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Texas Instruments SN74AHC245DGSR
- Part No.:
- SN74AHC245DGSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-TFSOP (0.118", 3.00mm Width)
- Datasheet:
-
SN74AHC245DGSR.pdf
- Description:
- OCTAL BUS TRANSCEIVERS WITH TRI-
- Quantity:
- Payment:
- Shipping:
Inventory:10,000
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Product details
Overview
SN74AHC245DGSR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses. It operates from 2 V to 5.5 V, supports 5-V-to-3.3-V voltage translation, and features ±25 mA output drive per channel. It is used in PC motherboard I/O expansion, server memory interface buffering, and industrial control backplane communication.
For engineers reviewing the SN74AHC245DGSR datasheet, SN74AHC245DGSR pinout, SN74AHC245DGSR application, or SN74AHC245DGSR equivalent, key selection criteria include its VSSOP-20 package footprint, 3.3 V/5 V mixed-voltage bus isolation capability, 3-state enable timing (tPZH/tPLZ ≤ 15.5 ns at 3.3 V), and latch-up immunity exceeding 250 mA per JESD17.
Technical Context
The SN74AHC245DGSR implements dual-directional 8-bit data flow controlled by a single DIR input and enabled/disabled via OE. Its CMOS AHC logic family ensures balanced rise/fall times and low dynamic power dissipation (Cpd = 14 pF at 1 MHz). Input tolerance up to 5.5 V enables robust down-translation from 5 V to 3.3 V systems without level shifters.
Functional modes are strictly defined by OE and DIR: when OE = L, data flows A→B (DIR = H) or B→A (DIR = L); when OE = H, all outputs enter high-impedance state regardless of DIR. No internal pull-ups/pull-downs exist-external biasing is required for unused inputs to prevent floating states.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports mixed-voltage system interfacing and brown-out tolerant operation |
| Output Drive | ±25 mA per channel - sufficient to drive standard TTL loads and short PCB traces without external buffers |
| Propagation Delay | 4 ns (min) to 6.5 ns (max) at 5 V, CL = 15 pF - enables reliable 100+ MHz bus operation with margin |
| Input Voltage Tolerance | Up to 5.5 V independent of VCC - eliminates need for external level translators in 5 V → 3.3 V interfaces |
| Latch-up Immunity | >250 mA per JESD17 - ensures robustness against transient current faults in noisy industrial environments |
| ESD Rating | 1500 V HBM, 2000 V CDM - meets standard handling requirements for automated SMT assembly lines |
| Operating Temperature | –40 °C to +125 °C - qualified for extended industrial and automotive under-hood applications |
Pinout & Package
VSSOP-20 (DGS) package: 5.10 mm × 4.90 mm body size, 0.5 mm pitch, 20-pin surface-mount with exposed thermal pad (no thermal pad connection required for standard operation).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DIR (Pin 1) | Direction control input | Logic level selects data flow direction: H = A→B, L = B→A; no internal pull-up |
| A1–A8 (Pins 2–9) | Bus A I/O terminals | 8-bit bidirectional data port connected to local subsystem (e.g., microcontroller bus) |
| GND (Pin 10) | Ground reference | Primary return path for all signals and power; must be low-inductance connection |
| VCC (Pin 20) | Power supply | Single supply for both input and output logic; requires local 0.1 µF bypass capacitor |
| OE (Pin 19) | Output enable input | Active-low control: L enables transceiver, H places all A/B outputs in high-Z state |
| B1–B8 (Pins 11–18) | Bus B I/O terminals | 8-bit bidirectional data port connected to remote subsystem (e.g., peripheral module or memory) |
Key Features
| Feature | Design Value |
|---|---|
| Wide supply range (2–5.5 V) | Enables direct integration into 3.3 V and 5 V domains without external regulators or level shifters |
| Overvoltage-tolerant inputs | Accepts up to 5.5 V on any input pin regardless of VCC, simplifying mixed-voltage board design |
| Slow edge-rate control | Minimizes output ringing and EMI on long traces or unterminated stubs in backplane applications |
| High-impedance isolation mode | OE-driven tri-state disables all I/Os simultaneously, enabling clean bus arbitration and hot-swap capability |
| Low power dissipation | ICC ≤ 40 µA max at 5.5 V - suitable for battery-backed or always-on monitoring subsystems |
Applications
| PC Motherboard I/O Expansion | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Isolating legacy ISA or LPC bus segments from modern low-voltage controllers while maintaining signal integrity. IC Role / Device Role / Timing Role: Bidirectional bus buffer with direction and enable control, providing voltage translation and timing isolation between 5 V peripherals and 3.3 V host logic. Use Value: Eliminates discrete level-shifting components and reduces PCB layer count by consolidating translation and buffering in one VSSOP-20 device. | Use Scenario: Interfacing distributed I/O modules across a ruggedized 24 V DC-powered backplane with isolated 3.3 V controller domains. IC Role / Device Role / Timing Role: Fault-isolated data transceiver managing synchronous register reads/writes between master CPU and remote slave nodes. Use Value: Latch-up immunity >250 mA prevents catastrophic failure during field-induced transients common in factory-floor EMI environments. |
| Server Memory Subsystem Buffer | Wearable Health Sensor Hub |
Use Scenario: Buffering address/data/control signals between DDR4 memory controller and DIMM slots in compact 1U rack servers. IC Role / Device Role / Timing Role: Low-skew, high-drive octal transceiver supporting burst-mode transfers with tPHL/tPLH ≤ 6.5 ns at 5 V. Use Value: Meets tight setup/hold timing margins for DDR4 command/address bus routing while fitting within constrained board area using VSSOP-20 footprint. | Use Scenario: Aggregating sensor data streams (ECG, SpO₂, accelerometer) from multiple analog front-ends to a low-power ARM Cortex-M0+ MCU. IC Role / Device Role / Timing Role: Low-quiescent-current bidirectional bridge enabling shared SPI/I²C resource access between heterogeneous sensor ICs and host processor. Use Value: ICC ≤ 40 µA at 3.3 V extends battery life in wearable devices where continuous sensor polling occurs during sleep cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245APWR | Lower VCC range (1.65–3.6 V); 32 mA drive; 3.3 V only operation | Not suitable for 5 V systems or mixed-voltage translation | Select when full system operates at 3.3 V and higher drive is needed |
| 74AVCH245PWRE4 | Supports 0.8–3.6 V; auto-direction sensing; no DIR pin required | Eliminates direction-control logic but adds complexity in deterministic bus arbitration | Select for space-constrained designs needing automatic direction detection and lower voltage operation |
Compared with SN74LVC245APWR and 74AVCH245PWRE4, the SN74AHC245DGSR uniquely supports 5 V system compatibility, overvoltage-tolerant inputs, and deterministic DIR-controlled bidirectional flow-making it optimal for legacy-compatible industrial and computing interfaces where voltage translation and timing predictability are critical.
Availability
SN74AHC245DGSR is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial PLC backplane interfaces, and server memory subsystem buffering requiring stable component supply across multi-year production cycles.
Supply support for SN74AHC245DGSR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The SN74AHC245DGSR belongs to TI's AHC logic family, engineered for high-speed, low-power, mixed-voltage bus interfacing in computing and industrial control systems where reliability and voltage translation are essential.
FAQ
What is the maximum operating temperature for the SN74AHC245DGSR?
The SN74AHC245DGSR is rated for operation from –40 °C to +125 °C ambient temperature. This extended industrial temperature range allows deployment in harsh environments such as factory automation controllers, telecom infrastructure equipment, and automotive engine-control adjacent modules. The VSSOP-20 package's thermal metrics (RθJA = 118.4 °C/W) support this rating under typical PCB layout conditions with adequate copper pour.
Does the SN74AHC245DGSR require external pull-up resistors on DIR or OE pins?
Yes - the SN74AHC245DGSR has no internal pull-up or pull-down resistors on DIR or OE. To ensure deterministic startup behavior and prevent floating inputs during power-up/down, OE should be tied to VCC via a pull-up resistor (typically 10 kΩ), and DIR must be actively driven or externally biased. TI recommends this for reliable high-impedance isolation at power-on, especially in systems with uncontrolled reset sequencing.
Can the SN74AHC245DGSR translate 5 V logic signals to a 3.3 V microcontroller bus?
Yes - the SN74AHC245DGSR accepts input voltages up to 5.5 V regardless of VCC level, making it ideal for 5 V-to-3.3 V down-translation. When powered at 3.3 V, it safely interfaces with 5 V peripherals on the A or B bus while driving compliant 3.3 V logic levels (VOH ≥ 2.48 V, VOL ≤ 0.44 V at 4 mA) - eliminating the need for discrete level shifters in mixed-voltage designs.
What is the recommended bypass capacitor for the SN74AHC245DGSR VCC pin?
Texas Instruments recommends a 0.1 µF ceramic capacitor placed as close as possible to the VCC pin (Pin 20) of the SN74AHC245DGSR. For improved high-frequency noise suppression, pairing it with a 1 µF bulk capacitor in parallel is acceptable. This configuration stabilizes supply voltage during fast output transitions and meets the device's dynamic current demands without violating the 5.5 V absolute maximum rating.
Is the SN74AHC245DGSR pin-compatible with other packages in the SN74AHC245 family?
No - the SN74AHC245DGSR uses the VSSOP-20 (DGS) package, which shares the same 20-pin functional mapping but differs physically from SOIC-20 (DW), TSSOP-20 (PW), or TVSOP-20 (DGV) variants. While electrical pin functions match across packages, land patterns, thermal pads, and mechanical dimensions are not interchangeable. Board redesign is required when substituting between DGS and other footprints.
SN74AHC245DGSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-TFSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-VSSOP
SN74AHC245DGSR FAQ
1.How can I place an order for SN74AHC245DGSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC245DGSR 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 SN74AHC245DGSR reliable?
The price and inventory of SN74AHC245DGSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC245DGSR is usually 5 days.
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4.How is shipping managed for SN74AHC245DGSR?
SN74AHC245DGSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC245DGSR 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 SN74AHC245DGSR?
For technical support, including SN74AHC245DGSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC245DGSR requirements.
6.How does Aetrix verify that SN74AHC245DGSR is sourced from the original manufacturer or authorized distributors?
All SN74AHC245DGSR 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 SN74AHC245DGSR meets industry standards.
7.What is the process for return or replacement of SN74AHC245DGSR?
All SN74AHC245DGSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC245DGSR, 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 SN74AHC245DGSR part is unused and in its original packaging.
Return procedure for SN74AHC245DGSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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