Si8941/46/47 Data Sheet
Isolated Delta-Sigma Modulator for Current Shunt Measurement
KEY FEATURES The Si8941/46/47 is a galvanically isolated delta-sigma modulator which outputs a digital signal
proportional to the voltage level at the input. The low-voltage differential input is ideal for measuring voltage across a current shunt resistor or for any place where a sensor must be isolated
from the control system. Low noise, low error, and high precision ensure an accurate measurement of system current.
The output of the Si8941/46/47 comes from a 2nd order delta-sigma modulator. The modulator
can be clocked either from an onboard oscillator (Si8946/47) or from an external clock
(Si8941). The output is typically digitally filtered by a MCU or FPGA in the system. • Low voltage differential input
• ±62.5 mV and ±250 mV options
• Modulator clock options
• External clock up to 25 MHz
(Si8941)
• 10 MHz internal clock (Si8946)
• 20 MHz internal clock (Si8947)
• Typical input offset: ±40 µV The Si8941/46/47 isolated delta-sigma modulator utilizes Silicon Labs’ proprietary isolation
technology. It supports up to 5.0 kVrms withstand voltage per UL1577. This technology enables
higher performance, reduced variation with temperature and age, tighter part-to-part matching,
and longer lifetimes compared to other isolation technologies. • Typical gain error: ±0.1% Applications:
• Industrial, HEV and renewable energy inverters
• AC, Brushless, and DC motor controls and drives
• Variable speed motor control in consumer white goods
• Isolated switch mode and UPS power supplies
• Automotive BMS and charging • Typical 14-bit (ENOB) precision • Excellent drift specifications …
