AMC1305L25 Datasheet, PDF (27/39 Pages) Texas Instruments – AMC1305x High-Precision, Reinforced Isolated Delta-Sigma Modulators

www.ti.com
11 Power-Supply Recommendations
AMC1305L25, AMC1305M05, AMC1305M25
SBAS654C – JUNE 2014 – REVISED DECEMBER 2014
In a typical frequency inverter application, the high-side power supply (AVDD) for the device is derived from the
floating power supply of the upper gate driver. For lowest cost, a Zener diode can be used to limit the voltage to
5 V ±10%. Alternatively a low-cost low-drop regulator (LDO), for example the LM317-N, can be used to minimize
noise on the power supply. A low-ESR decoupling capacitor of 0.1 µF is recommended for filtering this power-
supply path. Place this capacitor (C₂ in Figure 55) as close as possible to the AVDD pin of the AMC1305 for best
performance. If better filtering is required, an additional 10-µF capacitor can be used. The floating ground
reference (AGND) is derived from the end of the shunt resistor, which is connected to the negative input (AINN)
of the device. If a four-pin shunt is used, the device inputs are connected to the inner leads, while AGND is
connected to one of the outer leads of the shunt.
For decoupling of the digital power supply on controller side, TI recommends using a 0.1-µF capacitor assembled
as close to the DVDD pin of the AMC1305 as possible, followed by an additional capacitor in the range of 1 µF to
10 µF.
Floating
Power Supply
HV+
20 V
to load
RSHUNT
Gate Driver
Z1
1N751A
R1
800 
C1
10F
5.1 V
C2
0.1F
AMC1305
AVDD
DVDD
AGND
DGND
C4
0.1F
C5
2.2F
3.3 V, or 5.0 V
AINP
DOUT
SD-Dx
Gate Driver
AINN
CLKIN
SD-Cx
TMS320F2837x
HV-
Figure 55. Zener-Diode-Based High-Side Power Supply
Copyright © 2014, Texas Instruments Incorporated
Submit Documentation Feedback
27
Product Folder Links: AMC1305L25 AMC1305M05 AMC1305M25