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onsemi DM74ALS652NT
- Part No.:
- DM74ALS652NT
- Manufacturer:
- onsemi
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
DM74ALS652NT.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,596
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Product details
Overview
DM74ALS652NT 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 A and B buses. It operates at 4.5–5.5 V, delivers ±24 mA output drive, features 10 ns data setup time, and is rated for 0°C to +70°C operation in a 24-pin PDIP package.
For engineers reviewing the DM74ALS652NT datasheet, pinout, applications, or equivalent options, key selection criteria include clock-controlled register storage, independent A/B bus enables (GAB/GBA), make-before-break select logic (SAB/SBA), and guaranteed 40 MHz clock frequency with 50 pF load switching performance.
Technical Context
The DM74ALS652NT integrates two independent 8-bit D-type registers clocked by CAB (A-register) and CBA (B-register), both triggered on the positive edge. Data storage and bus direction are decoupled: GAB/GBA control output enable and data flow direction, while SAB/SBA select between real-time or registered data paths without glitches.
Its totem-pole 3-STATE outputs drive high-capacitance bus lines directly-no pull-ups or interface buffers required. Electrical specs are fully guaranteed across 0°C to +70°C and 4.5–5.5 V supply, with propagation delays as low as 3 ns (tPHZ) and output disable times under 10 ns.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard TTL and 5 V logic systems |
| fCLK Max | 40 MHz - supports high-speed synchronous bus handshaking in register-based data routing |
| tSU (Data Setup) | 10 ns - defines minimum hold time before CAB/CBA rising edge for reliable register capture |
| IOL / IOH | 24 mA / −15 mA - drives heavy capacitive loads (e.g., backplane buses) without external buffers |
| Propagation Delay | 5–30 ns - low-latency signal path critical for real-time bus arbitration and multiplexing |
| Operating Temp | 0°C to +70°C - qualified for commercial-grade industrial control and computing applications |
| Package | N24C - 24-pin PDIP, JEDEC MS-001, 0.300" wide, through-hole compatible for prototyping and legacy systems |
Pinout & Package
DM74ALS652NT is housed in a 24-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300" wide, with through-hole mounting and standard 0.1" pin pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1–A8 | Bus A I/O port | 8-bit bidirectional data interface for Bus A; functions as input (store) or output (drive) depending on GAB/SAB state |
| B1–B8 | Bus B I/O port | 8-bit bidirectional data interface for Bus B; functions as input (store) or output (drive) depending on GBA/SBA state |
| CAB | Register A clock | Positive-edge-triggered clock input controlling data capture into A register from A1–A8 or B1–B8 |
| CBA | Register B clock | Positive-edge-triggered clock input controlling data capture into B register from B1–B8 or A1–A8 |
| GAB | Bus A output enable | Active-low enable for A-port 3-STATE outputs; controls real-time or stored data transfer to Bus A |
| GBA | Bus B output enable | Active-low enable for B-port 3-STATE outputs; controls real-time or stored data transfer to Bus B |
| SAB | Bus A data source select | High = stored A register data to Bus A; Low = real-time A port data to Bus A; "make-before-break" prevents glitches |
| SBA | Bus B data source select | High = stored B register data to Bus B; Low = real-time B port data to Bus B; "make-before-break" prevents glitches |
| VCC | Power supply | +5 V nominal supply (4.5–5.5 V range); powers all logic and output stages |
| GND | Ground reference | Common return for all inputs, outputs, and internal circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Edge-triggered dual registers | Independent CAB- and CBA-clocked 8-bit D flip-flops enable synchronized capture of A- and B-bus data without race conditions |
| Make-before-break select logic | SAB/SBA inputs eliminate output glitches during transitions between real-time and registered data paths |
| Direct bus driving capability | Totem-pole 3-STATE outputs deliver ±24 mA drive strength, eliminating need for external pull-ups or buffer ICs on shared buses |
| Four-mode functional flexibility | GAB/GBA combinations support isolated storage, bidirectional real-time transfer, or simultaneous register-to-bus output |
| Guaranteed AC/DC specs over full range | All switching and DC parameters validated across 0°C to +70°C and 4.5–5.5 V - no derating required in commercial environments |
Applications
| Microprocessor System Bus Interface | Industrial PLC I/O Expansion |
|---|---|
Use Scenario: Interfacing an 8-bit microprocessor data bus to peripheral memory or I/O devices with timing isolation. IC Role / Device Role / Timing Role: Acts as bidirectional bus transceiver with register staging to decouple CPU timing from slower peripherals. Use Value: Enables synchronous latch-and-forward data transfer using CAB/CBA clocks, reducing bus contention and improving system determinism. | Use Scenario: Adding modular digital I/O to programmable logic controllers with hot-swap-safe data buffering. IC Role / Device Role / Timing Role: Provides isolated, glitch-free register storage and 3-STATE bus driving for field I/O modules. Use Value: SAB/SBA make-before-break logic prevents transient shorts during mode switching, enhancing reliability in noisy factory environments. |
| Legacy Computer Backplane Buffering | Digital Test Equipment Data Routing |
Use Scenario: Driving long parallel address/data traces on vintage computer backplanes with high capacitance. IC Role / Device Role / Timing Role: Functions as a high-drive-strength, low-propagation-delay bus repeater with local register hold capability. Use Value: 24 mA IOL and 5 ns tPHZ allow clean signal integrity across >100 pF loads without termination networks. | Use Scenario: Configurable signal routing between test pattern generators, DUT interfaces, and acquisition logic. IC Role / Device Role / Timing Role: Serves as a programmable multiplexer with storage, enabling deterministic stimulus/response sequencing. Use Value: Independent GAB/GBA enables concurrent A→B real-time and B→A registered transfers, supporting complex test vector pipelines. |
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, identical pinout, but manufactured by Texas Instruments; slightly higher ICC (max 90 mA vs. 88 mA) and looser tPLH (12 ns min vs. 10 ns) | Drop-in replacement in TI-based designs; requires validation of power budget and timing margin at 40 MHz | Preferred where TI supply chain alignment or second-source assurance is required |
| 74F652PC | Fast TTL variant with faster propagation (3–15 ns), higher power (ICC up to 120 mA), and narrower VCC range (4.5–5.5 V same, but temp range −40°C to +85°C) | Better suited for extended temperature or lower-latency systems; not drop-in due to different AC characteristics and layout sensitivity | Select when sub-15 ns latency is mandatory and thermal/power design accommodates F-series dissipation |
Compared with SN74ALS652N and 74F652PC, the DM74ALS652NT offers tighter setup timing (10 ns), lower ICC (76 mA typical), and proven stability in commercial-temperature bus-holding applications-making it optimal for cost-sensitive, noise-tolerant legacy system upgrades.
Availability
DM74ALS652NT is available at Aetrix Electronics and suitable for microprocessor bus interfacing, industrial I/O expansion, legacy computer backplane buffering, and digital test equipment requiring stable component supply and long-lifecycle support.
Supply support for DM74ALS652NT 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 leading designer and manufacturer of analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; its legacy TTL and ALS logic families remain widely deployed.
The DM74ALS652NT belongs to Fairchild's 74ALS advanced low-power Schottky logic family, engineered for high-speed, low-power bus interface and data routing in commercial computing and industrial control systems.
FAQ
What is the primary function of the DM74ALS652NT?
The DM74ALS652NT is an octal 3-STATE bus transceiver with integrated dual 8-bit D-type registers. It enables bidirectional data transfer between two 8-bit buses (A and B), with selectable real-time or registered data paths controlled by SAB/SBA. Its core function is synchronized bus interfacing with storage capability-critical for isolating timing domains in microprocessor systems. The DM74ALS652NT achieves this using edge-triggered CAB/CBA clocks and active-low GAB/GBA enables.
Does the DM74ALS652NT support simultaneous data capture into both registers?
Yes, the DM74ALS652NT supports simultaneous data capture into both A and B registers when both CAB and CBA receive coincident positive-going clock edges under specific enable conditions (GAB = L, GBA = H). This is explicitly defined in the Function Table entry "Store A and B Data". The DM74ALS652NT uses independent clock inputs and flip-flop structures, allowing coordinated but non-interfering latching-essential for snapshotting mirrored bus states in diagnostic or test applications.
What does "make-before-break" mean for SAB and SBA on the DM74ALS652NT?
"Make-before-break" refers to the internal logic design of the SAB and SBA select inputs on the DM74ALS652NT, ensuring that the newly selected data path (real-time or stored) is established before the previous path is disconnected. This eliminates momentary open-circuit or short-circuit glitches during transitions-particularly vital when switching between registered and live bus data in noise-sensitive environments. The DM74ALS652NT implements this via internal overlap timing, confirmed in the General Description and Function Table notes.
Can the DM74ALS652NT drive a 100 pF bus load reliably?
The DM74ALS652NT is characterized for 50 pF loads per switching specification, but its ±24 mA output drive (IOL = 24 mA, IOH = −15 mA) and 5 ns minimum output disable time (tPHZ) provide sufficient margin to drive 100 pF loads in most practical implementations. However, propagation delays increase with capacitance-measured tPLH/tPHL rise to ~30 ns at 50 pF, so at 100 pF, timing must be verified per application. The DM74ALS652NT's totem-pole outputs are designed for direct bus driving, but layout-dependent parasitics require empirical validation at 100 pF.
Is the DM74ALS652NT RoHS compliant?
The original DM74ALS652NT was manufactured prior to RoHS implementation and uses leaded PDIP packaging (N24C) with SnPb eutectic leads. It is not RoHS compliant by modern standards. For RoHS-compliant alternatives, consider surface-mount equivalents like the SN74ALS652D (SOIC) from Texas Instruments or consult Aetrix Electronics for re-engineered or drop-in replacements meeting current environmental requirements. The DM74ALS652NT remains available for legacy repair and obsolescence management.
DM74ALS652NT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ALS
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- 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:
- Through Hole
- Supplier Device Package:
- 24-PDIP
DM74ALS652NT FAQ
1.How can I place an order for DM74ALS652NT through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74ALS652NT 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 DM74ALS652NT reliable?
The price and inventory of DM74ALS652NT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS652NT is usually 5 days.
3.What payment methods are accepted for DM74ALS652NT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS652NT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74ALS652NT?
DM74ALS652NT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74ALS652NT 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 DM74ALS652NT?
For technical support, including DM74ALS652NT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS652NT requirements.
6.How does Aetrix verify that DM74ALS652NT is sourced from the original manufacturer or authorized distributors?
All DM74ALS652NT 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 DM74ALS652NT meets industry standards.
7.What is the process for return or replacement of DM74ALS652NT?
All DM74ALS652NT units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS652NT, 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 DM74ALS652NT part is unused and in its original packaging.
Return procedure for DM74ALS652NT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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