CSD18503Q5A - 40V N-Channel NexFET MOSFET 4.3mOhm | Texas Instruments
MPN: CSD18503Q5A β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.28 | $12.80 |
| 100 | $1.12 | $112.00 |
| 500 | $0.98 | $490.00 |
| 1,000 | $0.85 | $850.00 |
Drop-in alternatives for CSD18503Q5A β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
CSD18563Q5A
β Drop-Inπ Reference alternative (not in catalog)
CSD18502Q5B
β Drop-Inπ Reference alternative (not in catalog)
CSD18540Q5B
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
CSD19534Q5A
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
VBGQA1403
β Drop-Inπ Reference alternative (not in catalog)
BSC040N10NS5
β‘ Same Package β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
CSD18503Q5A Maximum Ratings & Electrical Characteristics
| Polarity | N-Channel |
| Drain-Source Voltage (VDS) | 40 V |
| On-Resistance (RDS(on)) | 4.3 mOhm (3.4 mOhm typical) |
| Continuous Drain Current (Ta) | 19 A |
| Continuous Drain Current (Tc) | 100 A |
| Power Dissipation (Ta) | 3.1 W |
| Power Dissipation (Tc) | 120 W |
| Technology | NexFET |
| Package | 8-VSONP (DQJ), 5 mm x 6 mm |
| Mounting Type | Surface Mount |
| Operating Junction Temperature | -55C to +150C |
| Configuration | Single |
| Number of Pins | 8 |
CSD18503Q5A Pin Configuration
| Pin 1-3 | GATE β Gate drive input (pins 1-3 common gate) |
| Pin 4-5 | SOURCE β Source connection |
| Pin 6-8 | SOURCE β Source connection (continue) |
| Pin PAD | DRAIN β Exposed drain pad for electrical and thermal connection |
Safe Operating Area
Typical Applications
CSD18503Q5A is suitable for 6 applications: DC-DC Converter Power Stage, Synchronous Rectification, Motor Drive Half-Bridges, Hot-Swap and ORing Load Switches, Battery Protection and BMS, Automotive Body Power and Loads.
DC-DC Converter Power Stage
In 12 V and 24 V input buck converters, the CSD18503Q5A serves as the high-side or low-side switch. Its 40 V VDS covers transient overshoot, and the 4.3 mOhm RDS(on) keeps conduction loss low: at 20 A it dissipates only about 1.7 W at hot temperature. NexFET gate-charge optimization reduces switching loss at converter frequencies of 100 kHz to 500 kHz, improving overall efficiency versus older trench MOSFETs. Pair with a synchronous controller for best results.
Recommended
Synchronous Rectification
As a secondary-side rectifier in isolated supplies or low-side FET in synchronous bucks, conduction loss dominates. The CSD18503Q5A 3.4 mOhm typical RDS(on) at 10 V drive minimizes IR loss; at 50 A conduction, dissipation is roughly 13.5 W hot, manageable with the SON exposed-drain-pad thermal design. The NexFET low Qrr reduces body-diode reverse recovery loss during commutation, improving efficiency and thermal margins in high-current rectifier positions.
Recommended
Motor Drive Half-Bridges
The CSD18503Q5A fits 12 V/24 V motor drive half-bridge stages such as BLDC and brushed DC motor drivers. The 40 V rating handles inductive kickback with margin, and 4.3 mOhm RDS(on) limits resistive loss during continuous stall or high-torque events. The 5x6 mm SON package with exposed drain pad spreads heat into the PCB copper, supporting pulse loads; verify pulsed-current limits against the SOA curves in the TI datasheet for stall and PWM conditions.
Recommended
Hot-Swap and ORing Load Switches
In backplane hot-swap and ORing FET applications on 12 V or 24 V rails, the CSD18503Q5A operates as a series pass element. Its low 4.3 mOhm RDS(on) reduces voltage drop and inrush-path loss; at 10 A load, drop is only 43 mV at hot conditions. The 40 V VDS provides headroom for fault transients. Pair with a hot-swap controller that manages gate slew during inrush to keep the MOSFET within its SOA during startup events.
Recommended
Battery Protection and BMS
In 10S to 12S battery packs for portable and light-industrial equipment, the CSD18503Q5A serves as a discharge/charge path MOSFET. The 40 V class covers cell-stack transients, and the 4.3 mOhm RDS(on) reduces heat at continuous pack currents of 20 A to 40 A. The -55C to +150C junction range supports harsh environments. Place the SON package drain pad over a full copper area to keep junction temperature within limits during sustained discharge.
Recommended
Automotive Body Power and Loads
For 12 V automotive loads such as pumps, fans, and lighting drivers, the CSD18503Q5A provides a robust switching element with 40 V VDS covering load-dump-adjacent transients in clamped systems. The NexFET technology achieves low RDS(on) of 4.3 mOhm for high-current channels, while the SON 5x6 mm footprint suits compact ECUs. For automotive-qualified designs, verify AEC-Q101/Q100 requirements and consider TI Q1-graded MOSFETs in the same family where qualification is mandatory.
Recommended
Recommended Products Summary
Engineering reference data for CSD18503Q5A β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CSD18563Q5A | CSD18502Q5B | VBGQA1403 |
|---|---|---|---|---|
| Package | 8-VSONP (DQJ) 5x6 mm | 8-VSONP (DQJ) 5x6 mm - same | 8-VSONP (DQJ) 5x6 mm - same | SON 5x6 mm - compatible |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Will Semiconductor (VBsemi) |
| Drain-Source Voltage | 40 V | 40 V | 40 V | [DATA_NEEDED] |
| RDS(on) | 4.3 mOhm | [DATA_NEEDED] | Lower than CSD18503Q5A (Q5B generation) | [DATA_NEEDED] |
| Continuous Current (Ta) | 19 A | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Continuous Current (Tc) | 100 A | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Technology | NexFET | NexFET | NexFET | Trench MOSFET |
| Power Dissipation (Tc) | 120 W | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
Key Differentiators
- Low conduction loss (vs CSD18540Q5B)
- NexFET FOM optimization (vs VBGQA1403)
- High case-power capability (vs CSD18502Q5B)
Design Notes
At 4.3 mOhm RDS(on), conduction loss dominates: 50 A with hot junction yields roughly 13.5 W, well above the 3.1 W free-air rating. The SON exposed drain pad must sit on a minimum 1-square-inch copper pour with thermal vias to the inner layers. Usable current is determined by thermal design, not the 100 A case rating.
Solder the exposed drain pad to a full ground/drain plane using an array of thermal vias (0.3 mm drill, filled or plugged). Minimize the power loop area between high-side and low-side MOSFETs and input bulk capacitors to reduce parasitic inductance and ringing on the drain node during switching transitions.
Verify pulsed-load limits against the SOA curves in the TI datasheet for inrush, stall, and short-circuit events. Ensure gate drive reaches the full 10 V specified for the 4.3 mOhm RDS(on) point; driving at lower VGS substantially increases on-resistance. Do not exceed the 40 V VDS rating - add clamping for inductive loads.
Compliance Information
Compliance data not present in provided web data. Verify RoHS/REACH status on the TI product page quality documentation.
