S1

S1

C

=3pF

INP

C

=3pF

INN

VINN

VINP

VDD1

GND1

GND1

GND1

3pF

R

=28kW

IN

3pF

VINN

VINP

Equivalent

Circuit

R

=

IN

f

C

·

CLK

DIFF

1

(

=10MHz)

f

CLK

C

=3.6pF

IND

GND1

GND1

400W

400W

S2

S2

AGND+0.8V

AGND+0.8V

AMC1200, AMC1200B

www.ti.com

SBAS542D – APRIL 2011 – REVISED JULY 2015

The safety-limiting constraint is the operating virtual junction temperature range specified in the Absolute

Maximum Ratings table. The power dissipation and junction-to-air thermal impedance of the device installed in

the application hardware determine the junction temperature. The assumed junction-to-air thermal resistance in

the Thermal Information table is that of a device installed in the JESD51-3, Low Effective Thermal Conductivity

Test Board for Leaded Surface Mount Packages and is conservative. The power is the recommended maximum

input voltage times the current. The junction temperature is then the ambient temperature plus the power times

the junction-to-air thermal resistance.

7.3.6 Regulatory Information

VDE/IEC

UL

Certified according to VDE V 0884-10

Recognized under 1577 component recognition program

Certificate number: 40016131

File number: E181974

7.3.7 Isolation Amplifier

The AMC1200 device consists of a second order delta-sigma modulator input stage including an internal

reference and clock generator. The output of the modulator and clock signal are differentially transmitted over the

integrated capacitive isolation barrier that separates the high- and low-voltage domains. The received bitstream

and clock signals are synchronized and processed by a third-order analog filter with a nominal gain of 8 on the

low-side and presented as a differential output of the device, as shown in Functional Block Diagram section.

7.3.8 Analog Input

The analog input range is tailored to directly accommodate a voltage drop across a shunt resistor used for

current sensing. However, there are two restrictions on the analog input signals, VINP and VINN. If the input

voltage exceeds the range AGND – 0.5 V to AVDD + 0.5 V, the input current must be limited to 10 mA to prevent

the implemented input protection diodes from damage. In addition, the linearity and the noise performance of the

device are ensured only when the differential analog input voltage remains within ±250 mV.

The differential analog input of the AMC1200 and AMC1200B devices is a switched-capacitor circuit based on a

second-order modulator stage that digitizes the input signal into a 1-bit output stream. These devices compare

the differential input signal (VIN = VINP – VINN) against the internal reference of 2.5 V using internal capacitors

that are continuously charged and discharged with a typical frequency of 10 MHz. With the S1 switches closed,

CIND charges to the voltage difference across VINP and VINN. For the discharge phase, both S1 switches open

first and then both S2 switches close. CIND discharges to approximately AGND + 0.8 V during this phase.

Figure 31 shows the simplified equivalent input circuitry.

Figure 31. Equivalent Input Circuit

7.4 Device Functional Modes

The AMC1200 is operational when the power supplies VDD1 and VDD2 are applied as specified in the

Recommended Operating Conditions section.

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