DEMO CIRCUIT 537 LTC4230 QUICK START GUIDE LTC4230 Triple Hot Swap Con- troller with Multifunc- DESCRIPTION Demonstration circuit DC537A is designed to The board contains one LTC4230 Controller, three evaluate the performance of the LTC4230 Triple power channels, three resistive feedback signal Hot Swap Controller with multifunction current con- dividers, an ON pin circuit, and a circuit for con- trol. The board demonstrates all possible operation figuration of the FAULT pin function. Each power modes: power-up and power-down, when power channel includes a series connected power rails turn on or turn off, steady state with constant MOSFET and sense resistor. load and overload conditions. Design files for this circuit board are available. Call the LTC factory. LTC is a trademark of Linear Technology Corporation. PERFORMANCE SUMMARY Specifications are at TA = 25C PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Voltage V 2.700 16.5 CC1 V V CC2 CC1 Supply Voltage V 2.375 16.5 V CC2 V (V -1) CC3 CC1 Supply Voltage V 1.700 16.5 CC3 Undervoltage Lockout, Channel 1 VCC1 Low to High Transition 2.13 2.35 2.52 V Undervoltage Lockout, Channel 2 VCC2 Low to High Transition 1.98 2.15 2.32 V Undervoltage Lockout, Channel 3 VCC3 Low to High Transition 1.09 1.19 1.29 V Fast Comparator 19.1 21.4 23.8 A Circuit Breaker Trip Current Slow Comparator 5.65 7.14 8.65 GATEn Pin Pull-Up Slew Rate Charge Pump On, 0 V 0.2V 0.42 0.74 1.13 V/ms GATE Normal Gate Pull-Down Slew Rate ON Low, GATE=5V 14.70 V/ms FAULT Latched and Circuit Breaker Tripped V/s Fast Gate Pull-Down Slew Rate 10.0 or in UVLO ON High Threshold Voltage ON Low to High Transition 1.250 1.314 1.380 V ON Low Threshold Voltage ON High to Low Transition 1.172 1.234 1.27 V FB Low Threshold Voltage FB High to Low Transition 1.209 1.234 1.259 V FB Hysteresis 3 mV V V CC2 CC1 Supply Voltage VCC1 2.700 16.5 V V (V -1) CC3 CC1 Supply Voltage VCC2 V 2.375 16.5 Supply Voltage VCC3 V 1.700 16.5 Undervoltage Lockout, Channel 1 VCC1 Low to High Transition 2.13 2.35 2.52 V Undervoltage Lockout V Rising, 0C < T < 85C 2.5 V IN A V Rising 2.6 IN V Falling 1.6 IN 1 LTC4230 OPERATING PRINCIPLES The LTC4230 is a triple hot swap controller that Available in a 20 lead SSOP package, the controls three supply voltages from 1.7V to 16.5V LTC4230 is showcased on demonstration circuit with V V V . DC537A configured for 1.7 to 16.5 volt operation CC1 CC2 CC3 with a slow comparator current limit protection in The LTC4230 is suited to low voltage power con- the range of 5.71A - 8.57A and a fast comparator trol in applications for hot board insertion or re- in the range of 19.3A - 23.6A. moval and electronic circuit breaker functions. The LTC4230 provides a rich set of features to support Pull-up resistors are provided to monitor the RE- Hot Swap applications including: SETn pin signals. n Under voltage lockout MOSFET gate capacitors C7, C8, C9 define the n Programmable over voltage protection output voltage slew rate. Initially the board is popu- n Programmable soft start with inrush current limit- lated for nominal 0.74V/ms slew rate in each ing power channel. n Dual level over current fault protection The external ON control signal should be higher n Programmable over current response time than 2.8V. n Automatic retry or latched mode operation n Three optional Zener diodes (D4, D5, and D6) can User-programmable supply voltage power-up be used to protect the system against supply over- rate n voltage condition on the load side of the pass Output voltages V monitoring and RESETn OUTn transistor. signaling n Spurious RESETn signal elimination by the glitch filter QUICK START PROCEDURE Demonstration circuit 537 is easy to set up to With power off, connect three power supplies ca- evaluate the performance of the LTC4230. Refer to pable of supplying 25A to the appropriate V1 IN, Figure 1 for proper board connections with power V2 IN, V3 IN turrets and GND. Supplies voltages supplies, loads, and the ON control signal source. should satisfy the conditions shown in the PERFORMANCE SUMMARY and V V CC1 CC2 Demonstration Circuit 537 has three optional V (V -1). CC3 CC1 components R13, R10, and R7 for the output voltage monitoring value adjustments and one Connect the ON pin to a signal source capable of user configurable jumper JP1 option. developing 16V>V >1.39V to the turret labeled ON ON/OFF and be sure that the ON signal is initially Calculate R13, R10, and R7 resistors based at the zero (low). selected channel voltages and install them on the board. NO LOAD TEST Place jumper J1 in the AUTORETRY position to Turn on the power supplies, verify the input volt- evaluate automatic retry when current limit is ages, and then switch the ON control signal from reached, or in the STATUS position to evaluate low to high ( 1.39V). latched mode operation. All three outputs should come up. 2