TPS2359RHHTG4

TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Full-Featured, Dual-Slot AdvancedMC™ Controller Check for Samples: TPS2359 FEATURES APPLICATIONS • • • • • • • • • • • • 1 2 • • • ATCA AdvancedMC™ Compliant Full Control for Two AdvancedMC™ Modules Independent 12-V Current Limit and Fast Trip 3.3-V and 12-V FET ORing for MicroTCA™ Internal 3.3-V Current Limit and ORing Power Good and Fault Reporting Through I2C I2C Programmable Fault Times and Current Limits FET Status Bits for all Channels 36-Pin PQFN Package 3-V and 12-V Interlock for AdvancedMC Compliance ATCA Carrier Boards MicroTCA™ Power Modules AdvancedMC™ Slots Systems Using 12 V and 3.3 V Base Stations DESCRIPTION The TPS2359 dual-slot hot-plug controllers perform all necessary power interface functions for two AdvancedMC™ (Advanced Mezzanine Card) modules. Two fully integrated 3.3-V channels provide inrush control, over-current protection, and FET ORing. Two 12-V channels provide the same functions using external FETs and sense resistors. The 3.3-V current limits are factory set to AdvancedMC™ compliant levels and the 12-V current limits are programmed using external sense resistors. The accurate current sense comparators of the TPS2359 satisfy the narrow ATCA™ AdvancedMC™ current limit requirements. Figure 1. TPS2359 Application Diagram CSD16406Q3 x 2 12 V in 12 V .005 AdvancedMC 422 ™ Slot A 100 100 3.3 V SENPA SETA SENMA PASSA BLKA OUT12A IN12A OUT3A EN3A 3v3 in 6810 SUM12A IN3A VDD3A SUM3A 3320 SDA VINT SCL TPS2359 AGND IRPT\ A0 GNDA 36 QFN A1 GNDB A2 6810 EN3B SUM12B 3v3 in IN3B SUM3B VDD3B 3320 IN12B OUT3B SENPB SETB SENMB PASSB BLKB OUT12B 3.3 V 422 100 100 AdvancedMC ™ Slot B .005 12 V in 12 V Optional ORing FETs for Redundant Systems 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. AdvancedMC, MicroTCA are trademarks of PICMG. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2008–2013, Texas Instruments Incorporated TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com ORDERING INFORMATION (1) (2) (1) DEVICE TEMPERATURE PACKAGE (2) ORDERING INFORMATION TPS2359 -40°C to 85°C QFN36 TPS2359RHH Add an R suffix to the device type for tape and reel. For the most current package and ordering information see the Package Option Addendum at the end of this document or see the TI Web site at www.ti.com. ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range (unless otherwise noted) PARAMETER VALUE PASSx, BLKx -0.3 to 30 IN12x; OUT12x; SENPx; SENMx; SETx; IRPT -0.3 to 17 IN3x; OUT3x; EN3x; VDDx; SUMx; SDA, SCL -0.3 to 5 AGND, GNDx -0.3 to 0.3 A0, A1, A2 0 to VINT SUMx 5 VINT -1 to 1 OUT3x (1) UNIT V mA Internally limited Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only. Functional operation of the device under any conditions beyond those indicated under recommended operating conditions is neither implied nor guaranteed. Exposure to absolute maximum rated conditions for extended periods of time may affect device reliability. ELECTROSTATIC DISCHARGE (ESD) PROTECTION TEST METHOD MIN Human Body Model (HBM) 2 Charged Device model (CDM) 0.5 UNITS kV DISSIPATION RATINGS PACKAGE θJA - High-k (°C/W) 36 QFN 35 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) PARAMETER VIN12x Payload power input voltage VIN3x MIN TYP MAX UNIT 8.5 12 15 Management power input voltage 3 3.3 4 VVDD3x,3 Management power supply voltage 3 3.3 IOUT3x Management power output current ISUMx Summing pin current PASSx pin board leakage current -1 VINT bypass capacitance TJ 2 4 165 100 1 Operating junction temperature range -40 Submit Documentation Feedback 1000 1 10 V mA μA 250 nF 125 °C Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS IN3A = IN3B = VDD3A = VDD3B = 3.3 V. IN12A = IN12B = SENPA = SENPB = SENMA = SENMB = SETPA = SETPB = 12 V. EN3A = EN3B = AGND = GNDA = GNDB = 0 V. SUM12A = SUM12B = 6.8 kΩ to ground. SUM3A = SUM3B = 3.3 kΩ to ground. All other pins open. All I2C bits at default values. Over free air temperature operating range and all voltages referenced to AGND, -40°C ≤ TA ≤ 85°C, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS ENABLE Inputs Threshold voltage, falling edge 1.2 1.3 1.4 V Hysteresis 20 50 80 mV 5 8 15 1 5 Pullup current EN3x = 0 V Input bias current EN3x = 5 V 3.3-V turn off time EN3x deasserts to VOUT3x < 1.0 V, COUT = 0 μF 10 12-V turn off time EN3x deasserts to VOUT12x < 1.0 V, COUT = 0 μF, QGATE = 35 nF 20 μA μs VINT Output voltage 0 < IVINT < 50 μA 2 2.3 2.8 10.2 10.5 10.8 2.7 2.8 2.9 V Power GOOD Comparators Threshold voltage Hysteresis 12xPG, falling OUT12x 3xPG, falling OUT3x 12xPG, measured at OUT12x 130 3xPG, measured at OUT3x V mV 50 Fault Timer Fault time bit weight 3xFT[4:0] = 12xFT[4:0] = 00001B Timer duty cycle = (fault time) / (retry period) 0.45 0.70% 0.77% ms 0.80% 12-V Summing node Input referred offset VSENMx = 10.8 – 13.2 V, VSENPx = VSENMx + 50 mV, measure VSETx – VSENMx Summing threshold 12xCL[3:0] = 1111B, VPASSx = 15 V Leakage current VSETx = VSENMx – 10 mV –2 0.66 2 0.675 mV 0.69 V 1 μA 50 52.5 mV 40 μA 100 120 mV 200 300 ns 12-V Current limit Current limit threshold RSUMx = 6.8 kΩ, RSETx = 422 Ω, increase ILOADx and measure VSENPx – VSENMx when VPASSx = 15 V Sink current in current limit VSUMx = 1 V, VPASSx = 12 V, measure IPASSx 20 Fast trip threshold Measure VSENPx – VSENMx 80 Fast turn-off delay 20-mV overdrive, CPASSx = 0 pF, tp50-50 Bleed down resistance VOUT = 6 V Bleed down threshold Timer start threshold VPASSx – VINx when fault timer starts 47.5 1.1 1.6 2.1 kΩ 75 100 130 mV 5 6 7 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 V 3 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) IN3A = IN3B = VDD3A = VDD3B = 3.3 V. IN12A = IN12B = SENPA = SENPB = SENMA = SENMB = SETPA = SETPB = 12 V. EN3A = EN3B = AGND = GNDA = GNDB = 0 V. SUM12A = SUM12B = 6.8 kΩ to ground. SUM3A = SUM3B = 3.3 kΩ to ground. All other pins open. All I2C bits at default values. Over free air temperature operating range and all voltages referenced to AGND, -40°C ≤ TA ≤ 85°C, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS 12-V UVLO UVLO rising IN12x rising 8.1 8.5 8.9 UVLO hysteresis IN12x falling 0.44 0.5 0.59 V 12-V BLOCKING Turn-on threshold Measure VSENPx – VOUTx 5 10 15 Turn-off threshold Measure VSENPx – VOUTx –5 –3 0 Turn-off delay 20-mV overdrive, CBLKx = 0 pF, tp50-50 200 300 mV ns 12-V Gate drivers (PASSx, BLKx) Output voltage VINx = VOUTx = 10 V 21.5 23 24.5 V Sourcing current VIN12x = VOUT12x = 10 V, VPASSx = VBLKx = 17 V 20 30 40 μA Fast turnoff, VPASSx = VBLKx = 14 V 0.5 1 6 14 25 mA 14 20 26 kΩ 5 10 15 ms Sinking current Pulldown resistance Sustained, VPASSx = VBLKx = 4 – 25 V In OTSD (at 150 °C) Fast turnoff duration A Safety gate pulldown IRF3710, slew S or D 15 V in 1 ms 1.25 V Startup time IN12x rising to PASSx and BLKx sourcing 0.25 ms 675 695 mV 290 500 mΩ 170 195 225 240 300 400 750 1300 280 400 500 Ω 75 100 130 mV 3.3-V Summing node Summing threshold 655 3.3-V Current limit On resistance IOUT3x = 150 mA Current limit RSUM3x = 3.3 kΩ , VOUT3x = 0 V Fast trip threshold Fast turn-off delay IOUT3x = 400 mA, tp50-50 Bleed down resistance VOUT3x = 1.65 V Bleed down threshold mA ns 3.3-V UVLO UVLO rising IN3x rising 2.65 2.75 2.85 V UVLO hysteresis IN3x falling 200 240 300 mV 3.3-V Blocking Turn-on threshold Measure VIN3x – VOUT3x 5 10 15 Turn-off threshold Measure VIN3x – VOUT3x –5 –3 0 ORing turn-on delay VIN3x = 3.3 V, VOUT3x = 3.5 V, OUT3x = 100 Ω to GND, 3ORON = 1. Remove 3.5 V from OUT3x. Measure time from VOUT3x thru 2.9 V to VOUT3x = 3.2 V 300 350 μs Fast turnoff delay 20 mV overdrive, tp50-50 250 350 ns 4 Submit Documentation Feedback mV Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS (continued) IN3A = IN3B = VDD3A = VDD3B = 3.3 V. IN12A = IN12B = SENPA = SENPB = SENMA = SENMB = SETPA = SETPB = 12 V. EN3A = EN3B = AGND = GNDA = GNDB = 0 V. SUM12A = SUM12B = 6.8 kΩ to ground. SUM3A = SUM3B = 3.3 kΩ to ground. All other pins open. All I2C bits at default values. Over free air temperature operating range and all voltages referenced to AGND, -40°C ≤ TA ≤ 85°C, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Currents (IINx + ISENPx + ISENMx + ISETx + IVDDx) All channels enabled IOUT3A = IOUT3B = 0 All channels disabled 3.1 4 2.0 2.8 mA Thermal Shutdown Whole-chip shutdown temperature TJ rising, IOUT3A = IOUT3B = 0 140 150 3.3-V channel shutdown temperature TJ rising, IOUT3A or IOUT3B in current limit 130 140 Hysteresis Whole chip or 3.3-V channel °C 10 Serial Interface (SDA, SCL, A0–2, IRPT Lower logic threshold A0 – A2 0.33 0.35 0.37 Upper logic threshold A0 – A2 1.32 1.35 1.38 Input pullup resistance A0 – A2, VAx = 0 V 400 700 1000 Input pulldown resistance A0 – A2, VAx = VINT 200 350 550 Input open-circuit voltage IAx = 0 V 0.5 0.8 1.0 Threshold voltage, rising SDA, SCL Threshold voltage, falling SDA, SCL 1.0 Hysteresis SDA, SCL 165 Leakage SDA, IRPT Input clock frequency SCL 2.3 V kΩ V mV 1 µA 400 kHz Figure 2. Signal and Pin Naming Convention SIGNAL AND PIN NAMING Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 5 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com DEVICE INFORMATION TPS2359 BLOCK DIAGRAMS R SENSE R SET SENPx SENMx SETx 100 100 PASSx BLKx OUT12x pgat\ 12dis 100 mv + Q Pump ~25 V 30 uA ogat 10 us + IN12x 30 uA 10 us Fault Timer Vcp Vcp 12dis FLT12x\ EN12x\ PG3\ RSUM 6800 W 675 mV x (12xCL/1111) + DCC R1/4[7] SUM12x 60 mA 10 mv + -3 mv OUT12x + R Q S Q ogat OUT 100 us + pgat\ oren vpg PG12x\ Figure 3. Payload Power Channel (two channels per device) 6 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Management Power Channel (two channels per device) 0.1 W IN3 OUT3 2.8 V + gat 96 W VDD3 en 30 mv 30 us + Q Pump 2 PG\ to I C 30 uA + vcp ~25 v 12dis Fault Timer vcp 30 us FLT \ to I 2 C Control from I 2 C SUM3 3300 + en EN3 vthoc - [ 675 mv nominal ] 3ORON 10 mv + -3 mv OUT3 R Q S Q gat + Common Circuitry IN12A VINT en por IN12B IN3A PREREG IN3B POR 2.2 V OUT12A OUT12B OUT3A OUT3B AGND GNDA GNDB SDA SCL A0-2 I2C & Control Logic Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 7 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Top View 36-Pin QFN BLKA OUT12A GNDA PASSA EN3A EN3B VDD3A IN3A 3A A0 12A 36 35 34 33 32 31 30 29 28 IN12A 1 27 OUT3A SENPA 2 26 A2 SETA 3 25 SUM3A SENMA 4 24 IRPT VINT 5 23 AGND SUM12A 6 22 VDD3B SDA 7 21 SUM3B SCL 8 20 A1 SUM12B 9 19 OUT3B 36 Pin QFN I 2C 8 12 13 14 15 16 17 GNDB PASSB SENMB SETB SENPB IN12B Submit Documentation Feedback 18 IN3B 11 OUT12B 12B 10 BLKB 3B Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 TPS2359 TERMINAL FUNCTIONS PIN # NAME TYPE DESCRIPTION 1 IN12A VDD 2 SENPA I 12A input sense 3 SETA I 12A current limit set 4 SENMA I 12A current limit sense 5 VINT I/O Bypass capacitor connection point for internal supply, pullup for A0 – A2 6 SUM12A I/O 12A summing node 7 SDA I/O Serial data input/output 12A input 8 SCL I 9 SUM12B I/O Serial data clock 12B summing node 10 BLKB O 12B blocking transistor gate drive 11 OUT12B I/O 12B output 12 GNDB GND 13 PASSB O 12B pass transistor gate drive 14 SENMB I 12B current limit sense 15 SETB I 12B current limit set 16 SENPB I 12B input sense 17 IN12B VDD 12B input 18 IN3B VDD 3B input 19 OUT3B I/O 3B output 20 A1 I 21 SUM3B I/O 3B summing node 22 VDD3B VDD 3B charge pump input 23 AGND GND Analog ground 12B power ground I2C address programming bit, LSB+1 24 IRPT O Active low interrupt, asserts when a PG deasserts or when a FLT\ asserts 25 SUM3A I/O 3A summing node 26 A2 I 27 OUT3A I/O 3A output 28 IN3A VDD 3A input 29 VDD3A VDD 3A charge pump input 30 EN3B I 3B enable, active high I2C address programming bit, LSB+2 31 EN3A I 3A enable, active high 32 PASSA O 12A pass transistor gate drive 33 GNDA GND 34 OUT12A I/O 12A output 35 BLKA O 12A blocking transistor gate drive 36 A0 I I2C address programming bit, LSB 12A power ground Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 9 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com DETAILED PIN DESCRIPTION A0, A1, A2 These three pins select one of 27 unique I2C addresses for address of the TPS2359. Each pin may be tied to ground, tied to the VINT pin, or left open. See TPS2359 I2C Interface section for details and Table 17 for specific addresses. AGND Ground pin for analog circuitry inside the TPS2359. BLKx Gate drive pin for the 12x channel BLK FET. This pin sources 30 μA to turn the FET on. An internal clamp prevents this pin from rising more than 14.5 V above OUT12x. Setting the ORENx bit low holds the BLKx pin low. BLKx is pulled low when PASSx is commanded low. EN3x Active-high enable input. Pulling this pin low turns off channel 3x by pulling the gate of the internal pass FET to GND. An internal 200-kΩ resistor pulls this pin up to VINTwhen disconnected. GNDx Ground pin for power circuitry associated with the 12x channel. These pins should connect to a ground plane shared with the AGND pin. IN12x Supply pin for channel 12x internal circuitry. IN3x Supply pin for channel 3x internal pass FET. IRPT Open drain output that pulls low when internal circuitry sets any of the eight status bits in Register 7. Reading Register 7 restores IRPT to its high-Z state. Register 7 contains FLT and PG bits for all 4 channels. OUT12x Senses the output voltage of the channel 12x path. OUT3x Output of the channel 3x internal pass FET. If DCC R6 [7] = 0, then OUT3x must be > 2.85 V before the 12-V channel is allowed to turn on. PASSx Gate drive pin for the 12x channel PASS FET. This pin sources 30 μA to turn the FET on. An internal clamps prevents this pin from rising more than 14.5 V above IN12x. SCL Serial clock input for the I2C interface. For details of the SCL line, see TPS2359 I2C Interface section. SDA Bidirectional I2C data line. For details of the SDA line, see TPS2359 I2C Interface section for details. SENMx Senses the voltage on the low side of the channel 12x current sense resistor. SENPx Senses the voltage on the high side of the channel 12x current sense resistor. SETx A resistor connected from this pin to SENPx sets the current limit level in conjunction with the current sense resistor and the resistor connected to the SUM12x pin, as described in 12-V thresholds – setting current limit and fast over current trip section. The internal amplifier attemps to keep VSET = VSENM. SUMx A resistor connected from this pin to ground forms part of the channel x current limit. As the current delivered to the load increases, so does the voltage on this pin. When the voltage on this pin reaches a threshold (by default 675 mV), the current limit amplifier acts to prevent the current from further increasing. VDD3x Supply pin for channel3x internal circuitry. VINT This pin connects to the internal 2.35-V rail. A 0.1-μF capacitor must be connected from this pin to ground. One can connect the A0–A2 pins to this supply to pull them high, but no other external circuitry should connect to VINT. 10 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 TYPICAL CHARACTERISTICS IDD at 25°C vs 12-V VDD 3-V CHANNEL ORING TURN-ON THRESHOLD 12 2.45 2.40 11 IDD - mA mV 2.35 10 9 2.30 2.25 2.20 2.15 8 -50 0 50 100 2.10 150 -50 TJ - Temperature - °C 0 50 100 150 VDD - 25°C Figure 4. Figure 5. 12-V CURRENT LIMIT THRESHOLD 3-V CHANNEL ORING TURN-OFF THRESHOLD 51.0 -1.0 50.8 -2.0 50.6 mV mV 0.0 -3.0 50.4 -4.0 50.2 50.0 -5.0 -50 0 50 100 150 -50 TJ - Temperature - °C 0 50 100 150 TJ - Temperature - °C Figure 6. Figure 7. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 11 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) 3-V IDD vs TEMPERATURE 12-V CHANNEL ORING TURN-OFF THRESHOLD 0.0 0.26 -1.0 0.25 -2.0 mV IDD - mA 0.24 0.23 -3.0 0.22 -4.0 0.21 -5.0 0.20 -50 -50 0 50 100 0 150 50 100 150 TJ - Temperature - °C TJ - Temperature - °C Figure 8. Figure 9. 12-V CURRENT (mA) vs TEMPERATURE 12-V CHANNEL ORING TURN-ON THRESHOLD 12.0 2.4 11.5 11.0 2.3 mV Current - mA 10.5 10.0 2.2 6 9.5 9.0 2.1 8.5 8.0 2.0 -50 -50 0 50 100 150 TJ - Temperature - °C Figure 10. 12 0 50 100 150 TJ - Temperature - °C Figure 11. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 TYPICAL CHARACTERISTICS (continued) Figure 12. OUT3A Startup Into 22-Ω (150 mA) 150-μF Load Figure 13. OUT3A Load Stepped from 165 mA to 240 mA Figure 14. OUT3A Short Circuit Under Full Load (165 mA) Zoom View Figure 15. OUT3A Short Circuit Under Full Load (165 mA) Wide View Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 13 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) 14 Figure 16. OUT3A Startup Into Short Circuit Figure 17. OUT12A Startup Into 500-Ω, 830-μF Load Figure 18. OUT12A Startup Into 80-Watt, 830-μF Load Figure 19. OUT12A Short Circuit Under Full Load (6.7 A) Wide View Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 TYPICAL CHARACTERISTICS (continued) Figure 20. OUT12A Short Circuit Under Full Load (6.7 A) Zoom View Figure 21. OUT12A Startup Into Short Circuit Figure 22. OUT12A Overloaded While Supplying 6.7 A Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 15 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com REFERENCE INFORMATION The TPS2359 has been designed to simplify compliance with the PICMG-AMC.R2.0 and PICMG-MTCA.0 specifications. These specifications were developed by the PCI Industrial Computer Manufacturers Group (PICMG). These two specifications are derivations of the PICMG-ATCA (Advanced Telecommunication Computing Architecture) specification originally released in December, 2002. PICMG-AMC Highlights • • • • • • • • • AMC - Advanced Mezzanine Cards Designed to Plug into ATCA Carrier Boards AdvancedMC™ Focuses on Low Cost 1 to 8 AdvancedMC™ per ATCA Carrier Board 3.3-V Management Power – Maximum Current Draw of 150 mA 12-V Payload Power – Converted to Required Voltages on AMC Maximum 80-W Dissipation per AdvancedMC™ Hotswap and Current Limiting Must Be Present on Carrier Board For Details, see www.picmg.org/v2internal/AdvancedMC.htm PICMG-MTCA Highlights • • • • • • MTCA – MicroTelecommunications Computing Architecture Architecture for Using AMCs Without an ATCA Carrier Board Up to 12 AMCs per System, Plus Two MCHs, Plus Two CUs Focuses on Low Cost All functions of ATCA Carrier Board Must Be Provided MicroTCA is also known as MTCA, mTCA, or uTCA For Details, see www.picmg.org/v2internal/microTCA.htm Control and Status Registers Ten 8 bit registers are used to control and read the status of the TPS2359. Registers 0 and 1 control the 12A channel and register 2 controls the 3A channel. Similarly, registers 3 and 4 control the 12B channel and register 5 controls the 3B channel. Register 6 contains eight general configuration bits. Read-only registers 7, 8, and 9 report back system status to the I2C controller. All ten registers use the I2C protocol and are organized as follows: Table 1. Top Level Register Functions 16 REG R/W SLOT VOLTAGE 0 R/W A 12 Set current limit, power good threshold, and OR functions of 12A. FUNCTION 1 R/W A 12 Set fault time, enable, and bleed down functions of 12A. 2 R/W A 3.3 Set fault time, enable, and bleed down functions of 3A. 3 R/W B 12 Set current limit, power good threshold, and OR functions of 12B. 4 R/W B 12 Set fault time, enable, and bleed down functions of 12B. 5 R/W B 3.3 Set fault time, enable, and bleed down functions of 3B. 6 R/W A, B 3.3, 12 System configuration controls. 7 R A, B 3.3, 12 Fault and PG outputs for 3A, 12A, 3B, 12B – these bits set IRPT. 8 R A, B 12 9 R A, B 3.3, 12 Over current and fast trip latches for 3A, 12A, 3B, 12B. Channel status indicators for 3A, 12A, 3B, 12B. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Summary of Registers Table 2. Summary of Registers BIT NAME DEFAULT DESCRIPTION Register 0 Read/Write channel 12A configuration 0 12ACL0 1 Clearing bit reduces 12A current limit and fast threshold by 5%. 1 12ACL1 1 Clearing bit reduces 12A current limit and fast threshold by 10%. 2 12ACL2 1 Clearing bit reduces 12A current limit and fast threshold by 20%. 3 12ACL3 1 Clearing bit reduces 12A current limit and fast threshold by 40%. 4 12APG0 1 Clearing bit reduces 12A power good threshold by 600mV. 5 12APG1 1 Clearing bit reduces 12A power good threshold by 1.2 V. 6 12AHP 0 Setting bit shifts 12A OR VTURNOFF from –3 mV to +3 mV nominal. 7 12AOR 1 Clearing bit turns off 12A ORing FET by pulling BLKA low. Register 1 Read/Write channel 12A configuration 0 12AFT0 1 Setting bit increases 12A fault time by 0.45 ms. 1 12AFT1 0 Setting bit increases 12A fault time by 0.9 ms. 2 12AFT2 0 Setting bit increases 12A fault time by 1.8 ms. 3 12AFT3 0 Setting bit increases 12A fault time by 3.6 ms. 4 12AFT4 0 Setting bit increases 12A fault time by 7.2 ms. 5 12AEN 0 Clearing bit disables 12A by pulling PASSA and BLKA to 0 V. 6 12AUV 0 Setting bit prevents enabling unless OUT12A < bleed down threshold. 7 12ADS 0 Clearing bit disconnects OUT12A bleed down resistor. Register 2 Read/Write channel 3A configuration 0 3AFT0 1 Setting bit increases 3A fault time by 0.45 ms. 1 3AFT1 0 Setting bit increases 3A fault time by 0.9 ms. 2 3AFT2 0 Setting bit increases 3A fault time by 1.8 ms. 3 3AFT3 0 Setting bit increases 3A fault time by 3.6 ms. 4 3AFT4 0 Setting bit increases 3A fault time by 7.2 ms. 5 3AEN 0 Clearing bit disables 3A. 6 3AUV 0 Setting bit prevents enabling unless OUT3A < bleed down threshold. 7 3ADS 0 Clearing bit disconnects OUT3A bleed down resistor. Register 3 Read/Write channel 12B configuration 0 12BCL0 1 Clearing bit reduces 12B current limit and fast threshold by 5%. 1 12BCL1 1 Clearing bit reduces 12B current limit and fast threshold by 10%. 2 12BCL2 1 Clearing bit reduces 12B current limit and fast threshold by 20%. 3 12BCL3 1 Clearing bit reduces 12B current limit and fast threshold by 40%. 4 12BPG0 1 Clearing bit reduces 12B power good threshold by 600 mV. 5 12BPG1 1 Clearing bit reduces 12B power good threshold by 1.2 V. 6 12BHP 0 Setting bit shifts 12B OR VTURNOFF from –3 mV to +3 mV nominal. 7 12BOR 1 Clearing bit turns off 12B ORing FET by pulling BLKB low. Register 4 Read/Write channel 12B configuration 0 12BFT0 1 Setting bit increases 12B fault time by 0.45 ms. 1 12BFT1 0 Setting bit increases 12B fault time by 0.9 ms. 2 12BFT2 0 Setting bit increases 12B fault time by 1.8 ms. 3 12BFT3 0 Setting bit increases 12B fault time by 3.6 ms. 4 12BFT4 0 Setting bit increases 12B fault time by 7.2 ms. 5 12BEN 0 Clearing bit disables 12B by pulling PASSB and BLKB to 0 V. 6 12BUV 0 Setting bit prevents enabling unless OUT12B < bleed down threshold. 7 12BDS 0 Clearing bit disconnects OUT12B bleed down resistor. Register 5 Read/Write channel 3B configuration Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 17 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Table 2. Summary of Registers (continued) BIT NAME DEFAULT 0 3BFT0 1 Setting bit increases 3B fault time by 0.45 ms. DESCRIPTION 1 3BFT1 0 Setting bit increases 3B fault time by 0.9 ms. 2 3BFT2 0 Setting bit increases 3B fault time by 1.8 ms. 3 3BFT3 0 Setting bit increases 3B fault time by 3.6 ms. 4 3BFT4 0 Setting bit increases 3B fault time by 7.2 ms. 5 3BEN 0 Clearing bit disables 3B. 6 3BUV 0 Setting bit prevents enabling unless OUT3B < bleed down threshold. 7 3BDS 0 Clearing bit disconnects OUT3B bleed down resistor. Register 6 Read/Write system configuration 0 PPTEST 0 12-V pulldown test pin. Setting pin pulls the PASSx and BLKx pins to 0 V. 1 FLTMODE 0 Clearing bit latchs off channels after over-current fault. Setting bit allows channels to automatically attempt restart after fault. 2 SPARE 0 This bit must always be set to 0. 3 3ORON 0 Setting bit enables 3A and 3B to prevent reverse current flow. 4 12VNRS 0 Non Redundant System in rush control bit. Setting bit allows increased inrush current in 12A and 12B with proper setting of 12xCLx bits. 5 AIRM 0 Setting this masking bit prevents REG7 bits 3:0 from setting IRPT. 6 BIRM 0 Setting this masking bit prevents REG7 bits 7:4 from setting IRPT. 7 DCC 0 Setting bit allows the 12 V channels to operate despite loss of 3.3 V. This bit should be low for uTCA and AMC applications Register 7 Read only latched IRPT channel status indicators, cleared on read 0 12APG 0 Latches high when OUT12A goes from above VTH_PG to below VTH_PG. 1 12AFLT 0 Latches high when 12A fault timer has run out. 2 3APG 0 Latches high when OUT3A goes from above VTH_PG to below VTH_PG. 3 3AFLT 0 Latches high when 3A fault timer has run out. 4 12BPG 0 Latches high when OUT12B goes from above VTH_PG to below VTH_PG. 5 12BFLT 0 Latches high when 12B fault timer has run out. 6 3BPG 0 Latches high when OUT3B goes from above VTH_PG to below VTH_PG. 7 3BFLT 0 Latches high when 3B fault timer has run out. Register 8 Read only latched overcurrent indicators, cleared on Read 0 12AOC 0 Latches high when 12A enters over-current. 1 12AFTR 0 Latches high if 12A fast trip threshold exceeded. 2 3AOC 0 Latches high when 3A enters over-current. 3 3AFTR 0 Latches high if 3A fast trip threshold exceeded. 4 12BOC 0 Latches high when 12B enters over-current. 5 12BFTR 0 Latches high if 12B fast trip threshold exceeded. 6 3BOC 0 Latches high when 3B enters over-current. 7 3BFTR 0 Latches high if 3B fast trip threshold exceeded. Register 9 Read only unlatched FET status indicators 18 0 12ABS - High indicates BLKA commanded high. 1 12APS - Low indicates VPASSA > VOUT12A + 6 V. 2 3ABS - Low indicates IN3A > OUT3A. 3 12BBS - High indicates BLKB commanded high. 4 12BPS - Low indicates VPASSB > VOUTB + 6 V. 5 3BBS - Low indicates IN3B > OUT3B. 6 3AGS - Low indicates channel 3A gate is driven on ( VGATE > ( VIN + 1.75 V ). 7 3BGS - Low indicates channel 3B gate is driven on ( VGATE > ( VIN + 1.75 V ). Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Detailed Description of Registers Register 0 Table 3. Register 0: Channel 12A Configuration (Read/Write) BIT NAME DEFAULT 0 12ACL0 1 Clearing bit reduces 12A current limit and fast threshold by 5%. DESCRIPTION 1 12ACL1 1 Clearing bit reduces 12A current limit and fast threshold by 10%. 2 12ACL2 1 Clearing bit reduces 12A current limit and fast threshold by 20%. 3 12ACL3 1 Clearing bit reduces 12A current limit and fast threshold by 40%. 4 12APG0 1 Clearing bit reduces 12A power good threshold by 600 mV. 5 12APG1 1 Clearing bit reduces 12A power good threshold by 1.2 V. 6 12AHP 0 Setting bit shifts 12A OR VTURNOFF from –3 mV to +3 mV nominal. 7 12AOR 1 Clearing bit turns off 12A ORing FET by pulling BLKA low. 12ACL[3:0] These four bits adjusts the 12A current limit and fast trip threshold using the I2C interface. Setting the bits to 1111B places the 12A current limit at its maximum level, corresponding to 675 mV at SUM12A. The fast trip threshold then equals 100 mV. Clearing all bits reduces the current limit and fast trip threshold to 25% of these maximums. 12APG[1:0] These two bits adjust the 12A power good threshold. Setting the bits to 11B places the power good threshold at its maximum level of 10.5 V . Setting the bits to 00B places the threshold at its minimum level of 8.7 V. The lower thresholds may prove desirable in systems that routinely experience large voltage droops. 12AHP Setting this bit moves the 12A ORing turn off threshold from –3 mV to +3 mV. A positive threshold prevents reverse current from flowing through the channel, but it may cause the ORing FET to repeatedly cycle on-and-off if the load cannot maintain the required positive voltage drop across the combined resistance of the external FETs and the sense resistor. For further information, see Adjusting Oring Turn Off threshold For High Power Loads section 12AOR Clearing this bit forces the BLKA pin low, keeping the 12A ORing FET off. Clearing this bit does not prevent current from flowing through the FET’s body diode. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 19 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Register 1 Table 4. Register 1: Channel 12A Configuration (Read/Write) BIT NAME DEFAULT 0 12AFT0 1 Setting bit increases 12A fault time by 0.45 ms. DESCRIPTION 1 12AFT1 0 Setting bit increases 12A fault time by 0.9 ms. 2 12AFT2 0 Setting bit increases 12A fault time by 1.8 ms. 3 12AFT3 0 Setting bit increases 12A fault time by 3.6 ms. 4 12AFT4 0 Setting bit increases 12A fault time by 7.2 ms. 5 12AEN 0 Clearing bit disables 12A by pulling PASSA and BLKA to 0 V. 6 12AUV 0 Setting bit prevents enabling unless OUT12A < bleed down threshold. 7 12ADS 0 Clearing bit disconnects OUT12A bleed down resistor. 12AFT[4:0] These five bits adjust the 12A channel fault time. The least-significant bit has a nominal weight of 0.45 ms, so fault times ranging from 0.45 ms (for code 00001B) to 13.95 ms (for code 11111B) can be programmed. The code xFT = 00000B should not be used. In general the shortest fault time that fully charges downstream bulk capacitors without generating a fault should be used. Once the load capacitors have fully charged, the fault time can be reduced to provide faster short circuit protection. See Setting Fault Time section. 12AEN This bit serves as a master enable for channel 12A. Setting this bit allows the 12A channel to operate normally. Clearing this bit disables the channel by pulling PASSA and BLKA low. 12AUV Setting this bit prevents channel 12A from turning on until OUT12A falls below the bleed down threshold of 100 mV. This feature ensures that downstream devices reset by requiring their supply voltage to fall to nearly zero before the channel can enable them. 12ADS Clearing this bit disconnects the bleed down resistor that otherwise connects from OUT12A to ground. Systems using redundant power supplies should clear 12ADS to prevent the bleed down resistor from continuously sinking current. 20 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Register 2 Table 5. Register 2: Channel 3A Configuration (Read/Write) BIT NAME DEFAULT 0 3AFT0 1 Setting bit increases 3A fault time by 0.45 ms. DESCRIPTION 1 3AFT1 0 Setting bit increases 3A fault time by 0.9 ms. 2 3AFT2 0 Setting bit increases 3A fault time by 1.8 ms. 3 3AFT3 0 Setting bit increases 3A fault time by 3.6 ms. 4 3AFT4 0 Setting bit increases 3A fault time by 7.2 ms. 5 3AEN 0 Clearing bit disables 3A. 6 3AUV 0 Setting bit prevents enabling unless OUT3A < bleed down threshold. 7 3ADS 0 Clearing bit disconnects OUT3A bleed down resistor. 3AFT[4:0] These five bits adjust the 3A channel fault time. The least-significant bit has a nominal weight of 0.45 ms, so fault times ranging from 0.45 ms (for code 00001B) to 13.95 ms (for code 11111B) can be programmed. The code xFT = 00000B should not be used. In general the shortest fault time that fully charges downstream bulk capacitors without generating a fault should be used. See Setting Fault Time section. 3AEN This bit serves as a master enable for channel 3A. Setting this bit allows the 3A channel to operate normally, provided the EN3A pin is also asserted. Clearing this bit disables the channel by removing gate drive to the internal pass FET, regardless of the state of the EN3A pin. 3AUV Setting this bit prevents channel 3A from turning on until OUT3A falls below the bleed down threshold of 100 mV. This feature ensures that downstream devices reset by requiring their supply voltage to fall to nearly zero before the channel can enable them. 3ADS Clearing this bit disconnects the bleed down resistor that otherwise connects from OUT3A to ground. Systems using redundant power supplies should clear 3ADS to prevent the bleed down resistor from continuously sinking current. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 21 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Register 3 Table 6. Register 3: Channel 12B Configuration (Read/Write) BIT NAME DEFAULT DESCRIPTION 0 12BCL0 1 Clearing bit reduces 12B current limit and fast threshold by 5%. 1 12BCL1 1 Clearing bit reduces 12B current limit and fast threshold by 10%. 2 12BCL2 1 Clearing bit reduces 12B current limit and fast threshold by 20%. 3 12BCL3 1 Clearing bit reduces 12B current limit and fast threshold by 40%. 4 12BPG0 1 Clearing bit reduces 12B power good threshold by 600 mV. 5 12BPG1 1 Clearing bit reduces 12B power good threshold by 1.2 V. 6 12BHP 0 Setting bit shifts 12B OR VTURNOFF from –3 mV to +3 mV nominal. 7 12BOR 1 Clearing bit turns off 12B ORing FET by pulling BLKB low. 12BCL[3:0] These four bits adjusts the 12B current limit and fast trip threshold using the I2C interface. Setting the bits to 1111B places the 12B current limit at its maximum level, corresponding to 675 mV at SUM12B. The fast trip threshold then equals 100 mV. Clearing all bits reduces the current limit and fast trip threshold to 25% of these maximums. 12BPG[1:0] These two bits adjust the 12B power good threshold. Setting the bits to 11B places the power good threshold at its maximum level of 10.5 V . Setting the bits to 00B places the threshold at its minimum level of 8.7 V. The lower thresholds may prove desirable in systems that routinely experience large voltage droops. 12BHP Setting this bit moves the 12B ORing turn off threshold from –3 mV to +3 mV. A positive threshold prevents reverse current from flowing through the channel, but it may cause the ORing FET to repeatedly cycle on-and-off if the load cannot maintain the required positive voltage drop across the combined resistance of the external FETs and the sense resistor. For further information, see Adjusting ORing Turn Off threshold For High Power Loads section. 12BOR Clearing this bit forces the BLKB pin low, keeping the 12B ORing FET off. Clearing this bit does not prevent current from flowing through the FET’s body diode. 22 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Register 4 Table 7. Register 4: Channel 12B Configuration (Read/Write) BIT NAME DEFAULT 0 12BFT0 1 Setting bit increases 12B fault time by 0.45 ms. DESCRIPTION 1 12BFT1 0 Setting bit increases 12B fault time by 0.9 ms. 2 12BFT2 0 Setting bit increases 12B fault time by 1.8 ms. 3 12BFT3 0 Setting bit increases 12B fault time by 3.6 ms. 4 12BFT4 0 Setting bit increases 12B fault time by 7.2 ms. 5 12BEN 0 Clearing bit disables 12B by pulling PASSB and BLKB to 0 V. 6 12BUV 0 Setting bit prevents enabling unless OUT12B < bleed down threshold. 7 12BDS 0 Clearing bit disconnects OUT12B bleed down resistor. 12BFT[4:0] These five bits adjust the 12B channel fault time. The least-significant bit has a nominal weight of 0.45 ms, so fault times ranging from 0.45 ms (for code 00001B) to 13.95 ms (for code 11111B) can be programmed. The code xFT = 00000B should not be used. In general the shortest fault time that fully charges downstream bulk capacitors without generating a fault should be used. Once the load capacitors have fully charged, the fault time can be reduced to provide faster short circuit protection. See Setting Fault Time section. 12BEN This bit serves as a master enable for channel 12B. Setting this bit allows the 12B channel to operate normally. Clearing this bit disables the channel by pulling PASSB and BLKB low. 12BUV Setting this bit prevents channel 12B from turning on until OUT12B falls below the bleed down threshold of 100 mV. This feature ensures that downstream devices reset by requiring their supply voltage to fall to nearly zero before the channel can enable them. 12BDS Clearing this bit disconnects the bleed down resistor that otherwise connects from OUT12B to ground. Systems using redundant power supplies should clear 12BDS to prevent the bleed down resistor from continuously sinking current. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 23 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Register 5 Table 8. Register 5: Channel 3B Configuration (Read/Write) BIT NAME DEFAULT 0 3BFT0 1 Setting bit increases 3B fault time by 0.45 ms. DESCRIPTION 1 3BFT1 0 Setting bit increases 3B fault time by 0.9 ms. 2 3BFT2 0 Setting bit increases 3B fault time by 1.8 ms. 3 3BFT3 0 Setting bit increases 3B fault time by 3.6 ms. 4 3BFT4 0 Setting bit increases 3B fault time by 7.2 ms. 5 3BEN 0 Clearing bit disables 3B. 6 3BUV 0 Setting bit prevents enabling unless OUT3B < bleed down threshold. 7 3BDS 0 Clearing bit disconnects OUT3B bleed down resistor. 3BFT[4:0] These five bits adjust the 3B channel fault time. The least-significant bit has a nominal weight of 0.45 ms, so fault times ranging from 0.45 ms (for code 00001B) to 13.95 ms (for code 11111B) can be programmed. The code xFT = 00000B should not be used. In general the shortest fault time that fully charges downstream bulk capacitors without generating a fault should be used. See Setting Fault Time section. 3BEN This bit serves as a master enable for channel 3B. Setting this bit allows the 3B channel to operate normally, provided the EN3B pin is also asserted. Clearing this bit disables the channel by removing gate drive to the internal pass FET, regardless of the state of the EN3B pin. 3BUV Setting this bit prevents channel 3B from turning on until OUT3B falls below the bleed down threshold of 100 mV. This feature ensures that downstream devices reset by requiring their supply voltage to fall to nearly zero before the channel can enable them. 3BDS Clearing this bit disconnects the bleed down resistor that otherwise connects from OUT3B to ground. Systems using redundant power supplies should clear 3BDS to prevent the bleed down resistor from continuously sinking current. 24 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Register 6 Table 9. Register 6: System Configuration (Read/Write) BIT NAME DEFAULT DESCRIPTION 0 PPTEST 0 12-V pulldown test pin. Asserting this pulls the PASSx and BLKx pins to 0 V. 1 FLTMODE 0 Clearing bit forces channels to latch off after over-current fault. Setting bit allows channels to automatically attempt restart after fault. 2 SPARE 0 This bit must always be set to 0. 3 3ORON 0 Setting bit enables 3A and 3B to prevent reverse current flow.Clearing bit disables 3A and 3B ORing. 4 12VNRS 0 Non Redundant System in rush control bit. Setting bit allows increased inrush current in 12A and 12B. 5 AIRM 0 Setting this masking bit prevents REG7 bits 3:0 from setting IRPT. 6 BIRM 0 Setting this masking bit prevents REG7 bits 7:4 from setting IRPT. 7 DCC 0 Setting bit allows the 12 V channels to operate despite loss of 3.3 V. For uTCA and AMC applications this bit should be low. PPTEST This bit is used for testing the fast turnoff feature of the PASSx and BLKx pins. Setting this bit enables the fast turnoff drivers for all four pins. Clearing this bit restores normal operation. PPTEST allows the fast turnoff drivers to operate at full current indefinitely, whereas they would normally operate for only about 15 S. While using PPTEST the energy dissipated in the fast turnoff drivers must be externally limited to 1 mJ per driver to prevent damage to the TPS2359. FLTMODE Setting this bit allows a channel to attempt an automatic restart after an overcurrent condition has caused it to time out and shut off. The retry interval equals approximately 100 times the programmed fault time. The FLTMODE bit affects all four channels. If cross-connection is enabled (DCC = 0), a fault on channel 3A turns off channel 12A, and a fault on channel 3B turns off channel 12B. If a 3.3-V channel automatically restarts because FLTMODE = 1, the associated 12-V channel remains disabled until its enable bit (12AEN or 12BEN) is cycled on and off. SPARE This bit must always be set to 0. 3ORON Setting this bit allows the 3.3-V ORing function to operate normally. Clearing this bit prevents the 3.3-V channels from disabling if their output voltage exceeds their input voltage . This bit is typically cleared for nonredundant systems. 12VNRS Setting this bit increases the current limit for either 12-V channel to its maximum value during the initial inrush period that immediately follows the enabling of the channel. During inrush, the current limit behaves as if 12xCL[3:0] = 1111B. After the current drops below this limit, signifying the end of the inrush period, the current limit returns to normal operation. AIRM Setting this bit prevents the 12APG, 12AFLT, 3APG, and 3AFLT bits from setting the IRPT pin. BIRM Setting this bit prevents the 12APG, 12BFLT, 3BPG, and 3BFLT bits from setting the IRPT pin. DCC Setting this bit disables cross-connection. If DCC = 0, when a 3.3-V channel experiences a fault, both it and its associated 12-V channel turn off. Specifically, a fault on channel 3A turns off channel 12A, and a fault on channel 3B turns off channel 12B. If DCC = 1, then the 12-V channels continue to operate even if their associated 3.3-V channels experience faults. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 25 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Register 7 Table 10. Register 7: Latched IRPT Channel Status Indicators (Read-only, cleared on read) BIT NAME DEFAULT 0 12APG 1 Latches high when OUT12A goes from above VTH_PG to below VTH_PG. DESCRIPTION 1 12AFLT 0 Latches high when 12A fault timer has run out. 2 3APG 1 Latches high when OUT3A goes from above VTH_PG to below VTH_PG. 3 3AFLT 0 Latches high when 3A fault timer has run out. 4 12BPG 1 Latches high when OUT12B goes from above VTH_PG to below VTH_PG. 5 12BFLT 0 Latches high when 12B fault timer has run out. 6 3BPG 1 Latches high when OUT3B goes from above VTH_PG to below VTH_PG. 7 3BFLT 0 Latches high when 3B fault timer has run out. 12APG This bit is set at startup and each time OUT12A drops below the PG threshold set by the 12APG[1:0] bits. It is cleared on read if OUT12A is above the PG threshold. If AIRM = 0, setting this bit asserts the IRPT pin. 12AFLT This bit is set if the fault timer on channel 12A has run out, and it remains set until Register 7 is read. If AIRM = 0, setting this bit asserts the IRPT pin. 3APG This bit is set at startup and each time OUT3A drops below the PG threshold. It is cleared on read if OUT3A is above the PG threshold. If AIRM = 0, setting this bit asserts the IRPT pin. 3AFLT This bit is set if the fault timer on channel 3A has run out, and it remains set until Register 7 is read. If AIRM = 0, setting this bit asserts the IRPT pin. 12BPG This bit is set at startup and each time OUT12B drops below the PG threshold set by the 12BAPG[1:0] bits. It is cleared on read if OUT12B is above the PG threshold. If BIRM = 0, setting this bit asserts the IRPT pin. 12BFLT This bit is set if the fault timer on channel 12B has run out, and it remains set until Register 7 is read. If BIRM = 0, setting this bit asserts the IRPT pin. 3BPG This bit is set at startup and each time OUT3B drops below the PG threshold.It is cleared on read if OUT3B is above the PG threshold. If BIRM = 0, setting this bit asserts the IRPT pin. 3BFLT This bit is set if the fault timer on channel 3B has run out, and it remains set until Register 7 is read. If BIRM = 0, setting this bit asserts the IRPT pin. 26 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Register 8 Table 11. Register 8: Latched Status Indicators (Read-only, cleared on read) BIT NAME DEFAULT DESCRIPTION 0 12AOC 0 Latches high when 12A enters over-current. 1 12AFTR 0 Latches high if 12A fast trip threshold exceeded. 2 3AOC 0 Latches high when 3A enters over-current. 3 3AFTR 0 Latches high if 3A fast trip threshold exceeded. 4 12BOC 0 Latches high when 12B enters over-current. 5 12BFTR 0 Latches high if 12B fast trip threshold exceeded. 6 3BOC 0 Latches high when 3B enters over-current. 7 3BFTR 0 Latches high if 3B fast trip threshold exceeded. 12AOC This bit is set if the voltage on the PASSA pin drops below the timer start threshold, signifying a current limit condition. This bit remains set until Register 8 is read. 12AFTR This bit is set if the voltage across the sense resistor for channel 12A exceeds the fast trip threshold. This bit remains set until Register 8 is read. 3AOC This bit is set if the gate-to-source voltage on the channel 3A pass FET drops low enough to start the fault timer. This bit remains set until Register 8 is read. 3AFTR This bit is set if the current through channel 3A exceeds the fast trip threshold. This bit remains set until Register 8 is read. 12BOC This bit is set if the voltage on the PASSB pin drops below the timer start threshold, signifying a current limit condition. This bit remains set until Register 8 is read. 12BFTR This bit is set if the voltage across the sense resistor for channel 12B exceeds the fast trip threshold. This bit remains set until Register 8 is read. 3BOC This bit is set if the gate-to-source voltage on the channel 3B pass FET drops low enough to start the fault timer. This bit remains set until Register 8 is read. 3BFTR This bit is set if the current through channel 3B exceeds the fast trip threshold. This bit remains set until Register 8 is read. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 27 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Register 9 Table 12. Register 9: Unlatched Status Indicators (Read-only) BIT NAME DEFAULT DESCRIPTION 0 12ABS - High indicates BLKA commanded high. 1 12APS - Low indicates VPASSA > VOUT12A + 6 V. 2 3ABS - Low indicates IN3A > OUT3A. 3 12BBS - High indicates BLKB commanded high. 4 12BPS - Low indicates VPASSB > VOUTB + 6 V. 5 3BBS - Low indicates IN3B > OUT3B. 6 3AGS - Low indicates channel 3A gate is driven on (VGATE > VIN + 1.75 V). 7 3BGS - Low indicates channel 3B gate is driven on (VGATE > VIN + 1.75 V). 12ABS This bit goes high when the 12A ORing logic commands the BLKA pin high (25 V) and the BLKA FET should be on. 12APS This bit goes low when the 12A PASS pin is above the timer start threshold (OUT12A + 7 V), indicating that the 12A PASS FET should be on. 3ABS This bit goes low when the 3A ORing logic commands the pass 3A FET on, indicating that a reverse blocking condition does not exist. 12BBS This bit goes high when the 12B ORing logic commands the BLKB pin high ( 25 V ) and the BLKB FET should be on. 12BPS This bit goes low when the 12B PASS pin is above the timer start threshold (OUT12B + 7 V), indicating that the 12B PASS FET should be on. 3BBS This bit goes low when the 3B ORing logic commands the 3B pass FET on, indicating that a reverse blocking condition does not exist. 3AGS This bit goes low when the 3A FET gate-to-source voltage exceeds 1.75 V, indicating that the 3A FET should be on. 3BGS This bit goes low when the 3B FET gate-to-source voltage exceeds 1.75 V, indicating that the 3B FET should be on. 28 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 APPLICATION INFORMATION Introduction The TPS2359 controls two 12-V power paths and two 3.3-V power paths. Each power path can draw from a single common supply, or from two independent supplies. The TPS2359 occupies a 36-pin QFN package. An I2C interface not only enables the implementation of two AdvancedMC™ slots using one small integrated circuit, but it also provides many opportunities for design customization. The following sections describe the main functions of the TPS2359 and provide guidance for designing systems around this device. Control Logic and Power-On Reset The TPS2359's circuitry, including the I2C interface, draws power from an internal bus fed by a preregulator. A capacitor attached to the VINT pin provides decoupling and output filtering for this preregulator. It can draw power from any of four inputs (IN12A, IN12B, IN3A, or IN3B) or from any of four outputs (OUT12A, OUT12B, OUT3A, or OUT3B). This feature allows the internal circuitry to function regardless of which channels receive power, or from what source. The four external FET drive pins (PASSA, PASSB, BLKA, and BLKB) are held low during startup to ensure that the two 12-V channels remain off. The internal 3.3-V channels are also held off. When the voltage on the internal VINT rail exceeds approximately 1 V, the power-on reset circuit loads the internal registers with the default values listed in Detailed Description of Registers section. Enable Functions Table 13 lists the specific conditions required to enable each of the four channels of the TPS2359. The 3.3-V channels each have an active-high enable pin with a 200-kΩ internal pullup resistor. The enable pin must be pulled high, or allowed to float high, in order to enable the channel. The I2C interface includes an enable bit for each of the four channels. The bit corresponding to a channel must be set in order to enable it. All four channels also include bleed down threshold comparators. Setting the bleed down control bit ensures that a channel cannot turn on until its output voltage drops below about 100 mV. This feature supports applications in which removal and restoration of power re-initializes the state of downstream loads. The 12-V channels also include a crossconnection feature to support PICMG.AMC™ and MicroTCA™ requirements. When enabled, this feature ensures that when a 3.3-V output drops below 2.85 V the associated 12-V channel will automatically shut off. This feature can be disabled by setting the DCC bit in Register 6. Table 13. Enable Requirements Channel Enable pins Enable bits Bleed down 3A EN3A > 1.4 V 3AEN = 1 OUT3A < 0.1 V or 3AUV = 0 3B EN3B > 1.4 V Cross connection 3BEN = 1 OUT3B < 0.1 V or 3BUV = 0 12A 12AEN = 1 OUT12A < 0.1 V or 12AUV = 0 3APG = 0 or DCC = 1 12B 12BEN = 1 OUT12B < 0.1 V or 12BUV = 0 3BPG = 0 or DCC = 1 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 29 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Fault, Power Good, Overcurrent, and FET Status Bits The TPS2359 I2C interface includes six status bits for each channel, for a total of 24 bits. These status bits occupy registers 7, 8, and 9. The following table summarizes the locations of these bits: Table 14. TPS2359 Status Bit Locations (1) 12A 3A Power Good (PG) R7[0] R7[2] R7[4] R7[6] Overcurrent Time out Fault (FLT) R7[1] R7[3] R7[5] R7[7] Momentary Overcurrent (OC) R8[0] R8[2] R8[4] R8[6] Overcurrent Fast Trip (FTR) R8[1] R8[3] R8[5] R8[7] 12-V Block FET Status (12xBS) R9[0] 12-V Pass FET Status (12xPS) R9[1] FUNCTION 12B 3B REGISTER [bit] R9[3] R9[4] 3-V Block Status (3xBS) R9[2] R9[5] 3-V Gate Status (3xGS) R9[6] R9[7] (1) For a description of each bit, refer to Detailed Description of Registers section. Current Limit and Fast Trip Thresholds All four channels monitor current by sensing the voltage across a resistor. The 3.3-V channels use internal sense resistors with a nominal value of 290 mΩ. The 12-V channels use external sense resistors that typically lie in the range of 4 - 10 mΩ. Each channel features two distinct thresholds: a current limit threshold and a fast trip threshold. The current limit threshold sets the regulation point of a feedback loop. If the current flowing through the channel exceeds the current limit threshold, then this feedback loop reduces the gate-to-source voltage imposed on the pass FET. This causes the current flowing through the channel to settle to the value determined by the current limit threshold. For example, when a module first powers up, it draws an inrush current to charge its load capacitance. The current limit feedback loop ensures that this inrush current does not exceed the current limit threshold. The current limit feedback loop has a finite response time. Serious faults such as shorted loads require a faster response in order to prevent damage to the pass FETs or voltage sags on the supply rails. A comparator monitors the current flowing through the sense resistor, and if it ever exceeds the fast trip threshold, then it immediately shuts off the channel. The channel turns back on slowly, allowing the current limit feedback loop time to respond. One normally sets the fast trip threshold some 2 – 5 times higher than the current limit. 30 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 3.3V Current Limiting The 3.3-V management power channels include internal pass FETs and current sense resistors. The onresistance of a management channel - including pass FET, sense resistor, metallization resistance, and bond wires - typically equals 290 mΩ and never exceeds 500 mΩ. The AdvancedMC™ specification allows a total of 1 Ω between the power source and the load. The TPS2359 never consumes more than half of this budget. The 3.3-V fast trip function protects the channel against short-circuit events. If the current through the channel exceeds a nominal value of 300 mA, then the TPS2359 immediately disables the internal pass transistor and then allows it to slowly turn back on into current limiting. The 3.3-V current limit function internally limits the current to comply with the AdvancedMC™ and MicroTCA™ specifications. External resistor RSUM3x allows the user to adjust the current limit threshold. The nominal current limit threshold ILIMIT equals I LIMIT = 650V RSUM 3 x (1) A 3320-Ω resistor gives a nominal current limit of ILIMIT = 195 mA which complies with AdvancedMC™ and MicroTCA™ specifications. This resistance corresponds to an EIA 1% value. Alternatively, a 3.3-kΩ resistor will also suffice. Whenever a 3.3-V channel enters current limit, its fault timer begins to operate (see Fault Timer Programming section). The 3.3-V over-temperature shutdown trips if a 3.3-V channel remains in current limit so long that the die temperature exceeds approximately 140°C. When this occurs, any 3.3-V channel operating in current limit turns off until the chip cools by approximately 10°C. This feature prevents a prolonged fault on one 3.3-V channel from disabling the other 3.3-V channel, or disabling either of the 12-V channels. 3.3-V ORing The 3.3-V channels limit reverse current flow by sensing the input-to-output voltage differential and turning off the internal pass FET when this differential drops below -3 mV, which corresponds to a nominal reverse current flow of 10 mA. The pass FET turns back on when the differential exceeds +10 mV. These thresholds provide a nominal 13 mV of hysteresis to help prevent false triggering. This feature allows the implementation of redundant power supplies (also known as supply ORing). If the 3.3-V channels do not use redundant supplies, then one can clear the 3ORON bit to disable the ORing circuitry. This precaution eliminates the chance that transients might trigger the ORing circuitry and upset system operation. 12-V Fast Trip and Current Limiting Figure 23 shows a simplified block diagram of the circuitry associated with the fast trip and current limit circuitry within a 12-V channel. Each 12-V channel requires an external N-channel pass FET and three external resistors. These resistors allow the user to independently set the fast trip threshold and the current limit threshold, as described below. The 12-V fast trip function protects the channel against short-circuit events. If the voltage across external resistor RSENSE exceeds the 100-mV fast trip threshold, then the TPS2359 immediately disables the pass transistor. The 12xCL bits set the magnitude of the fast trip threshold. When 12xCL = 1111B, the fast trip threshold nominally equals 100 mV. The fast trip current IFT corresponding to this threshold equals I FT = 100mV RSENSE (2) Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 31 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com The recommended value of RSENSE = 5 mΩ sets the fast trip threshold at 20 A for 12xCL = 1111B. This choice of sense resistor corresponds to the maximum 19.4-A inrush current allowed by the MicroTCA™ specification. The 12-V current limit function regulates the PASSx pin voltage to prevent the current through the channel from exceeding ILIMIT. The current limit circuitry includes two amplifiers, A1 and A2, as shown in Figure 23. Amplifier A1 forces the voltage across external resistor RSET to equal the voltage across external resistor RSENSE. The current that flows through RSET also flows through external resistor RSUM, generating a voltage on the 12SUMx pin equal to: æR R V12 SUMx = ç SENSE SUM RSET è ö ÷ I SENSE ø (3) Amplifier A2 senses the voltage on the 12SUMx pin. As long as this voltage is less than the reference voltage on its positive input (nominally 0.675 V for 12xCL = 1111B), the TPS2359 sources current to PASSx. When the voltage on the 12SUMx pin exceeds the reference voltage, amplifier A2 begins to sink current from PASSx. The gate-to-source voltage of the pass FET drops until the the voltages on the two inputs of amplifier A2 balance. The current flowing through the channel then nominally equals: æ ö RSET I LIMIT = ç ÷ ´ 0.675V è RSUM RSENSE ø RSET (4) I R R = LIM SUM SENSE 0.675 (5) The recommended value of RSUM is 6810 Ω. This resistor should never equal less than 675 Ω to prevent excessive currents from flowing through the internal circuitry. Using the recommended values of RSENSE = 5 mΩ and RSUM = 6810 Ω gives: I LIMIT = ( 0.0198 A ) ´ RSET W (6) A system capable of powering an 80-Watt AdvancedMC™ module should provide 8.25 A, +/- 10%, according to MicroTCA™ specifications. The above equation suggests RSET = 417 Ω. The nearest 1% EIA value equals 422 Ω. The selection of RSET for MicroTCA™ power modules is described in the Redundant vs. Non-redundant Inrush Current Limiting section. R SENSE IN12x R SET SETx 100 SENPx SENMx PASSx + 100 mV Fast Trip Comparator + A1 Current Limit Amp 60 uA 675 mV 30 uA + A2 SUM12x R SUM Figure 23. 12-V Channel Threshold Circuitry 32 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Redundant vs Non-Redundant Inrush Current Limiting The TPS2359 can support either redundant or non-redundant systems. Redundant systems generally use a single fixed current limit, as described above. Non-redundant systems can benefit from a higher current limit during inrush to compensate for the lack of a redundant supply. The MicroTCA™ standard allows up to 19.4 A for up to 200 ms in non-redundant systems, while limiting individual supplies in redundant systems to 9.1 A at all times. One can optimize the performance of the system for either application by properly setting the 12VNRS bit that controls inrush limiting. The ability to change the inrush profile using 12VNRS makes it possible to reconfigure a controller for redundant or non-redundant operation with a single bit. This is particularly useful for MicroTCA Power Modules which may be deployed in redundant or non-redundamnt systems. The 12VNRS bit affects the value of the 12xCL bits during inrush. Setting 12VNRS causes the current limit threshold and fast trip threshold to behave as if 12xCL = 1111B during inrush. Once the current flowing through the channel falls below the current limit threshold, the current limit threshold and fast trip threshold correspond to the actual values of the 12xCL bits. 12VNRS = X 12xCL[3:0] = 1111B IMAX If 12xCL[3:0] = 1111B, 12VNRS has no effect .6IMAX IMAX .6IMAX .6IMAX B T 0 12VNRS = 0 12xCL[3:0] = 0111B IMAX A 0 ILIMIT ILIMIT ILIMIT Figure 24 helps illustrate the behavior of the 12VNRS bit. Figure 24A shows that setting the 12xCL bits to 1111B results in a current limit equal to IMAX. Figure 24B shows how the 12xCL bits affect the current limit when the 12VNRS bit is cleared. Setting 12xCL = 0111B reduces the current limit to 60% of IMAX. Figure 24C shows how the 12xCL bits affect the current limit when the 12VNRS bit is set. The current limit initially equals IMAX, but as soon as the current drops below this level, the current limit resets to 60% of IMAX and remains there so long as the channel remains enabled. TFAULT C T 0 0 TFAULT 12VNRS = 1 12xCL[3:0] = 0111B 0 T 0 TFAULT Figure 24. Current Limits in Redundant and Non-Redundant Systems Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 33 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Example 1: Set up 12A to start into an 80 W load and charge a 1600 uF capacitor in less than 3 ms. Set an operational ILIMIT of 8.25 A +/ - 10%. First, calculate how much current is needed for capacitor charging and powering the load; ISTARTUP = ICHARGE + ILOAD = 6.4A + 6.67 A = 13.7 A Where; ICHARGE = CV/T = 1600uF x 12V / .003 s = 6.4 A ILOAD = PLOAD / VLOAD = 80 W / 12V = 6.67 A Now calculate RSET for an ILIMIT of 13.7 A. RSET = ( ILIMIT x RSENSE x RSUM ) / 0.675 = 691 ! " ( closest 1% value = 698 ! ) Where; RSUM = 6810 ! " RSENSE = 5 m! Now ILIMIT = 0.675RSET / ( RSUM RSENSE ) = 13.83 A If R0 [3:0] are set to 0111 and R6 [4] = 1 the current limit will drop to 60% of the programmed maximum after dropping out of current limit following inrush. The operational current limit is now; ILIMIT = 0.6 x IINRUSH = 0.6 x 13.83 = 8.3 A The 8.3 A limit complies with 8.25 A +/ - 10 %. Note - These calculations use all nominal values and neglect di/dt rates at turn on. Figure 25. Inrush Current Limiting Example 1 34 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Example 2: Set up 12A to startup into an 80 W load and charge a 1600 uF at not more than 17 A nominal. Then drop to an operational ILIMIT of 8.25 A +/ 10%. ISTARTUP = 17 A First, the correct RSET must be found to set maximum ILIMIT to less than 17 A. RSET = ( ILIMIT x RSENSE x RSUM ) / 0.675 = 857 ! " ( closest 1% value = 845 ! ) Where; RSUM = 6810 ! " RSENSE = 5 m! Now ILIMIT = 0.675RSET / ( RSUM RSENSE ) = 16.75 A Neglecting current slew time, this will charge the 1600 uF capacitor in 1.9 ms. If R0 [3:0] are set to 0101 and R6 [4] = 1 the current limit will drop to 50% of the programmed maximum after dropping out of current limit following inrush. The operational current limit is now; ILIMIT = 0.5 x IINRUSH = 0.5 x 16.75 = 8.38 A The new 8.38 A current limit is within the spec of 8.25 A +/ - 10 %. Note - These calculations use all nominal values. Figure 26. Inrush Current Limiting Example 2 Table 15. Configuring 12-V Current Limits in Non-Redundant Systems ILIMIT - INRUSH 12VNRS RSET 12xCLx [3:0] R6[4]=0 R6[4]=1 8.17 ILIMIT OPERATIO NAL 12VNRS = 1 CBULK CHARGE TIME (ms) PLOAD (W) 8.17 FAULT TIME (ms) 800 μF 1600 μF 800 μF 1600 μF 80 6.4 12.8 8.5 17 412 1111 8.17 698 111 13.84 8.3 8.3 80 1.34 2.68 2 3.5 845 101 16.75 8.38 8.38 80 0.95 1.9 1.5 3 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 35 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Multiswap Operation in Redundant Systems TheTPS2359 features an additional mode of operation called Multiswap redundancy. This technique does not require a microcontroller, making it simpler and faster than the redundancy schemes described in the MicroTCA™ standard. Multiswap is especially attractive for AdvancedMC™ applications requiring redundancy, but need not comply with the MicroTCA™ power module standard. In order to implement multiswap redundancy, connect the SUM pins of the redundant channels together and tie a single RSUM resistor from this node to ground. The current limit thresholds now apply to the sum of the currents delivered by the redundant supplies. When implementing multiswap redundancy on 12-V channels, all of the channels must use the same values of resistors for RSENSE and RSET. Figure 27 compares the redundancy technique advocated by the MicroTCA™ specification with multiswap redundancy. MicroTCA™ redundancy independently limits the current delivered by each power source. The current drawn by the load cannot exceed the sum of the current limits of the individual power sources. Multiswap redundancy limits the current drawn by the load to a fixed value regardless of the number of operational power sources. Removing or inserting power sources within a multiswap system does not affect the current limit seen by the load. MicroTCA TM Redundancy Power Source 2 mC TPS2359 SUM3x SUM12x TPS2359 SUM3x SUM12x RSUM12x mC SUM12x RSUM12x SUM3x RSUM3x RSUM12x SUM12x TPS2359 Power Source 2 Backplane SUM3x RSUM3x TPS2359 Power Source 1 RSUM3x Power Source 1 Multiswap Redundancy Backplane Figure 27. MicroTCA Redundancy vs. Multiswap Redundancy 36 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 12-V Inrush Slew Rate Control As normally configured, the turn-on slew rate of the 12-V channel output voltage VOUT12x equals: dVout I src @ dt Cg (7) where ISRC equals the current sourced by the PASSx pin (nominally 30 μA) and Cg equals the effective gate capacitance. For purposes of this computation, one can assume that the effective gate capacitance approximately equals the reverse transfer capacitance, CRSS. To reduce the slew rate, increase Cg by connecting additional capacitance from PASSx to ground. Place a resistor of at least 1000 Ω in series with the additional capacitance to prevent it from interfering with the fast turn off of the FET. Since gate charge current is 30 µA and the TPS2359 current limits at start up it is unlikely that this RC is required. R SENSE IN12 100 C R > 1k PASS Figure 28. RC Slew Rate Control Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 37 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com 12-V ORing Operation for Redundant Systems The 12-V channels use external pass FETs to provide reverse current blocking. The TPS2359 pulls the BLKx pin high when the input-to-output differential voltage IN12x-OUT12x exceeds a nominal value of 10 mV, and it pulls the pin low when this differential falls below a nominal value of -3 mV. These thresholds provide a nominal 13 mV of hysteresis to help prevent false triggering. The source of the blocking FET connects to the source of the pass FET, and the drain of the blocking FET connects to the load. This orients the body diode of the blocking FET such that it conducts forward current and blocks reverse current. The body diode of the blocking FET does not normally conduct current because the FET turns on when the voltage differential across it exceeds 10 mV. Applications that do not use the blocking FET should clear the associated 12xOR bit to turn off the internal circuitry that drives the BLKx pin. 12-V ORing for High-Power Loads The 12AHP and 12BHP bits adjust the ORing turn-off thresholds of the 12A and 12B channels, respectively. Clearing these bits sets the ORing turn-off thresholds to the default nominal value of -3 mV. Setting these bits shifts the thresholds up by 6 mV to a nominal value of +3 mV (Figure 29). Shifting the turn-off threshold to a postive value ensures that the blocking FET shuts off before any reverse current flows. A light load may not draw sufficient current to keep the input-to-output differential VIN12x–OUT12x above 3 mV. When this happens, the blocking FET shuts off and then the differential voltage increases until it turns back on. This process endlessly repeats, wasting power and generating noise. Therefore 12AHP or 12BHP should only be set for high-power loads that satisfy the relationship I LOAD > 10mV RSENSE + RDSonPASS + RDSonBLK (8) where ILOAD equals the current drawn by the load, RSENSE equals the value of the sense resistor, RDS(on)PASS equals the maximum on-resistance of the pass FET, and RDSo(n)BLK equals the maximum on-resistance of the blocking FET. Example: If RSENSE = RHSFET = RORFET = 5 mΩ then a high-power load must always draw at least 667 mA. Most, although not all, AdvancedMC™ loads can benefit from using the high-power bits 12AHP and 12BHP. 12xHP = 1 VGATE VGATE 12xHP = 0 Gnd 10 mV V OR 25 V 3 mV 10 mV Gnd - 3 mV 25 V V OR Figure 29. 12-V ORing Thresholds - High Power vs. Low Power 38 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Internal Bleed-Down Resistors and Bleed-Down Thresholds The TPS2359 includes two features intended to support downstream loads that require removal and reapplication of power to properly reset their internal circuitry. Disabling and re-enabling a channel of the TPS2359 will not necessarily reset such a load because the capacitance attached to the output bus may not fully discharge. The TPS2359 includes four bleed down comparators that monitor the output rails through pins OUT12A, OUT12B, OUT3A, and OUT3B. The I2C interface includes four bits that enable these comparators — 3ADS, 3BDS, 12ADS, and 12BDS. Enabling a bleed down comparator prevents its corresponding channel from turning on until the output voltage drops below about 100 mV. This precaution ensures that the output rail drops so low that all downstream loads properly reset. In case the downstream load cannot quickly bleed off charge from the output capacitance, the TPS2359 also includes bleed down resistors connected to each output rail through pins OUT12A, OUT12B, OUT3A, and OUT3B. Internal switches connect these resistors from their corresponding rails to ground when the channels are disabled, providing that one sets the appropriate bits in the I2C interface. These bits are named 12AUV, 12BUV, 3AUV, and 3BUV. Clearing these bits ensures that the corresponding resistors never connect to their buses. If redundant supplies connect to an output, then one should clear the corresponding bleed-down threshold and bleed-down resistor bits. Failing to clear the bleed-down threshold bit will prevent the channel from enabling so long as the redundant supply continues to hold up the output rail. Failing to clear the bleed-down resistor bit will cause current to continually flow through the resistor when the TPS2359 is disabled and the redundant supply holds up the output bus. Fault Timer Programming Each of the TPS2359's four channels includes a fault timer. This timer is counting whenever VGS of the FET is less than 6 ±1 V. If the channel remains in current limit so long that the fault timer runs out, then the channel turns off the pass FET and reports a fault condition by means of the xFLT bit in the I2C interface. The four fault timers are independently programmable from 0.45 to 13.95 ms in steps of 0.45 ms using the appropriate xFT bits. A code of xFT = 00001B corresponds to a time of 0.45 ms. The code xFT = 00000B should not be used. The locations of the fault timer programming bits are: Table 16. Fault Time Control Bits CHANNEL REGISTER [bit] 7.2 ms 3.6 ms 1.8 ms 0.9 ms 0.45 ms 12A R1[4] R1[3] R1[2] R1[1] R1[0] 12B R4[4] R4[3] R4[2] R4[1] R4[0] 3A R2[4] R2[3] R2[2] R2[1] R2[0] 3B R5[4] R5[3] R5[2] R5[1] R5[0] The user should select the shortest fault times sufficient to allow down-stream loads and bulk capacitors to charge. Shorter fault times reduce the stresses imposed on the pass FETs under fault conditions. This consideration may allow the use of smaller and less expensive pass FETs for the 12-V channels. The TPS2359 supports two modes of fault timer operation. Clearing the FLTMODE bit causes a channel to latch off whenever its fault timer runs out. The channel remains off until it has been disabled and re-enabled (see Enable Functions section). The TPS2359 operates in this manner by default. Setting the FLTMODE bit causes a faulted channel to automatically attempt to turn back on after a delay roughly one hundred times the fault time. This process repeats until either the fault disappears or the user disables the channel. The pass FET for a 12-V channel with a shorted output must therefore continuously dissipate Pfault » 0.01 × VIN 12 x I CL (9) where VIN12x equals the voltage present at the input of the 12-V channel and ICL equals the current limit setting for this channel (the inrush current if 12VNRS is set). Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 39 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com TPS2359 I2C Interface The TPS2359 digital interface meets the specifications for an I2C bus operating in the high-speed mode. One can configure the interface to recognize any one of 27 separate I2C addresses using the A0, A1, and A2 pins (Table 17 I2C Addressing). These pins accept any of three distinct voltage levels. Connecting a pin to ground generates a low level (L). Connecting a pin to VINT generates a high level (H). Leaving a pin floating generates a no-connect level (NC). Table 17. I2C Addressing I2C (Device) ADDRESS EXTERNAL PINS A2 A1 A0 Dec Hex Binary L L L 8 8 1000 L L NC 9 9 1001 L L H 10 0A 1010 L NC L 11 0B 1011 L NC NC 12 0C 1100 L NC H 13 0D 1101 L H L 14 0E 1110 L H NC 15 0F 1111 L H H 16 10 10000 NC L L 17 11 10001 NC L NC 18 12 10010 NC L H 19 13 10011 NC NC L 20 14 10100 NC NC NC 21 15 10101 NC NC H 22 16 10110 NC H L 23 17 10111 NC H NC 24 18 11000 NC H H 25 19 11001 H L L 26 1A 11010 H L NC 27 1B 11011 H L H 28 1C 11100 H NC L 29 1D 11101 H NC NC 30 1E 11110 H NC H 31 1F 11111 H H L 32 20 100000 H H NC 33 21 100001 H H H 34 22 100010 The I2C hardware interface consists of two wires known as serial data (SDA) and serial clock (SCL). The interface is designed to operate from a nominal 3.3-V supply. SDA is a bidirectional wired-OR bus that requires an external pullup resistor, typically a 2.2-kΩ resistor connected from SDA to the 3.3-V supply. The I2C protocol assumes one device on the bus acts as a master and another device acts as a slave. The TPS2359 supports only slave operation with two basic functions called register write and register read. 40 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Data Stop Register Number Ack 0 Ack A ddress Ack Start Register Write: Figure 30 Format of a Register Writeshows the format of a register write. First the master issues a start condition, followed by a seven-bit I2C address. Next the master writes a zero to signify that it wishes to conduct a write operation. Upon receiving an acknowledge from the slave, the master writes the eight-bit register number across the bus. Following a second acknowledge, the master writes the eight-bit data value for the register across the bus. Upon receiving a third acknowledge, the master issues a stop condition. This action concludes the register write. Figure 30. Format of a Register Write. Shaded Regions Denote Bus Control by TPS2358/9 Data Ack 1 Stop I2C Address Ack Register Number Ack 0 Start I2C Address Ack Start Register Read: Figure 31 Format of a Register Read shows the format of a register read. First the master issues a start condition followed by a seven-bit I2C address. Next, the master writes a zero to signify that it will conduct a write operation. Upon receiving an acknowledge from the slave, the master writes the eight-bit register number across the bus. Following a second acknowledge, the master issues a repeat start condition. Then the master issues a seven-bit I2C address followed by a one to signify that it will conduct a read operation. Upon receiving a third acknowledge, the master releases the bus to the TPS2359. The TPS2359 then writes the eight-bit data value from the register across the bus. The master acknowledges receiving this byte and issues a stop condition. This action concludes the register read. Figure 31. Format of a Register Read. Shaded Regions Denote Bus Control by TPS2358/9 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 41 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Using the TPS2359 to Control Two AdvancedMC™Slots The TPS2359 has been designed for use in systems under I2C control. Figure 32 shows the TPS2359 in a typical system implementing redundant power sources. A non-redundant application would omit the blocking FETs and leave the BLKx pins unconnected. CSD16406Q3 x 2 12 V in 12 V .005 AdvancedMC 422 100 1u SENPA SETA SENMA PASSA BLKA IN12A Slot A 3.3 V OUT12A OUT3A EN3A 3v3 in ™ 100 6810 SUM12A IN3A VDD3A SUM3A 3320 SDA VINT TPS2359 SCL AGND IRPT\ A0 GNDA 36 QFN A1 GNDB A2 6810 EN3B SUM12B 3v3 in IN3B SUM3B VDD3B 3320 IN12B OUT3B SENPB SETB SENMB PASSB BLKB OUT12B 1u 100 422 3.3 V 100 AdvancedMC ™ Slot B .005 12 V in 12 V Figure 32. Block Diagram of TPS2359 In a Redundant System 42 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Layout Consideration TPS2359 applications require careful attention to layout in order to ensure proper performance and minimize susceptibility to transients and noise. Important points to consider include: 1. Connect AGND, GNDA, and GNDB to a ground plane. 2. Place 0.01-μF or larger ceramic bypass capacitors on IN12A, IN12B, VDD3A, and VDD3B. Minimize the loop area created by the leads running to these devices. 3. Minimize the loop area between the SENMx and SENPx leads by running them side-by-side. Use Kelvin connections at the points of contact with RSENSE (Figure 33). 4. Minimize the loop area between the SETx and SENPx leads. Connect the SETx leads to the same Kelvin points as the SENPx leads, or as close to these points as possible. 5. Size the following runs to carry at least 20 Amps: – Runs on both sides of RSENSE – Runs from the drains and sources of the external FETs 6. Minimize the loop area between the OUT12x and SENPx leads. 7. Size the runs to IN3x and OUT3x to carry at least 1 Amp. 8. Soldering the powerpad of the TPS2359 to the board will improve thermal performance. LOAD CURRENT PATH LOAD CURRENT PATH SENSE RESISTOR TPS2359 SET SENM SENP SET RSET SENM SENP RSET TPS2359 (a) (b) Figure 33. SENMx and SENPx Runs Side-by-Side to Maximize Common Mode Rejection NOTE Additional details omitted for clarity. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 43 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com Transient Protection The need for transient protection in conjunction with hot-swap controllers should always be considered. When the TPS2359 interrupts current flow, input inductance generates a positive voltage spike on the input and output inductance generates a negative voltage spike on the output. The following equation estimates the magnitude of these voltage spikes: VSPIKE = VNOM + I LOAD L C (10) where VNOM equals the nominal supply voltage, ILOAD equals the load current, C equals the capacitance present at the input or output of the TPS2359, and L equals the effective inductance seen looking into the source or the load. The inductance due to a straight length of wire equals approximately æ 4L ö LStraightWire » 0.2 ´ L ´ ln ç - 0.75 ÷ nH è D ø (11) where L equals the length of the wire and D equals its diameter. If sufficient capacitance to prevent transients from exceeding the absolute ratings of the TPS2359 cannot be included the application will require the addition of transient protectors. Output Protection Considerations for MicroTCA Power Systems MicroTCA power systems have particular transient protection requirements because of the basic power architecture. Traditional protection methods must be adjusted to accommodate these systems where the supplies are OR’ed together after the inrush control and current limit circuits. However, minor changes to some standard techniques will yield very good results. Unlike systems which have hotswap/inrush control at the load, uTCA power modules and their hot swap circuitry are often a significant distance (up to 1 m of trace length, two way) from the load module. Even with the best designed backplanes this distance results in stray inductance which will store energy while current is being delivered to the load. The inductive energy can cause large negative voltage spikes at the power module output when the current is switched off under load. The spikes become especially severe when the channel shuts off due to a short circuit, which drives the current well above normal levels just before shut off. The lowest voltage allowed on the device pins is -0.3 V. If a transient makes a pin more negative than -0.3 V the internal ESD Zener diode attached to the pin will become forward biased and current will be conducted across the substrate to the ground pins. This current may disrupt normal operation or, if large enough, damage the silicon. Typical protection solutions involve capacitors, TVSs ( Transient Voltage Suppressors ) and/or a Schottky diode to absorb the energy which appears at the power module output in the form of a large negative voltage spike. 44 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 The Risk With Output Capacitors Putting transient filter capacitors at the output of a uTCA power module can cause nuisance trips when that power module is plugged into an active bus. If there is no series resistance with the capacitor and the bus is low impedance an inrush surge can cause the active supply to “detect” a short circuit and shut down. One possible solution is to put a few Ohms of resistance in series with the cap to limit inrush below the fast trip level. A better solution is to put a Schottky diode across the output to clamp the transient energy and shunt it to ground as shown in Figure 34. Although the Schottky diode will absorb most of the energy, the extremely fast di/dt at shutoff allows some of the leading edge energy to couple through the parasitic capacitances of the hotswap FET and the ORing FET, ( CDS, CGS, CGD ) and into the BLK and GATE pins. Protection for these pins is provided by 100-Ω GATE resistors which have little effect on normal operation but provide good isolation during transient events. Simplified PASS FET Simplified BLK FET CDS CDS OUT12 LP RP L P +L EMI_FILTER IN12 CGD C GS 100 SENP ESD Diode C GD CGS E=LI 2 /2 1k 100 PASS BLK ESD Diode OUT12 ESD Diode ESD Diode RP LP LP E=LI 2 /2 TPS2359 POWER MODULE BACKPLANE AMC Figure 34. Parasitic Inductance and Transient Protection Output Bleed Down Resistance When the TPS2359 commands the 12-V channel off there is a small leakage current sourced by the OUT12 pin. If this leakage is ignored it can eventually charge any external capacitance to approximately 6 V. In some systems this may be acceptable but, if not, the leakage can be bled to GND by commanding the internal bleed down resistor on by setting 12xDS high. • 12ADS = R1[7] • 12DSB = R4[7] If a hardware solution is preferred then a 1-kΩ resistor from OUT12 to GND will suffice. Maximum leakage is around 23 µA and can be modeled as a 6-V source in series with a 280-kΩ resistor. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 45 TPS2359 SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision E (November 2009) to Revision F • Page Changed leakage typo in the EC table from mA to µA ......................................................................................................... 5 Changes from Revision F (August 2010) to Revision G Page • Changed Fault Timer TYP values from 1 ms, and 0.5 ms to 0.5 and 0.41. ......................................................................... 3 • Changed Table 2 Register 1, Register 2, Register 4, and Register 5 From: fault time by 0.5, 1, 2, 4, and 8 ms To: 0.41, 0.82, 1.64, 3.28 and 6.56 ms. .................................................................................................................................... 17 • Changed Table 4 fault time by From: 0.5, 1, 2, 4, and 8 ms To: 0.41, 0.82, 1.64, 3.28 and 6.56 ms. .............................. 20 • Changed 12AFT[4:0] values from 0.5 ms to 0.41 in two places and 15.5 ms to 12.7 ms. ................................................. 20 • Changed Table 5 falut time by From 0.5, 1, 2, 4, and 8 ms To: 0.41, 0.82, 1.64, 3.28 and 6.56 ms ................................ 21 • Changed 3AFT[4:0] values from 0.5 ms to 0.41 in two places and 15.5 ms to 12.7 ms. ................................................... 21 • Changed Table 7 fault time by From: 0.5, 1, 2, 4, and 8 ms To: 0.41, 0.82, 1.64, 3.28 and 6.56 ms ............................... 23 • Changed 12BFT[4:0] values from 0.5 ms to 0.41 ms in two places and 15.5 ms to 12.7 ms. ........................................... 23 • Changed Table 8 fault time by From: 0.5, 1, 2, 4, and 8 ms To: 0.41, 0.82, 1.64, 3.28 and 6.56 ms ............................... 24 • Changed 3BFT[4:0] values from 0.5 ms to 0.41 in two places and 15.5 ms to 12.7 ms. ................................................... 24 • Changed Table 10 default values from 0 to 1 in four places. ............................................................................................. 26 • Changed 12APG text from "This bit is set if the voltage on OUT12A drops below the power-good threshold set by the 12APG[1:0] bits, and it remains set until Register 7 is read." to "This bit is set at startup and each time OUT12A drops below the PG threshold set by the 12APG[1:0] bits. It is cleared on read if OUT12A is above the PG threshold." ........................................................................................................................................................................... 26 • Changed 3APG text from "This bit is set if the voltage on OUT3A drops below the power-good threshold, and it remains set until Register 7 is read." to "This bit is set at startup and each time OUT3A drops below the PG threshold.It is cleared on read if OUT3A is above the PG threshold." ............................................................................... 26 • Changed 12BPG text from "This bit is set if the voltage on OUT12B drops below the power-good threshold set by the 12BPG[1:0] bits, and it remains set until Register 7 is read." to "This bit is set at startup and each time OUT12B drops below the PG threshold set by the 12BAPG[1:0] bits. It is cleared on read if OUT12B is above the PG threshold." ........................................................................................................................................................................... 26 • Changed 3BPG text from "This bit is set if the voltage on OUT3B drops below the power-good threshold, and it remains set until Register 7 is read." to "This bit is set at startup and each time OUT3B drops below the PG threshold.It is cleared on read if OUT3B is above the PG threshold." ............................................................................... 26 • Changed amplifier to TPS2359. .......................................................................................................................................... 32 • Changed values in the Fault Timer Programming section: 0.5 ms to 0.41 in two places and 16 ms to 12.7 ms. ............. 39 • Changed Table 16 values From: 8, 4, 2, 1 and 0.5 ms To: 6.56, 3.28, 1.64, 0.82 and 0.41 ms. ...................................... 39 • Changed From: If a hardware solution is preferred then a -kΩ To: If a hardware solution is preferred then a 1-kΩ ......... 45 46 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 TPS2359 www.ti.com SLUS792H – FEBRUARY 2008 – REVISED MAY 2013 Changes from Revision G (November 2011) to Revision H Page • Changed the Fault Timer section section of the ELECTRICAL CHARACTERISTICS table ................................................ 3 • Changed Table 2 Register 1, Register 2, Register 4, and Register 5 From: fault time by 0.41, 0.82, 1.64, 3.28, and 6.56 ms To: 0.45, 0.9, 1.8, 3.6 and 7.2 ms. ........................................................................................................................ 17 • Changed Table 4 fault time by From: 0.41, 0.82, 1.68, 3.28, and 6.56 ms To: 0.45, 0.9, 1.8, 3.6 and 7.2 ms. ................ 20 • Changed the 12AFT[4:0] description .................................................................................................................................. 20 • Changed Table 5 fault time by From: 0.41, 0.82, 1.68, 3.28, and 6.56 ms To: 0.45, 0.9, 1.8, 3.6 and 7.2 ms. ................ 21 • Changed the 3AFT[4:0] description .................................................................................................................................... 21 • Changed Table 7 fault time by From: 0.41, 0.82, 1.68, 3.28, and 6.56 ms To: 0.45, 0.9, 1.8, 3.6 and 7.2 ms. ................ 23 • Changed the 12BFT[4:0] description .................................................................................................................................. 23 • Changed Table 8 fault time by From: 0.41, 0.82, 1.68, 3.28, and 6.56 ms To: 0.45, 0.9, 1.8, 3.6 and 7.2 ms. ................ 24 • Changed the 3BFT[4:0] description .................................................................................................................................... 24 • Changed the Fault Timer Programming section and Table 16 ........................................................................................... 39 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: TPS2359 47 PACKAGE OPTION ADDENDUM www.ti.com 14-Oct-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) TPS2359RHHR ACTIVE VQFN RHH 36 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TPS2359 Samples TPS2359RHHT ACTIVE VQFN RHH 36 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TPS2359 Samples (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of