DICE/DWF SPECIFICATION RH3845MK DICE Radiation Hardened High Voltage Synchronous Step-Down Controller Description Absolute Maximum Ratings The RH3845MK is a high voltage, synchronous, current mode controller for medium to high power, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum start-up voltage). An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN. (Note 1) Additional features include an adjustable fixed operating frequency synchronizable to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, low shutdown current, short-circuit protection, and a programmable soft-start. Note that Burst Mode® operation, available in the LT3845, is not available in the RH3845 version. VIN.............................................................................65V BOOST.......................................................................80V BOOST to SW............................................................24V VCC, MODE.................................................................24V SENSE+, SENSE–........................................................40V SENSE+ TO SENSE–...................................................±1V SYNC, VFB, AND CSS....................................................5V SHDN Pin Current.....................................................1mA Operating Junction Temperature Range....–55°C to 125°C Storage Temperature Range.................... –65°C to 150°C L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. DICE Pinout 1 PAD FUNCTION 20 18 2 17 16 3 15 4 5 14 6 13 7 8 9 DIE CROSS REFERENCE 19 10 11 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. VIN SHDN CSS MODE VFB VC SYNC fSET GND GND 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. GND SENSE– SENSE+ PGND BG VCC SW TG BOOST GND LTC® Finished Part Number Order Part Number RH3845MK RH3845MK RH3845MK DICE RH3845MK DWF* Please refer to LTC standard product data sheet for other applicable product information. *DWF = DICE in wafer form. 12 113mils × 124mils, Backside Metal: Alloyed Gold Layer Backside Potential: GND 1 DICE/DWF SPECIFICATION Table 1: DICE/DWF Electrical Test Limits – + Specifications are at TA = 25°C, VIN = 20V, VCC = BOOST = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE = SENSE = 10V, SGND = PGND, SW = 0V. PARAMETER CONDITIONS MIN VIN Minimum Start Voltage (Note 2) VIN UVLO Threshold (Falling) 3.6 TYP MAX UNITS 7.5 V 4.0 V VIN Supply Current VCC > 9V 200 μA VIN Shutdown Current VSHDN = 0.3V 100 μA BOOST Supply Current (Note 3) VCC Supply Current 2 mA 4.5 mA V SHDN Enable Threshold (Rising) 1.30 1.40 Reference Voltage 1.214 1.250 V 50 nA VFB Input Bias Current VFB Error Amp Transconductance 350 Error Amp Sink/Source Current 35 MODE Pin Current (Note 4) µS µA 2 µA Peak Current Limit Sense Voltage 90 120 mV Soft-Start Charge Current 8 14 µA Sense Pins Common-Mode Range 0 36 V Sense Pins Input Current VSENSE(CM) > 4V 400 µA Reverse Protect Sense Voltage VMODE = 7.5V 120 mV Reverse Current Sense Voltage Offset VMODE = VFB Switching Frequency RT = 49.9k Programmable Frequency Range 2 20 mV 270 360 kHz 100 500 kHz DICE/DWF SPECIFICATION Table 2: Electrical Characteristics (Pre-Irradiation) Specifications are at TA = 25°C, VIN = 20V, VCC = BOOST = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE– = SENSE+ = 10V, SGND = PGND, SW = 0V. PARAMETER CONDITIONS VIN Minimum Start Voltage (Note 2) SUBGROUP MIN TA = 25°C TYP 1 VIN UVLO Threshold (Falling) 1 VIN Supply Current VCC > 9V 1 VIN Shutdown Current VSHDN = 0.3V 3.6 MAX SUBGROUP 7.5 2, 3 –55°C ≤ TA ≥ 125°C MIN TYP MAX 7.5 3.6 3.8 UNITS V 3.8 4.0 2, 3 4.0 V 130 200 2, 3 800 μA 1 65 100 2, 3 200 μA BOOST Supply Current (Note 3) 1 1.4 2 2, 3 3.5 mA VCC Supply Current 1 3.8 4.5 2, 3 5.5 mA 2, 3 –40 1.4 2, 3 1.30 1.5 V 2, 3 100 200 mV 1.214 VCC Current Limit 1 –40 –150 SHDN Enable Threshold (Rising) 1 1.30 1.35 SHDN Hysteresis 1 Reference Voltage 1 VFB Input Bias Current 1 140 1.214 1.232 1.250 2, 3 20 50 2, 3 mA 1.250 20 V nA VFB Error Amp Transconductance 1 350 450 2, 3 340 Error Amp Sink/Source Current 1 35 50 2, 3 20 Peak Current Limit Sense Voltage 1 90 105 120 2, 3 85 125 mV 12 14 2, 3 8 16 µA 36 2, 3 0 36 V Soft-Start Charge Current 1 8 Sense Pins Common-Mode Range 1 0 540 µS µA Sense Pins Input Current VSENSE(CM) > 4V 1 320 400 2, 3 500 µA Reverse Protect Sense Voltage VMODE = 7.5V 1 108 120 2, 3 140 mV Reverse Current Sense Voltage Offset VMODE = VFB Switching Frequency RT = 49.9k 1 15 20 2, 3 25 mV 1 270 300 360 2, 3 240 390 kHz Programmable Frequency Range 1 100 500 2, 3 100 500 kHz External Sync Frequency Range 1 100 600 2, 3 100 600 kHz Non-Overlap Time TG to BG 1 250 2, 3 ns Non-Overlap Time BG to TG 1 250 2, 3 ns TG Minimum On-Time 1 400 2, 3 ns TG Minimum Off-Time 1 300 2, 3 ns 8.75 2, 3 TG, BG Drive On Voltage VCC = 10V TG, BG Drive Off Voltage 1 8 1 0.1 2, 3 8 V 0.1 V TG, BG Drive Rise Time CTG = CBG = 3300pF 1 45 2, 3 ns TG, BG Drive Fall Time CTG = CBG = 3300pF 1 45 2, 3 ns 3 DICE/DWF SPECIFICATION (Post-Irradiation) Specifications are at TA = 25°C, Table 3: Electrical Characteristics – + VIN = 20V, VCC = BOOST = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE = SENSE = 10V, SGND = PGND, SW = 0V. PARAMETER VIN Minimum Start Voltage (Note 2) VIN UVLO Threshold (Falling) VIN Supply Current VIN Shutdown Current BOOST Supply Current (Note 3) VCC Supply Current VCC Current Limit SHDN Enable Threshold (Rising) SHDN Hysteresis Reference Voltage VFB Input Bias Current VFB Error Amp Transconductance Error Amp Sink/Source Current Peak Current Limit Sense Voltage Soft-Start Charge Current Sense Pins Common-Mode Range Sense Pins Input Current Reverse Protect Sense Voltage Reverse Current Sense Voltage Offset Switching Frequency Programmable Frequency Range Non-Overlap Time TG to BG Non-Overlap Time BG to TG TG Minimum On-Time TG Minimum Off-Time TG, BG Drive On Voltage TG, BG Drive Off Voltage TG, BG Drive Rise Time TG, BG Drive Fall Time CONDITIONS 10KRADS (Si) 20KRADS (Si) 50KRADS (Si) 100KRADS (Si) 200KRADS (Si) MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX 7.5 4 200 100 2 4.5 VCC > 9V VSHDN = 0.3V –40 1.30 1.5 100 180 1.214 1.250 50 350 35 90 120 8 16 36 400 VSENSE(CM) > 4V 120 VMODE = 7.5V 20 VMODE = VFB 270 370 RT = 49.9k 100 500 350 350 500 350 8 VCC = 10V 0.1 60 CTG = CBG = 3300pF 60 CTG = CBG = 3300pF Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability. Note 2: VIN voltages below the start-up threshold (7.5V) are only supported when the VCC is externally driven above 6.5V. 7.5 4 200 100 2 4.5 7.5 4 200 100 2 4.5 –40 –40 1.30 1.5 1.30 1.5 100 180 100 180 1.210 1.246 1.208 1.244 100 120 330 300 35 35 85 120 85 120 8 16 6 16 36 36 400 400 120 120 20 20 270 370 270 370 100 500 100 500 350 350 350 350 500 500 350 350 8 8 0.1 0.1 60 60 60 60 7.5 4 200 100 2 4.5 –40 1.30 100 1.204 280 35 80 5 270 100 1.5 180 1.240 250 120 16 36 400 120 20 370 500 350 350 500 360 8 7.5 4 200 100 2 4.5 –40 1.30 80 1.187 250 30 75 4 270 100 1.5 180 1.223 350 120 16 36 400 120 20 370 500 350 350 500 360 8 0.1 60 60 0.1 60 60 UNITS V V μA μA mA mA mA V mV V nA µS µA mV µA V µA mV mV kHz kHz ns ns ns ns V V ns ns Note 3: Supply current specification does not include switch drive currents. Actual supply currents will be higher. Note 4: Connect the MODE pin to VFB for pulse-skipping mode or VCC for forced continuous mode. Burst Mode operation is not available in the RH3845 version of this part. Table 4: Electrical Test Requirements MIL-STD-883 TEST REQUIREMENTS SUBGROUP Final Electrical Test Requirements (Method 5004) 1*, 2, 3 Group A Test Requirements (Method 5005) 1, 2, 3 Group B and D for Class S, End Point Electrical Parameters (Method 5005) 1, 2, 3 *PDA applies to subgroup 1. See PDA Test Notes. 4 PDA Test Notes The PDA is specified as 5% based on failures from Group A, Subgroup 1, tests after cooldown as the final electrical test in accordance with method 5004 of MIL-STD-883. The verified failures of Group A, Subgroup 1, after burn-in divided by the total number of devices submitted for burn-in in that lot shall be used to determine the percent for the lot. Linear Technology Corporation reserves the right to test to tighter limits than those given. DICE/DWF SPECIFICATION Total Dose Bias Circuit — Run Mode R5 1k R1 4.99k BOOST VIN 3V R2 8.82k 0.1µF R3 1k SHDN TG CSS SW VCC MODE RH3845MK VFB BG VC + – 5V fSET 30V R9 750Ω R7 200k SENSE+ GND 0.1µF 20V R10 750Ω 10V R11 1.24k PGND SYNC R4 49.9k R8 750Ω R6 200k SENSE– + – 40V RH3845MK RUN MODE Total Dose Bias Circuit — Shutdown Mode R4 1k VIN R1 2k 2.5V R2 2.49k BOOST SHDN TG CSS SW MODE VCC RH3845MK VFB BG 0.1µF VC + – R6 200k SENSE+ GND R7 10k 30V R8 10k PGND SYNC fSET R5 200k SENSE– 20V R9 10k 10V R10 10k R3 49.9k 5V 0.1µF + – 40V RH3845MK SHDN MODE Burn-In Circuit — Run Mode 1k VIN 100Ω SHDN 4.87k CSS SYNC 3.3V 10µF 10V 1k BOOST TG SW MODE RH3845MK VCC VFB VC + – GND BG PGND fSET SENSE+ GND SENSE– GND GND 1k 1W 1k 200k 200k 499Ω 10V 1W 10V 1W 10V 1W 10V 1W 10V 1W 10V 1W + – 70V 1µF 150V RH3845MK BURN IN-RUN Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 5 DICE/DWF SPECIFICATION Typical Performance Characteristics Feedback Voltage Reference vs TID Operating Switching Frequency vs TID 1.4 350 3.5 1.3 325 3.0 2.5 2.0 1.5 1.0 1.2 1.1 1.0 0.9 0.8 0.5 0 SWITCHING FREQUENCY (kHz) 4.0 REFERENCE VOLTAGE (V) VCC SUPPLY CURRENT (mA) VCC Supply Current vs TID 0 100 50 150 TOTAL DOSE (kRADS) 0.7 200 0 50 100 200 150 TOTAL DOSE (kRADS) RH3845MK G01 RH3845MK G02 Rad Hard die require special handling as compared to standard IC chips. Rad Hard die are susceptible to surface damage because there is no silicon nitride passivation as on standard die. Silicon nitride protects the die surface from scratches by its hard and dense properties. The passivation on Rad Hard die is silicon dioxide that is much “softer” than silicon nitride. LTC recommends that die handling be performed with extreme care so as to protect the die surface from scratches. If the need arises to move the die around from the chip tray, use a Teflon-tipped vacuum wand. 300 275 250 225 200 0 50 100 150 TOTAL DOSE (kRADS) 200 RH3845MK G03 This wand can be made by pushing a small diameter Teflon tubing onto the tip of a steel-tipped wand. The inside diameter of the Teflon tip should match the die size for efficient pickup. The tip of the Teflon should be cut square and flat to ensure good vacuum to die surface. Ensure the Teflon tip remains clean from debris by inspecting under stereoscope. During die attach, care must be exercised to ensure no tweezers touch the top of the die. Wafer level testing is performed per the indicated specifications for dice. Considerable differences in performance can often be observed for dice versus packaged units due to the influences of packaging and assembly on certain devices and/or parameters. Please consult factory for more information on dice performance and lot qualifications via lot sampling test procedures. Dice data sheet subject to change. Please consult factory for current revision in production. 6 I.D.No. 66-13-3845 Linear Technology Corporation LT 1115 REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014