Layout Considerations

To take full tracking advantage of the switch response

time to an output fault condition, it is important to keep

all traces as short as possible and to maximize the

high-current trace dimensions to reduce the effect of

undesirable parasitic inductance. Place the MAX5918/

MAX5919 close to the card’s connector. Use a ground

plane to minimize impedance and inductance. Minimize

the current-sense resistor trace length (< 10mm), and

ensure accurate current sensing with Kelvin connections

(Figure 6).

When the output is short circuited, the voltage drop

across the external MOSFET becomes large. Hence,

the power dissipation across the switch increases, as

does the die temperature. An efficient way to achieve

good power dissipation on a surface-mount package is

to lay out two copper pads directly under the MOSFET

package on both sides of the board. Connect the two

pads to the ground plane through vias, and use

enlarged copper mounting pads on the top side of the

board (refer to the MAX5919 EV Kit).

Chip Information

TRANSISTOR COUNT: 3542

PROCESS: BiCMOS

Low-Voltage, Dual Hot-Swap Controllers with

Independent ON/OFF Control

______________________________________________________________________________________

13

PART

OUTPUT UNDERVOLTAGE/OVERVOLTAGE

PROTECTION/MONITOR

FAULT MANAGEMENT

MAX5918AEEE

Protection

Autoretry

MAX5918LEEE

Protection

Latched

MAX5919AEEE

Monitor

Autoretry

MAX5919LEEE

Monitor

Latched

Selector Guide

ON_

IN_

GATE_

SENSE_

MAX5918

MAX5919

BACKPLANE

REMOVABLE CARD

WITH NO HOT-INSERTION

PROTECTION

Figure 5. Using the MAX5918/MAX5919 on a Backplane

SENSE RESISTOR

HIGH-CURRENT PATH

MAX5918

MAX5919

Figure 6. Kelvin Connection for the Current-Sense Resistors