circuit
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In the board I am designing I am using a LT1761 adjustable voltage regulator to generator 3.5V for my AVDD.
This is what the datasheet says
The adjustable version of the LT1761 has an output voltage range of 1.22V to 20V. The output voltage is set by the ratio of two external resistors as shown in Figure 1. The device servos the output to maintain the ADJ pin voltage at 1.22V referenced to ground. The current in R1 is then equal to 1.22V/R1 and the current in R2 is the currentin R1 plus the ADJ pin bias current. The ADJ pin bias current, 30nA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 1.
The value of R1 should be no greater than 250k to minimize errors in the output voltage caused by the ADJ pin bias current. The adjustable device is tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.22V. Specifications for output voltages greater than 1.22V will be proportional to the ratio of the desired output voltageto 1.22V: VOUT/1.22V.
Attatching the figure,
This is simple, but I want to check if this is right , I need a output of
V1 = 3.5V I use R1 = 10k and R2 = 18.7K
V2 = 2.4V I use R1 = 10K and R2 = 9.7K
or should I choose like 100K and 97.6K,
Here is the link to the datasheet
https://www.emesystems.com/pdfs/parts/LT1761.pdf
And how/where do I provide the heat sink for this chip because it only tells me
For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices.
This is what the datasheet says
The adjustable version of the LT1761 has an output voltage range of 1.22V to 20V. The output voltage is set by the ratio of two external resistors as shown in Figure 1. The device servos the output to maintain the ADJ pin voltage at 1.22V referenced to ground. The current in R1 is then equal to 1.22V/R1 and the current in R2 is the currentin R1 plus the ADJ pin bias current. The ADJ pin bias current, 30nA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 1.
The value of R1 should be no greater than 250k to minimize errors in the output voltage caused by the ADJ pin bias current. The adjustable device is tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.22V. Specifications for output voltages greater than 1.22V will be proportional to the ratio of the desired output voltageto 1.22V: VOUT/1.22V.
Attatching the figure,
This is simple, but I want to check if this is right , I need a output of
V1 = 3.5V I use R1 = 10k and R2 = 18.7K
V2 = 2.4V I use R1 = 10K and R2 = 9.7K
or should I choose like 100K and 97.6K,
Here is the link to the datasheet
https://www.emesystems.com/pdfs/parts/LT1761.pdf
And how/where do I provide the heat sink for this chip because it only tells me
For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices.