Texas Instruments LM34904ITMX/NOPB

Overview

LM34904ITMX/NOPB from Texas Instruments is a 0.5A PFET power switch IC for accessory detection and controlled power delivery in portable electronics. It operates from 2.8V to 5.3V VCC, features 0.4Ω typical R_ON, integrated load detection (ACC_DET), power-good signaling (POK), and thermal shutdown - deployed in handsets and tablets to manage USB/3.5mm accessory insertion events.

For engineers reviewing the LM34904ITMX/NOPB datasheet, LM34904ITMX/NOPB pinout, LM34904ITMX/NOPB application, or LM34904ITMX/NOPB equivalent, key selection criteria include its 6-bump DSBGA package, dual-control logic (ENABLE + ACC_DET), current-limiting behavior at 500mA, and open-drain POK status reporting under dynamic load conditions.

Technical Context

The LM34904ITMX/NOPB implements a single-channel PFET switch with independent enable and accessory-detection inputs. Its internal logic requires both ENABLE high and ACC_DET low to activate the switch, and de-asserts POK when either control signal changes state or over-current/thermal limits are exceeded.

It integrates peak-current limiting (500mA typ.), thermal shutdown at 135°C, and input hysteresis (55mV) on ACC_DET/ENABLE pins. The device draws only 1µA leakage current in shutdown mode and maintains 47–100µA quiescent current across its operating temperature range (−40°C to +85°C).

Key Specifications

Pinout & Package

LM34904ITMX/NOPB uses a 6-bump thin DSBGA package (YFQ), measuring 1.24 × 0.84 mm with 0.4mm pitch. The package is RoHS-compliant, moisture-sensitivity Level-1 rated, and optimized for space-constrained portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar accessory power-switch applications.

Compared with TPL7407LDR and TPS22915BYFPR, the LM34904ITMX/NOPB uniquely integrates dual-input control (ENABLE + ACC_DET), thermal shutdown, and open-drain POK reporting in a 1.24 × 0.84 mm package - making it the only option that autonomously manages accessory insertion without host CPU intervention or external protection circuitry.

Availability

LM34904ITMX/NOPB is available at Aetrix Electronics and suitable for smartphone accessory detection, tablet USB peripheral power control, and notebook docking station port protection requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM34904ITMX/NOPB 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 personal electronics markets.

The LM34904ITMX/NOPB belongs to TI's load switch and power management portfolio, designed specifically for intelligent accessory power control in space-constrained portable devices with strict thermal and quiescent current requirements.

FAQ

What is the function of the ACC_DET pin on the LM34904ITMX/NOPB?

The ACC_DET pin on the LM34904ITMX/NOPB is a dedicated accessory presence input that must be pulled low by the connected accessory to confirm mechanical insertion. When ACC_DET is low and ENABLE is high, the internal PFET turns on. If ACC_DET goes high, the PFET shuts off immediately and POK floats - ensuring safe power removal during unplugging. This pin eliminates the need for external detection circuitry in designs like smartphone headphone jacks or USB-C accessories.

Does the LM34904ITMX/NOPB provide over-temperature protection?

Yes, the LM34904ITMX/NOPB includes integrated thermal shutdown that activates at 135°C junction temperature. When triggered, the PFET switch turns off and the POK pin transitions from grounded to open-drain (floating), signaling the fault to the host system. Recovery occurs automatically once the die cools below the hysteresis threshold. This protection is independent of current limit and operates even under no-load conditions, safeguarding against PCB layout issues or ambient overheating.

What is the minimum ENABLE pulse width required for reliable operation of the LM34904ITMX/NOPB?

The LM34904ITMX/NOPB requires a minimum ENABLE low-to-high transition hold time of 300ns after ACC_DET is asserted, and ENABLE must remain low for at least 300ns before toggling high again to ensure proper internal flip-flop reset. This timing prevents metastability during rapid enable cycling. The datasheet specifies this as the "minimum ENABLE cycle time" (T3), and violating it may result in inconsistent PFET turn-on behavior - especially critical in systems with fast GPIO toggling or noisy control lines.

Can the LM34904ITMX/NOPB operate with a 1.8V logic supply for ENABLE and ACC_DET?

No - the LM34904ITMX/NOPB requires ENABLE and ACC_DET logic high levels to meet VIH ≥ 1.35V (min) and VIL ≤ 0.45V (max), with hysteresis of 55mV. While 1.8V logic meets the VIH requirement, the device's internal reference is tied to VCC, not VIO. Therefore, if VCC is 2.8V, a 1.8V logic signal is acceptable; however, if VCC drops near 2.2V, the 1.8V signal may fall below VIH. For guaranteed compatibility, use VCC-referenced GPIO or level-shifting when interfacing with sub-2V logic families.

What is the typical on-resistance of the LM34904ITMX/NOPB and how does it affect system performance?

The LM34904ITMX/NOPB has a typical total on-resistance (R_ON) of 0.4Ω at 25°C and 500mA load. At full rated current, this results in ≤200mV voltage drop and ~100mW conduction loss - minimizing thermal rise and preserving voltage margin for sensitive accessories. R_ON increases with temperature (up to 0.6Ω max over −40°C to +85°C), so system design must verify worst-case dropout at high ambient temperatures and maximum load to ensure accessory functionality remains within spec.