Texas Instruments CSD17556Q5B

Overview

CSD17556Q5B from Texas Instruments is a 30-V, 1.2-mΩ N-channel NexFET™ power MOSFET in a VSON-CLIP (DNK) 5 mm × 6 mm package, rated for 100-A continuous drain current (package-limited), with ultra-low gate charge (30 nC at 4.5 V) and avalanche energy rating (500 mJ), optimized for high-efficiency synchronous buck converters in telecom and computing point-of-load systems.

For engineers reviewing the CSD17556Q5B datasheet, CSD17556Q5B pinout, CSD17556Q5B application, or CSD17556Q5B equivalent, key selection criteria include R_DS(on) at 4.5 V (1.5 mΩ), Q_gd/Q_g ratio (0.25), thermal resistance (R_θJC = 1.3°C/W), SOA robustness under unclamped inductive switching, and compatibility with 3.3-V/5-V gate drivers in high-frequency (>500 kHz) power stages.

Technical Context

This device employs a silicon-limited trench-gate process with copper-clip packaging to achieve low R_DS(on) and minimized parasitic inductance. Its gate threshold voltage (1.4 V typ) and transconductance (197 S) support fast, stable switching with standard logic-level gate drivers.

The MOSFET features integrated body diode with 68 nC reverse recovery charge and 36 ns recovery time, enabling efficient synchronous rectification without external Schottky diodes. Its 1.3°C/W junction-to-case thermal resistance enables high-power density designs when mounted on thermally enhanced PCB pads.

Key Specifications

Pinout & Package

VSON-CLIP (DNK) 8-pin plastic package with exposed thermal pad (5.00 mm × 6.00 mm footprint); top-side source and gate terminals, bottom-side drain paddle for optimal thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CSD17556Q5B, CSD17573Q5B trades 13% higher conduction loss for 17% lower gate charge, while IRLHS6242 sacrifices avalanche robustness and Miller immunity for marginal cost reduction-making CSD17556Q5B optimal for high-reliability, high-current POL and ORing designs.

Availability

CSD17556Q5B is available at Aetrix Electronics and suitable for point-of-load synchronous buck, synchronous rectification, and active ORing applications requiring stable component supply, long-term industrial lifecycle support, and traceable TI production lots.

Supply support for CSD17556Q5B 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 across industrial, automotive, and communications markets since 1930.

The CSD17556Q5B belongs to TI's NexFET™ power MOSFET product line, engineered specifically for high-frequency, high-current DC/DC conversion in space-constrained infrastructure equipment where thermal performance and switching efficiency are critical.

FAQ

What is the maximum continuous drain current rating for the CSD17556Q5B at 25°C case temperature?

The CSD17556Q5B has a silicon-limited continuous drain current of 215 A at T_C = 25°C, though its package-limited rating is 100 A under standard PCB mounting conditions. This dual rating reflects its robust die design and thermally optimized VSON-CLIP package, allowing designers to scale thermal solution to unlock higher current capability in custom layouts.

Does the CSD17556Q5B support 3.3-V gate drive, and what is its typical threshold voltage?

Yes, the CSD17556Q5B supports 3.3-V gate drive with a typical gate threshold voltage (V_GS(th)) of 1.4 V and a guaranteed range of 1.15 V to 1.65 V. At V_GS = 3.3 V, it delivers ~25 A drain current, making it fully compatible with 3.3-V microcontrollers and PWM controllers without level-shifting circuitry.

What is the recommended PCB layout for thermal performance of the CSD17556Q5B?

TI recommends a minimum 1-in² (6.45 cm²) 2-oz copper pad connected to the exposed drain paddle via ≥8 thermal vias (0.3-mm diameter, 0.8-mm pitch). The CSD17556Q5B achieves its specified R_θJC = 1.3°C/W only with full-solder coverage of the drain paddle and proper via thermal relief design per TI's SLPA005 layout guide.

Is the CSD17556Q5B suitable for avalanche operation, and what is its single-pulse rating?

Yes, the CSD17556Q5B is fully avalanche-rated with a single-pulse avalanche energy (E_AS) of 500 mJ when tested at I_D = 100 A, L = 0.1 mH, and R_G = 25 Ω. This rating validates its use in hotswap, ORing, and unclamped inductive switching applications where transient overvoltage events occur.

What is the gate-to-drain charge (Q_gd) of the CSD17556Q5B, and why does it matter for synchronous buck design?

The CSD17556Q5B has a Q_gd of 7.5 nC (typical), which is 25% of its total gate charge (Q_g = 30 nC). This low Q_gd/Q_g ratio improves switching controllability, reduces Miller-induced false turn-on in high-side configurations, and enhances dv/dt immunity-critical for stable operation in high-frequency synchronous buck converters.