推荐
Frequency Divider and Modulo Control
CD4520BD is useful in frequency-divider and modulo-control designs because each 4-bit section can represent a finite sequence of binary states and count upward on each active clock edge. The verified 8 MHz maximum operating frequency permits division of signals below that documented limit, while the 3 V to 18 V supply range supports multiple CMOS voltage domains. A designer can combine the counter with combinational decoding to produce repeatable enable, step, or period signals. The exact maximum operating rate at each supply voltage and output load must be taken from the manufacturer timing data rather than inferred solely from the 8 MHz headline figure. Reset must be asserted and released in the intended order so the divider begins from a known state. PCB layout should keep clock traces short and return current paths continuous, particularly when the divider drives downstream logic through external decode gates. The device is not a substitute for a dedicated phase-locked loop when the application requires adjustable fractional or closed-loop frequency synthesis.
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Instrumentation and Measurement Logic
CD4520BD can serve as a state and event counter in instrumentation or measurement logic that needs deterministic binary advancement rather than analog signal conditioning. The dual-counter arrangement permits separate functions, such as counting acquisition intervals or coordinating two measurement phases, within a single 16-SOIC package. Its 8 MHz maximum operating frequency is suitable for counting qualified digital events, and the 3 V to 18 V supply range allows the counter to coexist with suitable higher-voltage control logic. A measurement system should use comparator or latch circuitry ahead of the clock input to convert the quantity being measured into clean edges. Shielding, grounding, and layout isolation remain important because the counter itself does not provide analog noise rejection. Engineers must also account for propagation delay when relating a counted event to a sampled measurement and should validate clock jitter if the input is asynchronous. For laboratory or metrology use, verify the exact temperature and electrical grades of the ordered source.
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推荐产品汇总
工程参考数据： CD4520BD ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 |
|---|---|
| Package | 16-SOIC |
| Brand | Harris Corporation |
| Counter Type | Binary up-counter |
| Number of Counter Elements | 2 elements |
| Counter Width | 4 bits |
| Supply Voltage Range | 3 V to 18 V |
| Maximum Operating Frequency | 8 MHz |
| Timing | 80 ns |
| Logic Family | CMOS |
| Clock Edge | Positive edge triggered |
| Verified Starting Price | $0.0909 as of 2026-10-30 |
| RoHS Status | Compliant |
关键差异点
- Dual counter architecture consolidates two counting sections （对比 Single-section general-purpose counter)
- Wide verified CMOS supply range （对比 5 V-only CMOS counter)
- Documented operating-speed capability （对比 Low-frequency ripple counter)
设计说明
Do not treat the CD4520BF comparison result as proof that the part is a drop-in replacement for CD4520BD. The supplied cross-reference snippet describes similar functional characteristics but also inconsistent main parameters and a possible circuit-structure change. Verify package dimensions, the complete pin list, clock and reset polarity, propagation timing, output configuration, and operating-voltage limits in the manufacturer documentation before changing an approved BOM or reusing an existing 16-SOIC footprint.
Keep the counter clock route short and provide a continuous ground reference beneath the device and associated logic. The CD4520BD has an 8 MHz maximum operating frequency, but practical timing also depends on clock slew rate, trace loading, output fan-out, and supply level. Avoid routing the clock adjacent to noisy switching nodes, and use a ground-return arrangement that does not force return current through the same path as the clock signal. Bypass the supply pins with the capacitance recommended by the manufacturer datasheet.
Operate the counter only within its verified 3 V to 18 V supply range and confirm that every driven input remains within the selected manufacturer variant’s valid logic levels. CMOS input pins must not be allowed to float; unused inputs should be tied to a defined inactive logic level. Before power-up, verify that reset sequencing cannot create an unintended count or transient on outputs connected to external equipment. The exact quiescent current and output-drive limits were not present in the supplied data and must be obtained from the datasheet.
合规信息
RoHS compliance is stated in the verified JLCPCB component listing. Separate REACH, halogen-free, conflict-minerals, and lead-free declarations were not provided. AEC-Q100 qualification was not identified and is recorded as not applicable for the listed general-purpose logic device.
