Datasheet

Customizing the Design

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Figure 9. LM5066 Design Tool

Design inputs are keyed in on the left side following steps 1 though 5. General operating conditions should

be entered in step 1 of the design tool. These inputs help set bounds on the startup time and application

voltage ranges.

Step 2 allows the user to tailor the MOSFET protection features to be specific to the target application.

Current limit is pin-configurable and software configurable, and circuit breaker is software-configurable. If

CL switch is used to set the current limit, make sure the GUI selection matches the pin-configurable CL bit

setting on the board. By clicking on the MOSFET SOA Profile button the user can select SOA data from

several popular MOSFETs or enter the SOA data for the desired MOSFET. The resistor R

PWR

can then be

calculated to keep Q

within its SOA profile.

Step 3 allows the user to select the under- and over-voltage lockout values (UVLO/OVLO), and power

good (PGD) thresholds. Note that with the correct values for R1 - R4, and RFB1 and RFB2 installed, the

LM5066 will indicate a fault condition when the input and/or output voltages are outside of their

programmed range.

Step 4 allows the user to set the fault time-out period and the fault response. The fault time-out should be

set to be below the MOSFET SOA data for a given time. For example, if a design is done to adhere to the

10 ms pulsed MOSFET SOA data, the desired fault time-out must be less than 10ms. The fault time-out

time entered will set the value for C

. It also sets the insertion delay and fault retry delay. The initial power

up retry behavior is also selected in this design step. Make sure to change the RETRY switch to match the

design tool schematic when changing the default retry setting.

In Step 5 the user enters the desired PMBus address. Note changing the PMBus address of the device in

step 5 does not change the device address, but shows how the address pins of the device need to be

configured to achieve a desired address. Once the ADR pin switches are configured for a particular

address, power to the device needs to be cycled and the GUI restarted in order for the new address to

take affect.

AN-2160 LM5066 Evaluation Board SNVA487A–August 2011–Revised April 2013

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