Positive High-Voltage, Hot-Swap Controllers

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13

Layout Considerations

To achieve accurate current sensing, a Kelvin connec-

tion is recommended. The minimum trace width for 1oz

copper foil is 0.02in per amplifier to ensure the trace

stays at a reasonable temperature. However, 0.03in.

per amplifier or wider is recommended. Note that 1oz

copper exhibits a sheet resistance of approximately

530µ

Ω/square. Small resistances add up quickly in

high-current applications. To improve noise immunity,

connect the resistor-divider to ON close to the device,

capacitor from ON to GND also helps reject induced

noise. Figure 14 shows a layout that addresses these

issues. It is recommended that 2oz copper is used,

particularly as the external MOSFET must be thermally

coupled to the MAX5933_/MAX5947_ to ensure proper

thermal-shutdown operation.

R6

1k

Ω

5%

C1

10nF

D1

CMPZ5248B

Q1

IRF530

R5

10

Ω

5%

0.01

Ω

R3

143k

Ω

1%

R4

4.22k

Ω

1%

R7

47k

Ω

5%

220

µF

R2

10.2k

Ω

1%

R1

294k

Ω

1%

C2

0.68

µF

MAX5933A

GND

TIMER

ON

PWRGD

FB

GND

SENSE

GATE

5

1

3

2

4

87

6

SHORT

PIN

ON/OFF

0.1

µF

60

40

20

2

4

6

8

10

12

14

16

0

080

Figure 13. Gate Drive vs. Supply Voltage

Figure 12. Active-Low Enable Module