QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 536 HOT SWAP CONTROLLER WITH MULTIFUNCTION CURRENT CONTROL LTC4211 DESCRIPTION Demonstration circuit DC536 is a Hot Swap controller The DC536 permits evaluating the LTC4211 during with multifunction current control featuring the turn-on and turn-off transients as well as during steady LTC4211. The DC536 is configured to operate with up to state conditions. 7A as populated by the factory. Optional component Design files for this circuit board are available. Call pads are provided for a higher power pass FET and the LTC factory. sense resistor for operation up to 20A. , LTC and Hot Swap are registered trademarks of Linear Technology Corpora- tion. Table 1. Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Supply Voltage Rated operating limits 2.5V VCC 16.5V Under Voltage Lockout Transition to operating mode 2.13V V 2.47V CC(UVL) ON Pin Threshold Voltage, High 1.23V V 1.39V CC(UVL) ON Pin Threshold Voltage, Low 1.20V V 1.26V CC(UVL) Gate Pull-Up current Charge Pump On, V 0.2V 7.5A I 12.5A GATE GATE Normal Gate Pull-Down Current ON Pin Signal Low 130A I 270A GATE Fast Gate Pull-Down Current Latched and Circuit Breaker Tripped or in UVLO 50mA Si4410 and 7mW SENSE Resistor 5.7A I 8.5A LIMIT Current Limit FDB8030L and 2.5mW SENSE Resistor 16A I 24A LIMIT Supply Voltage Rated operating limits 2.5V VCC 16.5V Under Voltage Lockout 2.13V V 2.47V CC(UVL) ON Pin Threshold Voltage, High 1.23V V 1.39V CC(UVL) ON Pin Threshold Voltage, Low 1.20V V 1.26V CC(UVL) Gate Pull-Up current Charge Pump On, V 0.2V 7.5A I 12.5A GATE GATE Normal Gate Pull-Down Current ON Pin Signal Low 130A I 270A GATE OPERATING PRINCIPLES The LTC4211 is a low voltage hot swap controller that sembly options for load current. The DC536 as supplied has a 2.5V to 16.5V operating range and a 17V absolute by the factory is populated with an Si4410 MOSFET in an maximum operating voltage for the Vcc pin. This demo SO-8 package and a 7mW current sense resistor provid- circuit is populated for +5V operation, but it can easily ing a minimum 5A load current. The DC536 has provi- be re-adjusted for any voltage between 2.5V to 16.5V by sion for an FDB8030L MOSFET in the DD package which replacing R3 and R1 (top resistors in the feedback di- when used with a 2.5mW sense resistor provides a vider and the ON pin signal divider). There are two as- minimum16A load current. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 536 HOT SWAP CONTROLLER WITH MULTIFUNCTION CURRENT CONTROL QUICK START PROCEDURE Demonstration circuit 536 is easy to set up to evaluate the performance of the LTC4211. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 1. The DC536 is factory setup to operate in a 5 volt 7. After any necessary component changes have been system at current levels up to 5 amps. If the made, connect a suitable load between VOUT and LTC4211 is to be evaluated at a different operating GND. This may be a passive resistive load or an ac- condition, follow 2-6 below, otherwise skip to 7. tive electronic load box. 2. If evaluating at a voltage other than 5V, R3 must be 8. Connect a power supply capable of supplying adjusted for proper RESET PIN response. Select 1.5I between the VIN and GND turrets. The LOAD R3=V 15K/1.223-15K, where V is the mini- minimum current capability of the supply must ac- MIN MIN mum output voltage expected for normal operation. commodate the tolerance of the circuit breaker threshold of 20%. With the 7mW factory installed 3. The ON pin operates as a precision comparator and sense resistor, the overload circuit breaker will trip can accurately provide an adjustable under voltage at between 5.7A to 8.5Amp (7Amp nominal). lockout. The DC536 is initially configured to turn on Connect the ON/OFF turret to the VIN turret to at 4.15V . If 3.3V logic will drive this pin, R1 can MIN enable power to the load. A function generator can be replaced with a short. If the ON pin will be used be used to generate a single event and trigger a to provide under voltage lockout, then select R1 scope. The DC536 provides convenient turrets for such that R1=V 10K/1.39-10K, where V is UVLO UVLO observing the FAULT, RESET and VOUT signals. the minimum turn on voltage. Refer to the data sheet figure 3 for common configurations 9. The following experiments can be run. Turn on into a nominal load. Turn on into an overload. 4. If the DC536 will operate at other than 7Amps max, Turn on into a short circuit. Turn on into a nomi- increase the value of R =0.99I /40mV for a SENSE LOAD nal load and increase the load until the LTC4211 1% tolerance current sense resistor. trips off. A digital storage scope provides a con- 5. If the DC536 will be operating above 7Amps, re- venient means of observing the turn on and over- place Q1 with a suitable DD package MOSFET such load events. Observe the input or output current as the FDB8030L suitable for up to 20Amps. There using a current probe. A current transformer can is a DD package footprint on the back of the board. be used to observe turn on current transients if a current probe is not available. 6. The soft start and power good (RESET release) de- lay is factory set to 6.2ms. This delay can be ad- justed by changing C refer to the data sheet TIMER Table 1 for common values and the SYSTEM TIMING section for more detailed information. 2