MP8861 – 2.85V - 18V, 6A, SYNCHRONOUS, STEP-DOWN CONVERTER

MP8861 Rev. 1.1

www.MonolithicPower.com

27

5/28/2020

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© 2020 MPS. All Rights Reserved.

5) Reg04 Output Voltage

R

egister 04 is an output voltage-indicating

register. After the part starts up, the output

voltage

can

be

read

through

the

I2C

communication. In light load, if the mode bit is

set to 0, the MP8861 works in PFM mode. At

extremely light-load or no-load condition, the

ADC only works when the first pulse comes,

and then the MP8861 refreshes the output

voltage register before entering sleep mode.

At this moment, the sensed output voltage is at

its maximum value, not the average output

voltage. Therefore, the I2C read-back voltage is

slightly higher than the set point. When applying

some load to the part, a higher sense accuracy

can be achieved. The Mode bit can be set to 1

(PWM

mode)

for good

voltage

sensing

accuracy at light load. Table 5 shows the output

voltage chart from 0.5V to 5.643V.

NAME

BITS

DEFAULT

DESCRIPTION

Output

voltage

D[7:0]

0000 0000 Output voltage monitor bits. Table 5 shows the output voltage monitor chart.

Table 5: Output Voltage Chart

D[7:0]

VOUT

(V)

D[7:0]

VOUT

(V)

D[7:0]

VOUT

(V)

D[7:0]

VOUT

(V)

D[7:0]

VOUT

(V)

D[7:0]

VOUT

(V)

0000 0000

0.500

0010 1011

1.367

0101 0110

2.235

1000 0001

3.102

1010 1100

3.969

1101 0111

4.837

0000 0001

0.520

0010 1100

1.387

0101 0111

2.255

1000 0010

3.122

1010 1101

3.989

1101 1000

4.857

0000 0010

0.540

0010 1101

1.408

0101 1000

2.275

1000 0011

3.142

1010 1110

4.010

1101 1001

4.877

0000 0011

0.561

0010 1110

1.428

0101 1001

2.295

1000 0100

3.162

1010 1111

4.030

1101 1010

4.897

0000 0100

0.581

0010 1111

1.448

0101 1010

2.315

1000 0101

3.183

1011 0000

4.050

1101 1011

4.917

0000 0101

0.601

0011 0000

1.468

0101 1011

2.335

1000 0110

3.203

1011 0001

4.070

1101 1100

4.937

0000 0110

0.621

0011 0001

1.488

0101 1100

2.356

1000 0111

3.223

1011 0010

4.090

1101 1101

4.958

0000 0111

0.641

0011 0010

1.509

0101 1101

2.376

1000 1000

3.243

1011 0011

4.110

1101 1110

4.978

0000 1000

0.661

0011 0011

1.529

0101 1110

2.396

1000 1001

3.263

1011 0100

4.131

1101 1111

4.998

0000 1001

0.682

0011 0100

1.549

0101 1111

2.416

1000 1010

3.283

1011 0101

4.151

1110 0000

5.018

0000 1010

0.702

0011 0101

1.569

0110 0000

2.436

1000 1011

3.304

1011 0110

4.171

1110 0001

5.038

0000 1011

0.722

0011 0110

1.589

0110 0001

2.456

1000 1100

3.324

1011 0111

4.191

1110 0010

5.058

0000 1100

0.742

0011 0111

1.609

0110 0010

2.477

1000 1101

3.344

1011 1000

4.211

1110 0011

5.079

0000 1101

0.762

0011 1000

1.630

0110 0011

2.497

1000 1110

3.364

1011 1001

4.231

1110 0100

5.099

0000 1110

0.782

0011 1001

1.650

0110 0100

2.517

1000 1111

3.384

1011 1010

4.252

1110 0101

5.119

0000 1111

0.803

0011 1010

1.670

0110 0101

2.537

1001 0000

3.404

1011 1011

4.272

1110 0110

5.139

0001 0000

0.823

0011 1011

1.690

0110 0110

2.557

1001 0001

3.425

1011 1100

4.292

1110 0111

5.159

0001 0001

0.843

0011 1100

1.710

0110 0111

2.578

1001 0010

3.445

1011 1101

4.312

1110 1000

5.179

0001 0010

0.863

0011 1101

1.730

0110 1000

2.598

1001 0011

3.465

1011 1110

4.332

1110 1001

5.200

0001 0011

0.883

0011 1110

1.751

0110 1001

2.618

1001 0100

3.485

1011 1111

4.352

1110 1010

5.220

0001 0100

0.903

0011 1111

1.771

0110 1010

2.638

1001 0101

3.505

1100 0000

4.373

1110 1011

5.240

0001 0101

0.924

0100 0000

1.791

0110 1011

2.658

1001 0110

3.526

1100 0001

4.393

1110 1100

5.260

0001 0110

0.944

0100 0001

1.811

0110 1100

2.678

1001 0111

3.546

1100 0010

4.413

1110 1101

5.280

0001 0111

0.964

0100 0010

1.831

0110 1101

2.699

1001 1000

3.566

1100 0011

4.433

1110 1110

5.300

0001 1000

0.984

0100 0011

1.851

0110 1110

2.719

1001 1001

3.586

1100 0100

4.453

1110 1111

5.321

0001 1001

1.004

0100 0100

1.872

0110 1111

2.739

1001 1010

3.606

1100 0101

4.473

1111 0000

5.341

0001 1010

1.024

0100 0101

1.892

0111 0000

2.759

1001 1011

3.626

1100 0110

4.494

1111 0001

5.361

0001 1011

1.045

0100 0110

1.912

0111 0001

2.779

1001 1100

3.647

1100 0111

4.514

1111 0010

5.381

0001 1100

1.065

0100 0111

1.932

0111 0010

2.799

1001 1101

3.667

1100 1000

4.534

1111 0011

5.401

0001 1101

1.085

0100 1000

1.952

0111 0011

2.820

1001 1110

3.687

1100 1001

4.554

1111 0100

5.421

0001 1110

1.105

0100 1001

1.972

0111 0100

2.840

1001 1111

3.707

1100 1010

4.574

1111 0101

5.442

0001 1111

1.125

0100 1010

1.993

0111 0101

2.860

1010 0000

3.727

1100 1011

4.595

1111 0110

5.462

0010 0000

1.145

0100 1011

2.013

0111 0110

2.880

1010 0001

3.747

1100 1100

4.615

1111 0111

5.482

0010 0001

1.166

0100 1100

2.033

0111 0111

2.900

1010 0010

3.768

1100 1101

4.635

1111 1000

5.502

0010 0010

1.186

0100 1101

2.053

0111 1000

2.920

1010 0011

3.788

1100 1110

4.655

1111 1001

5.522

0010 0011

1.206

0100 1110

2.073

0111 1001

2.941

1010 0100

3.808

1100 1111

4.675

1111 1010

5.543

0010 0100

1.226

0100 1111

2.093

0111 1010

2.961

1010 0101

3.828

1101 0000

4.695

1111 1011

5.563

0010 0101

1.246

0101 0000

2.114

0111 1011

2.981

1010 0110

3.848

1101 0001

4.716

1111 1100

5.583

0010 0110

1.266

0101 0001

2.134

0111 1100

3.001

1010 0111

3.868

1101 0010

4.736

1111 1101

5.603

0010 0111

1.287

0101 0010

2.154

0111 1101

3.021

1010 1000

3.889

1101 0011

4.756

1111 1110

5.623

0010 1000

1.307

0101 0011

2.174

0111 1110

3.041

1010 1001

3.909

1101 0100

4.776

1111 1111

5.643

0010 1001

1.327

0101 0100

2.194

0111 1111

3.062

1010 1010

3.929

1101 0101

4.796

0010 1010

1.347

0101 0101

2.214

1000 0000

3.082

1010 1011

3.949

1101 0110

4.816