ISL8215M 15A 42V Single-Channel Step-Down Power Module
Welcome to the product presentation for the industry’s first encapsulated 42V 15A power module, the ISL8215M.
A Fully Integrated DC to DC Power Supply
A classic point‐of‐load implementation requires a careful selection of the appropriate controller, gate drivers, power MOSFETs, inductor, as well as resistors and capacitors. By integrating most of these discrete components in a single 13mm x 19mm package, the ISL8215M provides two immediate benefits: a more compact design leading to increased power density; and a simplified design, leading to shorter development time.
ISL8215M: 15A 42V Single-Channel Step-Down Power Module
Let’s now review some of the key specifications for the ISL8215M.
The highly efficient ISL8215M operates from a wide input voltage up to 42V covering 12V/24V industry standard voltage rails and delivers up to 15A of continuous current. The ISL8215M is perfectly suited to generate the common intermediate bus rails such as 5V/3.3V and 12V voltage rails.
The ISL8215M is based on a valley current mode PWM control scheme and provides a very fast transient response as well as an excellent loop stability. It offers an adjustable output voltage range of 0.6V to 12V with lower than 1.5% accuracy over line, load, and temperature. A 40ns typical minimum on time and an adjustable operating frequency helps to support low duty cycle operations with a single‐step conversion. The ISL8215M can also be synchronized with an external clock signal up to 1MHz.
Dedicated enable and power good signals allow for simple power sequencing. The ISL8215M is highly reliable due to fully integrated protection feature sets such as under voltage lockout also known as UVLO, over temperature, over current or short‐circuit, and over voltage protection.
The typical application circuit shown here illustrates how simple and easy it is to implement your power supply using the ISL8215M. The ISL8215M is designed to reduce the components count by providing configuration pins that can be directly tied to VCC or GND; a simple resistor or capacitor further expands the options; For instance: adjust the switching frequency, select the light load mode, set the soft‐start ramp time and program the over current threshold.
Next, let’s cover some technical highlights.
Performance – Efficiencies for 24V Vin
The default switching frequency of 300kHz or 600kHz can be set by tying the RT pin directly to ground or VCC. The ISL8215M can also be easily configured to operate over a range of 300kHz to 2MHz by connecting the RT pin to ground using a resistor. This flexibility can not only serve to operate in a specific frequency band when EMI is a concern, but can also be used to optimize efficiencies and transient response for a given conversion ratio and load step when powering microcontrollers, FGPAs or DSPs that require burst of power for a short period of processing time.
Capable of achieving a peak efficiency of 96.5%, the ISL8215M is easily tuned to provide an excellent efficiency over a wide range of output currents and conversion ratios.
During the light load conditions roughly below 2A, the ISL8215M can selectively enter pulse skipping mode (PSM) which reduces the switching losses by effectively reducing the switching frequency and therefore increasing the converter efficiency.
Performance – Selectable Light Load Mode
The ISL8215M offers a selectable light load efficiency mode which greatly enhances efficiencies under low current conditions.
Selection of the operational mode, PWM only or PWM/PSM mode, is simply achieved by connecting the MOD/SYNC pin to either VCC or to ground. In PWM only mode, the switching frequency is constant which mitigates any EMI concerns. In this mode, switching losses significantly affect the overall efficiency at light load. Selecting the PWM/PSM mode, however, forces the ISL8215M to operate in a pulse skipping mode with diode emulation mode when the output current falls below 2A. While each pulse is still synchronized to the PWM clock, this mode effectively reduces the resulting operating frequency and greatly improves the light load efficiencies.
Increasing power density in a point‐of‐load design depends on the package size and output current. Using a smaller package size typically results in a limited thermal dissipation capability and therefore, a lower output current supported when considering operations over a wide range of temperatures.
One of the key differentiators for the ISL8215M, and in fact, for Intersil power modules, is our differentiated packaging technology which allows for highly efficient heat transfer to the PCB. The thermal tests, as shown here, show that the ISL8215M can safely deliver 10A of continuous current at 85°C ambient temperature on a 24V to 3.3V conversion, thereby delivering 33W of power at 85°C ambient with no airflow or dedicated heat sink.
Array of Protection Features
An array of protection features is integrated into the ISL8215M which guarantees safe operations under abnormal operating conditions. These protections include under voltage lockout also known as UVLO, over temperature, over current or short‐circuit, and over voltage protection.
As mentioned earlier, the highly integrated ISL8215M provides several configuration settings to optimize operations and performance. One of which being the capability to control the ramp‐up of the output voltage and therefore limiting the in‐rush current. This provides a more reliable and robust design by avoiding current spikes and allows usage of smaller input and output capacitors. The ISL8215M has a default soft‐start delay of 1.5ms. If a different delay is required, simply connect a small capacitor to the SS/TRK pin. The ISL8215M output voltage ramp up can also be set up to track a master voltage by simply selecting a resistive divider network applied to the SS/TRK pin.
An array of online resources are available to select, evaluate, simulate, and design in the ISL8215M. Datasheet, user guide and design files are available for the ISL8215M. To access all resources, please visit us at www.intersil.com/powermodules.