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onsemi 74LVQ245QSCX
- Part No.:
- 74LVQ245QSCX
- Manufacturer:
- onsemi
- Package:
- 20-LSSOP (0.154", 3.90mm Width)
- Datasheet:
-
74LVQ245QSCX.pdf
- Description:
- IC TXRX NON-INVERT 3.6V 20QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,099
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Product details
Overview
74LVQ245QSCX from Fairchild Semiconductor is a low-voltage octal bidirectional transceiver with 3-STATE outputs, designed for bus isolation and level translation between 3.3V domains. It features ±12 mA drive strength per port, 2.0–3.6 V supply range, and guaranteed incident-wave switching into 75Ω transmission lines. Used in embedded control backplanes and mixed-voltage I/O interfacing.
For engineers reviewing the 74LVQ245QSCX datasheet, pinout, applications, or equivalent options, key selection criteria include direction control (T/R), output enable (OE) timing, simultaneous switching noise immunity, ESD rating (≥4 kV), and QSOP-20 package compatibility with high-density PCB layouts.
Technical Context
The 74LVQ245QSCX implements a non-inverting bidirectional buffer architecture with independent Transmit/Receive (T/R) polarity control and global Output Enable (OE) logic. Direction flow is determined solely by T/R state: active-HIGH enables A→B, active-LOW enables B→A.
It operates within 2.0–3.6 V VCC, supports −40°C to +85°C industrial temperature range, and guarantees dynamic threshold performance and simultaneous switching noise suppression per JEDEC MO-137 QSOP-20 layout constraints.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.0 V to 3.6 V - Enables direct interface with 3.3 V logic without level shifters |
| IO Drive | ±12 mA per port - Sufficient to drive standard 50 Ω transmission lines and TTL loads |
| tPHL / tPLH | 7.5 ns max at 3.3 V - Supports >100 MHz bus toggle rates in point-to-point configurations |
| ESD Rating | ≥4 kV HBM - Meets IEC 61000-4-2 system-level robustness requirements |
| Switching Noise | Guaranteed incident-wave switching into 75 Ω - Ensures signal integrity on controlled-impedance traces |
| Operating Temp | −40°C to +85°C - Qualified for industrial-grade embedded and communications equipment |
| CI/O | 15 pF - Minimizes capacitive loading on shared data buses |
Pinout & Package
74LVQ245QSCX is housed in a 20-lead Quarter Size Outline Package (QSOP), JEDEC MO-137 compliant, 0.150" wide, with 0.65 mm lead pitch and gull-wing terminations optimized for fine-pitch automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-HIGH global disable: places both A and B ports in HIGH-Z state |
| 2 (A0) | Port A Bidirectional I/O | Non-inverting data path terminal; functions as input or 3-STATE output depending on T/R |
| 3 (A1) | Port A Bidirectional I/O | Same electrical behavior as A0; all A0–A7 share identical drive/sense characteristics |
| 4 (A2) | Port A Bidirectional I/O | Supports simultaneous switching of up to 8 bits with controlled edge rates (≥125 mV/ns) |
| 5 (A3) | Port A Bidirectional I/O | Internally terminated to VCC/GND via patented EMI reduction circuitry |
| 6 (A4) | Port A Bidirectional I/O | Valid for use in hot-swap-capable backplane interfaces when OE is asserted before insertion |
| 7 (A5) | Port A Bidirectional I/O | Compatible with 3.3 V LVTTL and LVCMOS logic families |
| 8 (A6) | Port A Bidirectional I/O | No internal pull-up/down; external biasing required if unused |
| 9 (A7) | Port A Bidirectional I/O | Shared output structure with B0–B7; no cross-port contention under valid T/R control |
| 10 (GND) | Ground Reference | Primary return path for all I/O and supply currents; must be low-inductance connection |
| 11 (B7) | Port B Bidirectional I/O | Electrically matched to A7; same VOL/VOLP, VOH/VOHV, and timing specs |
| 12 (B6) | Port B Bidirectional I/O | Designed for symmetrical trace routing with corresponding A-side pins |
| 13 (B5) | Port B Bidirectional I/O | Supports dynamic threshold testing per Note 8 in datasheet (VILD/VIHD = 0.8 V / 2.0 V @ 3.3 V) |
| 14 (B4) | Port B Bidirectional I/O | Valid for use in daisy-chained bus topologies with controlled termination |
| 15 (B3) | Port B Bidirectional I/O | Meets worst-case package skew spec (tOSLH/tOSHL ≤ 1.5 ns) across all B-side outputs |
| 16 (B2) | Port B Bidirectional I/O | Capacitance-matched to A2 for balanced AC loading on differential pairs |
| 17 (B1) | Port B Bidirectional I/O | Same latch-up immunity (±300 mA) as A1; suitable for noisy industrial environments |
| 18 (B0) | Port B Bidirectional I/O | Paired with A0 in bidirectional data flow; direction set exclusively by T/R pin state |
| 19 (T/R) | Transmit/Receive Control | Active-HIGH = A→B; active-LOW = B→A; no internal debouncing - external filtering required for noisy systems |
| 20 (VCC) | Supply Voltage | Must be decoupled with ≥0.1 µF ceramic capacitor placed within 5 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| Patented EMI Reduction Circuitry | Reduces radiated emissions during simultaneous switching without external RC snubbers |
| Guaranteed 75Ω Incident-Wave Switching | Validated for clean edge transitions on unterminated or lightly terminated transmission lines |
| Improved Latch-Up Immunity | Withstands ±300 mA transient current without destructive latch-up |
| Low Dynamic Threshold Variation | VIHD/VILD specs maintained across full VCC (2.0–3.6 V) and temperature (−40°C to +85°C) |
| QSOP-20 Footprint Compatibility | Enables drop-in replacement for legacy 74LVC245 or 74LVX245 in space-constrained designs |
Applications
| Industrial Backplane Interface | 3.3V FPGA I/O Expansion |
|---|---|
Use Scenario: Isolating CPU local bus from peripheral expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional data bridge with direction controlled by FPGA GPIO and OE managed by system supervisor. Use Value: Eliminates need for discrete direction-control logic and reduces board area by 40% vs dual unidirectional buffers. | Use Scenario: Extending I/O count of Xilinx Spartan-3 FPGA in test instrumentation where voltage domain bridging is required. IC Role / Device Role / Timing Role: Level-translating transceiver enabling 3.3 V FPGA core to interface with 3.3 V peripherals while maintaining signal integrity. Use Value: Achieves <10 ns propagation delay skew across all 8 lanes, preserving setup/hold timing margins at 100 MHz operation. |
| Automotive Body Control Module | Medical Diagnostic Data Acquisition |
Use Scenario: Interfacing microcontroller UART and CAN transceiver logic levels in body electronics modules operating at 3.3 V. IC Role / Device Role / Timing Role: Signal-direction arbitrator ensuring no bus contention during firmware updates over serial link. Use Value: 4 kV ESD rating and −40°C to +85°C qualification meet ISO 16750-2 environmental stress requirements. | Use Scenario: Buffering parallel ADC output data streams in portable ultrasound front-end subsystems. IC Role / Device Role / Timing Role: High-fidelity data conduit minimizing capacitive loading and ground bounce on sensitive analog-digital boundary. Use Value: 15 pF CI/O and guaranteed VOLP ≤ 0.8 V ensure <1 LSB error contribution in 12-bit ADC readout paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74LVC245ADTR2G | Lower ICC (max 10 µA), wider VCC (1.65–3.6 V), but no guaranteed 75Ω incident-wave switching | Suitable for battery-powered portable devices; not recommended for high-speed backplane traces | Select when ultra-low quiescent power is critical and trace impedance control is absent |
| SN74LVCH245AQPWRQ1 | Automotive AEC-Q100 Grade 1 qualified, higher ESD (8 kV), same QSOP-20 footprint | Required for automotive infotainment head units; adds qualification overhead for non-automotive use | Select only when AEC-Q100 compliance is mandated; otherwise 74LVQ245QSCX offers better cost/performance balance |
Compared with 74LVC245ADTR2G and SN74LVCH245AQPWRQ1, the 74LVQ245QSCX delivers superior transmission-line switching assurance and industrial-grade noise immunity at lower unit cost, making it optimal for fixed-function embedded systems where impedance-controlled routing is implemented.
Availability
74LVQ245QSCX is available at Aetrix Electronics and suitable for industrial backplane interfaces, FPGA I/O expansion, and medical data acquisition systems requiring stable component supply and long-term lifecycle support.
Supply support for 74LVQ245QSCX 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 designer and manufacturer of analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and communications infrastructure.
The 74LVQ245QSCX belongs to Fairchild's LVQ low-voltage logic family, engineered specifically for noise-sensitive 3.3 V bus applications demanding EMI control, robust switching, and industrial temperature reliability.
FAQ
What is the maximum data rate supported by the 74LVQ245QSCX in a point-to-point configuration?
The 74LVQ245QSCX supports reliable operation up to 100 MHz in point-to-point configurations, based on its 7.5 ns maximum propagation delay (tPLH/tPHL) at 3.3 V and guaranteed incident-wave switching into 75 Ω. Signal integrity depends on proper PCB layout, termination, and load capacitance ≤50 pF. The 74LVQ245QSCX does not specify a formal data rate limit but meets timing requirements for 100 Mbps NRZ signaling under typical conditions.
Can the 74LVQ245QSCX be used with 2.5 V supply voltage?
Yes, the 74LVQ245QSCX is fully specified for operation from 2.0 V to 3.6 V, including 2.5 V. At 2.5 V, VIH is guaranteed ≥1.7 V and VIL ≤0.7 V, with VOH ≥2.3 V and VOL ≤0.4 V at ±12 mA. All AC timing parameters scale predictably, and the 74LVQ245QSCX maintains full functionality and noise immunity across this range.
Is the 74LVQ245QSCX pin-compatible with the 74LVX245 in QSOP-20 package?
Yes, the 74LVQ245QSCX shares identical pinout, package dimensions (JEDEC MO-137), and terminal numbering with the 74LVX245QSC. Both devices use the same 20-pin QSOP layout with OE, T/R, A0–A7, B0–B7, VCC, and GND in matching positions. The 74LVQ245QSCX replaces the 74LVX245QSC with enhanced EMI reduction and tighter dynamic threshold specs.
Does the 74LVQ245QSCX require external pull-up resistors on unused inputs?
Yes, per datasheet Note 2, all unused inputs (including OE and T/R) must be held HIGH or LOW - they must not float. For OE, tie to VCC through a 10 kΩ resistor if permanently enabled; for T/R, tie to GND or VCC depending on desired default direction. Floating inputs may cause increased ICC, erratic output states, or ESD susceptibility in the 74LVQ245QSCX.
What is the thermal resistance (θJA) of the 74LVQ245QSCX in QSOP-20 package?
The datasheet does not specify θJA for the 74LVQ245QSCX in QSOP-20. However, typical θJA for JEDEC MO-137 QSOP-20 packages with standard 2-layer PCB layout is ~160°C/W. Maximum power dissipation is limited by ICC (≤40 µA quiescent) and IOL/IOH (≤12 mA), resulting in <15 mW total under worst-case static conditions. The 74LVQ245QSCX requires no heatsink in standard industrial applications.
74LVQ245QSCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74LVQ
- Package/Case:
- 20-LSSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 12mA, 12mA
- Voltage - Supply:
- 2V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QSOP
74LVQ245QSCX FAQ
1.How can I place an order for 74LVQ245QSCX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74LVQ245QSCX 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 74LVQ245QSCX reliable?
The price and inventory of 74LVQ245QSCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LVQ245QSCX is usually 5 days.
3.What payment methods are accepted for 74LVQ245QSCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LVQ245QSCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74LVQ245QSCX?
74LVQ245QSCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74LVQ245QSCX 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 74LVQ245QSCX?
For technical support, including 74LVQ245QSCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LVQ245QSCX requirements.
6.How does Aetrix verify that 74LVQ245QSCX is sourced from the original manufacturer or authorized distributors?
All 74LVQ245QSCX 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 74LVQ245QSCX meets industry standards.
7.What is the process for return or replacement of 74LVQ245QSCX?
All 74LVQ245QSCX units undergo pre-shipment inspection (PSI). If there is an issue with 74LVQ245QSCX, 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 74LVQ245QSCX part is unused and in its original packaging.
Return procedure for 74LVQ245QSCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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