Texas Instruments SN74LVCC3245ANSR

Overview

SN74LVCC3245ANSR from Texas Instruments is an octal noninverting bus transceiver with dual supply rails (VCCA: 2.3–3.6 V, VCCB: 3–5.5 V), enabling bidirectional level translation between 2.5/3.3 V and 5 V domains. It features 3-state outputs controlled by DIR and active-low OE, 24 mA drive strength at 3 V, and operates from –40°C to +85°C. It is used in ultrasound scanners and string inverters for isolated data bus interfacing.

For engineers reviewing the SN74LVCC3245ANSR datasheet, SN74LVCC3245ANSR pinout, SN74LVCC3245ANSR application, or SN74LVCC3245ANSR equivalent, this page delivers verified electrical specs, functional mode behavior, VCC isolation behavior, glitch-free sequencing validation, and real-world implementation constraints - all confirmed against TI's SCAS585R production datasheet.

Technical Context

The SN74LVCC3245ANSR implements asynchronous bidirectional translation using independent A- and B-port supply domains. Control logic (DIR, OE) is referenced solely to VCCA, while I/O voltage levels track their respective VCC rails - enabling robust 2.5 V ↔ 5 V or 3.3 V ↔ 5 V translation without external biasing. Its Ioff circuitry ensures <±2 µA power-off leakage when either VCCA or VCCB is near 0 V.

VCC isolation triggers high-impedance output states if either VCCA or VCCB falls below 100 mV or floats, preventing backdrive damage. Glitch-free sequencing guarantees no spurious transitions during asymmetric power-up/down, critical for mixed-voltage industrial control buses where supply ramp order cannot be guaranteed.

Key Specifications

Pinout & Package

Packaged in a 24-pin SSOP (DB) with 8.2 mm × 7.8 mm footprint, SN74LVCC3245ANSR uses a standard surface-mount layout compatible with automated assembly and IPC-7351B land patterns.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional level translation applications.

Compared with TXB0108PWR and SN74AVC8T245RHLR, SN74LVCC3245ANSR uniquely supports true 5 V B-port operation with VCC isolation and glitch-free sequencing - making it the only viable option for industrial systems requiring mixed 2.5/3.3 V control logic and legacy 5 V peripherals.

Availability

SN74LVCC3245ANSR is available at Aetrix Electronics and suitable for ultrasound scanner subsystems, photovoltaic string inverters, and industrial single-board computers requiring stable component supply across extended temperature and mixed-voltage environments.

Supply support for SN74LVCC3245ANSR 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 connectivity solutions for industrial, automotive, and communications markets.

The SN74LVCC3245ANSR belongs to TI's LVCC logic family, engineered specifically for robust bidirectional voltage translation in mixed-rail systems where supply sequencing cannot be controlled - targeting solar energy, medical imaging, and factory automation.

FAQ

What is the function of the DIR pin on the SN74LVCC3245ANSR?

The DIR (direction) pin on the SN74LVCC3245ANSR determines data flow direction: logic high enables A→B transmission, while logic low enables B→A transmission. It is referenced exclusively to VCCA, not VCCB, ensuring consistent control behavior regardless of B-port voltage. This pin must be driven within VCCA-referenced VIH/VIL limits specified in the datasheet - for example, ≥2.0 V at VCCA = 3.3 V. The SN74LVCC3245ANSR does not auto-detect direction.

Does the SN74LVCC3245ANSR support 5 V on the B port while operating at 2.5 V on the A port?

Yes, the SN74LVCC3245ANSR explicitly supports VCCA = 2.5 V and VCCB = 5 V simultaneously, as validated in Section 6.3 of the SCAS585R datasheet. At these conditions, it delivers VOHB(min) ≥ 3.2 V and VOLB(max) ≤ 0.5 V under 24 mA load, meeting 5 V TTL logic thresholds. This configuration is used in ultrasound scanners to interface 2.5 V FPGAs with 5 V analog front-end components.

How does VCC isolation work on the SN74LVCC3245ANSR?

VCC isolation on the SN74LVCC3245ANSR forces all A- and B-port I/Os into high-impedance state when either VCCA or VCCB falls below 100 mV or is left floating - preventing back-current flow and potential latch-up. This behavior is hardware-enforced and requires no external circuitry. For example, if VCCB is disconnected during maintenance while VCCA remains at 3.3 V, the SN74LVCC3245ANSR automatically disables all outputs to protect downstream 5 V devices.

Can the SN74LVCC3245ANSR be used without external bypass capacitors?

No - the SN74LVCC3245ANSR requires local bypass capacitors on both VCCA and VCCB pins per TI's layout guidance (Section 8.3). A 0.1 µF ceramic capacitor placed within 2 mm of each VCC pin is mandatory to suppress supply noise and ensure stable switching. Omitting them risks increased propagation delay variation, output glitches during fast transitions, and failure to meet ESD immunity specifications. The SN74LVCC3245ANSR's performance is validated only with proper decoupling.

What is the maximum capacitive load the SN74LVCC3245ANSR can drive on the B port?

The SN74LVCC3245ANSR can reliably drive up to 50 pF total load on the B port while maintaining specified tPLH/tPHL ≤ 9.9 ns and VOLB ≤ 0.5 V at 24 mA sink current (per Figure 6-2 and Table 5.6). This includes PCB trace capacitance, input capacitance of connected devices (e.g., ≤18.5 pF Cio per port), and probe/jig effects. Exceeding 50 pF degrades edge rate and may violate setup/hold timing in high-speed interfaces like SPI or parallel ADC buses.