 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
MCP2003 Datasheet(PDF) 11 Page - Microchip Technology |
|
||||||||||||||||||||||||||||||
MCP2003 Datasheet(HTML) 11 Page - Microchip Technology |
|
|
11 / 34 page  2010-2014 Microchip Technology Inc. DS20002230F-page 11 MCP2003/4/3A/4A 1.6 MCP2003/4 and MCP2003A/4A Difference Details The differences between the MCP2003/4 and the MCP2003/4A devices are isolated to the wake-up func- tionality. The changes were implemented to make the device more robust to LIN bus conditions, outside of the normal operating conditions. The MCP2003/4 will wake-up from Power-Down mode during any LIN falling edge held low longer than 20 µs. In the case where a LIN system is designed to minimize stand-by current by disconnecting all bus pull-ups resistors (including the external master pull-up resistor to VBB), the original MCP2003/4 could wake-up, if the floating bus drifted to a valid low level. The MCP2003/4A revisions were modified to require a ris- ing edge after a valid low level. This will prevent an undesired system wake-up in this scenario, while main- taining functional capability with the original version. It should be noted that the original MCP2003/4 meets all LIN transceiver specification requirements and mod- ules can be designed to pass all LIN system require- ments. However, when all bus pull-up resistors are disconnected, the MCP2003/4 requires the module designer to write firmware to monitor the LIN Bus after any wake-up event to prevent the transceiver from automatically transitioning from Ready mode to Operational mode. If the MCP2003/4 is placed into Operational mode, VBB to LBUS pull-up resistor is automatically connected, which will raise the LIN bus to a recessive level; then putting the device to Power-Down mode may cause LBUS to be floating, and thus wake-up all bus nodes. To prevent this, the designer should ensure TXD (MCP2003) or TXE (MCP2004) is held low until valid bus activity is verified (see Figure 1-6). This will ensure the transceiver transitions from Ready mode to Transmitter Off mode, until bus activity can be verified. In the case of valid bus activity, the transceiver can shift to Operation mode, while if there is no bus activity, the device can be again placed into Power Down. The design practices needed to accomplish this are fully detailed in Tech Brief TB3067 – “MCP2003 Power- Down Mode and Wake-Up Handling in Case of LIN Bus Loss ” (DS93067). The revised MCP2003/4A devices now eliminate the need for firmware to prevent system wide wake-up. The revised devices now require a longer valid bus low (see updated tBDB value in Section 2.3 “DC Specifi- cations” and Figure 2-7), which enables a rising edge detect circuit. The device will now only wake-up after a rising edge, following a low longer than tBDB. While the module designer can still hold TXD (MCP2003) or TXE (MCP2004) low during wake-up, to enter Transmit- ter Off mode from Ready mode, it is not required to prevent an advertent system wake-up. In addition to the longer tBDB value, the time from wake- up detect to VREN enable is shortened as documented in Section 2.3 “DC Specifications”. FIGURE 1-6: MCP2003/2004 SWITCHING TIMING DIAGRAM FOR THE FORCED POWER- DOWN MODE SEQUENCE TXD VREN CS Ready Mode Transmitter OFF Mode Power Down Mode after Master Sleep instruction Power Down Mode tTx2CS 100 ns tCSactive 100 µs TXD to forced externally TXD state depending on how the Slave Microcontroller is powered LBUS State LIN bus disconnected |
Similar Part No. - MCP2003_14 |
|
Similar Description - MCP2003_14 |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
