ISL85014

The ISL85014 is a highly efficient, monolithic, synchronous buck regulator that can deliver 14A of continuous output current from a 3.8V to 18V input supply. The device uses current mode control architecture with a fast transient response and excellent loop stability. The ISL85014 integrates very low ON-resistance high-side and low-side FETs to maximize efficiency and minimize external component count. The minimum BOM and easy layout footprint are extremely friendly to space constraint systems. The operation frequency of this device can be set using the FREQ pin: 600kHz (FREQ = float) and 300kHz (FREQ = GND). The device can also be synchronized to an external clock up to 1MHz. Both high-side and low-side MOSFET current limit, along with reverse current limit, fully protects the regulator in an overcurrent event. Selectable OCP schemes can fit various applications. Other protections, such as input/output overvoltage and over-temperature, are also integrated into the device and provide required system level safety in the event of fault conditions. The ISL85014 is offered in a space saving 15 Ld 3.5mmx3.5mm Pb-free TQFN package with great thermal performance and 0.8mm maximum height.

Applications: 

• Servers and cloud infrastructure POLs 

• IPCs, factory automation, PLCs 

• Telecom and networking systems 

• Storage systems 

• Test measurement

Key Features:

The Sandler State-Space Average VRM model (SSAM) can be used for both frequency and time domain analyses:

• This model is designed to support true end-to-end power integrity simulation and modeling using Keysight ADS.

• VRM models provide small signal load ripple and large signal VRM switching ripple.

• Large signal analysis, including assessing large signal effects

• Small signal analysis

• Harmonic balance simulation

• Transient analysis

• AC analysis

• Phase noise analysis

• EMI Analysis

• Monte Carlo or worst-case circuit analysis

• Voltage ripple noise analysis

• VRM and power supply efficiency modeling

• Crosstalk analysis between power domains and sensitive signals

• PDN and impedance analysis

• Stability analysis (NISM, Bode - phase, gain, and stability margins)

• Input impedance, output impedance, startup, and transient step load response

• VRM control loop design, stability, and modeling

• Cascaded VRM and power supply analysis

• Cascaded VRM modeling

• DC drop analysis

• Voltage droop analysis

• Power Supply Rejection Ratio (PSRR) analysis

• Rogue wave analysis

• Target impedance analysis

• Supports multiphase designs – including current sharing between phases

• This model supports both DCM and CCM modes in addition to the voltage mode and current mode.

What's Included:

• Archived ADS library will be made available at checkout.

• The ADS library includes LTM4624 single-phase SSAM.

Pulling this model into an existing ADS workspace only requires a few mouse clicks.

Click here for our 4-step guide to help you add the SES Models to your ADS workspace.

Why Use a Sandler State-Space Model:

Behavioral models like SIMPLIS are available but are not designed to run fast with electromagnetic (EM) extracted S-parameter models representing the power distribution network (PDN) and cannot support end-to-end simulation.

The use of state-space average models for switched mode power supplies was started in the 1970s [1] and is an effective technique for averaging the switching behavior to get the small signal AC behavior of the switching power supply control loop in the frequency domain. Solving for the small signal behavior enables one to use that load-dependent operational point to drive the large signal switching behavior. This is what the Sandler-developed SSAM model does and makes it possible to simulate PSRR, power rail ripple, input/output impedances, switch node pulse width modulation (PWM), and regulator stability.

The SSAM is a behavioral model that simulates all noise sources going into and out of the switched mode power supply or voltage regulator module (VRM), as it is often called in the high-speed digital world.

This SSAM accurately predicts the complete VRM performance, while simple lumped models have limited use.

The SSAM, like any model, has its limits. It assumes that one is operating the regulator at a switching frequency at least six times higher than the control loop bandwidth. Keeping the VRM loop bandwidth less than 1/6th the switching frequency ensures a predictable behavior and avoids instabilities as one approaches the pulse width modulation switching frequency. At frequencies above 1/6th the switching frequency, it is the job of the PDN decoupling capacitors to deliver power.

For the highest-fidelity simulation and results, these models should be used with PCB and package effects to assess the true circuit performance.

References:

[1] S. Cuk and R. Middlebrook, “A general unified approach to modeling switching DC-to-DC converters in discontinuous conduction mode,” Power Electronics Specialists Conference, IEEE, 1977.