DEMO CIRCUIT 1594 LTC4219 QUICK START GUIDE LTC4219 5A Integrated Hot Swap Controller DESCRIPTION Demonstration circuit DC1594A is a +5V or +12V rail tween Iset and GND pins, and it can be adjusted dynami- with hot swap functionality featuring the LTC4219 - 5A cally during transient. Integrated Hot Swap Controller. As a Controller has two The Controller monitors a load current generating ground dedicated voltage versions- for 5.0V and 12V operation- reference signal proportional to the sense resistor volt- the DC1594 also has similar variation-DC1594A-A (5.0V) age. Thermal limit and power good signaling increase and DC1594A-B ((12V). The DC1594A allows evaluating Controller reliability and options in application. performance of the LTC4219 in the transient conditions, Design files for this circuit board are available. Call such as turning on and off the power rail, in the steady the LTC factory. state conditions with different load and in the fault condi- tions, when Controller interrupts its functions from over- L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy current, nonproprietary voltage level, or thermal condi- Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode tion. Dimming, No Latency , No Latency Delta-Sigma, No RSENSE, Operational Filter, PanelPro- tect, PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names The LTC4219 features 5% accuracy in 5.4A current limit may be trademarks of the companies that manufacture the products. and has a current limiting foldback characteristic. Current limit can be reduced by placing the external resistor be- PERFORMANCE SUMMARY Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Supply Range 2.9 15 V DD V Input Supply Undervoltage Lockout V Rising 2.65 2.73 2.85 V DD(UVL) DD V Output Power Good Threshold LTC4219-12 Only V Rising 10.2 10.5 10.8 Vo OUT(PGTH)) OUT LTC4219-5 Only V Rising 4.2 4.35 4.5 V OUT V Output Power Good Hysteresis LTC4219-12 Only 127 170 213 mV OUT(PGHYST) LTC4219-5 Only 53 71 89 mV V t GATE Pin Turn-On Ramp Rate 0.15 0.3 0.55 A GATE/ R MOSFET+Sense Resistor ON Resistance 15 33 50 m ON I Current Limit Threshold V = 1.23V 5.0 5.4 5.8 A LIM(TH) FB V = 0V 1.0 1.4 1.9 A FB V = 1.23V, R = 20k 2.3 2.7 3.2 A FB SET V TIMER Pin High Threshold V Rising 1.2 1.235 1.28 V TIMER(H) TIMER V TIMER Pin Low Threshold V Falling 0.1 0.21 0.3 V TIMER(L) TIMER I TIMER Pin Pull-Up Current V =0 80 100 120 A TIMER(UP) TIMER I TIMER Pin Pull-Down Current V =1.2V 1.4 2 2.6 A TIMER(DN) TIMER I TIMER Pin Current Ratio I I 1.6 2 2.7 % TIMER(RATIO) TIMER(DN)/ TIMER(UP) 1 LTC4219 OPERATING PRINCIPLES n The LTC4219A-12 and LTC4219A-5 are suited accord- 5% Accurate Current Limit for 5.4A,, n ingly for 12V and 5V power control in applications for hot Adjustable Current Limit for lower than 5.4A, n board insertion or removal with electronic circuit breaker Adjustable Inrush Current Control, n function, foldback current limiting, load current monitor- Load Current Monitoring, n ing, power good and fault signaling. The LTC4219A has a Adjustable duration for Current Limit before switch is rich set of features to support hot swap applications in- turned off, n cluding: Power good and Fault signaling. QUICK START PROCEDURE The Demo Board DC1594A includes the LTC4219-12 or load. For LTC4219-12 this time must be in the range LTC4219-5 5A Integrated Hot Swap Controller, four LEDs (22.0-80.0) ms, and for LTC4219-5 - (9.0-34) ms. to indicate input and output voltages (D2, D4), and the 5. Connect a Low Capacitive Load (5600uf for both state of the fault (D3) and Power Good (D5) pins, three Controllers-LTC4219-12 and LTC4219-5) to the out- jumpers, and a few associated components. put of hot swap circuitry (OUT turret). Turn on the Demonstration circuit DC1594A is easy to set up to controller. This power up should be successful and evaluate the performance of the LTC4219. Refer to Error two LEDs (OUT green- and PG -orange) lights must Reference source not found. for proper measurement indicate this. equipment setup and follow the procedure below: 6. Connect a High Reset Capacitive Load (6800uf for The performance evaluation for LTC4219-12 and both Controllers-LTC4219-12 and LTC4219-5) to the LTC4219-5 is identical. The difference is in a value of the output of hot swap circuitry. Turn on a controller. loading components and power supply voltage. This power up should be unsuccessful, and no light of the two LEDs, - OUT and PG,- and the light of the 1. Place jumpers in the following positions: FLT LED (red) confirms this. Reset controller after a JP1 CT OFF, fault. JP2 EN1 DISABLE, 7. Load the output with a Low Resistive Load (2.5 Ohms for LTC4219-12 and 1.1 Ohms for LTC4219- JP3 EN2 ENABLE. 5) and turn the controller on. Controller should suc- 2. With power off, connect the power supply termi- cessfully keep this load. Verify performance of the nals to the VDD (E1) and GND (E3) turrets. current monitoring. 3. In all evaluations steps the Demo Board is con- 8. Load the output with a High Resistive Load (2.0 nected to the appropriative power supply (+12V or Ohms for LTC4219-12 and 0.8 Ohms for LTC4219- +5.0V), Controller is turned on by replacing the 5) and turn the controller on. Controller should fail to jumper head JP2 position from the DISABLE to the keep this load. Reset Controller after a fault. ENABLE, and a resetting Controller is achieved by 9. Pay special attention to the MOSFET Safe operat- first placing the jumper head JP2 on the DISABLE ing Area, when TIMER period is changed. position and then on the ENABLE. 4. Place a scope probe to the output turret, turn on the Controller, and measure a power-up time with no 2