Texas Instruments CSD17578Q5AT

Overview

CSD17578Q5AT from Texas Instruments is a 30 V, 5.9 mΩ N-channel NexFET™ power MOSFET in an 8-pin SON 5 mm × 6 mm package, optimized as a control FET in high-frequency synchronous buck converters for networking and telecom systems, with 7.9 nC total gate charge at 4.5 V and ±20 V gate-to-source voltage rating.

For engineers reviewing the CSD17578Q5AT datasheet, CSD17578Q5AT pinout, CSD17578Q5AT application, or CSD17578Q5AT equivalent, this device is selected for low-R_DS(on) and low-Q_g requirements in point-of-load DC/DC stages where thermal resistance (R_θJC = 3.8°C/W) and avalanche ruggedness (E_AS = 23 mJ) are critical.

Technical Context

This MOSFET employs a silicon-limited design with 59 A continuous drain current capability at T_C = 25°C and 16 A package-limited current at T_A = 25°C, supporting high-efficiency switching in thermally constrained layouts. Its low Q_gd/Q_g ratio (2.0/7.9 nC) enables fast, low-loss turn-on/turn-off transitions under 10 V gate drive.

The device features integrated body diode with 0.8–1.0 V forward voltage at 10 A and 6.5 nC reverse recovery charge, enabling robust synchronous rectification. Thermal performance is validated with R_θJA = 50°C/W on 1-inch² 2-oz copper, and R_θJC = 3.8°C/W for direct heatsink mounting.

Key Specifications

Pinout & Package

Package: VSONP (DQJ), 8-pin SON 5 mm × 6 mm plastic package with exposed thermal pad. Pin 1–8 arranged in two rows (1–4 top, 5–8 bottom), with pins 1, 2, 3, 4 as Drain, pins 5 as Gate, pins 6, 7, 8 as Source - verified per TI SLPS526 Figure P0093-01 and M0137-01/M0137-02 top-view diagrams.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel power MOSFET applications.

Compared with IRF7759L2TRPBF and SiR626DP-T1-GE3, the CSD17578Q5AT delivers optimal balance of low Q_g, low R_DS(on), and guaranteed avalanche ruggedness in a thermally enhanced 5×6 mm SON package-making it preferred for high-reliability, high-frequency PoL converters where layout area and thermal headroom are constrained.

Availability

CSD17578Q5AT is available at Aetrix Electronics and suitable for networking point-of-load converters, telecom base station DC/DC supplies, and industrial PLC power modules requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for CSD17578Q5AT 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 designing analog, embedded processing, and digital signal processing technologies for industrial, automotive, and communications markets.

The CSD17578Q5AT belongs to TI's NexFET™ power MOSFET product line, engineered specifically for high-efficiency, high-frequency DC/DC conversion in space-constrained infrastructure equipment where low gate charge and thermal resistance are decisive.

FAQ

What is the maximum continuous drain current rating for CSD17578Q5AT at 25°C case temperature?

The CSD17578Q5AT has a silicon-limited continuous drain current of 59 A at T_C = 25°C, as specified in the Absolute Maximum Ratings table of TI's SLPS526 datasheet. This rating assumes ideal heatsinking; the package-limited current is 25 A at T_A = 25°C. Derating applies above 25°C case temperature per the normalized current vs. temperature curve (Figure D012).

Does CSD17578Q5AT support 3.3 V gate drive in logic-level applications?

Yes, the CSD17578Q5AT has a typical threshold voltage (V_GS(th)) of 1.5 V and guarantees R_DS(on) ≤ 9.3 mΩ at V_GS = 4.5 V and I_D = 10 A. While full enhancement occurs at ≥4.5 V, it conducts usable current at 3.3 V - however, R_DS(on) rises significantly (≈20 mΩ), so 3.3 V drive is only recommended for low-duty-cycle or low-current biasing, not full-power switching.

What is the thermal resistance from junction to case (R_θJC) for CSD17578Q5AT, and how is it measured?

The CSD17578Q5AT has a maximum R_θJC of 3.8°C/W, measured with the device mounted on a 1 inch² (6.45 cm²), 2 oz. copper pad on FR4 PCB per JEDEC JESD51-14. This value reflects the intrinsic thermal path from die junction to the exposed thermal pad - critical for heatsink-integrated designs - and is independent of board layout, unlike R_θJA.

Is CSD17578Q5AT avalanche-rated, and what is its single-pulse energy rating?

Yes, the CSD17578Q5AT is avalanche-rated with a guaranteed single-pulse avalanche energy (E_AS) of 23 mJ when tested at I_AV = 22 A and L = 0.1 mH, per the Absolute Maximum Ratings table. This rating validates robustness during inductive switching events in synchronous buck freewheeling, eliminating need for external snubbers in many designs.

What is the gate-to-drain charge (Q_gd) of CSD17578Q5AT, and why is it important for synchronous buck operation?

The CSD17578Q5AT has a Q_gd of 2.0 nC (typical) at V_DS = 15 V and I_D = 10 A. This parameter directly governs Miller plateau duration and influences shoot-through immunity and switching speed. A low Q_gd/Q_g ratio (25%) enables faster, more controllable turn-off - essential for minimizing dead-time losses and improving efficiency in high-frequency synchronous buck converters.