VOUTP

VOUTN

VDD2

GND2

GND1

VINN

VINP

VDD1

AMC1200

HV+

HV-

to load

Floating

Power Supply

20 V

3.3 V, or 5.0 V

RSHUNT

Gate Driver

Gate Driver

5.1 V

R1

800

Z1

1N751A

C1

0.1F

R2

12

R3

12

C3

330pF

C4

0.1F

ADS7263

AMC1200, AMC1200B

SBAS542D – APRIL 2011 – REVISED JULY 2015

www.ti.com

9 Power Supply Recommendations

In a typical frequency inverter application, the high-side power supply for the AMC1200 (VDD1) is derived from

the system supply, as shown in Figure 36. For lowest cost, a Zener diode can be used to limit the voltage to 5 V

± 10%. TI recommends using a 0.1-µF, low-ESR decoupling capacitor for filtering this power-supply. TI also

recommends using a 0.1-µF decoupling capacitor for filtering the power-supply on the VDD2 side. For best

performance, place these capacitors (C1 and C4) as close as possible to the VDD1 and VDD2 pins respectively.

If better filtering is required, an additional 1-µF to 10-µF capacitor can be used in parallel to C1 and C4.

Figure 36. Zener Diode Based High-Side Supply

For higher power efficiency and better performance, a buck converter can be used; an example of such an

approach is based on the LM5017. A reference design including performance test results and layout

documentation can be downloaded at PMP9480, Isolated Bias Supplies + Isolated Amplifier Combo for Line

Voltage or Current Measurement.

10 Layout

10.1 Layout Guidelines

A layout recommendation showing the critical placement of the decoupling capacitors that be placed as close as

possible to the AMC1200 while maintaining a differential routing of the input signals is shown in Figure 37.

To maintain the isolation barrier and the high CMTI of the device, the distance between the high-side ground

(GND1) and the low-side ground (GND2) should be kept at maximum; that is, the entire area underneath the

device should be kept free of any conducting materials.

18

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