LT7170/LT7170-1 Silent Switcher® Step-Down Regulators

ADI's LT7170 and LT7170-1 are monolithic DC/DC synchronous step-down regulators that deliver up to 20 A of continuous output current. The LT7170-1 option has two switching phases 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 and 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 (f_SW) at a low output voltage (V_OUT) with excellent transient response in a small overall solution size.

V_OUT, f_SW, 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 and LT7170-1 actively pull down the output using V_SENSEP when the output is disabled. The LT7170 and LT7170-1 wait until the V_OUT is less than 0.2 V before enabling the output and beginning a soft start. This V_OUT discharge threshold is programmable from 0.2 V to 2.2 V. The LT7170 and LT7170-1 use forced-continuous switching operation.

Features

• Silent Switcher architecture: enables a compact, efficient, low EMI solution
• PMBus/I²C serial interface
• Telemetry readback includes V_OUT, I_OUT, V_IN, 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
• Key parameters selectable by resistor
• V_OUT set point range: 0.4 V to 5.5 V
• V_OUT accuracy: ±0.25%, 0.6 V ≤ V_OUT ≤ 1.375 V
• Differential remote V_OUT sense
• Fast transient response
• Wide V_IN supply range: down to 2.9 V or 1.5 V with EXTV_CC
• Programmable and synchronizable: 400 kHz to 4 MHz
• 24-lead (3.5 mm × 4 mm) LQFN package