LTC1538-AUX Linear Technology, LTC1538-AUX Datasheet
LTC1538-AUX
Related parts for LTC1538-AUX
LTC1538-AUX Summary of contents
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... C1 RUN/SS1 C V SGND PGND DSC PROG2 C1A C1 SS1 OSC 220pF 10k 0.1 F 56pF *NOT REQUIRED FOR LTC1538-AUX BOLD LINES INDICATE HIGH CURRENT PATHS LTC1538-AUX/LTC1539 Dual High Efficiency, U 1538-AUX/LTC1539 are dual, synchronous step STANDBY V IN 5.2V TO 28V CMDSH 16V ...
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... IN Peak Output Current < (TGS1, 2) .............. 250mA INTV Output Current ........................................ 50mA CC Operating Temperature Range LTC1538-AUXCG/LTC1539CGW............ – LTC1538-AUXIG/LTC1539IGW .......... – Junction Temperature (Note 1) ............................ 125 C + 0.3V to – 0.3V CC Storage Temperature Range ................ – 150 C to – 0.3V CC Lead Temperature (Soldering, 10 sec)................. 300 C ...
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... Phase Detector Output Current PLLLPF Sinking Capability Sourcing Capability Power-On Reset V POR1 Saturation Voltage SATPOR1 I POR1 Leakage LPOR1 V POR1 Trip Voltage THPOR1 t POR1 Delay DPOR1 LTC1538-AUX/LTC1539 15V unless otherwise noted RUN/SS1,2 CONDITIONS V V Pins Open (Note 2) PROG1, PROG2 (Note ...
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... D LTC1538CG-AUX )(95 C/ LTC1539CGW )(85 C/ Note 2: The LTC1538-AUX and LTC1539 are tested in a feedback loop which servos V to the balance point for the error amplifier OSENSE1 1.19V). ITH1 15V RUN/SS1,2 CONDITIONS ...
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... Regulation CC vs INTV Load Current CC 100 2 EXTV = – – INTV LOAD CURRENT (mA) CC LTC1538-AUX/LTC1539 Efficiency vs Load Current 100 V = 10V OUT R = 0.33 SENSE Burst Mode 75 OPERATION 70 65 Adaptive Power 60 MODE 55 50 0.001 ...
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... LTC1538-AUX/LTC1539 W U TYPICAL PERFORMANCE CHARACTERISTICS Normalized Oscillator Frequency vs Temperature –5 –10 – 40 – 110 135 TEMPERATURE ( C) 1538/39 • G10 Maximum Current Comparator Threshold Voltage vs Temp 154 152 150 148 146 – 40 – 110 135 TEMPERATURE ( C) 1538/39 • ...
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... Connects to the (–) input for the – internally connected to sensing point preventing true OUT pin. The second controller can be PROG1 pin (see Table 1). LTC1538-AUX LTC1539 5V or 3.3V Only, Secondary Feedback Loop Adjustable Only 5V/3.3V/Adjustable Remote Sensing Remote Sensing POR1 Output . ...
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... LTC1538-AUX/LTC1539 PIN FUNCTIONS + + SENSE 1, SENSE 2: The (+) Input to Each Current Comparator. Built-in offsets between SENSE + SENSE 1 pins in conjunction with R trip threshold (same for second controller Receives the remotely sensed feedback voltage for OSENSE2 the second controller either from the output directly or from an external resistive divider across the output ...
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... CC + SGND INTERNAL *NOT AVAILABLE ON BOTH CHANNELS **NOT AVAILABLE ON LTC1538-AUX AUXDR: Open Drain Output of the Auxiliary Regulator/ Comparator. The base of an external PNP device is con- nected to this pin when used as a linear regulator. An external pull-up resistor is required for use as a compara- tor. A voltage > 9.5V on AUXDR causes the internal 12V resistive divider to be connected in series with the AUXFB pin ...
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... TH1 TH2 normal operation to resume. When both RUN/SS1 and RUN/SS2 are low, all LTC1538-AUX/LTC1539 functions are shut down except for the 5V standby regulator, internal reference and a comparator. Refer to the LTC1438/LTC1439 for applications which do not require a 5V standby regulator. ...
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... POR1 after 2 (65536) oscillator cycles. Auxiliary Linear Regulator The auxiliary linear regulator in the LTC1538-AUX and LTC1539 controls an external PNP transistor for operation up to 500mA. A precise internal AUXFB resistive divider is invoked when the AUXDR pin is above 9.5V to allow regulated 12V VPP supplies to be easily implemented. ...
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... LTC1538-AUX/LTC1539 U U APPLICATIONS INFORMATION Allowing some margin for variations in the LTC1538-AUX/ LTC1539 and external component values yield: 100 mV R SENSE I MAX The LTC1538-AUX/LTC1539 work well with values of R from 0.005 to 0.2 . SENSE C Selection for Operating Frequency OSC The LTC1538-AUX/LTC1539 use a constant frequency ...
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... DS(ON) gate charge. (A higher R capacitance and thus requires less current to charge its gate). For all LTC1538-AUX and cost sensitive LTC1539 applications, the small MOSFET is not required. The circuit then begins Burst Mode operation as the load current drops. ...
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... LTC1538-AUX/LTC1539 U U APPLICATIONS INFORMATION The MOSFET power dissipations at maximum output current are given by OUT MAIN MAX 1. MAX RSS V – OUT SYNC MAX V IN where is the temperature dependency constant inversely related to the gate drive current. ...
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... An internal P-channel low dropout regulator produces 5V at the INTV pin from the V supply pin. INTV CC IN the drivers and internal circuitry within the LTC1538-AUX/ LTC1539, as well as any “wake-up” circuitry tied externally to the INTV pin. The INTV pin regulator can supply CC ...
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... SENSE 1 pin in Controller 1. For fixed output voltage applications the SENSE voltage as shown in Figure 5a. When using an external resistive divider for Controller 2, the V voltage Figure 5a. LTC1538-AUX/LTC1539 Fixed Output Applications when the CC voltage across INTVCC Figure 5b. LTC1538-AUX/LTC1539 Adjustable Applications + + 0 ...
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... F, followed by a similar time to reach full current on that controller. By pulling both RUN/SS controller pins below 1.3V, the LTC1538-AUX/LTC1539 are put into shutdown (I < 200 A). These pins can be driven directly from logic Q as shown in Figure 6 ...
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... LTC1538-AUX/LTC1539 U U APPLICATIONS INFORMATION 1 0.7 0 0.5 1.0 1.5 V (V) PLLLPF Figure 7. Operating Frequency vs V Phase-Locked Loop and Frequency Synchronization The LTC1539 has an internal voltage-controlled oscillator and phase detector comprising a phase-locked loop. This allows the top MOSFET turn- locked to the rising edge of an external source. The frequency range of the ...
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... LBO MOSFET which can sink up to 10mA. The voltage on AUXDR determines whether or not an internal 12V resis- tive divider is connected to AUXFB as described below. A 1538 F10 pull-up resistor is required on AUXDR and the voltage must not exceed 28V. LTC1538-AUX/LTC1539 in Figure 4a is given by: SEC ...
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... INPUT + 1.19V REFERENCE Figure 11c. Auxiliary Comparator Configuration is set as follows: OAUX AUX DR < 8. 12V AUX DR 1 1.19V 1 + > 1V) SEC OAUX R5 AUXDR R6 R8 SFB1 AUXFB + LTC1538-AUX LTC1539 AUXON ON/OFF 1538 F11b 7.5V OUTPUT 1538 F11c 12V V OAUX 10 F ...
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... APPLICATIONS INFORMATION where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, four main sources usually account for most of the losses in LTC1538-AUX/LTC1539 circuits. LTC1538-AUX/ LTC1539 V current, INTV current topside MOSFET transition losses. ...
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... Note that the transient suppressor should not conduct during double battery operation, but must still clamp the input voltage below breakdown of the converter. Although the LTC1538-AUX/LTC1539 has a maximum input voltage of 36V, most applications will be limited to 30V by the MOSFET BV ...
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... PC trace spacing? The filter capacitors be tween SENSE 1 (SENSE 2) and SENSE should be as close as possible to the LTC1538-AUX/ LTC1539 will result the (+) plates of C topside MOSFETs as closely as possible? This capaci- tor provides the AC current to the MOSFETs. ...
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... LTC1538-AUX/LTC1539 U U APPLICATIONS INFORMATION turns ratio for the secondary flyback winding. Keep these switch-node-related PC traces small and away from the “quiet” side of the IC (not just above and below each other on the opposite side of the board). The electromagnetic or current-loop induced feedback ...
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... PROG2 SW2 OSENSE2 15 22 – SENSE 2 TGL2 SENSE 2 BOOST RUN/SS2 AUXON B2 0 AUXDR AUXFB Figure 13. LTC1539 Physical Layout Diagram LTC1538-AUX/LTC1539 C M1 IN1 SENSE1 + V OUT1 OUT1 – GROUND PLANE – C OUT2 OUT2 R SENSE2 ...
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... LTC1538-AUX/LTC1539 U TYPICAL APPLICATIONS 26 + ...
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... U TYPICAL APPLICATIONS LTC1538-AUX/LTC1539 27 ...
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... LTC1538-AUX/LTC1539 U TYPICAL APPLICATIONS 28 ...
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... U TYPICAL APPLICATIONS LTC1538-AUX/LTC1539 29 ...
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... LTC1538-AUX/LTC1539 U PCB LAYOUT A D FIL Silkscreen Top Copper Layer 1 Copper Layer (Gerber files for this circuit board are available. Call the LTC factory.) Silkscreen Bottom Copper Layer 2 Ground Plane Copper Layer 4 ...
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... TYP 0.031 (0.800) TYP ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE LTC1538-AUX/LTC1539 0.397 – 0.407* (10.07 – 10.33 0.301 – 0.311 (7.65 – 7.90 0.068 – ...
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... LTC1538-AUX/LTC1539 U TYPICAL APPLICATION 2.9V AUXON ON/OFF RELATED PARTS PART NUMBER DESCRIPTION LTC1142/LTC1142HV Dual High Efficiency Synchronous Step-Down Switching Regulators LTC1148/LTC1148HV High Efficiency Step-Down Switching Regulator Controllers LTC1159 High Efficiency Step-Down Switching Regulator Controller ® LT 1375/LT1376 1.5A, 500kHz Step-Down Switching Regulators LTC1430 High Power Step-Down Switching Regulator Controller ...