SCLA049 August   2021 SN74HCS08


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Functional Block Diagram

Figure 1-1 shows a simplified micro inverter block diagram to illustrate the logic and translation use cases. Each red block has an associated use-case document. Links are provided in Table 1-1 and Table 1-2. For a more complete block diagram, see the interactive online end equipment reference diagram for micro inverters.

GUID-20210716-CA0I-P1LJ-CXBP-NK5BPSPRGZ9J-low.gif Figure 1-1 Simplified Block Diagram for Micro Inverters

Logic and Translation Use Cases

Each use case links to a separate document that provides additional details including a block diagram, design tips, and part recommendations. The nearest block and use-case identifiers are listed to match up exactly to the use cases shown in the provided simplified block diagram.

Table 1-1 Logic Use Cases
Nearest Block Use-Case Identifier Use Case
Self-Diagnostics/Monitoring Fault Latch

Catch a Digital Pulse

Fault Combination Use Fewer Inputs to Monitor Error Signals
Digital Processing Buffer Redrive Digital Signals
Output User Interface LED Driver Drive Indicator LEDs
Table 1-2 Translation Use Cases
Nearest Block Use-Case Identifier Use Case
Wireless Interface UART Voltage Translation for Wireless Interface Modules
Wired Interface RGMII Translate Voltages for RGMII

Voltage Translation for Wireless Interface Modules

It is common to see micro inverters utilizing wireless interface modules to communicate due to their distributed nature. These modules often use UART for internal communication, and commonly are operating at a different logic voltage level from the primary system controller. The addition of a voltage level translator protects low-power system controllers and ensures accurate communication to the peripheral module.

GUID-4A446FF7-6845-4E06-8594-FD7DDEA8668F-low.gif Figure 1-2 Example Two-Wire UART Voltage Translation Block Diagram

See more about this use case in the Logic Minute video Voltage Level Translation for UART Interface

  • Some devices support up to 5 Mbps UART communication; most are limited to 115 kbps or less
  • Translators enable communication when devices have mismatched logic voltage levels
  • Prevent damage to devices that cannot support higher voltage inputs
  • Improve data rates over discrete translation solutions
  • Protect controller while peripheral is not connected
  • [FAQ] How does a slow or floating input affect a CMOS device?
  • Need additional assistance? Ask our engineers a question on the TI E2E™ Logic Support Forum
Table 1-3 Recommended Parts
Part Number Automotive Qualified Voltage Translation Range Features
SN74AXC2T245-Q1 0.65 V to 3.6 V Glitch-free power supply sequencing
Outputs are disabled when either supply is 0 V
Active translation architecture
TXB0102 1.2 V to 3.6 V
1.65 V to 5.5 V
Active translation architecture
TXS0102-Q1 1.2 V to 3.6 V
1.65 V to 5.5 V
Internal pull-up resistors
Passive translation architecture

For more devices, browse through the online parametric tool where you can sort by desired voltage, channel numbers, and other features.