Tweaking S6BP401A Family Output Voltage – KBA220615

Version: **

 

Question: How do I tweak S6BP401A family output voltage?

 

Answer: S6BP401A is a family of 6-channel PMICs. MPNs in the S6BP401A family reflect the output voltage combinations of the six channels that are factory-configured. Because MPNs are available as limited samples, there might be the possibility that output voltages need to be tweaked at customer evaluation stage. Output voltages of the four DC/DC channels can be tweaked to a larger one as described below. However, note that output voltages of the two LDO channels cannot be adjusted).

To tweak the output voltage of the DDx channel (x: 1~4), add two resistors to the FBx pin as shown in Fig.1 instead of connecting FBx pin directly to VOUTx rail.

The tuned output voltage is calculated as following:

 

 

To minimize the influence of the FBx pin input resistance RFBx, R1 and R2 should be much smaller than RFBx, which is 95 k038F (min) as shown in the datasheet. A total resistance of about 10 kâ„Ĥ is recommended for R1 and R2.

Note that this connection has the following side effects:

  1. R1 and R2 cause an additional load current, VOUTx / (R1 + R2) . However, the additional load current does not affect the efficiency because of the fixed PWM operation of the S6BP401A family.
  2. The discharge time becomes longer as follows (See the “Discharge Operation” section of the datasheet).
    TDIS [ms] = 2.3 * (RDIS + R1) [kohm] * COUT [μF]