Generic leadless power MOSFET packages on copper and switching paths for 60 V MOSFET comparison

CSD18540Q5B vs CSD18532Q5B: Selecting a 60 V Power MOSFET

CSD18540Q5B and CSD18532Q5B are Texas Instruments 60 V N-channel NexFET power MOSFETs in an 8-pin 5 mm × 6 mm SON/VSON-CLIP package. Both are logic-level devices, both have a ±20 V gate-to-source rating, and both are package-limited to 100 A in TI’s headline parametric data.

The CSD18540Q5B has lower specified maximum on-resistance and a higher maximum junction-temperature rating. The two datasheets also report different typical charge values, but several measurements use different drain-current conditions. Those listed gate-charge and reverse-recovery values are therefore useful screening data, not strict same-condition comparisons. A shared footprint is useful for evaluation, but it is not enough to declare the devices directly interchangeable.

Quick comparison

Parameter CSD18540Q5B CSD18532Q5B
Type N-channel MOSFET N-channel MOSFET
VDS maximum 60 V 60 V
VGS maximum ±20 V ±20 V
RDS(on), max at VGS = 10 V 2.2 mΩ (ID = 28 A) 3.2 mΩ (ID = 25 A)
RDS(on), max at VGS = 4.5 V 3.3 mΩ (ID = 28 A) 4.3 mΩ (ID = 25 A)
Typical total gate charge at 10 V 41 nC at ID = 28 A 44 nC at ID = 25 A
Typical gate-drain charge 6.7 nC at ID = 28 A 6.9 nC at ID = 25 A
Typical output charge at 30 V 83 nC 52 nC
Typical reverse-recovery charge 145 nC at IF = 28 A 111 nC at IF = 25 A
Package-limited continuous drain current 100 A 100 A
Silicon-limited current at TC = 25°C 205 A in Rev. B datasheet; current TI product page lists 221 A 172 A
Junction-to-case thermal resistance 0.8°C/W max 0.8°C/W max
Operating junction temperature –55°C to +175°C –55°C to +150°C
Package 8-pin SON, 5 mm × 6 mm 8-pin SON, 5 mm × 6 mm

The listed Qg, Qgd and Qrr values use different drain-current conditions for the two devices, as shown in the table. They are not strict apples-to-apples measurements. Use them for screening only, then recalculate and test at the application’s voltage, current, gate resistance and temperature. TI’s Rev. B CSD18540Q5B datasheet lists 205 A silicon-limited current, while the current TI product page lists 221 A; neither value is a board-level current recommendation.

Conduction loss favors CSD18540Q5B

At both 10 V and 4.5 V gate drive, TI specifies a lower maximum RDS(on) for CSD18540Q5B. The first-order conduction-loss estimate is:

Pcond ≈ IRMS² × RDS(on)

At the same RMS current and junction temperature, the lower-resistance device will generally dissipate less conduction power. However, do not calculate production limits from the 25°C headline alone. MOSFET on-resistance rises with junction temperature. Use the normalized RDS(on)-versus-temperature curve, the guaranteed room-temperature limit, expected current waveform and realistic thermal model.

The published 100 A package limit is also not a board-level operating recommendation. Connector resistance, copper area, vias, thermal interfaces, ambient temperature and airflow can impose much lower practical limits. TI separately lists silicon-limited current at a controlled case temperature; that value should not be copied into a system specification without the stated test conditions.

Switching behavior requires a full loss model

TI’s tables list slightly lower typical total gate charge and gate-drain charge for CSD18540Q5B, but those values are measured at 28 A versus 25 A for CSD18532Q5B. The listed reverse-recovery values also use 28 A versus 25 A. These figures are not strict same-condition comparisons; they show why a complete application-specific switching-loss model and bench test are required.

That tradeoff matters in synchronous converters, half bridges and motor drives. Reverse-recovery and output-capacitance behavior can influence switching loss, voltage overshoot, ringing and EMI. A MOSFET with the lowest RDS(on) is not automatically the most efficient device at high switching frequency.

Build the loss estimate from at least conduction loss, turn-on and turn-off overlap, gate-drive loss, output-capacitance energy, body-diode conduction and reverse-recovery effects. Then measure the real switch node using appropriate high-bandwidth probing. Gate-driver source/sink current, external gate resistance, dead time, parasitic inductance and PCB layout can dominate the result.

Temperature range and thermal design

TI specifies CSD18540Q5B for an operating junction range up to +175°C, versus +150°C for CSD18532Q5B. Both datasheets list a maximum junction-to-case thermal resistance of 0.8°C/W under TI’s stated test methodology.

The shared RθJC value does not mean the two parts will reach the same junction temperature in an application. Their electrical losses differ, and junction-to-ambient performance is strongly dependent on PCB copper and airflow. TI explicitly notes that RθJA is determined by the user’s board design.

For qualification, estimate steady-state and transient junction temperature. Include maximum RDS(on), temperature rise, switching loss, tolerances and worst-case ambient. Review transient thermal impedance for pulsed loads and safe operating area for startup, current limiting, short-circuit or hot-swap events.

Package and pinout: similar, but verify the land pattern

Both devices use TI’s 5 mm × 6 mm, 8-pin SON/VSON-CLIP format and show the same source, gate and drain arrangement at a high level. Still compare the latest mechanical drawings, recommended land pattern, stencil design and exposed thermal/drain pad requirements.

The suffix also affects carrier. TI lists the base Q5B orderable device on a large reel and a “T” suffix option on a smaller reel. Purchasing should not silently add or remove a carrier suffix, because feeder setup, minimum packaging quantity and incoming documentation can differ even when the silicon is the same.

Can CSD18540Q5B replace CSD18532Q5B?

It is a credible engineering comparison because voltage, polarity and package family align, but approval must be application-specific. Replacing CSD18532Q5B with the lower-RDS(on) CSD18540Q5B may reduce conduction loss and increase temperature-headroom potential. At the same time, output-charge and reverse-recovery differences can change switching behavior.

The reverse direction is more sensitive to conduction loss and the lower +150°C junction limit. Recalculate worst-case junction temperature and verify current limit, efficiency and fault behavior. In either direction, retest switching waveforms, dead time, gate ringing, drain overshoot, EMI, thermal performance and safe operating area.

For broader supplier, traceability, alternate-part and approval controls, use our electronic component BOM sourcing process alongside the device-specific checks below.

Procurement verification checklist

  • Confirm the full MPN and whether the assembly requires the base or “T” carrier suffix.
  • Verify 60 V VDS rating against steady-state bus voltage plus worst-case transients.
  • Verify gate-driver high and low levels and the ±20 V absolute gate limit.
  • Use maximum RDS(on) at the actual qualified gate voltage.
  • Recalculate conduction and switching loss at hot junction.
  • Review Qg, Qgd, Qoss and Qrr under comparable operating conditions.
  • Confirm 5 mm × 6 mm package drawing, land pattern and stencil.
  • Verify package-limited current separately from silicon-limited current.
  • Check safe operating area and transient thermal impedance for abnormal modes.
  • Repeat double-pulse or in-circuit switching, thermal and EMI tests before approval.

FAQ

Which MOSFET has lower on-resistance?
CSD18540Q5B. TI lists maximum RDS(on) of 2.2 mΩ at 10 V versus 3.2 mΩ for CSD18532Q5B.

Do both use the same voltage rating?
Yes. Both are 60 V N-channel devices with a ±20 V VGS rating.

Which supports the higher junction temperature?
CSD18540Q5B is specified up to +175°C; CSD18532Q5B is specified up to +150°C.

Is CSD18540Q5B always more efficient?
No. It has a conduction-loss advantage, but switching efficiency also depends on charge, recovery, driver, dead time, frequency and layout.

Does the 100 A package rating mean the PCB can continuously carry 100 A?
No. It is a component limit under stated conditions, not a complete thermal or interconnect rating for the application.

Engineering boundary

This comparison is not a declaration of direct replacement. Final selection requires the latest TI datasheets, worst-case electrical and thermal calculations, mechanical-footprint verification, safe-operating-area review and testing in the actual power stage.

Related catalog pages

Review the exact catalog entries for CSD18540Q5B and CSD18532Q5B. Use the contact page to confirm the required suffix, quantity and documentation for a specific RFQ.

Official references

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