ATSGA204A View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'ATSGA204A' PDF : 93 Pages View PDF
Figure 5-1. 3-wire Configuration for Single-Wire Interface
VCC
SDA
GND
ATSHA204A
Single-Wire Interface
5.6.1
2-lead Configuration
There is an internal gated switch that is connected between the SDA and VCC pins which permits the
ATSHA204A to steal power from the SDA pin and store it on the bypass capacitor. In this case, the VCC
pin does not need to be connected to the Host’s power supply. This configuration permits the board
containing the ATSHA204A and a bypass capacitor to be connected to the Host’s microprocessor using
just two leads (that is, SDA and GND).
If the system supply voltage level is at least 3V, the pull-up resistor should be no greater than 1K and the
capacitor no less than 0.03 μF. The device operates properly keeping VCC at or above the specification
level of 2V. Contact Microchip for other configuration information.
In a 2-lead configuration, the SDA pin must be driven high to VCC using an active driver capable of
supplying ICC for the entire duration of any command execution and a totem pole driver should be used to
send data to the device. The SDA line should only be reliant on the pull-up resistor during transmission of
data from the ATSHA204A to the system
Figure 5-2. 2-lead Configuration for Single-Wire Interface
VCC
SDA
GND
© 2018 Microchip Technology Inc.
DS40002025A-page 27
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