STMicroelectronics ST2349QTR

Overview

ST2349QTR from STMicroelectronics is a 4-bit dual-supply bidirectional level translator IC with no direction control pin, supporting VL = 1.65–3.6 V and VCC = 1.8–5.5 V, 90 Mbps max data rate (totem pole drive), and 5.5 V-tolerant OE pin. It enables voltage translation between low-voltage ASICs/PLDs (e.g., 1.8 V I²C) and higher-voltage systems (e.g., 3.3 V or 5 V UART), used in mobile phone baseband-to-peripheral interfaces.

For engineers reviewing the ST2349QTR datasheet, ST2349QTR pinout, ST2349QTR application, or ST2349QTR equivalent, key selection criteria include bi-directional auto-direction operation, power-down mode behavior (high-Z when either supply is off), open-drain/totem-pole driver compatibility, and QFN16 (2.6 × 1.8 mm) thermal and layout constraints.

Technical Context

The ST2349 employs transmission-gate-based architecture to achieve true bi-directional level shifting without direction control logic - signal flow is determined dynamically by relative voltage levels on VL and VCC sides. Its internal one-shot circuit enables fast state transitions while maintaining high-impedance outputs during OE deactivation.

It supports two distinct driver types: open-drain inputs require external pull-ups on both I/OVL and I/OVCC ports, while totem-pole drivers directly drive the inputs; output rise/fall times and maximum data rates vary significantly between these configurations (e.g., 8 Mbps vs. 90 Mbps). The device enters power-down mode when OE = low or either supply is absent, forcing all I/Os into high-impedance state with ≤24 µA quiescent current.

Key Specifications

Pinout & Package

ST2349QTR is housed in a thermally enhanced QFN16 package (2.6 mm × 1.8 mm, 0.5 mm pitch) with exposed thermal pad. The package supports automated optical inspection and offers low thermal resistance for sustained 90 Mbps operation under ambient conditions up to +85 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bi-directional level translation applications.

Compared with TXS0104E and SN74AVC4T245, ST2349QTR uniquely combines OE-based bus isolation, 5.5 V-tolerant control, and true auto-direction operation - making it optimal for mobile I²C/UART subsystems requiring dynamic power gating and mixed-voltage interoperability without direction arbitration.

Availability

ST2349QTR is available at Aetrix Electronics and suitable for mobile phone design, wearable electronics development, and industrial I²C subsystem integration requiring stable component supply and long-term lifecycle support.

Supply support for ST2349QTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in microcontrollers, analog ICs, power management, and automotive-grade silicon.

The ST2349 belongs to ST's level translation portfolio designed specifically for low-voltage, high-density portable electronics - emphasizing ultra-small footprint, zero-direction-control operation, and robust power-down behavior.

FAQ

Can ST2349QTR translate between 1.2 V and 5 V?

No. ST2349QTR's VL supply range is strictly 1.65 V to 3.6 V per datasheet Table 5; operation below 1.65 V violates recommended conditions and risks incorrect logic thresholds or latch-up. For 1.2 V interfaces, consider TXS0104E or similar 1.2 V–3.6 V translators.

What happens if VCC is powered but VL is unconnected?

When VL is floating or disconnected while VCC is active and OE = high, the I/OVL pins enter undefined states and may draw excessive current due to internal gate biasing. Datasheet Section 3.3 mandates VL be grounded or actively driven - never left floating - to ensure high-impedance safety and prevent damage.

Is the QFN16 thermal pad required to be soldered?

Yes. Figure 7 and Table 15 specify an exposed thermal pad (EP) that must be soldered to a PCB thermal land with ≥4 thermal vias to inner ground planes. Omitting this compromises thermal performance and risks exceeding junction temperature limits at 90 Mbps continuous operation.

Does ST2349QTR support hot-swap or live-insertion?

No. The device lacks built-in hot-swap protection circuitry. Applying VCC before VL (or vice versa) without OE held low may cause transient current spikes or undefined I/O states. Always sequence supplies with OE = low during power-up/down, per datasheet Section 3.3 Power Off Feature.