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Level Shifter

Full-featured, power efficient systems often contain subsystems with different voltage requirements. For example, a wearable may normally operate at 1.8 V, but when charging, portions of the design will operate at the USB standard 5 V. Similarly, the display may operate at a different voltage than the sensors. Often, a number of discrete passive or fixed-function level shift devices are needed to make these voltage domains work together. With GreenPAK™, getting these different voltage domains working together, efficiently and with the flexibility of programmable mixed-signal, is a snap with any of our Dual Supply part numbers.

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GreenPAK™ Benefits for Level Shift:

Dual Supply

  • Dual Supply GreenPAK enables high efficiency level-shift without the need for external pull-up resistors
  • Dual Supply GreenPAK can support 1.8 V to 5.0 V for VDD and 1.8 V to VDD for VDD2

System Stability

  • GreenPAK is zero code – Implementing features in hardware ensures stability
  • GreenPAK can integrate many components ensuring fewer points of failure

Power Consumption

  • GreenPAK is low-power – Can operate continuously without ruining power budget

Size

  • GreenPAK is as small as 1.2 mm²

Flexibility

  • GreenPAK GPIO are configurable – Pull-up/pull-down resistors, Push-Pull, Open drain, etc.
  • GreenPAK GPIO routing is flexible – Ensuring the least complexity in PCB routing
  • GreenPAK integrates many common components – Generating custom timing and logic to further eliminate external components while bridging voltage domains and signal requirements

Uni-directional

Bi-directional with Dedicated Ports

Bi-directional with External Direction Indicator

Bi-directional, Auto-sensing

The simplest form of level-shift is uni-directional. Shifting a single direction, up or down, is easy in GreenPAK since all GPIO can be configured as inputs or outputs

Similar to uni-directional, using GreenPAK’s configurable GPIO to dedicate specific pins or groups of pins as input or output is easy. Each pin tied to a specific voltage domain can be configured independently allowing information to flow from lower to higher VDD or higher to lower VDD

 

With GreenPAK it is also possible to dual-purpose certain GPIO as digital input AND output using the output enable pin to control the direction. Using GreenPAK’s configurable digital and timing resources, it is even possible to implement an auto-sensing, bi-directional, level-shift solution such as the I2C Level-shift shown in AN-1104.
Key Design Considerations

Number of Signals – GreenPAK can support up to 9 inputs/8 outputs on a single voltage domain

IO Configuration – Configurable pull-up / pull-down resistors on GreenPAK’s GPIO make communicating with any IC a snap

Key Design Considerations

Number of Signals – GreenPAK can support up to 9 inputs/8 outputs on a single voltage domain

IO Configuration – Configurable pull-up / pull-down resistors on GreenPAK’s GPIO make communicating with any IC a snap

Key Design Considerations

Direction Signal Polarity – Using GreenPAK’s integrated LUTs configured as an inverter can accommodate any signal polarity

Direction Signal Origin – With GreenPAK, the direction signal input can be from either voltage domain

Key Design Considerations

Response Time – GreenPAK is capable of up to 400 kHz standard I2C

Example 1. Uni-directional level-shift implemented in GreenPAK
Example 1. Uni-directional level-shift implemented in GreenPAK

 

Example 2. Bi-directional level-shift with dedicated ports implemented in GreenPAK
Example 2. Bi-directional level-shift with dedicated ports implemented in GreenPAK

 

Example 3. Bi-directional level-shift with external direction signal implemented in GreenPAK
Example 3. Bi-directional level-shift with external direction signal implemented in GreenPAK

 

Example 4. Auto-sensing bi-directional I2C level-shift
Example 4. Auto-sensing bi-directional I2C level-shift

 

Example 1. Timing Diagram
Example 1. Timing Diagram

 

Example 2. Timing Diagram
Example 2. Timing Diagram

 

Example 3. Timing Diagram
Example 3. Timing Diagram

 

Example 4. AN-1104 - I2C Level Shift in SLG46620V
Example 4. AN-1104 - I2C Level Shift in SLG46620V

 

 

Dual Supply GreenPAK

GreenPAK can often implement multiple functions in one small device. This isn’t limited to level-shift applications. Just one GreenPAK device can implement glue logic, timing adjustment, reset, power sequencing, LED control, and more depending on design requirements and resource configuration.

Below is a list of our Dual Supply GreenPAK devices and the number of GPIO dedicated to each voltage domain.

 

Part Number VDD IO VDD2 IO
SLG46121V 5 4
SLG46535V 7 4
SLG46538V 9 8
SLG46621V 9 8

View the full list of the GreenPAK videos in our Training Video Library.