ZHCSPA6F September 2006 – January 2022
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3 Feature Description
- 7.4 Device Functional Modes
- 7.5
Programming
- 7.5.1 Serial Communication
- 7.5.2 Initialization
- 7.5.3 ROM Commands
- 7.5.4 Memory/Status Function Commands
- 7.5.5 READ MEMORY Commands
- 7.5.6 WRITE MEMORY Command
- 7.5.7 READ STATUS Command
- 7.5.8 WRITE STATUS Command
- 7.5.9 PROGRAM PROFILE Byte
- 7.5.10 SDQ Signaling
- 7.5.11 RESET and PRESENCE PULSE
- 7.5.12 WRITE Bit
- 7.5.13 READ Bit
- 7.5.14 PROGRAM PULSE
- 7.5.15 IDLE
- 7.5.16 CRC Generation
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
封裝選項
機械數(shù)據(jù) (封裝 | 引腳)
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
訂購信息
9 Power Supply Recommendations
The BQ2022A is a low-power device that only needs to be turned on when communicating. The device power comes from the voltage supply that is used for digital I/O in the system. A dedicated VCC pin does not exist in the device for which there is not a requirement of a supply input bypass capacitor. The device obtains its power from the SDQ communication input which can be sustained during normal communication activity.
The ramp time of the SDQ voltage when power is initially applied may be slow due to current limiting from the source. Ramp times greater than 200 μs might cause undesired bouncing of the POR circuit and result in the device not generating a presence pulse. To account for this undesired effect on the device a best practice for the communication master would be to issue a “hard” reset to the device by pulling down the SDQ line for >5 ms and then releasing the SDQ bus before issuing the reset pulse that is approximately 480 μs long.
Figure 9-1 Power Up
Best PracticeFigure 9-1 illustrates the best practice for dealing with initial power on ramps, shown as (1) in the figure, that may be long in duration. The host should issue a “hard” reset, (2), of > 5 ms, which resets the device and generate a presence delay and presence pulse, (3). After that, a “soft” reset of approximately 480 μs can be applied, (4), which also generates a high presence delay and low presence pulse, (5).