Ltc3621 -1A Synchronous Step-Down Regulator; Ltc4040 - 2.5A Battery Backup Power Manager; Using The Software; Setting Up Hardware For An A 2 B System - Analog Devices EVAL-AD2428WD1BZ Manual

LTC3621 -1A Synchronous Step-Down Regulator

Other features include a <1μA shutdown current and robust protection under short-circuit, thermal overload, and
output overvoltage conditions.
LTC3621 -1A Synchronous Step-Down Regulator
The The LTC3621 is a high efficiency 17V, 1A synchronous monolithic step-down regulator. The switching fre-
quency is fixed to 1MHz or 2.25MHz with a ±40% synchronizing range. The regulator features ultralow quiescent
current and high efficiencies over a wide VOUT range.
The step-down regulator operates from an input voltage range of 2.7V to 17V and provides an adjustable output
range from 0.6V to VIN while delivering up to 1A of output current. A user-selectable mode input is provided to
allow the user to trade off ripple noise for light load efficiency; Burst Mode operation provides the highest efficiency
at light loads, while pulse-skipping mode provides the lowest voltage ripple. The MODE pin can also be used to
allow the user to sync the switching frequency to an external clock.

LTC4040 - 2.5A Battery Backup Power Manager

The LTC4040 is a complete 3.5V to 5.5V supply rail battery backup system. It contains a high current step-up
DC/DC regulator to back up the supply from a single-cell Li-Ion or LiFePO4 battery. When external power is avail-
able, the step-up regulator operates in reverse as a stepdown battery charger.
The LTC4040's adjustable input current limit function reduces charge current to protect the main supply from
overload while an external disconnect switch isolates the external supply during backup. When the input supply
drops below the adjustable PFI threshold, the 2.5A boost regulator delivers power from the battery to the system
output.
An optional input overvoltage protection (OVP) circuit protects the LTC4040 from high voltage damage at the VIN
pin. One logic input selects either the Li-Ion or the LiFePO4 battery option, and two other logic inputs program
the battery charge voltage to one of four levels suitable for backup applications.

Using the Software

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The EVAL-AD2428WD1BZ evaluation board is intended to serve as the master node hosting an A B system. It can
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also function as either a local or bus-powered slave node on the A B bus. A host processor on the master node inter-
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faces directly with the A B master transceiver through which it programs and reads the register spaces of all discov-
ered slave transceivers. This configuration allows a full system initialization at start-up and status monitoring during
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operation. The examples furnished with the EVAL-AD2428WD1BZ A B master evaluation board assume a connec-
tion to specific slave boards, as noted in the following sections.
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Setting up Hardware for an A B System
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Use the following sequence to set up the hardware for a three node A B system.
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EVAL-AD2428WD1BZ A B Evaluation Board Manual