DEMO CIRCUIT 1134 LTC4222 QUICK START GUIDE LTC4222 Dual Hot Swap Controller 2 with I C Compatible Monitoring DESCRIPTION Demonstration Circuit DC1134A allows evaluation ON CONFIG for selecting independent or cou- of the performance of the LTC4222 UF Dual Hot pled rail operation, two jumpers ADIN1 and Swap Controller with I2C Compatible Monitoring in ADIN2 for selecting ADC1 and ADC2 input sig- +12V/5A and +3.3V/5A applications. nals, two jumpers EN1 and EN2 for selection EN1 and EN2 pin signals, I2C port and turret ter- The DC1134A can demonstrate turn-on and turn- minals for critical signals to facilitate evaluation in a off transients as well as the steady state mode of working system. Each rail channel includes a se- the LTC4222. The Controller responds to fault ries connected power MOSFET and sense resis- conditions such as input overvoltage (OV), input tor. undervoltage (UV), output power good (PWRGD) fault and overcurrent fault, and response may be The I2C port designed to interface with the verified by the Fault Alert LED. DC590A allows providing full control of the DC1134 with LTC s QuickEval software. The board contains one LTC4222 UF Controller, two rail channels, input clamps, input and output Design files for this circuit board are available. voltage dividers for setting the UV, OV and Call the LTC factory. PWRGD comparator thresholds, LEDs to indicate L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, the presence of input and output voltages, I2C and DirectSense, Easy Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode Dimming, No Latency , No Latency Delta-Sigma, No ALERT signals, three jumpers ADR0, ADR1, and R , Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SENSE ADR3 for I2C address programming, jumper SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names may be trade- TIMER SELECT for timer off period selection, marks of the companies that manufacture the products. jumper ON for ON pin signal selection, jumper PERFORMANCE SUMMARY Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Supply Range 2.9 29 V DDN V Input Supply Undervoltage Lockout V Rising 2.34 2.43 2.53 V DDN(UVL) DD DV 47.5 50 52.5 mV SENSE(TH) Circuit Breaker Threshold (VV DD- V ) SENSED DV Current Limit Voltage (VV V ) V =1.3V 46 50 54 mV SENSE DD- SENSED FB- V =0V 14 16.6 19 mV FB- Start-Up Timer Expired 130 150 165 mV V First Rail Operating Voltage 12 V DD1 V Second Rail Operating Voltage 3.3 V DD2 I Circuit Breaker Current Limit in both Rails Steady State Condition, after Power-Up 4.6 5 5.4 A LIMIT dU / Both Rails Output Voltage Slew Rate Rail Current Lower Current Limit Threshold 850 1200 1900 V/s OUT DT V CONFIG, ENn, FBn, ONn, OVn and UVn V Rising 1.215 1.235 1.255 V INPUT(TH) IN Pin Input Threshold 1 LTC4222 PERFORMANCE SUMMARY Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I External N-Channel Gate Pull-Up Current Gate On, V = 0V 8 12 18 A GATE(UP) GATE OPERATING PRINCIPLES The LTC4222 is a low voltage dual hot swap con- limit and 4.75A circuit breaker threshold. The cur- troller that has 2.9V to 29V operating range and rent limit and circuit breaker thresholds can be ad- 35V absolute maximum voltage for the VDD pins. justed by changing the channels sense resistor In the DC1134A the first channel operates on the (RS1 and RS2). To enable demonstration of higher +12V rail and the second channel on the +3.3V current applications up to 25A, provisions have rail. Each channel can easily be readjusted for any been made to replace the provided sense resistor voltage between 2.9V and 29V by replacing the with a 1W, 2512 size and replace Q1 and Q101 top resistors in the UV, OV and FB dividers (R1, with MOSFETs in a PowerPAK SO-8, such as the R2, R7 for the first channel and R101, R102, R107 Si7476ADP. The large turrets may be removed to for the second one). The DC1134 as supplied by permit installation of up to a 12 gauge wire for di- the factory is assembled with the Si4864DP MOS- rect, low resistance connections to the board. FETs in an SO-8 package and with 10mW current None of the turrets are swaged. sense resistors, setting a minimum of 4.6A current QUICK START PROCEDURE Demonstration circuit 1134 is easy to set up to R101 4.12(V /1.255) 1-1.215/V k. MAX3.3 MIN3.3 evaluate the performance of the LTC4222. Refer to Select a voltage divider middle resistor R2 and Figure 1 for proper measurement equipment setup R102 as and follow the procedure below: R2 14.7(1.215V /1.255V -1)k MAX12 MIN12 The DC1134 is factory set up to operate with 12V R102 4.12(1.215V /1.255V -1) k. and 3.3V rails and up to 5A. If the LTC4222 is to MAX3.3 MIN3.3 be evaluated at different operating conditions, fol- where V and V are the minimum and MIN MAX low steps 1 through 3 below, otherwise skip to step maximum output voltages expected for normal 4. operation. 1. If evaluating at a voltage other than 12V and Select resistors in the feedback dividers R7 or 3.3V, R1, R2, R101 and R102 must be ad- R107 as justed for proper UV and OV comparator re- R = 3.01 V /1.255-1 k MIN sponse. The values of the bottom resistor in the divider R3 (14.7k) and R103 (4.12k) may where V is the minimum output voltage ac- MIN be assigned arbitrarily. cepted as a good output. Select a voltage divider top resistor R1 and 2. If the DC1134 will operate at other than 5A R101 as max, change the value of the sense resistor R = 0.9947.5mV/I for a 1% tol- SENSE LOAD(MAX) R1 14.7(V /1.255) 1-1.215/V k, MAX/12 MIN12 erance current sense resistor. 2