Datasheet LTC3838-2 (Analog Devices) - 7
| 制造商 | Analog Devices |
| 描述 | Dual, Fast, Accurate Step-Down DC/DC Controller with External Reference Voltage and Dual Differential Output Sensing |
| 页数 / 页 | 56 / 7 — Typical perForMance characTerisTics. Soft Start-Up with Internal. Soft … |
| 文件格式/大小 | PDF / 968 Kb |
| 文件语言 | 英语 |
Typical perForMance characTerisTics. Soft Start-Up with Internal. Soft Start-Up Into. Soft Start-Up with External. Reference
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LTC3838-2
Typical perForMance characTerisTics Soft Start-Up with Internal Soft Start-Up Into Soft Start-Up with External Reference Prebiased Output Reference
RUN1 RUN1 RUN2 5V/DIV 5V/DIV 5V/DIV EXTV TRACK/SS1 REF2 500mV/DIV 200mV/DIV VOUT 500mV/DIV TRACK/SS2 TRACK/SS1 500mV/DIV VOUT 200mV/DIV 500mV/DIV VOUT 500mV/DIV 1ms/DIV 38382 G09 CSS = 10nF 1ms/DIV 38382 G10 CSS = 10nF 2ms/DIV 38382 G11 CSS = 10nF VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V EXTVREF2 = 1.2V FORCED CONTINUOUS MODE VOUT PRE-BIASED TO 0.75V VOUT = 1.2V FIGURE 17 CIRCUIT, CHANNEL 1 FIGURE 17 CIRCUIT, CHANNEL 1 FORCED CONTINUOUS MODE FIGURE 17 CIRCUIT, CHANNEL 2
Overcurrent Protection Short-Circuit Protection Overvoltage Protection
SHORT- CIRCUIT I TRIGGER L IL 10A/DIV 5A/DIV V OVERVOLTAGE CREATED BY APPLYING OUT V A CHARGED CAPACITOR TO V FULL CURRENT LIMIT 1V/DIV OUT OUT WHEN VOUT HIGHER CURRENT LIMIT STARTS TO FOLD BACK AS 100mV/DIV THAN HALF OF REGULATED VOUT DROPS BELOW HALF OF REGULATED AC-COUPLED IL COUT VOUT 10A/DIV RECHARGE BG1 100mV/DIV 5V/DIV AC-COUPLED IN = 12V 5ms/DIV 38382 G12 V 500µs/DIV 38382 G13 VIN = 12V 20µs/DIV 38382 G14 VIN = 12V V V OUT = 1.2V OUT = 1.2V VOUT = 1.2V BG STAYS ON UNTIL FORCED CONTINUOUS MODE ILOAD = 0A FORCED VOUT IS PULLED CURRENT LIMIT = 17A FIGURE 17 CIRCUIT, CHANNEL 1 CONTINUOUS MODE BELOW OVERVOLTAGE OVERLOAD = 7.5A TO 17.5A ILOAD = 0A THRESHOLD FIGURE 17 CIRCUIT, CHANNEL 1 FIGURE 17 CIRCUIT, CHANNEL 1
Phase Relationship: Phase Relationship: Phase Relationship: PHASMD = Ground PHASMD = Float PHASMD = INTVCC
PLLIN PLLIN PLLIN 5V/DIV 5V/DIV 5V/DIV SW1 SW1 SW1 0° 10V/DIV 0° 10V/DIV 0° 10V/DIV SW2 SW2 SW2 10V/DIV 180° 10V/DIV 180° 10V/DIV 240° CLKOUT CLKOUT CLKOUT 60° 5V/DIV 5V/DIV 90° 5V/DIV 120° 500ns/DIV 38382 G15 500ns/DIV 38382 G16 500ns/DIV 38382 G17 FIGURE 21 CIRCUIT FIGURE 21 CIRCUIT FIGURE 21 CIRCUIT VIN = 12V VIN = 12V VIN = 12V VOUT1 = 5V, VOUT2 = 3.3V VOUT1 = 5V, VOUT2 = 3.3V VOUT1 = 5V, VOUT2 = 3.3V LOAD = 0A LOAD = 0A LOAD = 0A MODE/PLLIN = 333kHz EXTERNAL CLOCK MODE/PLLIN = 333kHz EXTERNAL CLOCK MODE/PLLIN = 333kHz EXTERNAL CLOCK 38382fa For more information www.linear.com/3838-2 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
Typical perForMance characTerisTics Soft Start-Up with Internal Soft Start-Up Into Soft Start-Up with External Reference Prebiased Output Reference
RUN1 RUN1 RUN2 5V/DIV 5V/DIV 5V/DIV EXTV TRACK/SS1 REF2 500mV/DIV 200mV/DIV VOUT 500mV/DIV TRACK/SS2 TRACK/SS1 500mV/DIV VOUT 200mV/DIV 500mV/DIV VOUT 500mV/DIV 1ms/DIV 38382 G09 CSS = 10nF 1ms/DIV 38382 G10 CSS = 10nF 2ms/DIV 38382 G11 CSS = 10nF VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V EXTVREF2 = 1.2V FORCED CONTINUOUS MODE VOUT PRE-BIASED TO 0.75V VOUT = 1.2V FIGURE 17 CIRCUIT, CHANNEL 1 FIGURE 17 CIRCUIT, CHANNEL 1 FORCED CONTINUOUS MODE FIGURE 17 CIRCUIT, CHANNEL 2
Overcurrent Protection Short-Circuit Protection Overvoltage Protection
SHORT- CIRCUIT I TRIGGER L IL 10A/DIV 5A/DIV V OVERVOLTAGE CREATED BY APPLYING OUT V A CHARGED CAPACITOR TO V FULL CURRENT LIMIT 1V/DIV OUT OUT WHEN VOUT HIGHER CURRENT LIMIT STARTS TO FOLD BACK AS 100mV/DIV THAN HALF OF REGULATED VOUT DROPS BELOW HALF OF REGULATED AC-COUPLED IL COUT VOUT 10A/DIV RECHARGE BG1 100mV/DIV 5V/DIV AC-COUPLED IN = 12V 5ms/DIV 38382 G12 V 500µs/DIV 38382 G13 VIN = 12V 20µs/DIV 38382 G14 VIN = 12V V V OUT = 1.2V OUT = 1.2V VOUT = 1.2V BG STAYS ON UNTIL FORCED CONTINUOUS MODE ILOAD = 0A FORCED VOUT IS PULLED CURRENT LIMIT = 17A FIGURE 17 CIRCUIT, CHANNEL 1 CONTINUOUS MODE BELOW OVERVOLTAGE OVERLOAD = 7.5A TO 17.5A ILOAD = 0A THRESHOLD FIGURE 17 CIRCUIT, CHANNEL 1 FIGURE 17 CIRCUIT, CHANNEL 1
Phase Relationship: Phase Relationship: Phase Relationship: PHASMD = Ground PHASMD = Float PHASMD = INTVCC
PLLIN PLLIN PLLIN 5V/DIV 5V/DIV 5V/DIV SW1 SW1 SW1 0° 10V/DIV 0° 10V/DIV 0° 10V/DIV SW2 SW2 SW2 10V/DIV 180° 10V/DIV 180° 10V/DIV 240° CLKOUT CLKOUT CLKOUT 60° 5V/DIV 5V/DIV 90° 5V/DIV 120° 500ns/DIV 38382 G15 500ns/DIV 38382 G16 500ns/DIV 38382 G17 FIGURE 21 CIRCUIT FIGURE 21 CIRCUIT FIGURE 21 CIRCUIT VIN = 12V VIN = 12V VIN = 12V VOUT1 = 5V, VOUT2 = 3.3V VOUT1 = 5V, VOUT2 = 3.3V VOUT1 = 5V, VOUT2 = 3.3V LOAD = 0A LOAD = 0A LOAD = 0A MODE/PLLIN = 333kHz EXTERNAL CLOCK MODE/PLLIN = 333kHz EXTERNAL CLOCK MODE/PLLIN = 333kHz EXTERNAL CLOCK 38382fa For more information www.linear.com/3838-2 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts