Datasheet LTC3736 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Dual 2-Phase, No RSENSE , Synchronous Controller with Output Tracking |
| Pages / Page | 28 / 4 — TYPICAL PERFOR A CE CHARACTERISTICS TA = 25. C unless otherwise noted. … |
| File Format / Size | PDF / 447 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS TA = 25. C unless otherwise noted. Efficiency and Power Loss. Load Step. vs Load Current
Model Line for this Datasheet
Text Version of Document
LTC3736
W U TYPICAL PERFOR A CE CHARACTERISTICS TA = 25
°
C unless otherwise noted. Efficiency and Power Loss Load Step vs Load Current Load Step (Burst Mode Operation) (Forced Continuous Mode)
100 10 FIGURE 15 CIRCUIT 95 VOUT VOUT AC-COUPLED AC-COUPLED 90 1 100mV/DIV 100mV/DIV 85 POWER LOSS (W) 80 75 0.1 IL IL 70 2A/DIV 2A/DIV EFFICIENCY (%) V 65 OUT = 3.3V VOUT = 2.5V 0.01 60 VOUT = 1.8V V V OUT = 1.2V IN = 3.3V 100µs/DIV 3736 G02 VIN = 3.3V 100µs/DIV 3736 G03 55 VIN = 5V VOUT = 1.8V VOUT = 1.8V SYNC/FCB = VIN ILOAD = 300mA TO 3A ILOAD = 300mA TO 3A 50 0.001 SYNC/FCB = VIN SYNC/FCB = 0V 1 10 100 1000 10000 FIGURE 17 CIRCUIT FIGURE 17 CIRCUIT LOAD CURRENT (mA) 3736 G01
Load Step (Pulse Skipping Mode) Inductor Current at Light Load
Burst Mode VOUT OPERATION AC-COUPLED SYNC/FCB = VIN 100mV/DIV FORCED CONTINUOUS IL MODE 1A/DIV SYNC/FCB = 0V IL 2A/DIV PULSE SKIPPING MODE SYNC/FCB = 550kHz VIN = 3.3V 100µs/DIV 3736 G04 VIN = 3.3V 4µs/DIV 3736 G05 VOUT = 1.8V VOUT = 1.8V ILOAD = 300mA TO 3A ILOAD = 200mA SYNC/FCB = 550kHz EXTERNAL CLOCK FIGURE 17 CIRCUIT FIGURE 17 CIRCUIT
Tracking Start-Up with Internal Tracking Start-Up with External Oscillator Frequency Soft-Start (CSS = 0
µ
F) Soft-Start (C vs Input Voltage SS = 0.15
µ
F)
5 VOUT1 VOUT1 4 2.5V 2.5V VOUT2 VOUT2 3 1.8V 1.8V 2 500mV/ 500mV/ 1 DIV DIV 0 –1 –2 –3 VIN = 5V 200µs/DIV 3736 G06 VIN = 5V 40ms/DIV 3736 G07 R NORMALIZED FREQUENCY SHIFT (%) –4 LOAD1 = RLOAD2 = 1Ω RLOAD1 = RLOAD2 = 1Ω FIGURE 15 CIRCUIT FIGURE 15 CIRCUIT –5 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) 3736 G08 3736fa 4
W U TYPICAL PERFOR A CE CHARACTERISTICS TA = 25
°
C unless otherwise noted. Efficiency and Power Loss Load Step vs Load Current Load Step (Burst Mode Operation) (Forced Continuous Mode)
100 10 FIGURE 15 CIRCUIT 95 VOUT VOUT AC-COUPLED AC-COUPLED 90 1 100mV/DIV 100mV/DIV 85 POWER LOSS (W) 80 75 0.1 IL IL 70 2A/DIV 2A/DIV EFFICIENCY (%) V 65 OUT = 3.3V VOUT = 2.5V 0.01 60 VOUT = 1.8V V V OUT = 1.2V IN = 3.3V 100µs/DIV 3736 G02 VIN = 3.3V 100µs/DIV 3736 G03 55 VIN = 5V VOUT = 1.8V VOUT = 1.8V SYNC/FCB = VIN ILOAD = 300mA TO 3A ILOAD = 300mA TO 3A 50 0.001 SYNC/FCB = VIN SYNC/FCB = 0V 1 10 100 1000 10000 FIGURE 17 CIRCUIT FIGURE 17 CIRCUIT LOAD CURRENT (mA) 3736 G01
Load Step (Pulse Skipping Mode) Inductor Current at Light Load
Burst Mode VOUT OPERATION AC-COUPLED SYNC/FCB = VIN 100mV/DIV FORCED CONTINUOUS IL MODE 1A/DIV SYNC/FCB = 0V IL 2A/DIV PULSE SKIPPING MODE SYNC/FCB = 550kHz VIN = 3.3V 100µs/DIV 3736 G04 VIN = 3.3V 4µs/DIV 3736 G05 VOUT = 1.8V VOUT = 1.8V ILOAD = 300mA TO 3A ILOAD = 200mA SYNC/FCB = 550kHz EXTERNAL CLOCK FIGURE 17 CIRCUIT FIGURE 17 CIRCUIT
Tracking Start-Up with Internal Tracking Start-Up with External Oscillator Frequency Soft-Start (CSS = 0
µ
F) Soft-Start (C vs Input Voltage SS = 0.15
µ
F)
5 VOUT1 VOUT1 4 2.5V 2.5V VOUT2 VOUT2 3 1.8V 1.8V 2 500mV/ 500mV/ 1 DIV DIV 0 –1 –2 –3 VIN = 5V 200µs/DIV 3736 G06 VIN = 5V 40ms/DIV 3736 G07 R NORMALIZED FREQUENCY SHIFT (%) –4 LOAD1 = RLOAD2 = 1Ω RLOAD1 = RLOAD2 = 1Ω FIGURE 15 CIRCUIT FIGURE 15 CIRCUIT –5 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) 3736 G08 3736fa 4
