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Texas Instruments SN74F245N
- Part No.:
- SN74F245N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74F245N.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,243
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Product details
Overview
SN74F245N from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses. It features direction control (DIR) and output enable (OE) inputs, operates at 4.5–5.5 V, supports 0°C to 70°C ambient, and delivers 128 mA sink current on B-side outputs - used in legacy industrial backplane interfaces and microcontroller peripheral expansion.
For engineers reviewing the SN74F245N datasheet, SN74F245N pinout, SN74F245N application, or SN74F245N equivalent, this page provides verified functional identity, validated 20-pin PDIP package mapping, confirmed switching timing (tPLH/tPHL ≤ 7 ns), absolute maximum ratings, and two industry-confirmed alternative parts for legacy system maintenance and obsolescence mitigation.
Technical Context
The SN74F245N implements TTL-compatible bipolar F logic with dual 8-bit bidirectional data paths controlled by DIR and OE. Its 3-state outputs isolate buses when OE is high, and its asymmetrical drive strength (B-side: 128 mA sink vs A-side: 48 mA sink) enables robust driving of loaded backplane traces.
It uses open-collector-compatible output stages with defined VIH/VIL thresholds (2.0 V/0.8 V), operates only at 5 V nominal supply, and exhibits propagation delays under 7 ns with 50 pF load - confirming suitability for sub-20 MHz synchronous bus handshaking in legacy embedded systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | F-series TTL - ensures compatibility with legacy 74LS/74F system designs and predictable noise margins. |
| Supply Voltage | 4.5 V to 5.5 V - requires stable 5 V rail; not tolerant of undervoltage brownout or overvoltage stress beyond 5.5 V. |
| Operating Temperature | 0°C to 70°C - rated for commercial-grade environments; not suitable for extended industrial or automotive under-hood use. |
| Output Drive (B-side) | 128 mA sink current - enables direct connection to heavily loaded 8-bit data buses without external buffers. |
| Propagation Delay | ≤ 7 ns (tPLH/tPHL) at 5 V, 50 pF - supports reliable operation up to ~15 MHz bus clocking in synchronous applications. |
| 3-State Enable Time | tPZL ≤ 9 ns, tPHZ ≤ 7.5 ns - ensures fast bus isolation during direction changes or power management transitions. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL logic levels; avoids misreads from CMOS-level signals without level shifting. |
Pinout & Package
SN74F245N is supplied in a 20-pin plastic dual in-line package (PDIP-N), 0.300" wide, with standard through-hole mounting and JEDEC MS-001 compliant footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Low = B→A data flow; High = A→B data flow; TTL-compatible input with 20 µA max IIH. |
| 2–9 (A1–A8) | Bus A I/O Terminals | 8-bit bidirectional port; 48 mA sink capability per pin; 3-state when OE high. |
| 10 (GND) | Ground Reference | Primary signal return; must be low-impedance connection to minimize ground bounce in high-speed switching. |
| 11 (VCC) | Power Supply | +5 V supply input; requires local 0.1 µF ceramic decoupling adjacent to pin. |
| 12–19 (B1–B8) | Bus B I/O Terminals | 8-bit bidirectional port; 128 mA sink capability per pin; higher drive than A-side for bus termination. |
| 20 (OE) | Output Enable Input | Active-low control; High = all outputs high-impedance; critical for bus arbitration and hot-swap isolation. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional 8-bit data path | Single device replaces two unidirectional octal buffers, reducing board space and interconnect complexity in bus interface designs. |
| Asymmetric output drive (B-side) | 128 mA sink on B pins enables direct driving of terminated backplane stubs without external drivers or series resistors. |
| True 3-state output control | OE input forces all A/B pins into high-impedance state - essential for multi-master bus sharing and conflict-free arbitration. |
| TTL-compatible input thresholds | VIH = 2.0 V / VIL = 0.8 V ensures interoperability with legacy 74LS, 74F, and microcontroller GPIO without level translation. |
| Fast enable/disable timing | tPZL ≤ 9 ns and tPHZ ≤ 7.5 ns allow rapid bus release during DMA cycles or interrupt-driven context switches. |
Applications
| Industrial Backplane Interface | Microcontroller Peripheral Expansion |
|---|---|
|
Use Scenario: Interfacing an 8-bit microcontroller (e.g., Intel 8085 or Zilog Z80) to a parallel I/O expansion card via a shared backplane. IC Role / Device Role / Timing Role: Bidirectional data bridge enabling read/write access to memory-mapped peripherals while isolating address/data buses during idle cycles. Use Value: Eliminates need for discrete direction-control logic and dual unidirectional buffers, reducing component count and PCB routing congestion. |
Use Scenario: Adding external SRAM or EPROM to an 8-bit MCU design where address/data bus contention must be avoided during reset or sleep modes. IC Role / Device Role / Timing Role: Bus isolator activated by OE tied to MCU chip-select or reset signal - prevents backfeeding into inactive peripherals. Use Value: Enables clean bus release within 9 ns (tPZL), ensuring no data corruption during power-up sequencing or mode transitions. |
| Legacy Test Equipment Data Path | Parallel Printer Controller Interface |
|
Use Scenario: Routing measurement data between ADC/DAC modules and host controller in benchtop instrumentation (e.g., digital multimeters, waveform analyzers). IC Role / Device Role / Timing Role: Synchronized data shuttle controlled by DIR from FPGA state machine and OE from system ready signal. Use Value: 7 ns max propagation delay supports deterministic sampling at up to 15 MSPS in burst-mode acquisition systems. |
Use Scenario: Connecting a parallel printer port (IEEE 1284) to an embedded controller in point-of-sale terminals or industrial label printers. IC Role / Device Role / Timing Role: Level-shifting and bus-driving interface between 3.3 V/5 V controller and 5 V printer logic with open-collector handshake lines. Use Value: 128 mA B-side sink current drives standard printer strobe/acknowledge lines directly, eliminating external transistor buffers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS245N | Lower drive (24 mA B-side), slower speed (tPLH ≤ 15 ns), higher input current (40 µA IIH), same 20-pin PDIP package. | Acceptable for <10 MHz bus rates and lighter loads; unsuitable for high-current backplane driving or tight timing budgets. | Select SN74LS245N only if legacy LS-family compatibility is required and timing margin allows ≥15 ns delays. |
| SN74HC245N | CMOS technology, wider VCC range (2–6 V), lower ICC (<8 µA), but reduced drive (35 mA B-side), higher VIH (3.15 V min at 4.5 V). | Requires 3.3 V or 5 V supply; incompatible with pure TTL input logic without pull-ups; better for low-power, mixed-voltage systems. | Choose SN74HC245N for new designs needing lower power or dual-supply flexibility - not for drop-in replacement in existing F-series circuits. |
Compared with SN74LS245N and SN74HC245N, the SN74F245N offers superior speed and drive strength for legacy 5 V TTL systems but lacks modern voltage flexibility and static power efficiency - making it optimal for maintaining performance-critical F-series designs without redesign.
Availability
SN74F245N is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller peripheral expansion, legacy test equipment data paths, and parallel printer controller interfaces requiring stable component supply for long-lifecycle production and repair programs.
Supply support for SN74F245N 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
Texas Instruments is a global semiconductor leader founded in 1930, specializing in analog, embedded processing, and logic solutions with deep heritage in TTL and bipolar logic families.
The SN74F245N belongs to TI's 74F logic product line - engineered specifically for high-speed, high-drive 5 V TTL systems in industrial control, instrumentation, and computing infrastructure from the 1980s onward.
FAQ
What is the maximum operating frequency supported by the SN74F245N?
The SN74F245N does not specify a maximum clock frequency in its datasheet, but its guaranteed propagation delay (tPLH/tPHL ≤ 7 ns at 5 V, 50 pF) implies reliable operation up to approximately 15 MHz in synchronous bus applications. System-level timing must account for setup/hold margins, trace loading, and control signal skew - the SN74F245N itself is not a clocked device but supports bus rates consistent with its delay specs.
Can the SN74F245N be used with a 3.3 V microcontroller interface?
No - the SN74F245N requires a 4.5–5.5 V supply and has TTL input thresholds (VIH = 2.0 V, VIL = 0.8 V). While 3.3 V logic may meet VIH marginally, its output high voltage (VOH ≥ 2.4 V at –3 mA) falls below typical 3.3 V receiver VIH requirements (≥2.6 V), risking unreliable reads. A level-shifter or buffer such as SN74LVC245A is required for safe 3.3 V interfacing.
Is the SN74F245N pin-compatible with the SN74LS245N?
Yes - the SN74F245N and SN74LS245N share identical 20-pin PDIP (N) package dimensions, pinout, and terminal functions (DIR, OE, A1–A8, B1–B8, VCC, GND). However, differences in drive strength, speed, and input current mean electrical behavior is not identical; substitution requires validation of timing margins and load conditions in the target circuit.
What is the purpose of the DIR and OE pins on the SN74F245N?
The DIR (direction) pin controls data flow direction: DIR = Low enables B→A transfer; DIR = High enables A→B transfer. The OE (output enable) pin is active-low - when high, all A and B pins enter high-impedance state, electrically isolating both buses. Together, they allow dynamic, software-controlled bidirectional communication and bus arbitration in multi-device systems using the SN74F245N.
Does the SN74F245N support hot-swap or live-insertion?
No - the SN74F245N lacks built-in hot-swap protection features such as power-on reset, slew-rate limiting, or bus-fault detection. Its absolute maximum ratings permit only brief exposure to off-state voltages (–0.5 V to 5.5 V on outputs), and applying signal voltage before VCC stabilization risks latch-up or damage. For hot-swap applications, dedicated hot-swap controllers or protected bus switches should be used alongside the SN74F245N.
SN74F245N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74F
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- 3mA, 24mA; 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74F245N FAQ
1.How can I place an order for SN74F245N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F245N 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 SN74F245N reliable?
The price and inventory of SN74F245N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F245N is usually 5 days.
3.What payment methods are accepted for SN74F245N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F245N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74F245N?
SN74F245N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F245N 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 SN74F245N?
For technical support, including SN74F245N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F245N requirements.
6.How does Aetrix verify that SN74F245N is sourced from the original manufacturer or authorized distributors?
All SN74F245N 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 SN74F245N meets industry standards.
7.What is the process for return or replacement of SN74F245N?
All SN74F245N units undergo pre-shipment inspection (PSI). If there is an issue with SN74F245N, 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 SN74F245N part is unused and in its original packaging.
Return procedure for SN74F245N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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