The ISL8203MEVAL2Z evaluation board is designed to demonstrate the performance of the ISL8203M dual 3A/single 6A step-down DC/DC power module. The board is by default set up to demonstrate two 3A outputs independently, and can also be easily set up for current sharing 6A by changing placeholder resistors.
The ISL8203M is a complete, dual step-down power module with an integrated PWM controller, synchronous switching MOSFETs, inductors, and passives. The ISL8203M is rated for dual 3A output current or 6A current sharing operation with an input range of 2.85V to 6V. The two channels are 180° out-of-phase for input RMS current and EMI reduction.
The simplicity of the ISL8203M is its off-the-shelf, unassisted implementation. It is easy to apply this complete step-down power module to any low voltage/low power application.
ISL8203M includes a PWM controller, synchronous switching MOSFETs, inductors and passive components to simplify power supply design for FPGAs, ASICs, microprocessors, and DSPs for communications, test and measurement, and industrial systems.
Welcome to the ISL8203M module presentation.
The ISL8203M is a complete power supply in a package. Ideal for point of load (POL) applications where a step down voltage is required from 3.3V or 5V, the ISL8203M is capable of producing two independent outputs each rated at 3A. The Intersil modules integrate all of the main power components (controller, FETs and inductor) to offer a complete solution that provides a plug and play power supply. Utilizing a current mode control loop, it is possible to current share the device, allowing the two outputs to be combined to a single 6A output.
Offered in a small over-molded 9mm x 6.5mm QFN package, the ISL8203M provides a high power density design with minimal board space.
The key benefits of the ISL8203M is that it provides a fast, simple design for customers. By integrating all of the power components, few decisions and component selections need to be made. All that is required is selection of the bulk input and output capacitors and setting the output voltage. With the new QFN based module packaging the full 6A output current can be delivered at ambients as high as 85 °C without the need for heat sinks or fans.
Shown here is the typical application circuit for the dual output device. As can be noted, a minimum number of components are required.
Looking closely, you can see some of the features embedded in the device. It features dual enable pins for separate control of the outputs along with separate powergood pins. This allows sequencing between the outputs if needed. The output voltage can be adjusted through a simple resistor divider network.
With current mode control, in addition to a fast transient response, the device also allows current sharing of the two outputs. By connecting the two outputs together, a single supply capable of providing 6A output can be realized.
The ISL8203M utilizes a new QFN module packaging technology which provides a simple design approach similar to the QFN packages used for ICs with only the ground pad left floating in the middle of the package. This allows easy soldering and inspection for all of the pins on the PCB board. With dimensions of 9mm x 6.5mm x 1.85mm, this enables an extremely small power supply to be designed.
Next, we’ll discuss the availability of the ISL8203MEVAL2Z evaluation board.
A demo board is available for the ISL8203M module and can be ordered via the web. What you see on this board is two independent outputs can be configured or you can always jumper them together if you wanted the single 6A output. There are very few components around it; just a few input caps and a few output caps and those are small ceramic capacitors so minimal footprint. One of the main advantages of this board is on the left; you will see the jumpers and you can actually set the two different output voltages just by moving the jumpers around. This allows you to quickly customize a board without needing a soldering iron.
The board is configured for dual 3A outputs with a jumper selection on the left side allowing output voltages to be quickly adjusted without a soldering iron.
This slide shows the efficiency curves from the demo board running a 3.3V or 5V input voltage. This is based on a single output of 3A.
When the outputs are connected via jumpers, a combined 6A output is possible with a single regulated voltage. In this case, the efficiency curve shown on this slide can be realized.
Despite its small size, the ISL8203M is thermally efficiency. It is able to conduct any heat present from switching loss directly into the PCB through the bottom of the package. This means that with a full 6A output at 2.5V providing 15W output, the device will see a case temperature of 65.8 °C while running at room temperature with no airflow. This equates to a theta JA of 17 °C/W. The advantage is you can run this device at max ambient temperature, 85 °C full load without the need for air flow so that no heat sinking is required for this product.
Looking at several of the output characteristics of the device, with an integrated module the concern is always the low inductance and high output voltage ripple. In the case of the ISL8203M, this can be seen to be a non‐factor, having only an 8mVpp ripple with a 1V output. This equates to ±0.4% which is below the limit for μC and any analog rails it would power.
The other benefit of the device is a controlled soft-start voltage, allowing the device to ramp into heavy loads. In this scenario, the device is shown starting into a full 6A load from a 5V input. As can be seen, the input current is controlled such that no overshoot occurs, limiting the amount of capacitance required.
With the current mode control scheme, the device features accurate OCP protection allowing the device to react to overcurrent transients or short circuit conditions. The device allows continuous restart, without the risk of destruction even during prolonged shorts.
For EMI performance, the device is able to pass both radiated and conducted emission testing. On this slide, the conducted EMI test results are shown using the Intersil evaluation board without any additional components.
From a radiated EMI test, the device is able to pass with sufficient margin. The graph itself shows the peak scan data, while the CISPR 22 Class B specs only require a quasi peak scan to pass the limits, which is shown in the table on this slide.