PI2161 ® Cool-Switch Series 60 Volt, 12 Amp Full-Function Load Disconnect Switch Solution Description ® The Cool-Switch PI2161 is a complete full-function Load Disconnect Switch solution for medium voltage applications with a high-speed electronic circuit breaker and a very low on-state resistance MOSFET. It is designed to protect an input power bus from output load fault conditions. The PI2161 Cool-Switch solution is offered in an extremely small, thermally enhanced 7mm x 8mm LGA package. The PI2161 enables an extremely low power loss solution with fast dynamic response to an over current fault or EN high conditions. The PI2161 senses a small portion of the total MOSFET current and has a low voltage threshold allowing the use of low power sense resistors. The switch is closed when the EN input is low and is open when EN is high. Once enabled, the PI2161 monitors the MOSFET current through a sense resistor. If an over current level is sensed, the switch is quickly latched off to prevent the power source from being overloaded. Bringing the EN pin high will reset the over current latch allowing retry. The PI2161 has an internal 10kΩ bias resistor connected between the Drain (D) and VC to eliminate need for external resistor in a 44V bus application (41V to 48V). Features Integrated High Performance 12A, 8.5mΩ MOSFET Very small, high density fully-optimized solution with simple PCB layout Programmable latching over-current detection Fast 120ns disconnect response to load failures Low loss current sensing Fast disable via EN pin, typically 200ns. Load Status output (VO scaled load voltage) Applications N+1 Redundant Power Systems Servers & High End Computing Load Disconnect High Side Circuit Breaker Package Information The PI2161 is offered in the following package: 17-pin 7mm x 8mm thermally enhanced LGA package, achieving <10°C/W RθJ-PCB Typical Application: Figure 1: PI2161 High Side Disconnect switch Picor Corporation • picorpower.com Figure 2: PI2161 response time to output short fault condition PI2161 Rev1.1, Page 1 of 18 Pin Description Pin Name Pin Number EN 1 Enable: Logic level input, active low allows switch to reach 8.5mΩ typical in the on state within 2ms. A logic high input will turn the switch off in typically 200ns. Leave this pin open to allow switch to turn on after application of input power. VO 2 Load Status Output: This pin pulls to the load voltage once the switch is enabled through an internal 150kΩ resistor. Connect a resistor from this pin to ground to scale the load voltage to the appropriate logic or analog level. Ground this pin if unused. VC 3 Voltage Bias: This pin is the supply pin for the control circuitry and gate driver. Connect a 0.1μF capacitor between the VC pin and the PG pin. Voltage on this pin is regulated to 11.7V with respect to PG by an internal shunt regulator. A 10kΩ internal resistor (RD-VC) is connected between D pin and VC pin. PG 4 Control Circuitry Return: PG is the floating return path for the controller circuitry. Connect this pin via a resistor to the GND (ground), as shown in Figure 1. SP 5 Sense-Positive Input: Connect the SP pin to the SL pin side of the sense resistor as a Kelvin connection. The magnitude of the voltage difference between SP and SN provides an indication of the current through the sense resistor and the SL section of the MOSFET. SL 6,7 Source Low: A low percentage of the internal N-channel MOSFET source current passes through this to the sense resistor. Refer to the Current Sense section in the Functional Description. SN 8 Sense-Negative Input: Connect the SN pin to the SH pin side of the sense resistor as a Kelvin connection. The magnitude of the voltage difference between SP and SN provides an indication of the current through the sense resistor and the SL section of the MOSFET. Description SH 9, 10, 11, Source High: The Source of the internal N-channel MOSFET section providing the majority 17 of the load current and alternate bias to the control circuitry. D 12, 13, 14, Drain: The Drain of the internal N-channel MOSFET, connect to the input power source bus 16 voltage that provides the current to the load. GND 15 Ground: This pin is the return (ground) for the enable circuitry. Connect this pin to the logic/system power ground. Package Pin-Outs 7mm x 8mm 17 Pin LGA Top view pin-out Picor Corporation • picorpower.com PI2161 Rev1.1, Page 2 of 18 Absolute Maximum Ratings Note: Unless otherwise specified, all voltage nodes are referenced to “PG” Drain-to-Source Voltages (VD to VSH and VSL) 60V @ 25°C Source Current (ISH+ISL) Continuous 12A @ 25°C Source Current (ISH+ISL) Pulsed (10μs) 100A Source Current (ISH+ISL) Pulsed (300ns) (1) 150A Single Pulse Avalanche Current (T AV<11μs) (1) 33A Junction-to-Ambient Thermal Resistance (RθJ-A) 45°C/W (0LFM) Junction-to-PCB Thermal Resistance (RθJ-PCB) 10°C/W SH, SL, SP, SN to PG SH to SL -0.3V to 13V / 20mA (4) ± 1.5V VC to PG -0.3V to 13V / 10mA Drain (D) to PG, Drain (D) to GND -0.3V to 60V / 10mA -0.3V to 60V / 1mA VO, EN o o Storage Temperature -65 C to 150 C Operating Junction Temperature -40°C to 140°C Internal MOSFET Operating Junction Temperature -40°C to 150°C o Lead Temperature (Soldering, 20 sec) 250 C ESD Rating CDM Class IV Electrical Specifications Unless otherwise specified: -40C < TJ < 125C, VVC-PG =10.5V, VPG=VGND=0V, CVC=0.1μF Parameter Symbol Min VVC-PG 8.5 Typ Max Units Conditions 10.5 V 1.7 2.1 mA VC = 10.5V, SP=SN=VC VC = 8.5V, SP=SN=PG Control Circuit Supply (VC to PG) Operating Supply Range Quiescent Current Quiescent Current at Start Up IVC No VC limiting Resistor IVCSU 2.0 2.5 3.0 mA Clamp Voltage VVC-CLM 11 11.7 12.5 V IVC=3mA Clamp Shunt Resistance RSHUNT 10 Under-Voltage Rising Threshold VVCUVLO 6.2 7.32 8.5 V Delta IVC=10mA VD= VVC , measure when VD=VSH Under-Voltage Falling Threshold VVCUVF 6 7.00 7.9 V VVCUV-HS 240 320 400 mV VVD-GND 41 44 48 V RD-VC 8 10 14 kΩ VVD-UVLO 27 33 38 V Under-Voltage Hysteresis Drain Supply Operating Supply Range D to VC resistance D input UVLO Rising Threshold Picor Corporation • picorpower.com PI2161 RPG=6kΩ RPG=6kΩ, ISH=-1mA EN =0 Rev1.1, Page 3 of 18 Electrical Specifications Unless otherwise specified: -40C < TJ < 125C, VVC-PG =10.5V, VPG=VGND=0V, CVC=0.1μF Parameter Symbol Min Typ Max Units Conditions DIFFERENTIAL AMPLIFIER AND COMPARATORS Common Mode Input Voltage Differential Operating Input Voltage VCM (1) VPG VSP-SN VVC +0.3 250 mV SP-SN V SP Input Bias Current ISP 15 25 35 μA SP=SN=VC SN Input Bias Current ISN 25 37 50 μA SP=SN=VC 0.87 1.0 V ISN=3mA 70 77 mV 120 200 ns DBST Diode Forward Voltage (SN to VC) Low Range Overcurrent Threshold Low Range Overcurrent Turn-off Time High Range Overcurrent Threshold VDBST VOC-THL 63 TOC-OFF VC-SN=0V VSP-SN = 0~200mV step to 90% of VSH max, SN=VC VC-SN=6V VOC-THH 133 166 200 mV Overcurrent Hysteresis(1) Over Current Range switch over Threshold Over Current Range switch over delay(1): Low to high Threshold Over Current Range switch over delay: High to low threshold Internal N-Channel MOSFET VOC-HY 9 13 17 mV VSOTH 0.5 0.8 1 V VC-SN TSOL2H 100 170 300 ns VC-SN= -0.7V~1.7V TSOH2L 80 125 190 ns SN-VC= -1.7V~0.7V Drain-to-Source Breakdown Voltage BVDSS 60 V ID=2mA , Tj=25°C; Source Current Continuous ISH+ISL 12 A In ON state, Tj=25°C Drain to source Off State Current IDS-OFF 3.2 4.3 mA Drain-to-Source On Resistance RDSon 8.5 11 m 8 % 400 mV 153 k 5 μA 1.6 V Current Sense Ratio (3) KS EN =3.3V, VD=44V, VSH= VSL=0V In ON state, ID=10A. Tj=25°C ISL/ (ISH+ISL), ID=10A(4) Internal Schottky Diode (between PG and SH) DClamp Forward voltage VF VF=10mA, Tj=25°C Load Status Voltage (VO) Source (SH) to VO resistance Source to VO leakage RSH-VO 147 150 IVOLK Enable ( EN ) Threshold Voltage V EN Input bias @ 3.3V I EN 0.4 50 μA Note 1: These parameters are not production tested but are guaranteed by design, characterization, and correlation with statistical process control. Note 2: Current sourced by a pin is reported with a negative sign. Note 3: Refer to the Current Sense section in the Functional Description Note 4: A sense Resistor (Rs) has to be connected between SH and SL as shown in Figure 1, Rs ≤ 2Ω. Picor Corporation • picorpower.com PI2161 Rev1.1, Page 4 of 18 Functional Description: The PI2161 integrated Cool-Switch product takes advantage of two different technologies combining low RDS(on) N-channel MOSFETs with high density control circuitry to provide a high side fast Circuit Breaker solution. The PI2161’s 8.5m on state resistance MOSFET minimizes the voltage drop, at the maximum rated current of 12A, significantly reducing power dissipation and eliminating the need for heat sinking. KS Where: As shown in the typical application Figure 1 and the block diagram Figure 5, the unique aspect of the load current sensing scheme is that only a small portion of the total MOSFET source current is routed through the sense resistor (Rs). This allows using a much lower power component compared to the conventional method of sensing the total current to the load. Figure 5, Figure 6 and Figure 7 show the PI2161 block diagram, timing diagram and state diagram respectively. Current Sense: The PI2161 internal MOSFET source is split into two portions, Source High current (SH) and Source Low current (SL). SH conducts the majority of the current and SL conducts a small portion of the load current. SL current is routed through the sense Resistor (Rs) for current sensing. The value of the sense Resistor in the path of the sense current, will create a voltage drop and have an effect on the current ratio KS. The current ratio is expressed in the following equation as a function of RDS(on) and Rs. Note that the MOSFET RDS(on) value is temperature dependent and temperature will effect the current ratio. For one RDS(on) value the current ratio is constant with respect to the load current. Current ratio vs. sense resistor over temperature performance is shown in Figure 3. Picor Corporation • picorpower.com Rs : Sense Resistor value in [mΩ] RDS (on) : MOSFET ON resistance value [mΩ] KS : Current sense ratio I SL : SL sense current [A] I Load : Load Current [A] 6.6 6.4 Typical Rds(on) at 25°C = 8.5mΩ 6.2 6.0 Current Sense Ratio (Ks) [%] Differential Amplifier: The PI2161 integrates a high-speed fixed offset voltage differential amplifier to sense the difference between the Sense Positive (SP) pin and Sense Negative (SN) pin voltage. The amplifier output is connected to the control logic that determines the state of the fault latch. To avoid tripping the breaker due to load capacitance during initial power up, a higher threshold (VOC-THH) is used. The amplifier will detect if the drop across the sense resistor reaches 166mV and discharge the gate of the MOSFET if detected. Once the load voltage approaches the input potential, the threshold (VOC-THL) is lowered to 70mV. This allows for capacitive load charging and continuous current sensing without the use of a sense blanking timer. 12 * R DS ( on) I SL I Load 144 * R DS ( on) ( Rs 17.5) * (11) 5.8 5.6 5.4 Jun ctio n 5.2 5.0 Jun 4.8 4.6 ctio n 4.4 4.2 Te m pe Tem per ra t u re 4.0 atu =2 re = 125 °C 5°C 3.8 3.6 3.4 3.2 30 40 50 60 70 80 90 100 110 120 130 140 150 Sense Resistor Value [mΩ] Figure 3: Current ratio vs. sense resistor over temperature Figure 4 characterizes the trip current range between 25°C and 125°C over a range of sense resistor values. The equations and an example for calculating Rs value for a trip current level and the equation for the trip current at a given sense resistor value are provided in the Application Information section. Enable Input: ( EN ) This input provides control of the switch state enabling and disabling with logic level signals. The active low feature allows grounding or floating of the input resulting in switch closure upon application of input power. System control can disable the switch and reset the over current latch by pulling this pin to a logic high state. Once enabled the load voltage will reach the input voltage in typically 1 ms and the device will sense the current continuously once the POR interval has cleared relative to the VC to PG potential. The disable control with this input is very fast, turning the switch off in typically 200ns. The response to open during an PI2161 Rev1.1, Page 5 of 18 over current event is typically 120ns and the switch will latch off until reset by bringing this input high or recycling of the input power. of the MOSFET. The VC pin will be biased through the load potential once the MOSFET is enabled. In a high voltage application as shown in Figure 1 the lower bias resistor RPG placed between the PG pin and system ground is required. RPG creates an offset voltage at the PG pin to regulate VC with respect to PG when the MOSFET is enabled and the load voltage reaches the input voltage. The PI2161 has an integrated charge pump that approximately doubles the regulated VC with respect to PG enhancing the N-Channel MOSFET gate to source voltage. The internal gate driver controls the N-channel MOSFET such that in the on state, the gate driver applies current to the MOSFET gate driving it to bring the load up to the input voltage and into the RDS(on) condition. Figure 4: Over current trip vs. sense resistor over temperature. When an over current condition is sensed the gate driver pulls the gate low to PG and discharges the MOSFET gate with 4A peak capability. Load Status: (VO) VC Voltage Regulator and MOSFET Drive: The biasing scheme in the PI2161 uniquely enables the gate control relative to the PG pin via the resistor RPG shown in Figure 1. The VC input provides power to the control circuitry, the charge pump and the gate driver. An internal regulator clamps the VC voltage to 11.7V with respect to PG. When the Gate is enabled, a 150k resistor is connected to the MOSFET source and VO. An external resistor between VO and ground creates a voltage divider that scales the load voltage down to the desired level to interface with the diagnostic circuit to represent a logic state or analog voltage level. The external resistor RVO can be calculated using the following equation: The internal regulator circuit has a comparator to monitor VC voltage and pulls the gate low when VC to PG is lower than the VC Under-Voltage Threshold. RVO 150 K During start up or in a fault condition when the output (Load) is shorted, the VC pin is biased through a 10KΩ (RD-VC) internal resistor connected to the drain Where: VO : V SH : Picor Corporation • picorpower.com PI2161 VO VSH VO Desired voltage level at VO pin Enabled load or SH voltage Rev1.1, Page 6 of 18 Figure 5: PI2161 block diagram Figure 6: PI2161 timing diagram, referenced to Figure 1. Picor Corporation • picorpower.com PI2161 Rev1.1, Page 7 of 18 Figure 7: PI2161 State Diagram, referenced to Figure 1. Picor Corporation • picorpower.com PI2161 Rev1.1, Page 8 of 18 Typical Characteristics: Figure 8: Controller bias current vs. temperature. Figure 11: Internal MOSFET drain to source breakdown voltage vs. temperature. Figure 9: Low Range Overcurrent Threshold vs. temperature. Figure 12: Internal MOSFET on-state resistance vs. temperature Figure 10: Low Range Overcurrent Turn-off time vs. temperature. Figure 13: Internal MOSFET source to drain diode forward voltage (pulsed ≤300µs). Picor Corporation • picorpower.com PI2161 Rev1.1, Page 9 of 18 Thermal Characteristics: Figure 14: MOSFET Junction Temperature vs. Input Current for a given ambient temperature (0LFM) Figure 16: MOSFET Junction Temperature vs. Input Current for a given ambient temperature (200LFM) Figure 15: PI2161 input current de-rating based on the MOSFET maximum TJ=150°C vs. ambient temperature Figure 17: PI2161 input current de-rating vs. PCB temperature, for the MOSFET maximum TJ at 125°C and 150°C MOSFET PI2161 2 Figure 18: PI2161 mounted on a 1in pad of 0.5 oz copper. Thermal Image picture, Iout=10A, TA=25°C, Air Flow=0LFM Picor Corporation • picorpower.com PI2161 Rev1.1, Page 10 of 18 Figure 19: PI2161 response to an increase in load current Application Information The PI2161 Cool-Switch is a medium voltage high side load disconnect switch. The RPG worst case condition for power dissipation is a function of the maximum BUS voltage and minimum VC clamp voltage. This section describes in detail the procedure to follow when designing with the PI2161 load disconnect switch. Lower Bias Resistor selection: RPG As described in Functional Description section, in a floating application as shown in Figure 1 the lower bias resistor RPG placed between the PG pin and system ground is required. RPG creates an offset voltage at the PG pin to regulate VC with respect to PG when the MOSFET is enabled. Pd RPG R PG Where: VVD UVLO min : Drain input UVLO minimum voltage, 27V Vin max : Vin maximum voltage, 48V VC ClampMax : Controller maximum VC clamp voltage, 12.5V V DBST MAX : Maximum DBST Forward Voltage, 1.0V The RPG resistor can be calculated using the following expression: R PG (Vin max VC clampMIN ) 2 VC ClampMin : Controller minimum VC clamp voltage, 11V VVD UVLO min VC clampMAX V DBST MAX I VCMAX 100 A I VCMAX : Controller maximum VC bias current. 100A : 2.1mA 100μA is added for a margin Example: 41V < Vin < 48V Picor Corporation • picorpower.com PI2161 Rev1.1, Page 11 of 18 Make sure that the PI2161 to turn on below the minimum required voltage, use 27V for the minimum voltage to calculate RPG. R PG 27V 12.5V 1V 6.136 K or 6.04KΩ 2.1mA 100 A Pd RPG I TRIP Pd RS (48V 11V ) 227 mW 6.04 K The current trip point is a function of the Low Range Overcurrent Threshold (VOC-THL), the internal MOSFET on resistance (RDS(on)) and current sense resistor (Rs). To insure that PI2161 will not trip within the expected nominal operating current range, include the variation of VOC-THL and RDS(on) in the calculation when selecting Rs. VOC-THL is 70mV typical, 63mV minimum and 77mV maximum. The RDS(on) typical value at 25°C is 8.5mΩ and 11mΩ maximum. RDS(on) will increase with temperature as shown in Figure 12, and can be calculated by multiplying the RDS(on) value at 25°C by the normalized factor in Figure 12 at the expected operating junction temperature or use the following equation. RDS ( on) (TJ ) RDS ( on) (25C ) * 0.873 * e 3.75*TJ *10 0.041 2 Current sense resistor [mΩ] I TRIP : Current trip point [A] VOC _ THL : Low Range Overcurrent Threshold [mV], This input provides control of the switch state enabling and disabling with logic level signals. Current Sense Resistor Selection: Rs The Rs value can be selected from Figure 4 to set the nominal trip current at junction temperature for internal MOSFET of 25°C or 125°C. To set the minimum trip current at specific junction temperature use the following procedure. V TH MAX Rs Where: Rs : Enable Input: ( EN ) 3 12 * Rs * RDS ( on) Sense resistor Maximum power dissipation is: 2 VOC _ THL * 144 * RDS ( on) 11 * ( Rs 17.5) 63mV minimum VTH MAX : Maximum Overcurrent Threshold [mV], 77mV Current trip calculation example: Minimum current tripping point = 12A Maximum MOSEFET junction temperature = 100°C. The lowest tripping current will occur at the internal MOSFET maximum RDS(on) and its maximum junction temperature, and minimum Low Range Overcurrent Threshold (VOC-THL). The MOSET maximum RDS(on) is 11mΩ at 25°C and at maximum junction temperature will be 3 RDS ( on) (100) 11m * 0.873 * e 3.75*100*10 0.041 R DS ( on) (100) 14.42m Select Rs at minimum VOC-THL =63mV Rs 63 * 144 * 14.42 192.5 103.32m 12 * 12 * 14.42 11 * 63 Rs maximum power dissipation: 2 Where: Internal MOSFET Junction temperature TJ : R DS ( on) (TJ ) : Internal MOSFET RDS(on) at TJ in °C R DS ( on) (25C ) : Internal MOSFET RDS(on) at TJ = 25°C The sense resistor can be calculated from the following equation as a function of the trip current: Rs VOC _ THL * 144 * R DS ( on) 192.5 Pd RS This is a low power dissipation resistor and any package size work as far by selecting the nearest standard value. The closest resistor available value in 1% accuracy in an 0603 or 0805 package is 0.10Ω (100mΩ). If 0603 0.10Ω 1% resistor selected, then the minimum trip current is: 12 * I TRIP * RDS ( on) 11 * VOC _ THL I TRIP And the trip current can be calculated from the following equation: Picor Corporation • picorpower.com VTH MAX 0.077 2 57.6mW Rs 0.103 PI2161 63 * 144 * 14.42 11 * (100 17.5) 12.26 A 12 * 100 * 14.42 Rev1.1, Page 12 of 18 Internal N-Channel MOSFET BVDSS: The PI2161’s internal N-Channel MOSFET breakdown voltage (BVDSS) is rated for 60V at 25°C and will degrade to 55.5V at -40°C, refer to Figure 11. Drain to source voltage should not exceed BVDSS in nominal operation. During a fast switching transient the MOSFET can tolerate voltages higher than its BVDSS rating under avalanche conditions. Refer to the Absolute Maximum Ratings table. In load disconnect switch applications when the load is shorted, a large current is sourced from the input supply through the MOSFET. Depending on the input impedance of the system and the parasitic inductance, the current in the MOSFET may exceed the source pulsed current rating (150A) just before the PI2161 MOSFET is turned off. The peak current during an output short condition is calculated as follows, assuming that the output has very low impedance and it is not a limiting factor: I PEAK V D * t OC OFF L PARASITIC Where: I PEAK : Peak current in PI2161 MOSFET before it is turned off. : Input voltage or load voltage at D pin before VD input short condition did occur. t OC OFF : Low Range Overcurrent Turn-off Time. LPARASITIC : Circuit parasitic inductance The high peak current during an output short and before the MOSFET turns off, stores energy in the circuit parasitic inductance, and as soon as the MOSFET turns off, the stored energy at the drain side of the internal MOSFET will be released to produce a voltage higher than the input voltage while the MOSFET source is at ground. This event will create a high voltage difference between the drain and source of the MOSFET. The MOSFET will avalanche, but this avalanche will not affect the MOSFET performance because the PI2161 has a fast response time to the input fault condition and the stored energy will be well below the MOSFET avalanche capability. MOSFET avalanche energy during an output short event is calculated as follows: Picor Corporation • picorpower.com E AS 1.3 * BV DSS 1 2 * * LPARASITIC * I PEAK 2 1.3 * BV DSS VS Where: E AS : Avalanche energy BV DSS : MOSFET maximum rated voltage (60V) Power dissipation: In Load Disconnect Switch applications, the MOSFET is on in steady state operation and the power dissipation is derived from the total source current and the on-state resistance of the MOSFET. The PI2161 internal MOSFET power dissipation can be calculated with the following equation: Pd MOSFET Is 2 R DS ( on) Where: Is: Source Current Pd MOSFET :MOSFET power dissipation RDS(on): MOSFET on-state resistance Note: For the worst case condition, calculate with maximum rated RDS(on) at the MOSFET maximum operating junction temperature because RDS(on) is temperature dependent. Refer to Figure 12 for normalized RDS(on) values over temperature. The PI2161 maximum RDS(on) at 25°C is 11mΩ and will increase by 43% at 125°C junction temperature. The Junction Temperature rise is a function of power dissipation and thermal resistance. Trise RJA Pd MOSFET RJA Is 2 R DS (on) Where: RJA : Junction-to-Ambient thermal resistance (45°C/Watt) This calculation may require iteration to get to the final junction temperature. Figure 14 and Figure 16 show the PI2161 internal MOSFET final junction temperature curves versus conducted current at maximum RDS(on), given ambient temperatures and air flow. Load Status Resistor Selection: (RVO) RVO can be calculated using the following equation: RVO 150 K PI2161 VO VSH VO Rev1.1, Page 13 of 18 Typical Application Example: Load Disconnect Switch Requirement: Bus Voltage = 45V ±5V Maximum Load Operating Current = 9A Minimum Trip Current = 10A Maximum Ambient Temperature = 60°C, no air flow (0LFM) The current flow parasitic inductance is 60nH. System logic voltage is 3.3V and logic high = 2.0V Solution: In this application, PI2161 is used to protect the power source from load failure, configured as shown in the circuit schematic in Figure 21. Power Dissipation and Junction Temperature: First use Figure 14 (MOSFET Junction Temperature vs. Input Current) to find the final junction temperature for 9A load current at 60°C ambient temperature. In Figure 14 (illustrated in Figure 20) draw a vertical line from 9A to intersect the 60°C ambient temperature line. At the intersection draw a horizontal line towards the Y-axis (Junction Temperature). The Junction Temperature at maximum load current (9A) and 60°C ambient is 115°C. RDS(on) is 11mΩ maximum at 25°C and will increase as the Junction temperature increases. From Figure 12, at 115°C RDS(on) will increase by 38%, then RDS ( on) 11m 1.38 15.18m maximum at 115°C Maximum power dissipation is: RPG Selection: For a margin purpose, select RPG to operate at input voltage below the required operating voltage, use 27V minimum operating voltage: R PG R PG Pd max Iin 2 RDS ( on) (9 A)2 15.18m 1.23W Recalculate TJ: 45C TJ max 60C (9 A)2 15.18m 115.3C W VVD UVLO min VC clampMAX V DBST MAX I VCMAX 100 A 27V 12.5V 1V 6.136k 2.1mA 0.1mA The closest 1% resistor available is 6.04kΩ, RPG power dissipation will be: PdR PG (VS max VS PGMin ) 2 50V 11V 2 252mW RPG 6.04k The selected resistor should be capable of supporting the total power at maximum operating temperature, 60°C. An 0805 (2012) will support the power requirement. VO pin: In this application use the minimum voltage output VSH = 40V, and for VO use the logic high voltage (2.0V) with margin, VO = 2.1V RVO 150 K * 2.1V 8 .3 K 40V 2.1V Closest 1% resistor is 8.45kΩ to the high side Calculate VO at VSH = 40V and RVO=8.45kΩ Figure 20: Example 1 final MOSFET junction temperature at 9A/60°C TA Select Rs: The minimum trip current will occur at maximum MOSFET junction temperature and VOC-THL = 63mV: RVO 150 K RVO 8.45 K VO 40V * 2.133 150 K 8.45 K VO VSH * Picor Corporation • picorpower.com PI2161 Rev1.1, Page 14 of 18 MOSFET Junction Temperature for 10A at 60°C can be estimated using the graph in Figure 14 as illustrated in Figure 20. Draw a vertical line from 10A to intersect the 60°C ambient temperature line. At the intersection draw a horizontal line towards the Y-axis (Junction Temperature). The Junction Temperature at maximum load current (10A) and 60°C ambient is 133°C. 3 The minimum trip current is: I TRIP I TRIP VOC _ THL * 144 * RDS ( on) 11 * ( Rs 17.5) 12 * Rs * RDS ( on) 63 * 144 * 16.26 11 * (130 17.5) 9.85 A 12 * 130 * 16.26 RDS ( on) (TJ ) RDS ( on) (25C ) * 0.873 * e 3.75*TJ *10 0.041 3 RDS (on) (133) 11m * 0.873 * e 3.75*133*10 0.041 R DS ( on) (133) 16.26m Rs Rs VOC _ THL * 144 * R DS ( on) 192.5 12 * I TRIP * RDS ( on) 11 * VOC _ THL 63 * 144 * 16.26 192.5 126.9m 12 * 10 * 16.26 11 * 63 The closest 1% resistor available off-the-shelf is 130mΩ. Figure 21: PI2161 configured for 10A minimum trip current Layout Recommendation: Use the following general guidelines when designing printed circuit boards. An example of the typical land pattern for the PI2161 is shown in Figure 22. Use a solid ground (return) plane to reduce circuit parasitic. Connect Rs terminal at SN pin side and all S pads together with a wide trace to reduce trace parasitics and to accommodate the high current output, and also connect all D pads together with a wide trace to accommodate the high current input. Kelvin connect SP pin and SN pin to Rs terminals to the S pins. Connect SL pins together with a wide trace connect them to Rs. Place CVC very close to PI2161 to have very short traces to PI2161 pins without any PCB via in between. Use 1oz of copper or thicker if possible to reduce trace resistance and reduce power dissipation. Picor Corporation • picorpower.com Figure 22: PI2161 layout recommendation PI2161 Rev1.1, Page 15 of 18 Package Drawings All dimensions are in mm Ordering Information Part Number Package PI2161-01-LGIZ 7mm x 8mm 17-pin LGA Picor Corporation • picorpower.com Transport Media T&R PI2161 Rev1.1, Page 16 of 18 Footprint Recommendation: Picor Corporation • picorpower.com PI2161 Rev1.1, Page 17 of 18 Warranty Vicor products are guaranteed for two years from date of shipment against defects in material or workmanship when in normal use and service. This warranty does not extend to products subjected to misuse, accident, or improper application or maintenance. Vicor shall not be liable for collateral or consequential damage. This warranty is extended to the original purchaser only. EXCEPT FOR THE FOREGOING EXPRESS WARRANTY, VICOR MAKES NO WARRANTY, EXPRESS OR LIMITED, INCLUDING, BUT NOT LIMITED TO, THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Vicor will repair or replace defective products in accordance with its own best judgment. For service under this warranty, the buyer must contact Vicor to obtain a Return Material Authorization (RMA) number and shipping instructions. Products returned without prior authorization will be returned to the buyer. The buyer will pay all charges incurred in returning the product to the factory. Vicor will pay all reshipment charges if the product was defective within the terms of this warranty. Information published by Vicor has been carefully checked and is believed to be accurate; however, no responsibility is assumed for inaccuracies. Vicor reserves the right to make changes to any products without further notice to improve reliability, function, or design. Vicor does not assume any liability arising out of the application or use of any product or circuit; neither does it convey any license under its patent rights nor the rights of others. Vicor general policy does not recommend the use of its components in life support applications wherein a failure or malfunction may directly threaten life or injury. Per Vicor Terms and Conditions of Sale, the user of Vicor components in life support applications assumes all risks of such use and indemnifies Vicor against all damages. Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC modules and accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom power systems. Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor components are not designed to be used in applications, such as life support systems, wherein a failure or malfunction could result in injury or death. All sales are subject to Vicor’s Terms and Conditions of Sale, which are available upon request. Specifications are subject to change without notice. Vicor Corporation 25 Frontage Road Andover, MA 01810 USA Picor Corporation 51 Industrial Drive North Smithfield, RI 02896 USA Customer Service: [email protected] Technical Support: [email protected] Tel: 800-735-6200 Fax: 978-475-6715 Picor Corporation • picorpower.com PI2161 Rev1.1, Page 18 of 18