The high-side power supply (AVDD) is generated from a bootstrap circuit (R4, D1, C2). The low-side supply is

shared with circuitry in the signal domain. Use the optional 49.9Ω resistor on the DOUT pin for line-termination to

improve signal integrity on the receiving end.

The galvanic isolation barrier and high common-mode transient immunity (CMTI) of the AMC0106M25 provide

reliable and accurate operation even in high-noise environments.

7.2.1 Design Requirements

Table 7-1 lists the parameters for this typical application.

Table 7-1. Design Requirements

PARAMETER

VALUE

System voltage, power-stage

48V

Bootstrap supply voltage (VBS)

6V

Maximun ripple voltage on AVDD supply (VRIPPLE)

200mV

PWM frequency

16kHz

PWM duty cycle range

5% to 95%

Linear current sensing range

±5A

7.2.2 Detailed Design Procedure

In Figure 7-1, the high-side power supply (AVDD) is generated from a bootstrap circuit (R4, D1, C2).

The high-side ground reference (AGND) is derived from the end of the shunt resistor connected to the negative

input of the AMC0106M25 (INN). For a four-terminal shunt, connect the device inputs to the inner leads of

the shunt and connect AGND to the outer leads. To minimize offset and improve accuracy, route the ground

connection as a separate trace. Connect AGND directly to the shunt resistor rather than shorting AGND to INN

at the input to the device. See the Layout section for more details.

7.2.2.1 Shunt Resistor Sizing

The shunt resistor (RSHUNT) value is determined by the device linear input voltage range (±250mV) and the

desired linear current sensing range of ±5A. RSHUNT is calculated as 250mV / 5A = 50mΩ. The peak power

dissipated in the shunt resistor is RSHUNT × IPEAK 2 = 50mΩ × (5A)2 = 1.25W. For a linear response, operate

the shunt resistor at no more than 2/3 of the rated power. Therefore, a shunt resistor with a nominal power rating

of approximately 1.8W is selected.

Select a lower shunt resistor value if transient overcurrents are expected in the system that exceed the linear

input voltage range of the AMC0106M25. However, if reduced linearity and lower resolution is acceptable for

the overcurrent range, allow the voltage drop across the shunt to exceed the linear input voltage range up to

the clipping voltage of the AMC0106M25. In any case, make sure the voltage drop caused by the maximum

overcurrent does not exceed the input voltage that causes a clipping output. That is, make sure |VSHUNT| ≤

|VClipping|.

AMC0106M25

SBASAX1 – AUGUST 2024

www.ti.com

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