Dual, 4A/2A, 4MHz, Step-Down DC-DC Regulator with Tracking/Sequencing Capability

The MAX15021 is a dual-output, pulse-width-modulated (PWM), step-down DC-DC regulator with tracking (coincident and ratiometric) and sequencing options. The device operates from 2.5V to 5.5V and each output can be adjusted from 0.6V to the input supply (VAVIN). The MAX15021 delivers up to 4A (regulator 1) and 2A (regulator 2) of output current. This device offers the ability to adjust the switching frequency from 500kHz to 4MHz and provides the capability of optimizing the design in terms of size and performance.

The MAX15021 utilizes a voltage-mode control scheme with external compensation to provide good noise immunity and maximum flexibility in selecting inductor values and capacitor types. The dual switching regulators operate 180° out-of-phase, thereby reducing the RMS input ripple current and thus the size of the input bypass capacitor significantly.

The MAX15021 offers the ability to track (coincident or ratiometric) or sequence during power-up and powerdown operation. When sequencing, it powers up glitch-free into a prebiased output.

Additional features include an internal undervoltage lockout with hysteresis and a digital soft start/soft-stop for glitch-free power-up and power-down. Protection features include lossless cycle-by-cycle current limit, hiccup-mode output short-circuit protection, and thermal shutdown.

The MAX15021 is available in a space-saving, 5mm x 5mm, 28-pin TQFN-EP package and is specified for operation from -40°C to +125°C temperature range.

Applications

* Automotive Multimedia * Multivoltage Supplies * Networking/Telecom * Power-Over-Ethernet (PoE) IP Phones * RFID Reader Cards

* Integration Reduces Power-Supply Footprint for Space-Constrained Designs

* Dual-Output Synchronous Buck Regulators

* Integrated Switches for 4A and 2A Output Currents

* Programmable Switching Frequency from 500kHz to 4MHz

* 28-Pin TQFN Package (5mm x 5mm)

* 180° Out-Of-Phase Operation Reduces Input Ripple Current and Thus the Size of the Input Bypass Capacitors

* Sophisticated Tracking/Sequencing Functions Facilitate Reliable Processor Operation

* Digital Soft-Start and Soft-Stop for Tracking Applications

* Digital Soft-Start into a Prebiased Load for Sequencing Applications

* Sequencing or Coincident/Ratiometric Tracking

* Flexible Enough for Use in a Range of Designs

* 2.5V to 5.5V Input Voltage Range

* Output-Voltage Adjustable from 0.6V to VAVIN

* External Compensation for Maximum Flexibility

* 100% Maximum Duty Cycle

* Integrated Protection Features Save Space and Increase Reliability

* Lossless, Cycle-by-Cycle Current Sensing

* Thermal Shutdown and Hiccup-Mode Short-Circuit Protection

* 20µA Shutdown Current Extends Battery Life in Portable Applications