LM5041B

www.ti.com

SNVS605 – MAY 2009

Thermal Protection

Internal Thermal Shutdown circuitry is provided to protect the integrated circuit in the event that the maximum

junction temperature is exceeded. When activated, typically at 165 degrees Celsius, the controller is forced into a

low-power standby state, disabling the output drivers and the bias regulator. This feature is provided to prevent

catastrophic failures from accidental device overheating.

Differences Between LM5041, LM5041A and LM5041B

There are five differences between LM5041, LM5041A and LM5041B. In the LM5041A and the LM5041B

versions, the hiccup mode over-current protection is not employed and the VCC bias regulator is not disabled by

SS pin shutdown state. In the LM5041B version, both HD and LD will be low state when the PWM controller

disabled. In the LM5041 and the LM5041B version, PWM controller is disabled by either a UVLO pin low state or

SS pin shutdown state. Also in the LM5041B version, the REF pin output is not disabled by a UVLO pin low

state. However, if VCC does not receive power from an external source, the UVLO pin low state will disable the

internal VCC regulator and a VCC under-voltage condition will eventually disable REF as the VCC voltage falls.

Differences Between LM5041, LM5041A and LM5041B

ITEM

LM5041

LM5041A

LM5041B

Hiccup mode over-current protection

Available

N/A

N/A

VCC disabled by SS shutdown

Yes

No

No

REF disabled by UVLO pin low state

Yes

Yes

No

BUCK controller disabled by SS shutdown

Yes

No

Yes

HD : LOW

HD : LOW

HD : LOW

BUCK driver states when the controller disabled

LD :HIGH

LD : HIGH

LD : LOW

Logic Table

CONTROLS

PIN STATES

MODE

DEVICE

UVLO

SS

VCC

REF

HD

LD

PUSH&PULL

LM5041

Normal

HIGH

-

LM5041A

9V

5V

PWM

PWM

50% Duty Cycle

Operation

LM5041B

LM5041

HIGH

UVLO

LOW

-

LM5041A

GND

GND

LOW

LOW

Shutdown

LM5041B

LOW

LM5041

GND

GND

LOW

HIGH

SS

HIGH

LOW

LM5041A

LOW

Shutdown

9V

5V

50% Duty Cycle

LM5041B

LOW

Copyright © 2009, Texas Instruments Incorporated

Submit Documentation Feedback

13

Product Folder Links: LM5041B