Datasheet LT8705 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | 80V VIN and VOUT Synchronous 4-Switch Buck-Boost DC/DC Controller |
| Pages / Page | 44 / 7 — Typical perForMance characTerisTics TA = 25°C unless otherwise specified. … |
| File Format / Size | PDF / 508 Kb |
| Document Language | English |
Typical perForMance characTerisTics TA = 25°C unless otherwise specified. Efficiency vs Output Current
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LT8705
Typical perForMance characTerisTics TA = 25°C unless otherwise specified. Efficiency vs Output Current Efficiency vs Output Current Efficiency vs Output Current (Boost Region-Figure 14) (Buck-Boost Region-Figure 14) (Buck Region-Figure 14)
100 100 100 90 90 90 80 80 80 70 70 70 60 60 60 50 50 50 40 40 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 VIN = 36V 30 VIN = 48V 30 VIN = 72V VOUT = 48V VOUT = 48V VOUT = 48V 20 BURST 20 BURST 20 BURST 10 CCM 10 CCM 10 CCM DCM DCM DCM 0 0 0 10 100 1000 10000 10 100 1000 10000 10 100 1000 10000 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA) 8705 G01 8705 G02 8705 G03
Feedback Voltages FBOUT Voltages (Five Parts) Oscillator Frequency
1.23 1.23 400 VC = 1.2V VC = 1.2V RT = 124k 350 1.22 1.22 300 1.21 1.21 250 RT = 215k 1.20 1.20 200 150 PIN VOLTAGE (V) 1.19 R FBOUT VOLTAGE (V) 1.19 FREQUENCY (kHz) T = 365k IMON_OUT 100 1.18 IMON_IN 1.18 FBOUT 50 FBIN 1.17 1.17 0 –55 –30 –5 20 45 70 95 120 145 –45 –20 5 30 55 80 105 130 –40 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 8705 G04 8795 G05 8705 G06
Maximum Inductor Current Sense Inductor Current Sense Voltage at Maximum Inductor Current Sense Voltage vs Duty Cycle Minimum Duty Cycle Voltage at Minimum Duty Cycle
140 120 120 120 BUCK REGION BOOST REGION 100 100 120 100 80 80 100 60 60 CSP-CSN (mV) 80 BUCK REGION 40 40 80 BOOST REGION BUCK REGION 20 20 60 60 BOOST REGION 0 0 |CSP-CSN| (mV) CSN-CSP (mV) |CSP-CSN| (mV) 40 40 –20 –20 –40 –40 20 20 –60 –60 0 –80 –80 0 0 20 40 60 80 100 0.5 1 1.5 2 –40 –20 0 20 40 60 80 100 120 M2 OR M3 DUTY CYCLE (%) VC (V) TEMPERATURE (°C) 8705 G07 8705 G08 8705 G09 8705ff For more information www.linear.com/LT8705 7 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
Typical perForMance characTerisTics TA = 25°C unless otherwise specified. Efficiency vs Output Current Efficiency vs Output Current Efficiency vs Output Current (Boost Region-Figure 14) (Buck-Boost Region-Figure 14) (Buck Region-Figure 14)
100 100 100 90 90 90 80 80 80 70 70 70 60 60 60 50 50 50 40 40 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 VIN = 36V 30 VIN = 48V 30 VIN = 72V VOUT = 48V VOUT = 48V VOUT = 48V 20 BURST 20 BURST 20 BURST 10 CCM 10 CCM 10 CCM DCM DCM DCM 0 0 0 10 100 1000 10000 10 100 1000 10000 10 100 1000 10000 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA) 8705 G01 8705 G02 8705 G03
Feedback Voltages FBOUT Voltages (Five Parts) Oscillator Frequency
1.23 1.23 400 VC = 1.2V VC = 1.2V RT = 124k 350 1.22 1.22 300 1.21 1.21 250 RT = 215k 1.20 1.20 200 150 PIN VOLTAGE (V) 1.19 R FBOUT VOLTAGE (V) 1.19 FREQUENCY (kHz) T = 365k IMON_OUT 100 1.18 IMON_IN 1.18 FBOUT 50 FBIN 1.17 1.17 0 –55 –30 –5 20 45 70 95 120 145 –45 –20 5 30 55 80 105 130 –40 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 8705 G04 8795 G05 8705 G06
Maximum Inductor Current Sense Inductor Current Sense Voltage at Maximum Inductor Current Sense Voltage vs Duty Cycle Minimum Duty Cycle Voltage at Minimum Duty Cycle
140 120 120 120 BUCK REGION BOOST REGION 100 100 120 100 80 80 100 60 60 CSP-CSN (mV) 80 BUCK REGION 40 40 80 BOOST REGION BUCK REGION 20 20 60 60 BOOST REGION 0 0 |CSP-CSN| (mV) CSN-CSP (mV) |CSP-CSN| (mV) 40 40 –20 –20 –40 –40 20 20 –60 –60 0 –80 –80 0 0 20 40 60 80 100 0.5 1 1.5 2 –40 –20 0 20 40 60 80 100 120 M2 OR M3 DUTY CYCLE (%) VC (V) TEMPERATURE (°C) 8705 G07 8705 G08 8705 G09 8705ff For more information www.linear.com/LT8705 7 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
