AAT4601

DATA SHEET

1.8A Current Limited P-Channel Switch

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201913A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 3, 2012

9

Applications Information

Setting Current Limit

A simple three-step procedure can be used to adjust the

AAT4601’s current limit. First, the maximum current

required by the load should be determined. Second,

select a resistor that guarantees adequate current is

available to the load under normal conditions. Finally,

the maximum current that can pass through the switch

can be calculated and compared to the maximum current

available.

Step 1: The maximum current required by a load is usu-

ally defined in port specifications design application ref-

erences. For example, USB ports may be specified to

support loads of up to 500mA.

Step 2: The most convenient method for determining a

current limit resistor value is to look it up in Table 1,

that is greater than the maximum load current in the

given application; refer to the column, “Device Will Not

Current Limit Below.” The resistor value needed is in the

port requires 500mA. The lowest level where the device

will current limit above 500mA is 516mA. The corre-

Step 3: Now the required resistor value has been deter-

mined. The maximum current that can be drawn, even

with a short circuit applied to the output, can be deter-

mined by referring to the column labeled, “Device Always

Current Limits Below.” If the power supply connected to

the AAT4601’s input can provide this current level, the

power supply voltage will not collapse when a short cir-

cuit is applied to the load switch output. For example, a

notebook computer has a USB port which is powered by

an AAT4601 with a 2k resistor connected between the

SET pin and GND. If the power supply connected to the

AAT4601's IN pin can provide more than 917mA, this

supply will remain in regulation even if a short circuit is

applied to the USB port.

(Ω)

Current

Limit Typ

(mA)

Device Will

Not Current

Limit Below

(mA)

Device Always

Current Limits

Below (mA)

0

2510

1807

3213

10

2463

1773

3152

20

2423

1745

3102

30

2386

1718

3054

36

2361

1700

3022

47

2332

1679

2985

56

2297

1654

2940

68

2258

1626

2890

82

2214

1594

2834

100

2161

1556

2766

120

2107

1517

2697

150

2028

1460

2596

200

1918

1381

2455

240

1840

1325

2355

300

1737

1251

2223

360

1649

1187

2111

470

1585

1141

2029

510

1529

1101

1957

560

1466

1055

1876

620

1397

1006

1788

680

1334

960

1707

750

1266

911

1620

820

1206

869

1544

910

1144

823

1464

1000

1089

784

1394

1100

1034

745

1324

1200

986

710

1262

1300

941

677

1204

1500

865

623

1107

1600

829

597

1061

1800

769

554

985

2000

716

516

917

2200

673

485

861

2400

633

456

811

2700

582

419

745

3000

539

388

690

3300

502

362

643

3600

470

339

602

3900

442

318

565

4300

410

295

524

4700

382

275

489

5100

358

258

458

5600

332

239

424

6200

306

220

392

6800

283

204

362

7500

268

193

343