CD4508BD - CMOS Dual 4-Bit Latch, 5V, DIP-24
MPN: CD4508BD ✓ Active| Qty | Unit Price | Extended |
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CD4508BD Overview
What is a CMOS dual 4-bit latch? A CMOS latch is a clocked digital storage element that uses complementary MOS circuitry to capture logic states while minimizing power dissipation. The CD4508 family belongs to the logic IC hierarchy: dual 4-bit latch -> bus driver/latch -> CMOS logic -> integrated circuit. Its two latch sections can operate as independent storage channels, allowing a system to retain groups of digital signals without requiring separate single-bit latch packages.
Key features include two 4-bit latch sections, separate strobe and reset controls, output-disable capability, true CMOS-compatible outputs, and a 5 V nominal supply condition. The verified product listing identifies a 260 ns propagation delay and 50 pF load capability. The CD4508B family is also described as similar to the industry MC14508 type, which helps engineers identify legacy logic families during component migration. The DIP-24 mechanical format is appropriate where through-hole assembly, socketed prototyping, or hand repair is preferred.
The latch operating sequence is straightforward: when strobe is high, the corresponding D inputs can appear at Q outputs while disable is low; when strobe transitions low, the presented data is latched. A high reset level forces the outputs to the reset state defined by the device logic. Output disable provides a way to place the outputs in a high-impedance condition when multiple bus sections share a signal path, provided the system respects the device's enable and timing requirements.
Typical applications include microcontroller and microprocessor data buffering, peripheral interface isolation, bus transient holding, digital test equipment, and legacy CMOS control systems. The device is most appropriate where the signal rate is moderate and a 5 V CMOS environment is available. Its DIP-24 package also makes it convenient for educational prototypes, repair boards, and systems assembled with through-hole components.
When designing around the CD4508BD, verify every strobe, reset, and disable signal against the datasheet truth table and timing diagrams. Keep unused inputs at defined logic levels, provide adequate decoupling close to the supply pins, and account for the 260 ns propagation-delay figure when designing synchronous handshakes. Because the supplied data does not include complete electrical limits or a complete pin map, those details should be confirmed in the manufacturer datasheet before production release.
This page combines verified manufacturer and distributor information with a practical interpretation of the latch function, timing, package, and design implications. It also distinguishes verified CD4508BD information from parameters that remain datasheet-dependent rather than guessing missing values.
Drop-in alternatives for CD4508BD — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
CD4508B
✅ Drop-In📋 Reference alternative (not in catalog)
MC14508
✅ Drop-In📋 Reference alternative (not in catalog)
CD4508BD Maximum Ratings & Electrical Characteristics
| Product Type | CMOS dual 4-bit latch / bus driver |
| Number of Latch Sections | 2 |
| Bits per Section | 4 bits |
| Total Latched Data Width | 8 bits |
| Nominal Supply Voltage | 5 V |
| Propagation Delay | 260 ns |
| Load Capacitance | 50 pF |
| Control Functions | STROBE, RESET, and OUTPUT DISABLE per latch section |
| Output Behavior | True CMOS-compatible output |
| Industry Cross Reference | MC14508 |
| Package | 24-lead dual-in-line package (DIP-24) |
| Terminal Count | 24 terminals |
| Mounting Type | Through-hole |
| Temperature Grade | Military |
| Logic Family | CMOS 4000-series |
| Data Retention | Latch storage when strobe transitions low |
CD4508BD 24-lead dual-in-line package (dip-24) Pin Configuration Guide
Pin configuration for CD4508BD (24-lead dual-in-line package (dip-24) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for CD4508BD.
Refer to the datasheet for full pin configuration.
Typical Applications
CD4508BD is suitable for 6 applications: Microcontroller Data Bus Buffering, Peripheral Interface Isolation, Legacy CMOS Control Systems, Digital Test and Measurement Instruments, Bus Transient Holding, Educational Digital Logic Prototypes.
Microcontroller Data Bus Buffering
The CD4508BD fits between a controller and a slower or more exposed peripheral bus when temporary four-bit data holding is useful. Each 4-bit section can capture a group of signals, then present stable outputs while downstream logic processes them. The verified 260 ns propagation delay provides a concrete timing figure for moderate-speed control paths, while the DIP-24 package simplifies through-hole assembly. Confirm the complete pinout and timing behavior in the manufacturer datasheet before final routing.
Recommended
Peripheral Interface Isolation
Use the CD4508BD to isolate a group of peripheral control signals by placing the latch between a driving logic source and a connector or downstream device. The output-disable function can help place outputs in an inactive state during transitions, while reset provides a controlled initialization state. The 5 V nominal CMOS environment and 50 pF listed load condition make the device suitable for conventional digital interfaces, but external drivers and receivers must still be checked for voltage compatibility.
Recommended
Legacy CMOS Control Systems
The CD4508BD is appropriate for legacy control systems that already use CMOS 4000-series logic and require dual four-bit storage rather than modern high-speed registers. Its 24-terminal through-hole package supports repairable and inspectable assemblies, which is useful in industrial or educational equipment. The verified military temperature-grade listing adds a selection consideration for controlled environments, although the numeric temperature limits are not included here. Verify lifecycle, sourcing, and exact qualification documents before production use.
Recommended
Digital Test and Measurement Instruments
The dual latch structure can capture test vectors or temporarily isolate control outputs in digital test equipment. Four-bit organization is useful when the instrument controls grouped signals such as address bits, mode selects, or fixture enables. The verified 260 ns delay should be included in stimulus-response timing, and the 50 pF load specification should be compared with the actual PCB and cable capacitance. Through-hole DIP-24 construction also suits educational and service-oriented instrument boards.
Recommended
Bus Transient Holding
The CD4508BD can hold a captured bus state while another logic block resolves address decoding or control sequencing. This is helpful when a downstream device requires stable data during a nonconductive interval, especially in systems built from slower CMOS logic. The latch does not replace a complete bus transceiver or isolation barrier, so its output-disable and reset behavior must be integrated with the system’s enable strategy. Validate timing, contention, and power-up states in simulation and hardware.
Recommended
Educational Digital Logic Prototypes
The DIP-24 package and dual 4-bit organization make the CD4508BD convenient for breadboard and through-hole teaching platforms. Students can demonstrate the distinction between live input data and latched output data, experiment with strobe and reset timing, and observe output-disable behavior. The 5 V nominal supply simplifies connection to CMOS logic experiments. Because the supplied data does not include the complete pinout, use the official CD4508B datasheet for wiring and include decoupling close to the device.
Recommended
Recommended Products Summary
Engineering reference data for CD4508BD — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CD4508B | MC14508 |
|---|---|---|---|
| Package | DIP-24 | DIP-24 package option; verify exact suffix | DIP-24 package option; verify manufacturer pinout |
| Brand | Texas Instruments | Texas Instruments | onsemi |
| Function | CMOS dual 4-bit latch / bus driver | CD4508B family dual 4-bit latch | Industry-equivalent dual 4-bit latch type |
| Latch Organization | 2 sections, 4 bits per section | 2 sections, 4 bits per section | Dual 4-bit latch industry type |
| Control Signals | Separate STROBE, RESET, and OUTPUT DISABLE | Separate STROBE, RESET, and OUTPUT DISABLE | Verify control pin compatibility in datasheet |
| Industry Cross Reference | Similar to MC14508 | CD4508B family | Referenced industry type |
Key Differentiators
- Dual 4-bit organization in one package (vs MC14508)
- Verified 5 V nominal operating point and 260 ns delay (vs CD4508B)
- Separate reset and output-disable controls (vs CD4508B)
- Military temperature-grade listing (vs MC14508)
Design Notes
Do not treat the CD4508B family description as proof that every CD4508B ordering suffix is interchangeable. The verified data identifies CD4508BD as a 24-terminal DIP part, while the family also includes other package options. Before replacing it on an existing PCB, compare the exact pin names and numbering, package dimensions, supply limits, control polarity, and timing. Also confirm that the proposed part is the intended DIP-24 variant rather than a surface-mount or temperature-specific option.
Place the CD4508BD in a conventional through-hole logic layout and keep the supply bypass capacitor close to the device power pins. Route strobe, reset, and disable traces away from noisy analog or high-current switching paths because their transitions determine when data is captured or released. Preserve a continuous ground reference around the DIP footprint and avoid long unprotected traces where the listed 50 pF load condition could be exceeded. Check the manufacturer pinout before assigning physical pins.
Design the CD4508BD around a nominal 5 V CMOS environment and verify the complete electrical limits before connecting it to a mixed-voltage system. The verified 260 ns propagation delay is suitable for moderate-speed digital paths, but it does not guarantee signal integrity at arbitrary cable lengths or high fanout. Confirm input thresholds, output levels, supply current, and transition behavior against the datasheet, especially when interfacing with 3.3 V, TTL, or long external wiring.
Treat reset and strobe as timed digital control signals rather than incidental asynchronous inputs. Ensure reset deassertion and strobe transitions occur with adequate margin relative to data setup and hold requirements in the target circuit. When using output disable, account for the time required to enter and leave the inactive state and make sure external bus devices do not contend with enabled outputs. The supplied data does not provide the complete timing table, so validate the final sequence against the manufacturer datasheet.
Compliance Information
The supplied web results do not provide current RoHS, REACH, lead-free, halogen-free, conflict-minerals, or AEC-Q100 documentation for CD4508BD. Verify compliance for the exact manufacturer, package suffix, and distributor sourcing channel.
