Texas Instruments SN74CBTLV3245AZQNR

Overview

SN74CBTLV3245AZQNR from Texas Instruments is a low-voltage octal FET bus switch in a 20-pin QFN (RGY) package, featuring 5-Ω on-state resistance, rail-to-rail switching, and I_off support for partial-power-down mode. It provides bidirectional 8-bit port A ↔ port B connectivity with OE-controlled enable/disable, used in high-speed data path isolation for FPGA I/O expansion and memory interface buffering.

For engineers reviewing the SN74CBTLV3245AZQNR datasheet, SN74CBTLV3245AZQNR pinout, SN74CBTLV3245AZQNR application, or SN74CBTLV3245AZQNR equivalent, key selection criteria include on-resistance matching (<8 Ω at 3 V), I_off leakage (<40 µA at V_CC = 0), thermal impedance (37 °C/W), and QFN-20 footprint compatibility with JEDEC MO-220.

Technical Context

The SN74CBTLV3245AZQNR implements eight independent NMOS pass-gate switches with no internal level-shifting circuitry-each switch connects A_n to B_n directly when OE is low. Its rail-to-rail operation supports signal voltages from GND to V_CC (2.3–3.6 V), and the I_off feature disables current backflow when V_CC = 0, enabling safe hot-insertion in multi-rail systems.

Unlike traditional TTL or CMOS buffers, this device has no propagation delay specification per se-its t_pd is derived from RC time constant (typ. 0.15 ns at V_CC = 2.5 V, C_L = 30 pF). The OE input is CMOS-compatible with VIH ≥ 2.0 V (at V_CC = 3.6 V) and VIL ≤ 0.8 V, and all unused control inputs must be tied to V_CC or GND.

Key Specifications

Pinout & Package

SN74CBTLV3245AZQNR uses a 20-pin QFN package (RGY) with exposed thermal pad, compliant with JEDEC MO-220 and RoHS/Green specifications. Pin 1 is marked by a dot; pins are numbered counterclockwise with OE at pin 1, B1–B8 occupying pins 2–9 and 19–20, A1–A8 at pins 11–18, V_CC at pin 10, GND at pin 19, and NC at pins 1 and 20 (no internal connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus switch applications.

Compared with SN74CBTLV3245ADGVR and SN74CBTLV3245APWR, the SN74CBTLV3245AZQNR offers superior thermal management (37 °C/W) and smaller PCB area, making it optimal for space-constrained, high-density FPGA carrier boards where thermal dissipation and signal integrity are critical.

Availability

SN74CBTLV3245AZQNR is available at Aetrix Electronics and suitable for FPGA I/O expansion, DDR3 memory interface buffering, PCIe slot isolation, and industrial sensor multiplexing requiring stable component supply across automotive-grade temperature ranges (–40°C to 85°C).

Supply support for SN74CBTLV3245AZQNR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets since 1930.

The SN74CBTLV3245AZQNR belongs to TI's CBTLV (Crossbar Bus Transceiver Low-Voltage) family, engineered specifically for high-speed, low-distortion signal routing in dense digital systems where power efficiency and signal fidelity are co-prioritized.

FAQ

What is the maximum operating voltage for SN74CBTLV3245AZQNR?

The SN74CBTLV3245AZQNR has an absolute maximum supply voltage of 4.6 V, but its recommended operating range is strictly 2.3 V to 3.6 V. Operation outside this window risks exceeding the 5-Ω on-resistance spec and may degrade latch-up immunity below the guaranteed 250 mA per JESD 17. Always maintain V_CC regulation within ±3% for stable r_on performance in the SN74CBTLV3245AZQNR.

Does SN74CBTLV3245AZQNR support hot-swap applications?

Yes, the SN74CBTLV3245AZQNR supports hot-swap via its I_off feature: when V_CC = 0 V, leakage current stays below 40 µA even with A/B ports biased up to 3.6 V. This prevents back-current damage during live insertion, making the SN74CBTLV3245AZQNR suitable for modular backplanes and field-replaceable units without auxiliary power sequencing circuitry.

Can SN74CBTLV3245AZQNR be used for analog signal switching?

Yes-the SN74CBTLV3245AZQNR supports rail-to-rail analog switching from GND to V_CC, with flat on-resistance (5–8 Ω) and low OFF-capacitance (9 pF). It preserves signal linearity for ±10 V analog ranges when V_CC ≥ 10 V is not required; however, the SN74CBTLV3245AZQNR does not support voltages beyond its V_CC rail, so external clamping is needed for overvoltage conditions.

What is the thermal pad requirement for SN74CBTLV3245AZQNR?

The SN74CBTLV3245AZQNR QFN package includes an exposed thermal pad (EP) that must be soldered to a dedicated PCB copper pour connected to GND. TI recommends a 3×3 array of thermal vias (0.3 mm diameter, 0.5 mm pitch) under the EP to achieve the rated 37 °C/W θ_JA. Omitting the thermal pad connection raises junction temperature by >25°C at full 128 mA load, risking parametric drift in the SN74CBTLV3245AZQNR.

Is SN74CBTLV3245AZQNR pin-compatible with older 74-series bus switches?

The SN74CBTLV3245AZQNR follows the standard '245-type pinout (OE, A1–A8, V_CC, GND, B1–B8), making it mechanically and functionally compatible with 74LVC245 and 74ALVC245 in 20-pin packages. However, the SN74CBTLV3245AZQNR lacks output-enable inversion and has no 3-state output drivers-its high-impedance state is purely passive, requiring external pull-ups if driven by open-drain sources.