QUICK START GUIDE FOR LTC3576EUFE-1 DC1577A LTC3576EUFE-1 Switching Power Manager + USB On-the-Go + OVP + HV Buck VC Control + 3 Bucks DESCRIPTION L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered Demonstration Circuit DC1577A is a Switching Power trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy Manager with USB On-the-Go + Triple Step Down Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode Dimming, No Latency , No Latency Delta-Sigma, No R , Operational Filter, PanelProtect, SENSE DC/DCs. The LTC3576EUFE-1 is available in a 38-pin PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names (4mm 6mm) QFN surface mount package. may be trademarks of the companies that manufacture the products. PERFORMANCE SUMMARY Specifications are at T = 25C A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VUSB VUSB Input Voltage Range Input disabled from 6V30V 4.35 30 V VOUT VOUT Output Voltage Range Range is mode and load dependant 3.5 5.5 V V Output Float Voltage Constant voltage mode 4.1 V BAT I Output Charge Current Constant current mode 0.5 1 A BAT SOFTWARE GUI The DC1577A Demo Circuit can be controlled from a software GUI. Most of the features of the 2 LTC3576EUFE-1 are only accessible via the I C chan- SOFTWARE OPERATION nel. When the QuikEval program is active and a The software GUI automatically opens the control DC590 with a DC1577A connected and attached to panel shown above. This control panel allows con- the USB cable, the LTC3576 form should auto- trol of most major functions of the LTC3576EUFE-1. matically pop up and be fully operational: The EN1, EN2, EN3, and ENOTG signals are wire ORed with individual regulator enable regulator sig- 2 nals from the I C channel. Consequent to this, if the ENx or ENOTG signals are high, the regulators 2 will be enabled regardless of the state of the I C channel regulator control bits. Register A , B, C and D display These are not writeable and are provided as a pro- gramming aid. The current value of the I2C A, B, C and D registers are displayed. Update button Forces an immediate update of the I2C registers. Autoupdate button Figure 1. GUI control panel 1 LTC3576EUFE-1 If enabled (default) will update the I2C channel This form allows the feedback resistor divider net- whenever something is changed. work on each regulator to be changed. The infor- mation changed here, is saved, and is durable from Battery charger button session to session. However, the factory values can If on (default) the battery charger in the be recovered by pressing the Restore defaults LTC3576EUFE-1 will be enabled, and if off the bat- button tery charger will be disabled. VOUT1~VOUT3 buttons Individually enable or disable the three voltage regu- lators. These only function if the ENx pins are held low. Switchmode Regulators mode Set the mode of operation of all the switchmode regulators. VOUT1, VOUT2 and VOUT3 sliders Allow control of voltage regulator 1, 2 and 3 output voltages by adjusting the respective reference DACs. VOUT1~3 output and reference voltages These are not writeable, but reflect the current state of the reference DACs, and feedback resistors. Input current limit Set the maximum power drawn from the USB port. Change feedback divider resistor values This opens the form: Figure 2. Feedback resistor control panel 2