PTH08T230WAD Not Working

Suresh Samynathan1

Hi,

We are using PTH08T230WAD for 4.0V generation. The module was working fine for 3 weeks. After that the module is not starting up.

When we probed the Inductor point and Mosfet gate signal in the module, found no switching happing. When the power is first applied, the module is not giving any PWM. It is always low.

We removed the INH/UVLO resistor and still the module is not starting up.

I have atatched the schematics for reference. Please clarify why the module is not starting up.

over 12 years ago

0 Tom Guerin over 12 years ago

TI__Mastermind 38230 points

Suresh:

I reviewed the schematic above. There are questions on the output capacitors and turbo trans function resistor 29.4kΩ.

1. What is the type, part number and ESR on 330uF, on C215? Is this an aluminum capacitor type?

2. C208 and C203 are indicated as ceramic types. What is their size or type?

The remainder of the schematic is as per the specification.

Tom

0 Suresh Samynathan1 over 12 years ago in reply to Tom Guerin

Prodigy 50 points

Hi Tom,

C215 : Tantalum, Part Number - TPME337M010R0023, ESR=23mOhm

C208 and C203 : Type - Ceramic, X5R, Part Number - LMK325BJ107MM-T, Package - 1210

Suresh

0 Tom Guerin over 12 years ago in reply to Suresh Samynathan1

TI__Mastermind 38230 points

Hi Suresh:

Thanks for output capacitor type and ESR 23mΩ.

The ESR is too high when using turbo trans function. When the ESR is high versus the RTT turbo trans , it can force the unit into instability .This capacitor selection is the likely reason for this failure.

The recommendation is to remove the turbo trans resistor R272, 29.4kΩ. Then leave R272 open. Turbo trans function is minimally effective when Vout is greater than 3.3V. The transient response is only 60mV on a 4.0V Vout bus.

Tom

0 Suresh Samynathan1 over 12 years ago in reply to Tom Guerin

Prodigy 50 points

Hi Tom,

Thanks for the recommendation.

We are using some more power modules and would like to get the feedback on the same. Can you please provide your mail ID threfore I can send the analysis and circuits.

Suresh

0 Tom Guerin over 12 years ago in reply to Suresh Samynathan1

TI__Mastermind 38230 points

Suresh:

My e-mail address is tguerin@ti.com. Please send additional applications

Thanks

Tom

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PTH08T230WAD Not Working