MCU

Si8286

GNDA

4

VO

11

VSSB

9

IN-

2

IN+

1

DSAT

14

VDDA

3

VDDB

13

VMID

16

/FLT

6

NC

7

VDDB

12

/RST

5

NC

8

NC

15

VSSB

10

Q1

Q2

+ RAIL

- RAIL

DDSAT

RDSAT

RH

10uF

CBL

RL

0.1uF

0.1uF

10uF

+3.3V

0.1uF

1kΩ 10kΩ

100

Place RDSAT and DDSAT as

close to Q1 as possible

Place CBL as close to DSAT

pin as possible

Figure 3.3. Example Si8286 Application Circuit with RH and RL

3.1.1 Power

To power the Si828x, the supply for VDDA should be able to source 10 mA of current. The VDDB and VSSB supplies have to be able

to source the Si828x biasing current plus the average switch gate current drive. Each supply should have 0.1 μF and 10 μF parallel

bypass capacitors. As shown in Figures 3.1 to 3.3, a supply can be connected between VSSB and VMID to provide a negative bias

to the gate drive output, if desired. Such negative gate biases may help reduce switching losses. The VSSB pin should be shorted to

VMID if a negative gate bias is not utilized.

3.1.2 Inputs

The Si828x has both inverting and non-inverting gate control inputs (IN– and IN+). In some topologies, one of the inputs is not used and

should be connected to GNDA (IN–) or VDDA (IN+) for proper logic termination. Tying IN+ to VDDA allows active-low control of output

with IN- pin. Inputs should be driven by CMOS level drivers. It is recommended that the MCU or input driver be located as close to the

Si828x as possible to minimize PCB trace parasitics and noise coupling to the input circuit. In noisy environments, it is recommended

that one add a small series resistor and an approximately 56pF decoupling cap to the IN traces to attenuate glitches from electrical

noise and improve input-to-output signal integrity. The resistor and capacitor values should be large enough to minimize noise but not

so large that it affects PWM signals significantly.

The implementation of a differential interface circuit between the MCU and driver's input can greatly improve the noise immunity

performance and prevent faulty turn on during high current switching operation.

IN+

VH

_

IN

VL

HIGH

LOW

HIGH

LOW

Pull-up

Hi-Z

Hi-Z

Pull-down

VO (Si8286 only)

Pull-up

Pull-down

Figure 3.4. Si828x Complementary Input Diagram

Si8285/86 Data Sheet • Applications Information

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

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Rev. 2.0 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • October 12, 2021

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