QUICK START GUIDE FOR LTC3576EUFE DC1334A LTC3576EUFE 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 DC1334A 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 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 4.2 V BAT I Output Charge Current Constant current mode 0.5 1 A BAT SOFTWARE GUI The DC1334A Demo Circuit can be controlled from a software GUI. Most of the features of the SOFTWARE OPERATION 2 LTC3576EUFE are only accessible via the I C channel. The software GUI automatically opens the control When the QuikEval program is active and a DC590 panel shown above. This control panel allows con- with a DC1334A connected and attached to the USB trol of most major functions of the LTC3576. The cable, the LTC3576 form should automatically pop EN1, EN2, EN3, and ENOTG signals are wire ORed up and be fully operational: with individual regulator enable regulator signals 2 from the I C channel. Consequent to this, if the ENx or ENOTG signals are high, the regulators will be 2 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 If enabled (default) will update the I2C channel whenever something is changed. Figure 1. GUI control panel 1 LTC3576EUFE 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 LTC3576 be recovered by pressing the Restore defaults will be enabled, and if off the battery charger will be button 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 This form allows the feedback resistor divider net- work on each regulator to be changed. The infor- 2