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This is schematic given by https://www.instructables.com/Arduino-LTC6804-BMS-Bal...

shubhay

@copilot The bom says MOSFET-P SOT23-R Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12 P-Channel Mosfet is the FQP27P06 right choice

copilot

The FQP27P06 is a P-Channel MOSFET, so it's compatible with your specifications. I would note a few things:

The FQP27P06 is a through-hole component and comes in a TO-220 package, not a SOT23. If your PCB layout is meant for SOT23, then this might not fit.
This particular MOSFET has a Vds (drain-to-source voltage) of -60V, an Id (continuous drain current) of -27A, and a power dissipation of 130W. Ensure that these specifications match the requirements of your circuit.
If you still want to use a SOT23 component, you may have to look for another model.

If you provide more specifications/requirements for your design, I could assist you in choosing a more suitable component. The FQP27P06 component is a good choice if you're looking for a high current, high power P-Channel MOSFET and your circuit can accommodate a TO-220 package.

copilot

Given your requirement for a P-Channel MOSFET in a SOT23 package, the FQP27P06 is not suitable since it comes in a TO-220 package. Instead, you can consider P-Channel MOSFETs like BSS84 or AO3401, which both come in a SOT23 package.

It's important to note that the electrical characteristics of these components (like Vds and Id) may still not match the requirements of your circuit because we have not determined these parameters yet from your brief. Your project may require a MOSFET with certain specifications, so please ensure that your chosen MOSFET meets these before finalizing its design.

Without information on system voltage levels and maximum current, it's difficult to recommend an exact part. Make sure to verify the Vds (Drain-Source Voltage), Rds(on) (Drain-Source On-Resistance), and Id (Continuous Drain Current) ratings align with your application's requirements.

shubhay

I am looking for a Device - MOSFET-P and Package - SOT23-R P-Channel Mosfet this is all the details given in the BOM file by the author

copilot

Sure, I'd be happy to assist with your search for a suitable P-Channel MOSFET in a SOT23 package. Here are the key questions to consider:

Maximum Current: What will be the maximum current flowing through the MOSFET? You'll want to ensure the MOSFET can handle this without overheating.
Supply Voltage: What is the maximum supply voltage in the circuit in which the MOSFET will be used? This will inform the selection of a MOSFET with an appropriate rated Drain-Source Voltage (Vds).
Switching Frequency: At what frequency will the MOSFET switch? Higher frequencies can create more heat, requiring a MOSFET with a lower On Resistance (Rds(on)).
Logical Level Voltage: What is the logical level voltage? You need to verify that the Gate Threshold Voltage (Vgs(th)) of the MOSFET is compatible with the logical level voltage in your design.
Thermal Considerations: Does your application have specific thermal constraints (i.e., can it handle heat well, or does it need a low thermal footprint)?

The answers to these questions should help you narrow down your choices for a suitable MOSFET for your project.

shubhay

Ask me questions regarding the choice of MOSFET for this application and we will come to finalize one

copilot

The LTC6804 is a multicell battery monitor from Analog Devices. In a battery balancing application involving the LTC6804, the choices of MOSFETs used for discharging the cells are quite flexible.

Typically, you would be looking for a P-channel low on-resistance (Rdson), SOT23 packaged MOSFET that can conduct the balancing current at your expected power dissipation. The balancing current is usually in the range of 10mA to 100mA, depending on your application and battery chemistry.

One of the commonly used P-channel MOSFETs for similar applications is the BSS84 (from various manufacturers) due to its cost, availability and package. The BSS84 can handle a continuous drain current (Id) of -130 mA, and a peak Id of -500 mA which will be enough for most balancing applications.

Please keep in mind, the preferred choice may vary based on balancing current requirement, voltage levels, thermal conditions and reliable availability. Be sure to check these parameters with your exact circuit requirements.

shubhay

My circuit uses a LTC6804 to perform the balancing using this mosfet, which mosfet will be prefered choice

copilot

The BSS84AK,215 is indeed a P-Channel MOSFET packaged in a SOT23 (TO-236AB). The key parameters for this device are as follows:

$V_{DS}$ (Drain to Source Voltage): -50V
$V_{GS}$ (Gate to Source Voltage): ±20V
$I_{D}$ (Continuous Drain Current): -130 mA
$P_{D}$ (Power Dissipation): 350 mW

If the operation conditions of your circuit align with these specifications, especially the drain to source voltage, continuous drain current, and power dissipation, then BSS84AK,215 will be a suitable choice.

Moreover, as you are using this MOSFET for cell balancing in a battery management system with the LTC6804, check that the balancing current for each cell does not exceed the continuous drain current of the MOSFET, which is -130 mA in this case.

shubhay

BSS84AK,215 Is this mosfet right choice?

copilot

That sounds like a good decision. The BSS84AK,215 is a commonly used P-Channel MOSFET for battery balancing applications with the LTC6804 due to its high reliability, good thermal performance, and suitability for low to moderate balancing currents. If the specifications meet your application requirements, it should serve your project well. Remember to design your PCB layout to accommodate the heat dissipation of this SOT23 package, and follow good practices for trace widths to handle the expected current levels. Good luck with your project!

shubhay

Ok I will go with it

copilot

When it comes to selecting an LED, the decision typically revolves around the following factors:

Color: LEDs come in a variety of colors. Choose one that suits your application.
Brightness: This is often indicated by luminous intensity in the LED data sheet. The higher the intensity, the brighter the LED.
Forward Voltage (Vf): Different LEDs need different voltages to operate. Ensure that the forward voltage is suitable for your application.
Forward Current (If): This is the current that flows through the LED for normal operation without damaging the LED.
Viewing Angle: Depending on your application, you may want an LED with a wide viewing angle, or a narrow one.

Assuming you're looking for standard brightness and a popular color like red or green, there are several options available. For instance, the Lite-On LTST-C190KRKT is a red LED in an 0805 SMD package, with a typical forward voltage of 2V and a forward current of 20mA.

For green, you could consider the Kingbright AAP2012CGCK.

However, prices vary by supplier and quantity. I recommend checking on distributor websites like Digikey, Mouser, or Farnell for current prices and availability. Always remember to double-check the data sheets before making your final decision.

shubhay

I am looking for low cost led with package 0805 for mounting on pcb board which do you suggest

copilot

A popular choice would be the Panasonic ERJ-U series anti-sulfur resistors. The ERJ-U model that meets your specifications is the ERJ-U14F16R0C.

Key Specifications:

Resistance: 16Ω
Tolerance: ±1%
Power Rating: 0.5W
Size: 2512 (6432 Metric)

Do note that prices may vary and are usually dependent on the quantity ordered. Always check with multiple suppliers for the best prices and availability. Ensure the component suits your design constraints before you finalize the selection.

shubhay

I want a Resistor value - 16 Ohm Device - R-US_R2512 package - R2512

copilot

A commonly used 1kΩ resistor in an 0805 package would be the Yageo RC0805JR-071KL.

Here are some of its specifications:

Resistance: 1kΩ
Tolerance: ±5%
Power: 0.125W
Size/Package: 0805 (2012 Metric)

This chip resistor is widely available and relatively cost-effective. However, you may want to adjust your choice based on your specific circuit requirements (e.g., tolerance, power rating, etc.) and pricing/availability from your preferred components distributor. Remember to verify the specifications in the datasheet before finalizing your selection.

shubhay

Suggest 1k resistor with 0805 package

copilot

A popular choice for a 200Ω resistor in an 0805 package is the Yageo RC0805JR-07200RL.

Here's a quick look at some of its specifications:

Resistance: 200Ω
Tolerance: ±5%
Power: 0.125W
Size/Package: 0805 (2012 Metric)

Please verify these specifications against your needs for your circuit. Don't forget to check on its availability from your preferred distributor and always look over the datasheet before finalizing your component selection.

shubhay

Suggest 200 Ohm resistor 0805 package

shubhay

The BOM says MOSFET-P SOT23-R Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12 P-Channel Mosfet is the FQP27P06 right choice?

shubhay

@copilot This is schematic given by https://www.instructables.com/Arduino-LTC6804-BMS-Balance-Board/ where he uses the LT6804 pin S1 The internal MOSFETS are available through pins S1-S12 while the cells themselves are accessed using pins Net 1 .The schematic above shows one of the 12 identical bleed circuits. When Q1 is turned on, current will flow from Net1 to ground through R5, dissipating some of the charge in cell 1. I selected a 6 Ohm, 1 Watt resister, which should be able to handle several milliamps of bleed current.. There is an LED added so the user can see which cells are balancing at any given time. I want to know which P-Channel Mosfet to use for this task

copilot

Since the Instructable project you linked hasn't specified a particular P-Channel MOSFET, we will have to choose an appropriate one based on the specifications and application involved. To choose the correct P-Channel MOSFET for your project, you must consider the following factors:

Voltage Rating: The source-drain voltage (Vds) rating should be greater than the maximum voltage you are going to switch. In your case, it should be at least the maximum voltage of the cell.
Current Rating: It should carry the load current without overheating. You need to calculate the maximum current that will flow through the MOSFET when Q1 is turned on. It should be lower than the rated Drain-to-Source current (Id).
Rds(on) Value: Lower Rds(on) value would mean lower conduction losses, which is better for efficiency.

Based on the above parameters, a commonly used P-Channel Mosfet like FQP27P06 from Fairchild Semiconductor could be a good choice. It can handle up to -60V and -27A which should be more than capable for a cell balancing operation in a battery management system. Remember to verify the selected component with your particular use case and conditions.

Remember, the selected MOSFET should be connected in such a way that when Q1 (presumably controlled by the GPIOs of IC1) is turned on, the current flows from the battery cell (connected to Net1) to the ground through the bleed resistor (which could be _R_2 or R_3 depending on the schematic and D1 as per your description).

The specific connection would look something like this:

Drain connected to Cell1 (Net1)
Source is connected to one side of the resistance (R2 or R3) and diode (D1)
The resistor (R2 or R3) and diode (D1) are connected in parallel
The other side of the resistor (R2 or R3) and diode (D1) is connected to ground
The Gate is connected to the control pin(Q1)

Always cross-check with datasheet and relevant information to make sure the selected components meet your requirement and safety standards.

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Resistance

16 Ω

Resistance

200 Ω

IC1

Resistance

1000 Ω

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