“Do you have a single‑chip solution for both inputs and outputs?” That question comes up often, usually across a table and with high expectations. The answer matters to ease, simplify, and shorten the design cycle. Voltage output mode may seem simple, but it remains critical because many actuators and end nodes still depend on it.
As introduced in the previous blog post, AD74416H chip is versatile enough to meet a wide range of customer needs all within a single chip solution. Refer to my previous blog to get you started with the evaluation kit.
Setting up the Voltage Output (VOUT)
Any of 4 channels can be independently programmed to Voltage Output mode for demonstration purposes. I picked the CHA position in the bottom right corner of the EV-AD74416H-ARDZ.
To demonstrate the Voltage output capabilities, it is recommended to have available the adjustable load connected to the middle screw terminals –known as the potentiometer. The connection is shown in the figure below. The potentiometer value can be anything from 1kΩ to 100kΩ.
Figure 1: Potentiometer Connection diagram (Channel A of EV-AD74416H-ARDZ)
Once the physical load is connected to the channel, configure Voltage Output (VOUT) by clicking on the dropdown menu, and set output voltage to the desired value by modifying the DAC_CODE. Configuring ADC is optional in this mode; however, it offers additional current monitoring capabilities. Figure 2 below highlights the configurations mentioned.
Adjusting the value of the potentiometer will result in a change in the loading current. Once the current exceeds the default limit of approximately 16mA due to a short circuit, a flag (ANALOG_IO_SC) will be raised in the CHANNEL ALERTS tab, and the maximum current will be limited for channel protection.
Figure 2: AD74416H ACE plugin Voltage Output enabled
Voltage Output (VOUT): Additional Capabilities
Besides basic functionality, VOUT mode offers numerous features:
- VOUT_RANGE: Unipolar (0V to +12V) and Bipolar (-12V to +12V) Voltage Output Range
- I_LIMIT: Configurable short circuit current limit (~16mA or ~8mA) for channel protection.
- SLEW_EN, SLEW_LIN_STEP, SLEW_LIN_RATE: Configurable slew rate of the output channel.
- VOUT_4W_EN: 4 or 3 wire voltage output configurations, which allow precise voltage adjustment right onto the load.
Voltage Output: Feedback Sensing Configurations (VOUT_4W_EN)
The voltage output feedback sensing system could operate as 2, 3 or 4-wire voltage output configurations, depending on the hardware and software configuration. VOUT_4W_EN bit allows the configuration of AD74416H voltage feedback.
Two-wire voltage output is the default mode on the EV-AD74416H-ARDZ board; it utilizes the P46 jumper, which shorts the ISP_A pin (Input Sensing Positive) to the I/OP_A (Input/Output positive terminal). This allows simple configuration, behaving as two-wire voltage output; however internally AD74416H chip still uses ISP_A pin as voltage feedback pin to regulate output voltage. The voltage is regulated towards the screw terminal pin, ensuring set voltage across the screw terminals (I/OP_A and I/ON_A). In this case VOUT_4W_EN = 0 (disabled).
Three or four-wire voltage output allows for a more precise voltage setting on the desired load (connected actuator). It is especially advantageous for configurations, where long cables are involved. This setup compensates for the voltage drop developed across the cable to provide precise voltage at the point where it matters the most: the load/actuator.
The jumper P46 needs to be removed too test four or three-wire voltage output on EV-AD74416H-ARDZ, . Also, the ISP_A and ISN_A pins need to be wired directly to the load.
Figure 3: Four or three-wire Voltage Output (Channel A of EV-AD74416H-ARDZ)
ADDITIONAL TIP: Three wire voltage output mode can be used without any hardware changes on the channel. In such a case, ISP_A is permanently connected to the I/OP_A terminal and bit VOUT_4W_EN = 1 (enabled), ISN_A pin is wired to the negative terminal of the load. This setup enables three-wire operation through only software configuration.
With AD74416H, the answer is yes. Voltage output is just one of the roles a channel can take on, enabled through configuration rather than hardware changes. Each channel can generate accurate unipolar or bipolar voltages, monitor and limit current, control slew rate, and even regulate directly at the load using remote sensing. It delivers the simplicity voltage output is known for, while fitting into a flexible I/O architecture—one chip, many functions.
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