DC628A Analog Devices

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 628A SINGLE CHANNEL 5V HOT SWAP CONTROLLER LTC4210 DESCRIPTION Demonstration circuit 628A is a single channel 5V hot The LTC4210 features a fast current limit loop provid- swap controller featuring the LTC4210. ing active current limiting together with a circuit breaker timer. The signal at the ON pin turns the chip TM The LTC 4210 is a 6-pin SOT-23 Hot Swap con- on and off and is also used for the reset function. troller that allows a board to be safely inserted and removed from a live back plane. An internal high side Design files for this circuit board are available. Call switch driver controls the GATE of an external N- the LTC factory. channel MOSFET with a supply voltage ranging from 2.7V to 16.5V. The LTC4210 provides the initial tim- Hot Swap is a trademark of Linear Technology Corporation ing cycle and allows the GATE to be ramped up at an adjustable rate. Table 1. Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Minimum Input Voltage 2.7V Maximum Input Voltage (Limited by Transorb Z1) 12V Output Voltage V V = V -I (R +R ) =V -I (0.022W) OUT OUT IN LOAD SENSE FET IN LOAD I (V /R ) LIMIT< CB SENSE Maximum Output Current 6A Remember to consider tolerances (44mVV 56mV) CB On/Off Control Logic High Voltage-On 2.6V (Connection Sense Turret) V 160mV ONHYST OPERATING PRINCIPLES TM The LTC4210 combines Hot Swap inrush current the circuit breaker hold-off time and automatic retry limiting with an electronic circuit breaker function. duty cycle time. (The LTC4210-1 version provides The LTC4210 uses a single capacitor, C to set automatic retry while the LTC4210-2 version provides TIMER multiple timing cycles for the initial power up time, latch-off after fault timeout.) QUICK START PROCEDURE NOTE: Demonstration circuit 628A is easy to set up to 1. With power off, connect the input power supply to evaluate the performance of the LTC4210. Refer to V and GND and a load between V and GND. IN OUT Figure 1. for proper measurement equipment setup The load resistance should be >Vin/6A or pull less and follow the procedure below: than 6A. 2. Turn on the power at the input. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 628A SINGLE CHANNEL 5V HOT SWAP CONTROLLER NOTE: Make sure that the input voltage does not ex- NOTE: Connectors specifically designed for Hot ceed 12V or the transient suppressor Z1 will begin Swap have a special pin configuration that uses ex- to conduct. The transient suppressor Z1 protects tra long pins to first connect the GND and power the input from the turn off voltage spike resulting signal, then normal length pins for the rest of the from interrupting the high currents flowing through signals and a special short pin for the Connection the lead inductance of the back plane or leads from Sense signal. This pin configuration prevents turn- the power source. ing on the power to the Hot Swapped board before the connector is completely engaged. 3. Connect the Connection Sense turret to V to en- IN able the LTC4210. Monitor the output voltage turn 4. Once the proper output voltages are established, on time waveform or inrush current if a current increase the load above 6A and observe the circuit probe is available. breaker function. Disconnect the Connection Sense turret from V , connect a large (100uF) capacitor IN NOTE: If there is no output, temporarily disconnect across V and GND then connect the Connection OUT the load to make sure that the load is not set too Sense turret to V and monitor V . Observe the IN OUT high. current limiting action during turn on. Figure 1. Proper Measurement Equipment Setup 2