ESD DesEx 2023

The photodiode is a cheap surface mount silicon unit VBP104S, RS part number 768-9394. From the datasheet what is the active area of the photodiode?

Length: 6.4mm Height 3.9mm

$4.4 m m^{2}$ https://www.vishay.com/docs/81170/vbp104sr.pdf

What is the maximum current in D1 and D2?

If we assume our operating voltage is roughly around the max reverse: 60V

Our $I_{ma x}$ should be equal to $\frac{P _{v}}{V _{o p}} = \frac{215 * 1 0 ^{- 3}}{60} = 3.583 * 1 0^{- 3}$

The photodiode produces an output voltage of 1V peak across RPD. Choose a value for RPD

R_{P D} = \frac{V}{I} = \frac{1}{3.583 * 1 0 ^{- 3}}

The maximum analogue input to AIN is 3.3V. Choose values of R2 and R1 so that the required maximum input voltage to AIN is achieved. Note that R2 = R2’ and R1 = R1’

$R_{2} = 23 k, R_{1} = 10 k$

What is the maximum current in G4 and G7?

$I = \frac{V}{R}$

I = \frac{3.3}{23 k + 10 k} = 0.0001 A

From the datasheet of the 78M33 (RS part number 809-5472) what is the maximum current in G1?

6mA

A1 and A2 are type MCP6L01T-E/LT RS part number 768-1397. What is the maximum current in G3, G6?

+- 2mA

M1 and M2 draw up to 1A each. What is the maximum current in G10?

2A (1+1A)

The L298 is RS part number 636-384. What is the maximum current in G9? (Hint: It is equal to the maximum quiescent current in VS + the maximum quiescent current in VSS)

82mA

What is the maximum current in G0?

G0 = G1 + G2 + G3 + G4 + G5 + G6 + G7 + G8 + G9 + G10

G1 = 6mA G2 = G5 = 3.58mA G3 = G6 = 2mA G4 = G7 = 0.1mA G8 = 20mA (in first page for FRDM board) G9 = 82mA G10 = 2A

G0 = 2.12A

What is the typical resistance of a wire on a typical PCB? (Use this value for all subsequent calculations)

0.123

What voltage corresponds to a change in the least significant bit in the ADC input AIN? Note that the FRDM KL-25Z has a 16 bit ADC

\frac{3.3}{2 ^{16}} = 50.35 μ V

What voltage corresponds to a change in the least significant bit in the ADC input at the input of A1?

$A_{V} (A 1) = 3.3$

\frac{50.35}{3.3} = 15.26 μ V

For each ground connection state the maximum current which is flowing (from sheet 2) and the voltage it would generate in the resistance of a typical PCB track

$G_{0} = 2.12 A$ $G_{1} = 6 m A$ $G_{2} = G_{5} = 3.58 m A$ $G_{3} = G_{6} = 2 m A$ $G_{4} = G_{7} = 0.1 m A$ $G_{8} = 20 m A$ (in first page for FRDM board) $G_{9} = 82 m A$ $G_{10} = 2 A$

Voltage = Current * 0.123 $G_{0} = 0.321 V = 261 mV$ ** $G_{1} = 738 u V$ ** $G_{2} = G_{5} = 0.44 mV = 440 μ V$ $G_{3} = G_{6} = 0.246 mV = 246 μ V$ $G_{4} = G_{7} = 0.0123 mV = 12.3 μ V$ $G_{8} = 2.46 mV$ $G_{9} = 10.09 mV$ $G_{10} = 246 mV$

Answer Sheet 3

G8 to G0 = $(6 + 2 * 3.58 + 2 * 2 + 2 * 0.1 + 20) m A$ $531.36 m A$ 37.36 $65.36 mV$ 4.595

ESDDesEx23Q3.excalidraw

215mW over 4.4mm^2 4886.36mW/cm

20uA for 0.4886

for 4886 would be 20*10^-6 * 10^4 Which = 200mA

Quartz 4

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