MIC2178

Micrel

MIC2178

12

June 1998

The feedback resistors, RC compensation network, and

BIAS pin bypass capacitor should be located close to their

respective pins. To prevent ground bounce, their ground

traces and SGND should not be in the path of switching

BIAS

SGND

PWRGD

COMP

PGND

FB

SW

VIN

C2

100µF

10V

3.3V/1A

L1

50µH

C4

6.8nF

C3

0.01µF

MIC2178

PWM

Skip Mode

PWM Mode

SYNC

EN

R1

20k

R2

10k

4.5V to 16.5V

C1

22µF

35V

U1

20

11

10

18

13

14–17

19

12

4–7

3,8

1,2,9

D1

MBRS130L

U1 Micrel

MIC2178-3.3BWM

C1 AVX

TPSE226M035R0300, ESR = 0.3

Ω

C2 AVX

TPSD107M010R0100, ESR = 0.1

Ω

C3 Z5UorX7R Ceramic Dielectric Material

C4 X7RorNP0 Ceramic Dielectric Material

D1 Motorola

MBRS130LT3

L1

Coiltronics CTX50-4P, DCR = 0.097

Ω

L1

Coilcraft

DO3316P-473, DCR = 0.12

Ω

L1

Bi

HM77-11003, DCR = 0.073

Ω

Figure 1. MIC2178 4.5V–16.5V to 3.3V/1A Regulator

BIAS

SGND

PWRGD

COMP

PGND

FB

SW

VIN

C2

100µF

10V

5V/1A

L1

50µH

C4

6.8nF

C3

0.01µF

MIC2178

PWM

Skip Mode

PWM Mode

SYNC

EN

R1

20k

R2

10k

5.4V to 16.5V

C1

22µF

35V

U1

20

11

10

18

13

14–17

19

12

4–7

3,8

1,2,9

D1

MBRS130L

U1 Micrel

MIC2178-5.0BWM

C1 AVX

TPSE226M035R0300, ESR = 0.3

Ω

C2 AVX

TPSD107M010R0100, ESR = 0.1

Ω

C3 Z5UorX7R Ceramic Dielectric Material

C4 X7RorNP0 Ceramic Dielectric Material

D1 Motorola

MBRS130LT3

L1

Coiltronics CTX50-4P, DCR = 0.097

Ω

L1

Coilcraft

DO3316P-473, DCR = 0.12

Ω

L1

Bi

HM77-11003, DCR = 0.073

Ω

Figure 2. MIC2178 5.4V–16.5V to 5V/1A Regulator

currents returning to the power supply ground bus. SGND

and PGND should be tied together by a ground plane that

extends under the MIC2178.