Hi,
In the schematics of the "typical application" of LTC4269-2 the chip's supply voltage VIN rail is charged through a 33k resistor (the only source when not switching). Is that done just because that's the simplest and lowest cost solution, or are there any reasons to avoid using a kind of regulator for supplying VIN (also during switching)?
Best regards,
Adam
Hi
I have a DC2465A Demo board and i changed the Linear IC's from LT4320 to LT4320-1.
The Datasheet says with proper choice of MOSFET's this Demo board could operate at more than 600Hz.
Could anyone suggest suitable MOSFET's and any other changes needed for this ?
The board should finally rectify 3KW of power. (More than the 1.5KW rated MOSFET's currently on the Demo board)
Dear Team,
We have developed power management board with the reference of LTC4015 demo board. In our board the LTC4015 is getting burnt due to the inrush current when we power on the battery (Li-Ion battery, 26V, 3.5Ah). We implemented our own inrush current protection circuit with the reference of LT4356 demo board.
But still LTC4015 is getting burnt when we switch off and On frequently. Request your complete support to solve this issue. The MOSFET (Q1C) which we've used in the LT4356 board also went bad, this caused LTC4015 getting damaged. We've a delivery of this project to customer, sorry we are coming at the last moment. Definitely you guys have solved this kind of issues, Request you to provide the working schematic.
Thanks in Advance!!
Thank you,
Krishna
Hello,
I want to use the LTC4417 Power Path Controller in my next design.
The maximum current that flows through the PMOSFET will be up to 8A. I'm looking for a PMOSFET device with an small RDS(On) to keep the power dissipation low. The datasheet makes a few suggestion but form my point of view, the RDS(On) of these MOSFETs are to high. Another point is, that my design space is limited, so it would be great to have an Dual MOSFET Package.
I found the Si7997 that looks like an good candidate for me. First checks with the formulas from the datasheets looks ok.
https://www.mouser.com/datasheet/2/427/si7997dp-109454.pdf
Has someone experiences with this MOSFET? Or knows anyone a better choice?
I'm looking for an RDS(ON) <= 8mOhm per channel
Edge conditions:
Vmin =8V
Vmax =16V
Imax =8A
CL = 240uF
Temperature: -40°C to 85°C
Many thanks and best regards,
Till Hagemann
Hi,
I am planning to use an ideal diode to reduce power dissipation, while having the ability to turn on/off the ideal diode, as a kind of load-switch.
The input voltage is somewhat lower(lets say 5% lower) than the output voltage, so the ideal diode wouldn't be on at all times. Only when a transient loads the output, it would drop enough to turn on the ideal diode and supply current doing the transient.
In 1-FET ideal diodes, the FET body diode handles the initial current, until the FET turns on and "shorts" the body diode. However, I would like to use a 2-FET solution, as I also need to be able to completely disconnect the input from the output.
I was looking to use the LTC4359 as shown in figure 6 in the datasheet(without C1 and R4), but I am concerned about the turn-on speed of the system. As far as I can see, the max gate current supplied by the LTC4359 is 10uA(typ). The total gate charge of the FQA140N10 and FDMS86101 is about 340nC(250nC+55nC), so with 10uA, it would take about 34ms to fully turn on the FETs. Since the body diodes are purposely opposite facing, they can't take care of the initial transient, before the FETs turn on.
In figure 16, a 100k resistor is placed across Q2(The switch-FET) in order to bias the source pin. How does this decrease gate ramp time? It lifts the Q2 source and gate to the level of its drain, but how does this reduce the turn-on time, when the gate-source voltage is still zero? How can I estimate which turn-on time a certain value resistor will result in?
Thank you.
Hi All,
Would you let me know where SNS+, SNS- and TIMER pins to be connected to in case the overcurrent protection is not needed? Leave all three pins open is OK?
Regards,
Kazu
Hi,
My customers are considering LTM 8067.
Since it is used with 5 V output, I found RFB in Table 1, 8.25 kΩ.
However, if 8.25 kΩ is inserted into the formula for RFB of Datasheet P.8, Vout = 4.87 V.
For Vout DC Voltage on page 3, Vout = 5 V (typ) with RADJ = 8.25 kΩ.
From the calculation, it seems that Vout (typ) = 4.87 V,
Is the calculation different?
Best Regards,
Yuya
I'm using LTC3105 as a trickle charger for a Li-Po battery as shown in the first page of the datasheet, but with a 1W, 5V rated PV panel instead of a single cell one. I'm using a 390k resistor in the MPPC pin because I want the panel to work at 3.9V . Is this correct? When I measure the voltage in the MPPC it varies and usually is around 2.5V and 3V. If the block diagram in the datasheet is correct, there is an internal current source so the voltage should be constant. What is wrong?
Hi I am using LTC7000 as high side switch with Dual NFETs. The schematic is attached here.
The part number for M1 and M2 are IPB015N08N5ATMA1 but not the components shown in the schematic.
The I1 load is actually an electronic load.
In this test, I start the test with Iload gradually increase from 1A to 9A. When C4 (6.8mF) is not included, the LTC7000 is working properly and the dual MOSFETs are turned on properly. The Vgs of dual NFETs are 12V.
When C4 is included, the LTC7000 is working properly until the Iload reaches 7A. When Iload is 7A, it is found out the TGup pin and Vcc pin is 0V. Besides this, Vcc pin is shorted to Ground pin as well. This happens at the instance I turn On the power supply. I believe the LTC7000 has been damaged.
I have added in C8 and R4 to have a soft-start on dual NFETs as we have a large capacitor (6.8mF) on output side. Would you have any idea what might cause the damage on IC? Is there any way I can prevent this?
Hello,
We have designed a board based upon an LT3795 application note.
We are using the circuit to boost to 54 Volts from 24V. I am getting a relatively high ripple (0.5V). The surrounding of the coil is very hot (gets up to 80 degrees). I have taken a lot of spares and I'm using a 22uH 7mohm(15 Amps).
As far as I understand it should not be so hot. I would like to reduce the ripple to ~200mV.
Rt--> 10Kohm(700Khz switching frequency) instead of currently 23.K(i.e. 320KHz) that I'm using now. The inductor according to the calculation should be 8uH.
Before these changes can you approve my estimation and check the values of the design?
Do have any recommendation for switching frequency? are you familiar with the heating problem how can it be solved?
The diode, capacitor and the Fet near the coil are getting pretty hot. I assume the coil is the reason.
Hi,
I'm planning to use the ADM7170 as 1.2 V voltage source. According to the datasheet ordering guide table (page 23/23), the adjustable models (ADM7170ACPZ-R7 & ADM7170ACPZ-R2) are listed with an output voltage of 1.2 V.
As stated on page 16, every fixed version can be used as an adjustable one. So the "adjustable" model is the fixed one with 1.2 V, by connecting the SENSE pin direct to Vout and Do Not Install R2?
I'm little bit condused by the notation, as it seems every version is an adjustable one, and the "adjustable" one (ADM7170ACPZ-R7 & ADM7170ACPZ-R2) is the fixed one with 1.2V.
To sum it up, the models ADM7170ACPZ-R7 & ADM7170ACPZ-R2 are the fixed version with 1.2 V. Is that correct?
Is there any difference between the fixed models (1.3 V to 5 V) compared to the "adjustable" operated as 1.2 V source, by means of noise performence?
BR
Hi All -
Is the firmware for the PIC16F1459 that handles communications between the LTC4015 and QuickEval PC software available? I can't find it anywhere and assume it hasn't been published, yet, but wanted to ask to make sure.
Thanks!
Ty
I don't get 1 μF of bypass capacitor.
Therefore I think we'll set a bypass capacitor of VIN1,2 to 2.2 μF.
Would there be an anxious point?
Can I have advice?
Hi,
I want to add a resistor (e.g. 1k) between Current_Shunt and Sens-Pin, and a Resistor (e.g. 220K) from Vin to Sens-Pin.
A higher Input/output Voltage difference should then result in a lower current limitation. My goal is , to better adopt to the SOA of my Mosfet, during shortcut but to keep a good "current punch" during overload.
Is this possible ?
Thx,
Michael
Hello,
I am using LTC4071 to charge LiPo (3.7 1200ma) from Solar Panel. I have a custom made PCB for this. The connection on PCB is as follows:
NTCBAIS - Floating
NTC - connected to VCC
ADJ - Floating
LBSEL - connected to VCC
BAT - connected to LiPO
Everything works good if the Solar Panel is connected and is supplying the necessary power to charge the LiPO. I can see VCC to reach the programmed float voltage of 4.1V (ADJ pin float). But in order to simulate the absence of sun light I removed the solar panel from the board. As per datasheet it should supply voltage from LiPo (at least 3.7V of LiPo). But as soon as I remove the solar panel the VCC is drooping to 0V.
My question is why VCC is drooping to 0V?, it should supply system load either from Solar Panel or LiPo.
I hope my understanding is correct.
Let me know if you need additional information.
Regards,
Nahit
Can someone give me more detailed description of LTM4644 overcurrent protection function?
How does it work? (working theory)
Overcurrent threshold?
Response time (turn-off time)
Recovery time (turn-on time)
etc.
I wanted to do LTSpice simulations on a POE design and can't find a model for LT4925. Is one going to be available soon?
Dear Support,
is it known how PSRR of LT3045 depends on difference VIN-VOUT?
I plan to use it to produce voltage a bit below 3.0V from 3.3V rail. The datasheet specifies max. dropout voltage as 350mV, so theoretically 2.94V should be already correctly regulated. Can I expect high PSRR performance then? Would it get significantly better with output regulated to 2.9V or 2.87V?
Best regards,
Adam
I received 100W (ADP1046A-100-EVALZ) EVM board from the local distributor and started powering the board. I have change the output current parameters to 5A instead of 8A and corresponding light loads values are also changed.
Please guide us how to save the board settings after the changes.
please decode the date code for the following part
LTC3406BES5-1.2#TRMPBF
