LM5145 datasheet(41/69 Pages) TI

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10.2.1.1 Design Requirements

Table 10-2 shows the intended input, output, and performance parameters for this design example.

Table 10-2. Design Parameters

Design Parameter

Value

Input voltage range (steady state)

8 V to 18 V

Min transient input voltage (cold crank)

3.5 V

Max transient input voltage (load dump)

36 V

Output voltages

3.3 V, 5 V

Output currents

7 A

Switching frequency

2.1 MHz

Output voltage regulation

±1%

Standby current, output 1 enabled, no load

< 50 µA

Shutdown current

4 µA

The switching frequency is set at 2.1 MHz by resistor RRT. In terms of control loop performance, the target loop

crossover frequency is 60 kHz with a phase margin greater than 50°. The output voltage soft-start times are set

at 2 ms by 68-nF soft-start capacitors.

The selected buck regulator powertrain components are cited in Table 10-3, and many of the components are

available from multiple vendors. The MOSFETs in particular are chosen for both lowest conduction and switching

power loss, as discussed in detail in Section 10.1.1.4. This design uses a low-DCR, metal-powder composite

inductor, and ceramic output capacitor implementation.

Table 10-3. List of Materials for Application Circuit 1

Ref Des

Qty

Specification

Manufacturer(1)

Part Number

CIN

10 µF, 50 V, X7R, 1210, ceramic

Taiyo Yuden

UMJ325KB7106KMHT

10 µF, 50 V, X7S, 1210, ceramic

Murata

GCM32EC71H106KA03

TDK

CGA6P3X7S1H106M

47 µF, 6.3 V, X7R, 1210, ceramic

Murata

GCM32ER70J476KE19L

Taiyo Yuden

JMK325B7476KMHTR

47 µF, 6.3 V, X7S, 1210, ceramic

TDK

CGA6P1X7S0J476M

LO1, LO2

0.68 µH, 4.8 mΩ, 25 A, 7.3 × 6.6 × 2.8 mm

Würth Elektronik

744373460068

0.68 µH, 4.5 mΩ, 22 A, 6.95 × 6.6 × 2.8 mm

Cyntec

VCMV063T-R68MN2T

0.68 µH, 3.1 mΩ, 20 A, 7 × 6.9 × 3.8 mm

Würth Elektronik

744311068

0.68 µH, 7.4 mΩ, 12.2 A, 5.4 × 5.0 × 3 mm

TDK

SPM5030VT-R68-D

0.68 µH, 2.9 mΩ, 15.3 A, 6.7 × 6.5 × 3.1 mm

Coilcraft

XGL6030-681

Q1, Q2, Q3, Q4

40 V, 5.7 mΩ, 9 nC, SON 5 × 6

Infineon

IPC50N04S5L-5R5

RS1, RS2

Shunt, 7 mΩ, 0508, 1 W

Susumu

KRL2012E-M-R007

LM25143 42-V dual-channel/phase synchronous buck controller

Texas Instruments

LM25143RHAR

(1)

See the Third Party Products Disclaimer.

10.2.1.2 Detailed Design Procedure

10.2.1.2.1 Custom Design With WEBENCH® Tools

Click here to create a custom design using the LM25143 device with the WEBENCH® Power Designer.

1. Start by entering the input voltage (VIN), output voltage (VOUT), and output current (IOUT) requirements.

2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial.

3. Compare the generated design with other possible solutions from Texas Instruments.

The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time

pricing and component availability.

www.ti.com

LM25143

SNVSC10 – MARCH 2022

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