20 A, 16 V, Single- or Dual-Phase, Silent Switcher Step-Down Regulators with Digital Power System Management

The LT7170/LT7170-1 are monolithic DC/DC synchronous stepdown regulators that deliver up to 20 A of continuous output current. The LT7170-1 option has two switching phases that are connected to two inductors to drive a single-regulated output supply. The quick, clean, low-overshoot switching edges deliver high efficiency while minimizing electromagnetic interference (EMI) emissions. The I2C-based PMBus 1.3-compliant serial interface enables control of device functions while providing telemetry information for system monitoring. The LT7170/LT7170-1 are supported by the LTpowerPlay® graphical user interface (GUI) tool.

The controlled on-time valley current-mode control with 25 ns typical minimum on-time enables a high switching frequency (fSW) at a low output voltage (VOUT) with excellent transient response in a small overall solution size.

VOUT, fSW, and phase are selectable using external configuration resistors. Settings can also be set via the PMBus interface or stored in the on-chip, three times programmable nonvolatile memory (NVM).

To guarantee clean start-up of the powered devices, the LT7170/ LT7170-1 actively pull down the output using VSENSEP when the output is disabled. The LT7170/LT7170-1 wait until the VOUT is less than 0.2 V before enabling the output and beginning a soft start. This VOUT discharge threshold is programmable from 0.2 V to 2.2 V. The LT7170/LT7170-1 use forced-continuous switching operation.

* Silent Switcher® architecture: enables a compact, efficient, low EMI solution

* PMBus/I2C serial interface

* Telemetry read back includes VOUT, IOUT, VIN, die temperature, and faults

* Programmable voltage, current limit, sequencing, soft start and stop, undervoltage and overvoltage, phase, frequency (up

to 4 MHz), and loop compensation

* Integrated three times programmable NVM