TPS3801: TPS3801K33DCKR

Dear SIR:

Thanks for your reply.

May I double confirming" Is that your meaning detail as below for TPS3103 Dual power monitor ?"

That is correct replacement. I have a couple questions for the circuit:

1. Why is PFI on the first device only have a pull-up resistor? This is not the typical configuration and this will only trigger a reset if "5V_PG" or "3V_PG" fall below 0.551V. This is OK if this is expected.

2. Why does /MR on first device have a pull-up resistor? If this /MR is not being used, the pin can be left floating saving one resistor cost.

3. Is there a reason why /PFO pulls up to 1.8V and not VDD = 3.3V? This is OK but I am curious why this is chosen.

-Michael

Dear SIR:

Thank for your reply.

But,May I double confirming "Is your "couple questions " for "Original Circuit [A circuit] " or "after replace to TPS3103 circuit  [B circuit]" ?

If your "couple questions " for "after replace to TPS3103 circuit  [B circuit]" .

Is your meaning:

(i) "When MIC2774N-29 and MIC2774N-17  [ [A circuit]] change to  "TPS3103"  [B circuit] " that  "peripheral circuit" will different [keep Original peripheral will  incorrect] ? or ...?

(Sorry , I have confusing . because you reply "That is correct replacement." ,but have  "couple questions ")

Or

(ii) your meaning "couple questions " only for  "Original Circuit [A circuit] " . [  "after replace to TPS3103 circuit  [B circuit]" function and "peripheral circuit" the same  "Original Circuit [A circuit] " ]

(iii) Or...?

Thanks

Yes that is the correct replacement. But the original schematic didn't seem to be the typical configuration how both MIC2774N or TPS3803 is normally used.

Typically, the "IN" pin for MIC2774N and the "PFI" pin on TPS3803 use a resistor divider to set the trigger voltage. In both schematics, there is a single pull-up resistor. Although you have correctly replaced the device, I do not see these devices used this way. I would like to get a better understanding of the intended use for "IN" or "PFI" pins to make sure the circuit is working as expected.

-Michael

Dear SIR:

Thank for your reply.

May I double confirming:

(1)Therefore, "your "couple questions " only for "Original Circuit [A circuit] " ,Right ?

(2)Base on you mention "That is correct replacement",therefore  [A circuit]] change to  "TPS3103"  [B circuit] " that  "peripheral circuit" no need change .

    (Change another word: Is that your meaning "after replace to TPS3103 circuit  [B circuit]"  the same "Original Circuit [A circuit] ",Right ? )

    (Change another word2: Is that your meaning "after replace to TPS3103 circuit  [B circuit]"  =  "Original Circuit [A circuit] ",Right ? )

==================================================================================

As we know the "Original Circuit [A circuit] " is  MIC2774N-29 will issue pin 1 output  when monitor VDD and pin 4 IN =Low ,then  MIC2774N-17 will issue pin 1 output  when monitor VDD and pin 4 IN =Low     [ MIC2774N is "N" Version  ,Open Drain output and Active Low ]

<5V_PG and 3V_PG  is Open drain pin from 5V and 3V power IC

5V_PG and 3V_PG is Low for  MIC2774N-29 When 5V and 3V abnormal  or 5V and 3V not ready

5V_PG and 3V_PG will release (Open drain,pull High by external 100k with 3.3V )for  MIC2774N-29  when 5V and 3V normal  or 5V and 3V  ready>

MIC2774N-29 is Low for  MIC2774N-17 When 5V and 3V abnormal  or 5V and 3V not ready

MIC2774N-29 will release (Open drain,pull High by external 100k with 3.3V )for  MIC2774N-17 when 5V and 3V normal  or 5V and 3V  ready

MIC2774N-17 out pull by External with 1.8V , because "RESET" is 1.8V for END device.

Therefore, How about  "after replace to TPS3103 circuit  [B circuit]" ? 

Thanks

1. My questions are for both circuits. Both circuits use a voltage supervisor so I am talking about the typical configuration for both circuits as both circuits have the same functionality.

2. In both circuits, we typically do not see a pull-up resistor only on the "IN" or "PFI" input pins. Typically we see a resistor divider. The only case where a pull-up resistor only will work on "IN" or "PFI" is if monitoring an open-drain input which you mentioned is the case.

Very interesting use case. Normally, our devices along with our competitor voltage supervisors monitor an analog voltage input signal. It seems that in this case, the voltage supervisor is monitoring a digital signal (either logic low 0V, or logic high 5v or 3V). This will work, just not typically how we see these devices used.

For the correct configuration for both A circuit and B circuit, you should use a resistor divider with:

trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

Have the original circuit A been tested before?

-Michael

Dear SIR :

Thanks for your reply.

For the correct configuration for both A circuit and B circuit, you should use a resistor divider with:

trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

Have the original circuit A been tested before?

<Reply>==>No,original circuit A  We didn't test before. But ,It is come from main chip reference design . 

                    Base on circuit A  MIC2774-29  table list Vth is 2.93V ,  MIC2774-17  table list Vth is 1.69V  ,IN pin Vref is 300mV

                    "trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom" seems come from TPS3103 spec.

                    TPS3103 seems different MIC2774 , circuit B "peripheral circuit" will need to change and can't the same  circuit A ,Right ?

                    Therefore regarding  circuit B ,Would you have any advice ?

                    Thanks

The TPS3103 has a 2.941V version (TPS3103K33) but does not have a 1.69V version, the closest is 1.523V (TPS3103E16) or 1.843V (TPS3103H20).

For the PFI pin, the threshold is 0.551V so you use a resistor divider with

trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

as shown in Figure 16 of the datasheet: http://www.ti.com/lit/ds/slvs363g/slvs363g.pdf

Please let me know if this is clear.

-Michael

Dear SIR:

Thank for your reply.

But,May I double confirming :

(1) according to your reply:

      Is that meaning as below ?:

       For VDD pin or PFI pin Vref is 0.551V

      TPS3103K33 and TPS3103E16  's VDD pin have "internal resistor divider" therefore base on different sku.(for example: K33 ,E16 ) have different Vth.(K33 ->Vth is 2.941 ,E16 vth is 1.523)

      MR# pin have internal pull up to VDD resistor. 

      But, PFI pin without  "internal resistor divider" ,therefore PFI pin need add external resistor divider for met requirement by  Vth =0.551 x (Rtop + Rbottom) / Rbottom  calculator .

      Therefore ,

                        TPS3103K33 vs  MIC2774N-29:

      different I:  TPS3103K33  Vth = 2.941V     MIC2774N-29 Vth = 2.93V

      different II: TPS3103K33  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

                       TPS3103E16 vs  MIC2774N-17:

      different I:   TPS3103E16  Vth = 1.523V     MIC2774N-29 Vth = 1.69V

      different II:  TPS3103E16  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

     different III: TPS3103 RESET  internal Reset Logic Timer separate with PFI pin   vs   MIC2774N  internal AND  then delay .

     [As you mention before that recommend to wire  together between TPS3103 's RESET pin  PFO pin by external ,But ,the behavior will the same as MIC2774N ? How ? ]

     different IV: TPS3103 Delay Min= 65ms     MIC2774N  Delay Min= 140ms

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      The TPS3103 has a 2.941V version (TPS3103K33) but does not have a 1.69V version, the closest is 1.523V (TPS3103E16) or 1.843V (TPS3103H20).

      For the PFI pin, the threshold is 0.551V so you use a resistor divider with

      trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

(2) Seams  [A circuit] MIC2774N psec. mention that "It will remain asserted for no less than 140ms after Vin and VDD return above the threshold limits."

     But, TPS3103 spec. mention that Min :65ms Max:195ms.  Is that meaning TPS3103 min: 65ms and can't replace  MIC2774N  Min : 140ms ?

     (Or that TPS3103 min: 65 ms  Max:196 ms  base on different sku (for example: TPS3103K33 ,TPS3103E16 ,....) ,by different strap pin for select ,... that have different  ?)

Thanks

Dear SIR:

Thank for your reply.

But,May I double confirming :

(1) according to your reply:

      Is that meaning as below ?:

       For VDD pin or PFI pin Vref is 0.551V

      TPS3103K33 and TPS3103E16  's VDD pin have "internal resistor divider" therefore base on different sku.(for example: K33 ,E16 ) have different Vth.(K33 ->Vth is 2.941 ,E16 vth is 1.523)

      MR# pin have internal pull up to VDD resistor. 

      But, PFI pin without  "internal resistor divider" ,therefore PFI pin need add external resistor divider for met requirement by  Vth =0.551 x (Rtop + Rbottom) / Rbottom  calculator .

      Therefore ,

                        TPS3103K33 vs  MIC2774N-29:

      different I:  TPS3103K33  Vth = 2.941V     MIC2774N-29 Vth = 2.93V

      different II: TPS3103K33  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

                       TPS3103E16 vs  MIC2774N-17:

      different I:   TPS3103E16  Vth = 1.523V     MIC2774N-29 Vth = 1.69V

      different II:  TPS3103E16  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

     different III: TPS3103 RESET  internal Reset Logic Timer separate with PFI pin   vs   MIC2774N  internal AND  then delay .

     [As you mention before that recommend to wire  together between TPS3103 's RESET pin  PFO pin by external ,But ,the behavior will the same as MIC2774N ? How ? ]

     different IV: TPS3103 Delay Min= 65ms     MIC2774N  Delay Min= 140ms

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      The TPS3103 has a 2.941V version (TPS3103K33) but does not have a 1.69V version, the closest is 1.523V (TPS3103E16) or 1.843V (TPS3103H20).

      For the PFI pin, the threshold is 0.551V so you use a resistor divider with

      trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

(2) Seams  [A circuit] MIC2774N psec. mention that "It will remain asserted for no less than 140ms after Vin and VDD return above the threshold limits."

     But, TPS3103 spec. mention that Min :65ms Max:195ms.  Is that meaning TPS3103 min: 65ms and can't replace  MIC2774N  Min : 140ms ?

     (Or that TPS3103 min: 65 ms  Max:196 ms  base on different sku (for example: TPS3103K33 ,TPS3103E16 ,....) ,by different strap pin for select ,... that have different  ?)

Thanks

Dear SIR:

Would you help reply the confirming item ?

Thanks

Dear SIR:

Thank for your reply.

But,May I double confirming :

(1) according to your reply:

      Is that meaning as below ?:

       For VDD pin or PFI pin Vref is 0.551V

      TPS3103K33 and TPS3103E16  's VDD pin have "internal resistor divider" therefore base on different sku.(for example: K33 ,E16 ) have different Vth.(K33 ->Vth is 2.941 ,E16 vth is 1.523)

      MR# pin have internal pull up to VDD resistor. 

      But, PFI pin without  "internal resistor divider" ,therefore PFI pin need add external resistor divider for met requirement by  Vth =0.551 x (Rtop + Rbottom) / Rbottom  calculator .

      Therefore ,

                        TPS3103K33 vs  MIC2774N-29:

      different I:  TPS3103K33  Vth = 2.941V     MIC2774N-29 Vth = 2.93V

      different II: TPS3103K33  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

                       TPS3103E16 vs  MIC2774N-17:

      different I:   TPS3103E16  Vth = 1.523V     MIC2774N-29 Vth = 1.69V

      different II:  TPS3103E16  Vref = 0.551V     MIC2774N-29 Vref =0.3V 

     different III: TPS3103 RESET  internal Reset Logic Timer separate with PFI pin   vs   MIC2774N  internal AND  then delay .

     [As you mention before that recommend to wire  together between TPS3103 's RESET pin  PFO pin by external ,But ,the behavior will the same as MIC2774N ? How ? ]

     different IV: TPS3103 Delay Min= 65ms     MIC2774N  Delay Min= 140ms

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

      The TPS3103 has a 2.941V version (TPS3103K33) but does not have a 1.69V version, the closest is 1.523V (TPS3103E16) or 1.843V (TPS3103H20).

      For the PFI pin, the threshold is 0.551V so you use a resistor divider with

      trigger voltage = 0.551 x (Rtop + Rbottom) / Rbottom

     ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

(2) Seams  [A circuit] MIC2774N psec. mention that "It will remain asserted for no less than 140ms after Vin and VDD return above the threshold limits."

     But, TPS3103 spec. mention that Min :65ms Max:195ms.  Is that meaning TPS3103 min: 65ms and can't replace  MIC2774N  Min : 140ms ?

     (Or that TPS3103 min: 65 ms  Max:196 ms  base on different sku (for example: TPS3103K33 ,TPS3103E16 ,....) ,by different strap pin for select ,... that have different  ?)

Thanks