VREG

0.1

µF

IN1 ISET1

ISENSE1

GATE1

DISCH1

+

FAULT

FAULT

TIMER IN2

ISET2

ISENSE2 GATE2

DISCH2

ENABLE

DGND

AGND

+

ENABLE

1

µF ∼ 10 µF

1

µF ∼ 10 µF

3 V

∼ 13 V IN1

3 V

∼ 5.5 V IN2

TPS2321

System

Board

TPS2320

TPS2321

www.ti.com

SLVS276F – MARCH 2000 – REVISED JULY 2013

APPLICATION INFORMATION

Figure 26 shows a typical dual hot-swap application. The pullup resistor at FAULT should be relatively large

(e.g., 100 k

Ω) to reduce power loss, unless it is required to drive a large load.

Figure 26. Typical Dual Hot-Swap Application

INPUT CAPACITOR

A 0.1-

μF ceramic capacitor in parallel with a 1-μF ceramic capacitor should be placed on the input power

terminals near the connector on the hot-plug board to help stabilize the voltage rails on the cards. The

TPS2320/01 does not need to be mounted near the connector or to these input capacitors. For applications with

more severe power environments, a 2.2-

μF, or higher, ceramic capacitor is recommended near the input

terminals of the hot-plug board. A bypass capacitor for IN1 and for IN2 should be placed close to the device.

OUTPUT CAPACITOR

A 0.1-

μF ceramic capacitor is recommended per load on the TPS2320/21; these capacitors should be placed

close to the external FETs and to TPS2320/21. A larger bulk capacitor is also recommended on the load. The

value of the bulk capacitor should be selected based on the power requirements and the transients generated by

the application.

EXTERNAL FET

To deliver power from the input sources to the loads, each channel needs an external N-channel MOSFET. A

few widely used MOSFETs are shown in Table 3. But many other MOSFETs on the market can also be used

with TPS23xx in hot-swap systems.

Table 3. Some Available N-Channel MOSFETs

CURRENT RANGE

PART NUMBER

DESCRIPTION

MANUFACTURER

(A)

IRF7601

International Rectifier

0 to 2

MTSF3N03HDR2

ON Semiconductor

MMSF5N02HDR2

ON Semiconductor

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