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onsemi DM74ALS652WM
- Part No.:
- DM74ALS652WM
- Manufacturer:
- onsemi
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DM74ALS652WM.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24SOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,539
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Product details
Overview
DM74ALS652WM from Fairchild Semiconductor is an octal 3-STATE bus transceiver with dual edge-triggered D-type registers, supporting bidirectional real-time or stored data transfer between two 8-bit buses. It features totem-pole 3-STATE outputs (IOH = −15 mA, IOL = 24 mA), 40 MHz clock frequency, and operates across 0°C to +70°C at VCC = 4.5–5.5 V. It is used in buffered I/O ports and bidirectional bus interfaces in TTL-based industrial control systems.
For engineers reviewing the DM74ALS652WM datasheet, pinout, applications, or equivalent options, key selection criteria include register independence (CAB/CBA), make-before-break select logic (SAB/SBA), dual enable control (GAB/GBA), and SOIC-24 package compatibility with legacy 74ALS system designs.
Technical Context
The DM74ALS652WM integrates two independent 8-bit D-type registers clocked on positive edges of CAB (for A-bus register) and CBA (for B-bus register), enabling asynchronous storage of data from either bus. Its 3-STATE outputs are TTL-compatible and designed for direct bus driving without pull-ups, with guaranteed switching at 50 pF load.
Control logic implements four functional modes via GAB/GBA enables: real-time A→B or B→A transfer, internal storage from either bus, or retrieval of stored data to either bus. SAB/SBA select pins determine whether real-time or registered data appears at outputs, using a glitch-free "make before break" transition scheme.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL supply rails and noise margin stability |
| Max Clock Frequency | 40 MHz - supports high-speed synchronous bus handshaking in legacy computing and instrumentation |
| Output Drive | IOL = 24 mA / IOH = −15 mA - sufficient to drive 50 pF loads and multiple TTL inputs directly |
| Propagation Delay | tPLH/tPHL ≤ 30 ns (clock-to-bus), ≤ 18 ns (bus-to-bus) - enables sub-30 ns data path timing in backplane interfaces |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded control and test equipment environments |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL logic levels for seamless integration into 74ALS families |
| Package | 24-Lead SOIC (M24B, JEDEC MS-013, 0.300" wide) - surface-mount compatible with automated PCB assembly |
Pinout & Package
DM74ALS652WM is housed in a 24-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-013, 0.300" body width, with standard gull-wing leads and 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (GAB) | Enable A→B Transfer | Active-low control enabling real-time or stored data flow from bus A to bus B |
| 2–9 (A1–A8) | Bus A I/O | Bidirectional 8-bit data interface connected to upstream system bus or controller |
| 10 (GND) | Ground Reference | Primary signal return path for all logic and output stages |
| 11 (CAB) | A-Bus Register Clock | Positive-edge-triggered input capturing A-bus data into internal D-register |
| 12 (SAB) | A→B Select Control | HIGH selects stored A-data; LOW selects real-time A-data for B-bus output |
| 13 (VCC) | Power Supply | +5 V supply for all logic, register, and output driver circuitry |
| 14 (SBA) | B→A Select Control | HIGH selects stored B-data; LOW selects real-time B-data for A-bus output |
| 15 (CBA) | B-Bus Register Clock | Positive-edge-triggered input capturing B-bus data into internal D-register |
| 16 (GBA) | Enable B→A Transfer | Active-low control enabling real-time or stored data flow from bus B to bus A |
| 17–24 (B1–B8) | Bus B I/O | Bidirectional 8-bit data interface connected to downstream peripheral or memory bus |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent registers | Separate CAB and CBA clocks allow asynchronous capture of A- and B-bus data without interlock timing constraints |
| Make-before-break select logic | SAB/SBA transitions avoid glitches during real-time ↔ stored data switching-critical for glitch-sensitive bus arbitration |
| Direct bus driving capability | Totem-pole 3-STATE outputs eliminate need for external pull-up resistors or interface buffers on TTL buses |
| Four-mode operation control | GAB/GBA combinations support isolated storage, bidirectional transfer, and simultaneous register loading without external logic |
Applications
| Industrial Backplane Interface | Legacy System I/O Expansion |
|---|---|
Use Scenario: Interfacing CPU bus to modular I/O cards in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Bidirectional bus transceiver with register hold for synchronized data staging between processor and field modules. Use Value: Enables deterministic read/write cycles by decoupling CPU timing from slower peripheral response via stored-data mode. | Use Scenario: Adding parallel port capability to vintage microcomputer systems using ISA-like expansion slots. IC Role / Device Role / Timing Role: Octal buffer/register providing 3-STATE isolation and latch functionality for shared address/data bus segments. Use Value: Eliminates bus contention during DMA transfers by allowing real-time pass-through or registered hold based on control signals. |
| Test Equipment Data Capture | Embedded Controller Bus Bridge |
Use Scenario: Capturing parallel sensor data streams in automated test fixtures with precise timestamp alignment. IC Role / Device Role / Timing Role: Edge-triggered register capturing synchronized snapshots of 8-bit analog-to-digital converter outputs. Use Value: Achieves sub-30 ns setup/hold compliance with 40 MHz clocking, ensuring accurate sampling window alignment. | Use Scenario: Bridging local microcontroller bus to external memory-mapped peripherals in medical device controllers. IC Role / Device Role / Timing Role: Isolating and buffering bidirectional data paths while supporting both immediate and delayed (registered) transfers. Use Value: Reduces firmware overhead by offloading bus arbitration logic-enabling single-cycle register reads and multi-cycle memory writes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver and register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS652N | Same logic function and pinout; PDIP-24 package (N24C), higher θJA (44.5°C/W vs. 80.5°C/W), no SOIC thermal advantage | Preferred where through-hole assembly or socketing is required; unsuitable for high-density SMT layouts | Select SN74ALS652N only when board assembly process mandates DIP packaging or legacy socket compatibility |
| 74F652PC | Fast TTL variant: faster tPLH/tPHL (≤15 ns), higher ICC (up to 112 mA), same 24-pin SOIC footprint but not 3-STATE current compatible | Used in high-speed data acquisition where propagation delay dominates over power or drive strength constraints | Choose 74F652PC only when sub-15 ns timing is mandatory and system can accommodate higher supply current and reduced noise margin |
Compared with SN74ALS652N and 74F652PC, the DM74ALS652WM offers optimal balance of SOIC mountability, 3-STATE drive capability, and thermal performance for space-constrained commercial industrial systems-without requiring layout changes or logic redesign.
Availability
DM74ALS652WM is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system I/O expansion, and embedded controller bus bridges requiring stable component supply and long-term obsolescence management.
Supply support for DM74ALS652WM includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; known for robust TTL, CMOS, and power management solutions.
The DM74ALS652WM belongs to Fairchild's 74ALS logic family-designed for high-speed, low-power bipolar TTL applications in industrial control, test equipment, and computer peripheral interfaces.
FAQ
What is the primary function of the DM74ALS652WM?
The DM74ALS652WM is an octal 3-STATE bus transceiver with dual independent D-type registers, enabling bidirectional data transfer between two 8-bit buses with selectable real-time or registered output. It supports four operational modes via GAB/GBA enables and uses make-before-break logic on SAB/SBA to prevent glitches during mode transitions. The DM74ALS652WM is optimized for TTL-level bus interfacing in industrial and legacy computing systems.
Does the DM74ALS652WM support simultaneous register loading for both A and B buses?
Yes-the DM74ALS652WM supports simultaneous register loading when both CAB and CBA receive coincident positive-going clock edges while GAB and GBA are both LOW. This condition stores incoming A-bus and B-bus data into their respective registers in one cycle, as confirmed in the Function Table under "Store A and B Data." The DM74ALS652WM requires no additional control sequencing for this operation.
What are the absolute maximum ratings for the DM74ALS652WM?
The DM74ALS652WM has an absolute maximum supply voltage of 7 V, input voltage limits of 7 V on control inputs and 5.5 V on I/O ports, and operating temperature range of 0°C to +70°C. Storage temperature extends from −65°C to +150°C. Exceeding these values risks permanent damage. The DM74ALS652WM must be operated within its recommended conditions (VCC = 4.5–5.5 V, TA = 0–70°C) to guarantee all electrical characteristics.
Can the DM74ALS652WM drive a 50 pF capacitive load reliably?
Yes-the DM74ALS652WM specifies switching characteristics explicitly at 50 pF, including propagation delays (tPLH/tPHL ≤ 30 ns) and output drive (IOL = 24 mA, IOH = −15 mA). Its totem-pole 3-STATE outputs are characterized for direct bus driving under this load, making it suitable for standard backplane and ribbon-cable interconnects. The DM74ALS652WM meets all timing specs under these conditions across its full temperature and voltage range.
Is the DM74ALS652WM pin-compatible with other 74-series transceivers like the 74LS245?
No-the DM74ALS652WM is not pin-compatible with the 74LS245 or other standard octal transceivers. It features 24 pins with dedicated register clocks (CAB/CBA), select controls (SAB/SBA), and dual enables (GAB/GBA), whereas the 74LS245 uses 20 pins and lacks internal registers or select logic. The DM74ALS652WM serves a more complex function and requires unique PCB layout; substitution would necessitate schematic and layout revision.
DM74ALS652WM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOP
DM74ALS652WM FAQ
1.How can I place an order for DM74ALS652WM through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS652WM on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DM74ALS652WM reliable?
The price and inventory of DM74ALS652WM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS652WM is usually 5 days.
3.What payment methods are accepted for DM74ALS652WM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS652WM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS652WM?
DM74ALS652WM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS652WM order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DM74ALS652WM?
For technical support, including DM74ALS652WM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS652WM requirements.
6.How does Aetrix verify that DM74ALS652WM is sourced from the original manufacturer or authorized distributors?
All DM74ALS652WM products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DM74ALS652WM meets industry standards.
7.What is the process for return or replacement of DM74ALS652WM?
All DM74ALS652WM units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS652WM, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DM74ALS652WM part is unused and in its original packaging.
Return procedure for DM74ALS652WM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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