AR# 71901

Design Advisory ZCU104 and ZCU111 - Infineon IRPS5401 has a drive signal of 5V for an external power stage

Description

Voltage and current monitoring and control on the Zynq UltraScale+ MPSoC ZCU104 Evaluation Kit and Zynq UltraScale+ RFSoC ZCU111 Evaluation Kit are available on the power rails provided by the Infineon IRPS5401 power controllers.

Infineon have released information regarding the drive signal of the IRPS5401 device which impacts users of the ZCU104 and ZCU111 kits. 

This design advisory outlines the information released and the action, if any, that should be taken by customers.

Solution

The ZCU104 and ZCU111 Evaluation Kits use a PMBus power system from Infineon.

Part of this system involves communication between the Infineon IRPS5401 PMIC and the Infineon TDA21240 multichip module.

Infineon have informed customers that the datasheet for IRPS5401 incorrectly specifies the drive signal for an external power stage as 3.3V.
 
The correct drive signal is 5V. This incorrect specification resulted in the development and implementation of the ZCU104 and ZCU111 with a power stage that is potentially not compatible with a 5V PWM signal.

 

On the ZCU104 and the ZCU111, there is a PWM signal interface between IRPS5401 and TDS21240.

  • IRPS5401 uses a 5V PWM drive signal.
  • TDA21240 uses a 3.3V drive signal.
 
There are 2 instances of this on the ZCU104: 
  • U179 to U175
  • U180 to U176
 
There are 3 instances of this on the ZCU111:
  • U53 to U54
  • U55 to U56
  • U57 to U58

For customers that are using the ZCU104 or ZCU111 as evaluation kits, no further action is required.

 

For customers that use the power solution on the ZCU104 or ZCU111 as a reference when designing the power solution for their customer board, the following is advised:

If using the IRPS5401 and TDA21240 in a custom power solution, a resistor and Zener clamp must be added to the PWM output of the PMIC (IRPS5401).

This layout modification is required to clamp the IRPS5401 5V PWM_A signal:

 

71901-1_201901100230027241.png
 
Failures are not expected for lab conditions with Evaluation Kit applications. 

For production designs, the circuit change outlined above is a requirement.

Infineon have committed to updating documentation to correct the PWM voltage level and to include the voltage clamp circuit when using power stages limited to 3.3V PWM.

AR# 71901
Date 01/17/2019
Status Active
Type Design Advisory
Boards & Kits