DESCRIPTION
Evaluation circuit EVAL-LT8357-AZ features the LT®8357
as a 200kHz low EMI and low IQ, boost controller with a
24V output from 4.5V to 20V input. This evaluation circuit
features Spread Spectrum Frequency Modulation (SSFM)
and EMI filters to provide optimum EMI performance. The
board also contains placeholders and an outline to attach
clips for an optional EMI Shield attachment. This application
circuit can output 2A (see Figure 4 Maximum Output
Current vs VIN curve). When placed in shutdown, the converter
has very low quiescent current, ideal in automotive
and other battery-powered applications. PULSE SKIP
and BURST modes are selectable with jumper JP1. Each
user-selectable option enables low quiescent current at
light load and can also be combined with SSFM operation
using JP1.
The LT8357 boost controller IC operates over an input
range of 3V to 60V, suitable for automotive, telecom and
industrial applications. It exhibits a low quiescent current of
8μA, making it ideal for battery-operated systems. It drives
a low side N-channel power MOSFET with a 5V split gate
drive. The converter provides adjustable and synchronizable
operation from 100kHz to 2MHz with SSFM option. At
light load, either PULSE SKIP or low-ripple BURST mode
can be selected to improve the efficiency. The LT8357
packs popular features such as soft-start, input undervoltage
lockout, adjustable switching frequency and clock
synchronization. The Power Good (PGOOD) flag indicates
when the output voltage is in regulation.
The LT8357 comes in a thermally enhanced 12-lead plastic
MSE package. The LT8357 data sheet gives a complete
description of the part, pins, features, operation,
and application information. The data sheet must be read
in conjunction with this user guide for EVAL-LT8357-AZ.