Texas Instruments CSD17556Q5BT

Overview

CSD17556Q5BT from Texas Instruments is a 30-V, 1.2-mΩ N-channel NexFET™ power MOSFET in a VSON-CLIP (DNK) 8-pin package, rated for 100-A continuous drain current (package-limited), 30-nC total gate charge at 4.5 V, and avalanche energy of 500 mJ; it serves as a high-efficiency synchronous rectifier or high-side switch in point-of-load DC/DC converters for telecom and computing systems.

For engineers reviewing the CSD17556Q5BT datasheet, CSD17556Q5BT pinout, CSD17556Q5BT application, or CSD17556Q5BT equivalent, key selection criteria include R_DS(on) at 4.5 V (1.5 mΩ), thermal resistance (R_θJC = 1.3 °C/W), Q_gd/Q_g ratio (0.25), SOA robustness under unclamped inductive switching, and compatibility with 5-mm × 6-mm PCB layout footprints.

Technical Context

This device uses a silicon-limited trench-gate process optimized for low R_DS(on) and ultra-low gate charge, enabling high-frequency operation in synchronous buck topologies. Its VSON-CLIP package integrates exposed-drain thermal pad and clip-bonded source/drain terminals to minimize parasitic inductance and junction-to-case thermal resistance.

The MOSFET features a 1.4-V typical threshold voltage, 197-S transconductance at 40 A, and diode forward voltage of 0.8–1.0 V at 40 A - supporting efficient reverse-recovery performance in active ORing and hot-swap circuits where fast turn-off and low conduction loss are critical.

Key Specifications

Pinout & Package

VSON-CLIP (DNK) 8-pin package with 5.00-mm × 6.00-mm body, 0.80–1.05-mm height, and exposed thermal pad on bottom side for direct PCB thermal coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CSD17556Q5BT, CSD17573Q5B trades 0.2-mΩ higher R_DS(on) for 3-nC lower Q_g, favoring high-frequency light-load efficiency, while IRF6642 lacks avalanche rating and has incompatible pin mapping - making CSD17556Q5BT the preferred choice for thermally constrained, fault-tolerant POL and ORing applications.

Availability

CSD17556Q5BT is available at Aetrix Electronics and suitable for server point-of-load converters, telecom hot-swap modules, and industrial PLC power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for CSD17556Q5BT 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 specializing in analog, embedded processing, and power management ICs, with leadership in high-efficiency power conversion and signal chain solutions.

The CSD17556Q5BT belongs to TI's NexFET™ power MOSFET product line, engineered specifically for high-current, high-frequency DC/DC conversion in datacenter, telecom, and industrial power systems where low R_DS(on), low Q_g, and robust thermal performance are critical.

FAQ

What is the maximum continuous drain current rating for CSD17556Q5BT at 100°C case temperature?

The CSD17556Q5BT is rated for 100-A continuous drain current under package-limited conditions at T_C = 25°C. At 100°C case temperature, derating applies per the SOA curve: maximum continuous I_D drops to approximately 65 A due to thermal limits, assuming R_θJC = 1.3 °C/W and ambient cooling sufficient to maintain T_J ≤ 150°C. Full derating guidance is provided in Figure 12 of the CSD17556Q5BT datasheet.

Does CSD17556Q5BT support 3.3-V gate drive in synchronous buck applications?

Yes, the CSD17556Q5BT has a typical V_GS(th) of 1.4 V and guaranteed R_DS(on) of 1.8 mΩ at V_GS = 4.5 V, making it fully compatible with 3.3-V logic-level gate drivers. At 3.3 V, R_DS(on) rises to ~2.3 mΩ (per Figure 7), still enabling efficient operation in medium-current POL stages - confirmed by TI's reference design TIDA-010022 using CSD17556Q5BT with UCC27531 driver.

How does the VSON-CLIP package of CSD17556Q5BT improve thermal performance over standard QFN?

The CSD17556Q5BT uses TI's VSON-CLIP (DNK) package, which replaces wire bonds with copper clips for drain and source connections and incorporates an exposed drain thermal pad. This reduces R_θJC to 1.3 °C/W - 40% lower than standard 5×6-mm QFN packages - and lowers parasitic inductance by >30%, improving EMI and switching speed. The clip-bond structure also enhances power cycling reliability in high-thermal-stress applications.

Is CSD17556Q5BT suitable for active ORing in redundant 12-V power supplies?

Yes, the CSD17556Q5BT is explicitly qualified for active ORing and hot-swap applications per its datasheet Features section. Its 0.8–1.0-V V_SD, 68-nC Q_rr, and 36-ns t_rr enable fast reverse recovery, while its 500-mJ E_AS rating ensures robustness during supply switchover faults. TI reference design TIDA-01422 demonstrates CSD17556Q5BT in dual 12-V ORing with LM5050-1 controller.

What is the recommended PCB layout for optimal thermal and electrical performance of CSD17556Q5BT?

TI recommends a 1-in² (6.45-cm²) 2-oz copper thermal pad connected to internal ground or power planes via ≥8 thermal vias (0.3-mm diameter, 0.7-mm pitch). The CSD17556Q5BT datasheet Figure 7.2 specifies a 4.00-mm × 1.75-mm stencil aperture for the thermal pad. Source and drain traces must be wide and short to minimize loop inductance - TI's SLPA005 app note details routing techniques to suppress ringing in high-dI/dt layouts using CSD17556Q5BT.