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onsemi 74ACQ245PC
- Part No.:
- 74ACQ245PC
- Manufacturer:
- onsemi
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
74ACQ245PC.pdf
- Description:
- IC TXRX NON-INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,151
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Product details
Overview
74ACQ245PC from Fairchild Semiconductor is an octal bidirectional transceiver with 3-STATE inputs/outputs, designed for bus-oriented data transfer between two 8-bit buses. It operates across 2.0V–6.0V VCC, delivers ±24 mA output drive, features guaranteed pin-to-pin skew <1.5 ns at 5.0V, and uses Quiet Series™ technology to suppress simultaneous switching noise. It is used in industrial control backplanes requiring clean level translation between TTL/CMOS domains.
For engineers reviewing the 74ACQ245PC datasheet, pinout, applications, or equivalent options, key selection criteria include its 3.3V/5V dual-supply compatibility, dynamic input threshold guarantees (VIHD/VILD), quiet-output VOLP/VOLV noise margins, and PDIP-20 package suitability for prototyping and legacy board upgrades.
Technical Context
The 74ACQ245PC implements non-inverting bidirectional buffering controlled by separate T/R (direction) and OE (output enable) inputs. Its logic flow is fully static: when OE = LOW, direction is determined solely by T/R - HIGH enables A→B, LOW enables B→A; when OE = HIGH, both ports enter high-impedance state regardless of T/R.
It employs Fairchild's Quiet Series™ architecture with GTO™ output control and undershoot correction, plus split ground bus design. This reduces ICC and IOZ by 50% versus standard ACT245 and guarantees simultaneous switching noise performance per JEDEC test methodology using 1 MHz toggling with 50 pF load and 150 ps channel deskew.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.0V to 6.0V - supports mixed-voltage bus interfacing (e.g., 3.3V microcontroller to 5V peripheral bus) |
| Output Drive | ±24 mA - sufficient to directly drive standard TTL loads or terminate short PCB traces without external buffers |
| tPHL / tPLH | 5.0 ns max at 5.0V - enables reliable operation in 100+ MHz bus systems with margin for trace delays |
| tPZL / tPHZ | 9.0 ns / 10.0 ns max - fast enable/disable timing allows dynamic bus arbitration in shared-memory architectures |
| VOLP / VOLV | 1.5 V / 1.2 V max at 5.0V - quantified quiet-output dynamic low-voltage noise floor ensures signal integrity during heavy switching |
| VIHD / VILD | 2.2 V / 0.8 V at 5.0V - dynamically tested input thresholds improve noise immunity in electrically noisy industrial environments |
| ICC Quiescent | 40 µA max - ultra-low static power supports battery-backed or energy-sensitive control modules |
Pinout & Package
74ACQ245PC is housed in a 20-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide - compatible with through-hole prototyping, socket-based test fixtures, and legacy industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-LOW global control: asserts HIGH-Z on both A and B ports when HIGH - essential for bus contention avoidance |
| 2–9 (A0–A7) | Side A I/O Terminals | Bidirectional data lines; function as inputs or outputs depending on T/R state - connect to local processor/data bus |
| 10 (GND) | Ground Reference | Primary return path for all I/O and supply currents - must be low-inductance connection to minimize QUIET Series™ noise coupling |
| 11–18 (B0–B7) | Side B I/O Terminals | Bidirectional data lines mirroring A-side behavior - interface to peripheral bus, memory array, or expansion slot |
| 19 (T/R) | Transmit/Receive Control | Active-HIGH selects A→B direction; active-LOW selects B→A - enables full-duplex bus arbitration without external logic |
| 20 (VCC) | Positive Supply | 2.0V–6.0V tolerant rail - decoupling capacitor required within 10 mm for stable Quiet Series™ operation |
Key Features
| Feature | Design Value |
|---|---|
| GTO™ Output Control | Actively regulates edge rate to reduce EMI and overshoot - verified via 1 MHz simultaneous switching tests with 50 pF load |
| Split Ground Bus | Dedicated low-noise ground routing inside die separates I/O and core logic returns - improves dynamic threshold stability under load |
| Guaranteed Pin-to-Pin Skew | <1.5 ns (tOSHL/tOSLH) at 5.0V - ensures deterministic timing alignment across all 8 channels in high-speed bus applications |
| Improved Latch-Up Immunity | Rated to ±300 mA - protects against transient-induced CMOS latch-up in industrial power-up/power-down sequences |
| 50% Lower ICC/IOZ | Quiescent current ≤40 µA and off-state leakage ≤3.0 µA - extends uptime in always-on monitoring subsystems |
Applications
| Industrial Backplane Interface | Legacy System Bus Extension |
|---|---|
|
Use Scenario: Interfacing a modern 3.3V FPGA I/O bank to a legacy 5V ISA-style control bus in factory automation PLCs. IC Role / Device Role / Timing Role: Bidirectional voltage-tolerant transceiver managing data flow direction and isolation between mismatched voltage domains. Use Value: Eliminates need for discrete level-shifters while maintaining sub-10 ns propagation delay and noise-controlled edges per Quiet Series™ spec. |
Use Scenario: Upgrading a vintage test instrument's CPU bus to support additional memory-mapped peripherals without redesigning the motherboard. IC Role / Device Role / Timing Role: Octal bus buffer enabling hot-plug-compatible expansion slots via OE-controlled tristate arbitration. Use Value: PDIP-20 footprint matches original socket; 24 mA drive supports longer trace runs than older 74LS245 variants. |
| Programmable Logic Debug Bridge | Embedded Controller Data Mux |
|
Use Scenario: Real-time visibility into internal FPGA or CPLD data paths during bring-up using JTAG-accessible boundary-scan test points. IC Role / Device Role / Timing Role: Transparent bidirectional pass-through element allowing host PC software to read/write device registers via parallel debug port. Use Value: Guaranteed VIHD/VILD thresholds ensure reliable sampling even with marginal signal rise/fall times on debug cables. |
Use Scenario: Sharing a single 8-bit ADC data bus between multiple microcontrollers in a distributed sensor node with time-division multiplexing. IC Role / Device Role / Timing Role: Directionally controlled data switch synchronized to master clock and OE strobes from system controller. Use Value: Fast tPZL/tPHZ (≤9 ns) enables tight timing windows for multi-master arbitration without bus glitches. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACTQ245PC | 5.0V-only VCC range (4.5–5.5V); higher VIH/VIL thresholds; identical pinout and Quiet Series™ features | Optimized for pure 5V systems; not suitable for 3.3V mixed-voltage designs | Select when operating exclusively at 5V and requiring tighter input noise margins (VIHD = 2.2V vs ACQ's 1.9V) |
| SN74LVC245APWR | 3.3V-only (1.65–3.6V); lower drive (±24 mA same, but VOL higher at 3.3V); no Quiet Series™ noise suppression | Targets modern low-voltage portable/embedded systems; lacks dynamic noise characterization | Choose for cost-sensitive 3.3V-only designs where simultaneous switching noise is mitigated externally |
Compared with 74ACTQ245PC and SN74LVC245APWR, the 74ACQ245PC uniquely supports 2.0–6.0V operation with certified quiet-output noise performance - making it the only option for robust mixed-voltage bus bridging in electrically harsh industrial settings.
Availability
74ACQ245PC is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, and programmable logic debug bridges requiring stable component supply and long-term obsolescence management.
Supply support for 74ACQ245PC 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 U.S.-based analog and power IC manufacturer, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and automotive systems.
The 74ACQ245PC belongs to the Quiet Series™ family, engineered specifically for noise-critical bus applications where simultaneous switching noise and dynamic threshold instability degrade system reliability.
FAQ
What voltage range does the 74ACQ245PC support?
The 74ACQ245PC supports a VCC range of 2.0V to 6.0V, enabling interoperability between 3.3V and 5V logic domains without level-shifting circuitry. This specification is guaranteed across the full operating temperature range of –40°C to +85°C, and applies to both input thresholds and output drive capability - making the 74ACQ245PC suitable for mixed-voltage industrial backplanes where supply rails may vary.
How does the 74ACQ245PC differ from standard 74AC245 devices?
The 74ACQ245PC integrates Fairchild's Quiet Series™ technology - including GTO™ output control, undershoot correction, and a split ground bus - which reduces simultaneous switching noise and improves dynamic threshold performance. Unlike standard 74AC245, the 74ACQ245PC provides guaranteed VOLP/VOLV and VIHD/VILD values measured under JEDEC-defined noise test conditions, and achieves 50% lower ICC/IOZ. These enhancements are documented in the March 2005 revision of the 74ACQ245PC datasheet.
Is the 74ACQ245PC pin-compatible with other 74xx245 variants?
Yes, the 74ACQ245PC shares identical pinout and function mapping with 74AC245, 74ACT245, and 74ACTQ245 in the PDIP-20 package (N20A). All use the same OE, T/R, A0–A7, B0–B7, VCC, and GND assignments. However, differences in VCC range, input thresholds, and noise characteristics mean functional substitution requires validation of voltage domain compatibility and noise margin requirements in the target application.
What is the maximum output drive capability of the 74ACQ245PC?
The 74ACQ245PC delivers ±24 mA output sink/source current per I/O pin at VCC = 5.0V, with VOL ≤ 0.44 V and VOH ≥ 4.76 V under that load. This drive strength is specified across the full operating temperature range and supports direct interfacing to standard TTL loads, termination resistors, and moderate-length PCB traces - eliminating the need for external buffer stages in most industrial bus implementations using the 74ACQ245PC.
Does the 74ACQ245PC require special PCB layout considerations?
Yes - due to its Quiet Series™ architecture, the 74ACQ245PC requires low-inductance grounding: the GND pin (Pin 10) must connect to a solid ground plane within 10 mm, and a 0.1 µF ceramic decoupling capacitor should be placed adjacent to Pin 20 (VCC). Avoid routing noisy signals near the A/B I/O banks, and maintain separation between VCC and GND traces to preserve the split ground bus benefits confirmed in the 74ACQ245PC datasheet's noise characterization section.
74ACQ245PC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACQ
- Package/Case:
- 20-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:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
74ACQ245PC FAQ
1.How can I place an order for 74ACQ245PC through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACQ245PC 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 74ACQ245PC reliable?
The price and inventory of 74ACQ245PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACQ245PC is usually 5 days.
3.What payment methods are accepted for 74ACQ245PC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACQ245PC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACQ245PC?
74ACQ245PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACQ245PC 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 74ACQ245PC?
For technical support, including 74ACQ245PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACQ245PC requirements.
6.How does Aetrix verify that 74ACQ245PC is sourced from the original manufacturer or authorized distributors?
All 74ACQ245PC 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 74ACQ245PC meets industry standards.
7.What is the process for return or replacement of 74ACQ245PC?
All 74ACQ245PC units undergo pre-shipment inspection (PSI). If there is an issue with 74ACQ245PC, 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 74ACQ245PC part is unused and in its original packaging.
Return procedure for 74ACQ245PC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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