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NXP Semiconductors 74HC243DB,112
- Part No.:
- 74HC243DB,112
- Manufacturer:
- NXP Semiconductors
- Package:
- 14-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
74HC243DB,112.pdf
- Description:
- IC TXRX NON-INVERT 6V 14SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,801
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Product details
Overview
74HC243DB,112 from NXP Semiconductors (formerly Philips) is a quad non-inverting 3-state bus transceiver for asynchronous bidirectional data transfer between two 4-bit buses. It features dual independent output-enable inputs (OEA and OEB), true (non-inverting) logic paths in both directions, and operates across −40 °C to +125 °C with supply voltage from 2.0 V to 6.0 V. It is used in legacy industrial control backplanes and microcontroller peripheral expansion interfaces.
For engineers reviewing the 74HC243DB,112 datasheet, 74HC243DB,112 pinout, 74HC243DB,112 application, or 74HC243DB,112 equivalent, key selection considerations include propagation delay at 5 V (6 ns typ), 3-state enable/disable timing (14–28 ns), I/O capacitance (10 pF), ESD robustness (>2000 V HBM), and SSOP14 package compatibility with high-density PCB layouts.
Technical Context
The 74HC243DB,112 implements four independent bidirectional data channels, each with non-inverting signal flow and separate 3-state control via OEA (controls A→B and B→A paths for A-side) and OEB (controls same for B-side). Its CMOS architecture ensures TTL-level compatibility while delivering low static current (≤160 µA at 6 V, −40 °C to +125 °C) and rail-to-rail output swing.
Functional operation follows a 2-input control matrix: when OEA = LOW and OEB = LOW, bidirectional pass-through occurs (A↔B); either enable HIGH places its respective bus side into high-impedance. No internal direction control logic is present - directionality is determined solely by external enable sequencing and bus driver sourcing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and battery-backed operation down to 2 V |
| Propagation Delay (An↔Bn) | 6 ns typical at VCC = 5 V, CL = 15 pF - enables reliable 80+ MHz bus handshaking in synchronous edge-triggered systems |
| 3-State Enable Time (OEA/OEB) | 14 ns typical at VCC = 6 V - ensures fast bus arbitration and minimizes contention windows during mode switching |
| I/O Capacitance | 10 pF - limits capacitive loading on driven lines, preserving signal integrity in multi-drop bus configurations |
| ESD Protection | HBM >2000 V - provides robust handling tolerance during board assembly and field service without additional protection circuitry |
| Operating Temperature | −40 °C to +125 °C - qualified for under-hood automotive modules and industrial motor drive control cabinets |
| Quiescent Supply Current | 160 µA max at 6 V, full temp range - enables low-power standby modes in always-on embedded subsystems |
Pinout & Package
74HC243DB,112 is housed in a plastic shrink small outline package (SSOP14) with 14 leads, 5.3 mm body width, and 0.65 mm lead pitch - optimized for automated SMT placement and thermal performance in compact layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OEA (Pin 1) | Active-low output enable for A-side bus | Drives all A0–A3 I/Os into high-Z when HIGH; enables bidirectional A↔B transfer when LOW |
| n.c. (Pin 2) | No connection | Internally unconnected; must remain floating or grounded per layout best practice |
| A0–A3 (Pins 3–6) | Bidirectional data terminals (A-side) | Interface directly with microcontroller port or ASIC data bus; no internal pull-ups/downs |
| GND (Pin 7) | Ground reference | Primary return path for all I/O and supply currents; requires low-impedance PCB plane coupling |
| B3–B0 (Pins 8–11) | Bidirectional data terminals (B-side) | Connect to peripheral bus or memory interface; electrically identical to A-side pins |
| n.c. (Pin 12) | No connection | Internally unconnected; must remain floating or grounded |
| OEB (Pin 13) | Active-low output enable for B-side bus | Drives all B0–B3 I/Os into high-Z when HIGH; enables bidirectional A↔B transfer when LOW |
| VCC (Pin 14) | Positive supply | Accepts 2.0–6.0 V; bypass capacitor (100 nF) required within 5 mm of pin for noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| Non-inverting 3-state outputs | Preserves logic polarity in both directions without inversion gates, simplifying timing analysis and reducing gate count in bus isolation designs |
| Asynchronous 2-way bus communication | Enables real-time data exchange between independent clock domains (e.g., MCU core and FPGA peripheral bus) without handshake protocol overhead |
| JEDEC Std. 7A compliance | Guarantees interoperability with legacy LSTTL systems and validates pinout, voltage thresholds, and drive strength against industry-standard benchmarks |
| Wide temperature operation | Rated from −40 °C to +125 °C - eliminates derating calculations for industrial PLC I/O modules and automotive body control units |
| Low dynamic power dissipation | CPD = 26 pF enables µW-level dynamic power at low frequencies, critical for battery-powered diagnostic tools and portable test equipment |
Applications
| Industrial Backplane Interface | Microcontroller Peripheral Expansion |
|---|---|
Use Scenario: Isolating CPU address/data bus from modular I/O carrier boards in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional level-shifting and bus contention prevention between main controller and hot-swappable daughter cards. Use Value: Enables deterministic bus arbitration using OEA/OEB sequencing, eliminating need for external direction-control logic and reducing BOM count by one IC per slot. |
Use Scenario: Extending GPIO count of an 8-bit MCU via parallel-connected peripheral chips (ADCs, DACs, LED drivers). IC Role / Device Role / Timing Role: Synchronizing data transfers between MCU data bus and peripheral register banks using shared /RD and /WR strobes. Use Value: Provides sub-10 ns propagation delay and <30 ns 3-state switching - maintains setup/hold timing margins even at 20 MHz bus clocks. |
| Legacy System Bus Bridge | Automotive Diagnostic Interface |
Use Scenario: Interfacing modern ARM-based debug adapters to vintage 8086/80286-based test equipment with ISA-like parallel buses. IC Role / Device Role / Timing Role: Voltage-level translation (3.3 V ↔ 5 V) and bus isolation during adapter firmware updates. Use Value: JEDEC 7A compliance ensures drop-in replacement of obsolete 74LS243, avoiding redesign of existing backplane connectors and trace routing. |
Use Scenario: Connecting vehicle ECU diagnostic ports (K-line or proprietary parallel debug) to handheld scan tools. IC Role / Device Role / Timing Role: Buffering and isolating diagnostic command/response packets between tool and ECU to prevent ground loop interference. Use Value: −40 °C to +125 °C rating and >2000 V HBM ESD withstand allow direct integration into under-dash tool housings without external TVS diodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HC242DB,112 | Inverting outputs (A→B and B→A invert logic state); otherwise identical pinout, timing, and electrical specs | Requires complementary logic inversion in firmware or external gates to maintain signal polarity - unsuitable where true-level passthrough is mandatory | Select only if system design accommodates inverted data paths or uses differential signaling where polarity is irrelevant |
| SN74LVC243APW | Lower VCC range (1.65–3.6 V), higher speed (tPD = 3.8 ns typ @ 3.3 V), but not 5 V-tolerant on I/Os | Cannot interface directly with 5 V legacy buses without level shifters; better suited for modern 3.3 V-only systems with tighter timing budgets | Choose when migrating to 3.3 V platforms and requiring faster propagation; avoid for mixed-voltage or 5 V-only environments |
Compared with 74HC243DB,112, the 74HC242DB,112 trades polarity fidelity for functional equivalence in inversion-tolerant systems, while the SN74LVC243APW sacrifices 5 V compatibility to gain speed and lower voltage operation - making the 74HC243DB,112 the sole choice for robust, polarity-preserving, wide-supply-range bus bridging.
Availability
74HC243DB,112 is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller peripheral expansion, legacy system bus bridges, and automotive diagnostic interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74HC243DB,112 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
NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' pioneering logic IC development.
The 74HC243DB,112 belongs to NXP's legacy HC logic family, designed specifically for robust, pin-compatible replacement of bipolar TTL bus transceivers in space-constrained, thermally demanding embedded systems.
FAQ
What is the maximum operating frequency supported by the 74HC243DB,112?
The 74HC243DB,112 does not specify a maximum clock frequency, as it is an asynchronous transceiver. Its usable data rate depends on propagation delay (6 ns typ at 5 V) and 3-state switching times (14–28 ns). In practice, it reliably supports bus handshaking up to ~80 MHz in edge-triggered systems with proper load capacitance control and PCB layout.
Can the 74HC243DB,112 operate with a 3.3 V supply?
Yes, the 74HC243DB,112 is fully specified from 2.0 V to 6.0 V, including 3.3 V operation. At VCC = 3.3 V, VOH is ≥3.1 V (IO = −20 µA) and VOL is ≤0.26 V (IO = 6 mA), ensuring solid noise margins with 3.3 V CMOS logic families. Propagation delay increases to ~10 ns typical.
Are Pins 2 and 12 of the 74HC243DB,112 internally connected?
No - Pins 2 and 12 of the 74HC243DB,112 are explicitly designated "n.c." (not connected) in the official datasheet. They are electrically isolated from all internal circuitry and must be left unconnected or tied to GND per PCB layout guidelines to minimize parasitic coupling.
How does the 74HC243DB,112 differ from the 74HC243D variant?
The 74HC243DB,112 uses an SSOP14 package (SOT337-1, 5.3 mm width), while the 74HC243D uses SO14 (SOT108-1, 3.9 mm width). Both share identical electrical specifications, pinout, and temperature range (−40 °C to +125 °C), but the SSOP variant offers higher PCB density and improved thermal resistance due to larger exposed pad area in some revisions.
Does the 74HC243DB,112 support hot-swap insertion?
The 74HC243DB,112 has no built-in hot-swap protection. However, its 3-state outputs and high-impedance OFF-state (IOZ ≤ ±10 µA at 125 °C) allow safe insertion into powered-backplane systems when OEA and OEB are held HIGH during plug-in. External series resistors (22–47 Ω) on all data lines are recommended to limit inrush current.
74HC243DB,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HC
- Package/Case:
- 14-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SSOP
74HC243DB,112 FAQ
1.How can I place an order for 74HC243DB,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HC243DB,112 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 74HC243DB,112 reliable?
The price and inventory of 74HC243DB,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HC243DB,112 is usually 5 days.
3.What payment methods are accepted for 74HC243DB,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HC243DB,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HC243DB,112?
74HC243DB,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HC243DB,112 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 74HC243DB,112?
For technical support, including 74HC243DB,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HC243DB,112 requirements.
6.How does Aetrix verify that 74HC243DB,112 is sourced from the original manufacturer or authorized distributors?
All 74HC243DB,112 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 74HC243DB,112 meets industry standards.
7.What is the process for return or replacement of 74HC243DB,112?
All 74HC243DB,112 units undergo pre-shipment inspection (PSI). If there is an issue with 74HC243DB,112, 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 74HC243DB,112 part is unused and in its original packaging.
Return procedure for 74HC243DB,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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