Datasheet LTC3869, LTC3869-2 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Dual, 2-Phase Synchronous Step-Down DC/DC Controllers |
| Pages / Page | 44 / 1 — FeaTures. DescripTion. Dual, 180. Phased Controllers Reduce Required. … |
| File Format / Size | PDF / 687 Kb |
| Document Language | English |
FeaTures. DescripTion. Dual, 180. Phased Controllers Reduce Required. Input Capacitance and Power Supply Induced Noise
Model Line for this Datasheet
Text Version of Document
LTC3869/LTC3869-2 Dual, 2-Phase Synchronous Step-Down DC/DC Controllers
FeaTures DescripTion
n
Dual, 180
°
Phased Controllers Reduce Required
The LTC®3869 is a high performance dual synchronous
Input Capacitance and Power Supply Induced Noise
step-down switching regulator controller that drives all n
Accurate Multiphase Current Matching
N-channel synchronous power MOSFET stages. A constant n
RSENSE or DCR Current Sensing
frequency current mode architecture allows a phase- n
±0.75% 0.6V Output Voltage Accuracy
lockable frequency of up to 780kHz. Power loss and noise n
Phase-Lockable Fixed Frequency 250kHz to 780kHz
due to the ESR of the input capacitors are minimized by n High Efficiency: Up to 95% operating the two controller output stages out-of-phase. n Dual N-channel MOSFET Synchronous Drive OPTI-LOOP® compensation allows the transient response n Wide VIN Range: 4V to 38V (40V Max) Operation to be optimized over a wide range of output capacitance n Wide VOUT Range: 0.6V to 12.5V Operation and ESR values. A wide 4V to 38V input supply range n Adjustable Soft-Start Current Ramping or Tracking encompasses most battery chemistries. Independent TK/ n Foldback Output Current Limiting SS pins for each controller ramp the output voltage during n Output Overvoltage Protection start-up. Current foldback limits MOSFET heat dissipation n Power Good Output Voltage Monitor during short-circuit conditions. The MODE/PLLIN pin n 5V Low Dropout Regulator selects among Burst Mode® operation, pulse-skipping n Small 28-Lead QFN and Narrow SSOP Packages mode, or continuous inductor current mode and allows the IC to be synchronized to an external clock.
applicaTions
The LTC3869 is available in low profile 4mm × 4mm and n Server Systems 4mm × 5mm QFN packages. The LTC3869-2 is available n Telecom Systems in an SSOP-28 package. The LTC3869 is pin-compatible n Industrial and Medical Instruments with the LTC3850. n High Power Battery-Operated Devices L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule, OPTI-LOOP, Burst Mode n DC Power Distribution Systems and PolyPhase are registered trademarks and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6580258, 6498466, 6611131.
Typical applicaTion High Efficiency Dual 5V/3.3V Step-Down Converter Efficiency and Power Loss
VIN 7V TO 100 1300 24V V + IN = 12V, VOUT = 3.3V 22µF 90 V 4.7µF IN = 12V, VOUT = 5V 1200 VIN INTVCC 80 1100 TG1 TG2 POWER LOSS (mW) 70 1000 EFFICIENCY BOOST1 BOOST2 60 SW1 SW2 900 LTC3869 50 BG1 BG2 800 40 PGND EFFICIENCY (%) 700 30 SENSE1+ SENSE2+ 20 600 POWER LOSS 10 500 V SENSE1– OUT1 SENSE2– VOUT2 5V V 3.3V 0 400 FB1 VFB2 0.01 0.1 1 10 5A 147k 90.9k 5A ITH1 FREQ + LOAD CURRENT (A) 470pF I 56µF TH2 3869 TA01b 470pF + TK/SS1 SGND TK/SS2 47µF 20k 122k 20k PINS NOT USED IN 15k 0.1µF 0.1µF 15k THIS CIRCUIT: ILIM, MODE/PLLIN, PGOOD, RUN1, RUN2 3869 TA01 38692fb For more information www.linear.com/LTC3869 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FeaTures DescripTion
n
Dual, 180
°
Phased Controllers Reduce Required
The LTC®3869 is a high performance dual synchronous
Input Capacitance and Power Supply Induced Noise
step-down switching regulator controller that drives all n
Accurate Multiphase Current Matching
N-channel synchronous power MOSFET stages. A constant n
RSENSE or DCR Current Sensing
frequency current mode architecture allows a phase- n
±0.75% 0.6V Output Voltage Accuracy
lockable frequency of up to 780kHz. Power loss and noise n
Phase-Lockable Fixed Frequency 250kHz to 780kHz
due to the ESR of the input capacitors are minimized by n High Efficiency: Up to 95% operating the two controller output stages out-of-phase. n Dual N-channel MOSFET Synchronous Drive OPTI-LOOP® compensation allows the transient response n Wide VIN Range: 4V to 38V (40V Max) Operation to be optimized over a wide range of output capacitance n Wide VOUT Range: 0.6V to 12.5V Operation and ESR values. A wide 4V to 38V input supply range n Adjustable Soft-Start Current Ramping or Tracking encompasses most battery chemistries. Independent TK/ n Foldback Output Current Limiting SS pins for each controller ramp the output voltage during n Output Overvoltage Protection start-up. Current foldback limits MOSFET heat dissipation n Power Good Output Voltage Monitor during short-circuit conditions. The MODE/PLLIN pin n 5V Low Dropout Regulator selects among Burst Mode® operation, pulse-skipping n Small 28-Lead QFN and Narrow SSOP Packages mode, or continuous inductor current mode and allows the IC to be synchronized to an external clock.
applicaTions
The LTC3869 is available in low profile 4mm × 4mm and n Server Systems 4mm × 5mm QFN packages. The LTC3869-2 is available n Telecom Systems in an SSOP-28 package. The LTC3869 is pin-compatible n Industrial and Medical Instruments with the LTC3850. n High Power Battery-Operated Devices L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule, OPTI-LOOP, Burst Mode n DC Power Distribution Systems and PolyPhase are registered trademarks and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6580258, 6498466, 6611131.
Typical applicaTion High Efficiency Dual 5V/3.3V Step-Down Converter Efficiency and Power Loss
VIN 7V TO 100 1300 24V V + IN = 12V, VOUT = 3.3V 22µF 90 V 4.7µF IN = 12V, VOUT = 5V 1200 VIN INTVCC 80 1100 TG1 TG2 POWER LOSS (mW) 70 1000 EFFICIENCY BOOST1 BOOST2 60 SW1 SW2 900 LTC3869 50 BG1 BG2 800 40 PGND EFFICIENCY (%) 700 30 SENSE1+ SENSE2+ 20 600 POWER LOSS 10 500 V SENSE1– OUT1 SENSE2– VOUT2 5V V 3.3V 0 400 FB1 VFB2 0.01 0.1 1 10 5A 147k 90.9k 5A ITH1 FREQ + LOAD CURRENT (A) 470pF I 56µF TH2 3869 TA01b 470pF + TK/SS1 SGND TK/SS2 47µF 20k 122k 20k PINS NOT USED IN 15k 0.1µF 0.1µF 15k THIS CIRCUIT: ILIM, MODE/PLLIN, PGOOD, RUN1, RUN2 3869 TA01 38692fb For more information www.linear.com/LTC3869 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
