With GreenPAK™, getting different voltage domains working together, efficiently and with the flexibility of programmable mixed-signal, is a snap.
Often full-featured, power-efficient systems 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.
The best solution for this is any GreenPAK Dual Supply part number.
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
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
Example 1. Uni-directional level-shift implemented in GreenPAK
Example 1. Timing Diagram
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
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
Example 2. Bi-directional level-shift with dedicated ports implemented in GreenPAK
Example 2. Timing Diagram
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.
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
Example 3. Bi-directional level-shift with external direction signal implemented in GreenPAK
Example 3. Timing Diagram
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.
Response Time – GreenPAK is capable of up to 400 kHz standard I2C
Example 4. Auto-sensing bi-directional I2C level-shift
Example 4. AN-1104 - I2C Level Shift in SLG46620V
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 |