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Texas Instruments SN74HC245ADBR
- Part No.:
- SN74HC245ADBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74HC245ADBR.pdf
- Description:
- IC TXRX NON-INVERT 6V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,000
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Product details
Overview
SN74HC245ADBR from Texas Instruments is an 8-bit non-inverting bidirectional bus transceiver with 3-state outputs, designed for level-shifting and bus isolation in digital systems. It features direction control (DIR) and active-low output enable (OE), operates from 2 V to 6 V, supports −40 °C to +85 °C ambient range, and delivers 7 ns typical propagation delay at 4.5 V - used in microcontroller peripheral interfacing and memory address/data bus management.
For engineers reviewing the SN74HC245ADBR datasheet, SN74HC245ADBR pinout, SN74HC245ADBR application, or SN74HC245ADBR equivalent, key selection criteria include CMOS-level input compatibility, 3-state bus contention avoidance, bidirectional data flow control, and SSOP-20 package suitability for space-constrained PCB layouts.
Technical Context
The SN74HC245ADBR implements a dual-bus architecture where DIR selects signal flow direction between two 8-bit parallel ports (A0–A7 and B0–B7), while OE independently places all outputs in high-impedance state. Its CMOS input structure provides high noise immunity and low static current draw.
It integrates input clamp diodes enabling safe interface to voltages exceeding VCC when used with current-limiting resistors, and meets JEDEC JESD7A for logic family compliance. ESD protection exceeds 2000 V HBM and 200 V MM per JESD22-A114F/A115-A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage (VCC) | 2.0 V to 6.0 V - enables interoperability across 3.3 V and 5 V logic domains without level shifters. |
| Propagation delay (tpd) | 7 ns typical at VCC = 4.5 V, CL = 15 pF - supports >10 MHz bus clock rates in synchronous data transfer. |
| Output drive strength | ±6 mA at VCC = 4.5 V - sufficient to drive standard TTL loads and multiple CMOS inputs on shared buses. |
| Input leakage current | ±1.0 µA max over temperature - ensures minimal power impact in battery-backed or low-power standby modes. |
| Operating temperature | −40 °C to +85 °C - qualified for industrial-grade embedded control and instrumentation applications. |
| Input capacitance (CI) | 3.5 pF - reduces capacitive loading on driving sources, preserving signal integrity in high-speed routing. |
| Power dissipation capacitance (CPD) | 30 pF per buffer - enables accurate dynamic power estimation using PD = CPD × VCC² × fi × N. |
Pinout & Package
SN74HC245ADBR uses a 20-pin SSOP (Shrink Small Outline Package) with 5.3 mm body width (SOT339-1), optimized for higher I/O density than SOIC while maintaining surface-mount compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | LOW routes data from port A to port B; HIGH routes from port B to port A - enables full-duplex bus arbitration. |
| 2–9 (A0–A7) | Port A data I/O | Bidirectional data lines tied to microcontroller or FPGA I/O banks - clamped inputs tolerate overvoltage during hot-swap events. |
| 10 (GND) | Ground reference | 0 V return path for all internal logic and output drivers - must be low-impedance for stable noise margin. |
| 11–18 (B0–B7) | Port B data I/O | Parallel bus interface to memory, peripherals, or other logic - identical electrical behavior to port A pins. |
| 19 (OE) | Active-low output enable | Drives all outputs to high-impedance when HIGH - prevents bus contention during multi-master arbitration or power sequencing. |
| 20 (VCC) | Positive supply | Primary power rail for logic core and output buffers - requires local 100 nF decoupling near pin 20. |
Key Features
| Feature | Design Value |
|---|---|
| Octal bidirectional bus interface | Single device replaces eight discrete unidirectional buffers - reduces component count and layout area in 8-bit data paths. |
| Non-inverting 3-state outputs | Preserves logic polarity across both directions while enabling bus sharing among multiple masters without external logic. |
| CMOS-level input compatibility | VIH = 3.15 V min at VCC = 4.5 V - ensures reliable recognition of 3.3 V logic HIGHs when interfacing mixed-voltage systems. |
| Input clamp diodes | Allows safe connection to signals up to VCC + 0.5 V using series current-limiting resistors - eliminates need for external protection in many cases. |
| JEDEC JESD7A compliance | Guarantees interoperability with industry-standard HC logic families - simplifies design reuse and qualification documentation. |
Applications
| Microcontroller Peripheral Expansion | Memory Address/Data Bus Isolation |
|---|---|
|
Use Scenario: Expanding GPIO count of an ARM Cortex-M0+ MCU to drive 8-bit LCD controller and SPI flash simultaneously. IC Role / Device Role / Timing Role: Bidirectional data bridge between MCU's limited parallel port and external peripherals, controlled via DIR and OE signals synchronized to MCU timing. Use Value: Eliminates need for separate TX/RX buffers and reduces PCB layer count by consolidating bus direction control into one IC with deterministic 7 ns tpd. |
Use Scenario: Isolating Z80 CPU address/data bus from EPROM and RAM chips during write cycles to prevent back-driving. IC Role / Device Role / Timing Role: 3-state transceiver placed between CPU AD0–AD7 and memory devices, enabled only during valid read/write windows. Use Value: Prevents bus contention faults and latch-up risk during memory access transitions, with <45 ns disable time ensuring clean bus release before next cycle. |
| Industrial PLC I/O Module Interface | Legacy ISA Bus Signal Conditioning |
|
Use Scenario: Interfacing isolated 24 V digital inputs to a 3.3 V FPGA-based controller in a DIN-rail mounted PLC module. IC Role / Device Role / Timing Role: Level-shifting and buffering interface between optocoupler outputs and FPGA I/O banks, operating within −40 °C to +85 °C industrial range. Use Value: Input clamp diodes allow direct connection to 24 V signals with simple 22 kΩ series resistors, reducing BOM cost versus dedicated level translators. |
Use Scenario: Adapting vintage ISA bus signals (5 V TTL) to modern 3.3 V SoC-based diagnostic hardware for retro-computing restoration. IC Role / Device Role / Timing Role: Bidirectional data transceiver handling ISA D0–D7 lines, with DIR driven by ISA IOR/IOW and OE tied to chip select decoding. Use Value: CMOS inputs accept 5 V TTL logic levels reliably, while 3.3 V-compatible outputs meet modern SoC input thresholds - no external level shifters required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HC245DBR | Same function, identical pinout, but manufactured by NXP Semiconductors - slightly higher max ICC (160 µA vs. 80 µA at 25 °C) and wider VCC tolerance (2.0–6.0 V same). | Qualified to −40 °C to +125 °C - suitable for extended-temperature automotive or under-hood industrial use where SN74HC245ADBR's +85 °C limit is insufficient. | Select 74HC245DBR when extended temperature operation or alternate supply chain sourcing is required; otherwise SN74HC245ADBR offers tighter static current spec at room temperature. |
| SN74HCT245DBR | TTL-compatible inputs (VIH = 2.0 V min at VCC = 4.5 V) instead of CMOS - lower input threshold improves noise margin with legacy 5 V TTL drivers. | Designed specifically for interfacing 5 V TTL logic to 5 V CMOS buses - not recommended for 3.3 V-only systems due to marginal VIH margin at lower VCC. | Choose SN74HCT245DBR when connecting to older 5 V TTL sources; SN74HC245ADBR is preferred for mixed 3.3/5 V systems requiring robust CMOS input thresholds. |
Compared with SN74HC245ADBR, 74HC245DBR extends thermal range without altering pinout or logic behavior, while SN74HCT245DBR trades CMOS input sensitivity for guaranteed TTL compatibility - making each alternative optimal for distinct voltage-domain and environmental constraints.
Availability
SN74HC245ADBR is available at Aetrix Electronics and suitable for industrial control systems, embedded microcontroller interfaces, memory subsystems, and legacy bus adapters requiring stable component supply and long-term manufacturability.
Supply support for SN74HC245ADBR 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 specializing in analog, embedded processing, and logic solutions, with decades of heritage in industry-standard logic families including the 74HC series.
The SN74HC245ADBR belongs to TI's 74HC high-speed CMOS logic product line, engineered for low-power, high-noise-immunity digital interfacing in industrial, computing, and communications equipment.
FAQ
What is the maximum operating voltage for SN74HC245ADBR?
The SN74HC245ADBR supports a supply voltage range of 2.0 V to 6.0 V per its recommended operating conditions. Absolute maximum rating is +7 V, but sustained operation above 6.0 V risks reliability degradation. At 6.0 V, propagation delay is 7 ns typical and output drive reaches ±7.8 mA, making SN74HC245ADBR suitable for both 3.3 V and 5 V system integration.
Does SN74HC245ADBR support bidirectional data flow without external logic?
Yes, SN74HC245ADBR enables true bidirectional data transfer using only its DIR pin: when DIR = LOW, data flows from port A to port B; when DIR = HIGH, data flows from port B to port A. No external gates or control logic are needed - this native direction control is central to SN74HC245ADBR's role in bus expansion and memory interfacing.
How does the output enable (OE) pin function on SN74HC245ADBR?
The OE pin on SN74HC245ADBR is active-low: when OE = HIGH, all 16 I/O pins (A0–A7 and B0–B7) enter high-impedance state, effectively disconnecting both ports from the bus. When OE = LOW, direction and data transfer are enabled per DIR state. This allows SN74HC245ADBR to share buses among multiple devices without contention.
Can SN74HC245ADBR interface 3.3 V and 5 V logic domains safely?
Yes, SN74HC245ADBR can safely interface 3.3 V and 5 V domains. Its CMOS inputs accept 3.3 V logic HIGHs (VIH = 3.15 V min at VCC = 4.5 V), and its outputs swing rail-to-rail - delivering ~3.3 V HIGH when VCC = 3.3 V and ~5 V HIGH when VCC = 5 V. Input clamp diodes also permit overvoltage-tolerant connections with current-limiting resistors.
What package type is used by SN74HC245ADBR?
SN74HC245ADBR uses a 20-pin SSOP (Shrink Small Outline Package) with 5.3 mm body width (JEDEC MO-153, TI package code DB). This package offers higher pin density than SOIC while maintaining compatibility with standard SMT reflow processes - critical for compact industrial and portable electronics designs utilizing SN74HC245ADBR.
SN74HC245ADBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74HC245ADBR FAQ
1.How can I place an order for SN74HC245ADBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC245ADBR 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 SN74HC245ADBR reliable?
The price and inventory of SN74HC245ADBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC245ADBR is usually 5 days.
3.What payment methods are accepted for SN74HC245ADBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC245ADBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC245ADBR?
SN74HC245ADBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC245ADBR 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 SN74HC245ADBR?
For technical support, including SN74HC245ADBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC245ADBR requirements.
6.How does Aetrix verify that SN74HC245ADBR is sourced from the original manufacturer or authorized distributors?
All SN74HC245ADBR 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 SN74HC245ADBR meets industry standards.
7.What is the process for return or replacement of SN74HC245ADBR?
All SN74HC245ADBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC245ADBR, 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 SN74HC245ADBR part is unused and in its original packaging.
Return procedure for SN74HC245ADBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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