LTC1709-9 Linear Technology, LTC1709-9 Datasheet
LTC1709-9
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LTC1709-9 Summary of contents
Page 1
... H SW2 BG2 INTV SENSE2 – SENSE2 Figure 1. High Current Dual Phase Step-Down Converter Final Electrical Specifications LTC1709-8/LTC1709-9 2-Phase, 5-Bit VID, May 2000 U 1709-8/LTC1709-9 are 2-phase, VID program 28V 10 F 35V 4 0.002 1 H 0.002 V OUT 1.3V TO 3.5V 40A C + ...
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... LTC1709-8/LTC1709 ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (V ).........................36V to – 0.3V IN Topside Driver Voltages (BOOST1,2) .........42V to – 0.3V Switch Voltage (SW1, 2) .............................36V to – – SENSE1 , SENSE2 , SENSE1 , – SENSE2 Voltages ........................ (1.1)INTV + – EAIN EXTV , INTV , RUN/SS ATTENIN, ATTENOUT, PGOOD, BIAS VID0– ...
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... EXTVCC 20mA EXTVCC I = 20mA EXTVCC I = 20mA, EXTV Ramping Positive 20mA, EXTV Ramping Negative CC CC LTC1709-8 LTC1709-9 LTC1709-8: VID4 = 0; LTC1709-9 LTC1709-8: VID4 = 1 (Note 8) V < VID0–VID4 < 7V BIAS V = 1.2V PLLFLTR PLLFLTR V 2.4V PLLFLTR f < f PLLIN OSC f > f PLLIN OSC LTC1709-8/LTC1709 unless otherwise noted ...
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... T J dissipation P according to the following formula: D LTC1709EG • Note 4: The LTC1709-8/LTC1709-9 are tested in a feedback loop that servos specified voltage and measures the resultant V ITH W U TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Output Current (Figure 12) 100 80 V ...
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... Duty Factor DUTY FACTOR (%) Maximum Current Sense Threshold vs Sense Common Mode Voltage COMMON MODE VOLTAGE (V) LTC1709-8/LTC1709-9 INTV and EXTV Switch CC CC Voltage vs Temperature 5.05 INTV VOLTAGE CC 5.00 4.95 4.90 4.85 4.80 EXTV SWITCHOVER THRESHOLD CC 4.75 4. – 50 – 25 ...
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... LTC1709-8/LTC1709 TYPICAL PERFOR A CE CHARACTERISTICS Load Regulation 0.0 FCB = 15V IN FIGURE 1 –0.1 –0.2 –0.3 –0 LOAD CURRENT (A) 1629 G13 Maximum Current Sense Threshold vs Temperature –50 – TEMPERATURE ( C) Soft-Start (Figure 12) V ITH 1V/DIV ...
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... TH PLLFLTR (Pin 5): The phase-locked loop’s lowpass filter + and SENSE pins in is tied to this pin. Alternatively, this pin can be driven with voltage source to vary the frequency of the internal oscillator. LTC1709-8/LTC1709-9 Oscillator Frequency vs Temperature 350 V FREQSET 300 250 V ...
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... LTC1709-8/LTC1709 CTIO S PLLIN (Pin 6): External Synchronization Input to Phase Detector. This pin is internally terminated to SGND with 50k . The phase-locked loop will force the rising top gate signal of controller synchronized with the rising edge of the PLLIN signal. NC (Pins 7, 36): Do not connect. ...
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... V OS DIFFOUT V 0.80V REF 4.7V 5V – EXTV LDO CC REG INTV SGND INTERNAL SUPPLY 20k (LTC1709-8) ATTENIN 10k (LTC1709-9) ATTENOUT R1 VID0 W DUPLICATE FOR SECOND CONTROLLER CHANNEL DROP OUT DET BOT FORCE BOT SHDN I 1 – – 0.86V 4 SLOPE ...
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... LTC1709-8/LTC1709-9 U OPERATIO (Refer to Functional Diagram) Main Control Loop The LTC1709 uses a constant frequency, current mode step-down architecture with inherent current sharing. During normal operation, the top MOSFET is turned on each cycle when the oscillator sets the RS latch, and turned off when the main current comparator, I the RS latch ...
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... OUT a maximum average output current I value less half the peak-to-peak ripple current, I PolyPhase is a trademark of Linear Technology Corporation. LTC1709-8/LTC1709-9 are chosen based on the required peak output and an input common SENSE ). The current com- CC ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO Allowing a margin for variations in the LTC1709 and external component values yields 2(50mV/I ) SENSE MAX Operating Frequency The LTC1709 uses a constant frequency, phase-lockable architecture with the frequency determined by an internal capacitor. This capacitor is charged by a fixed current plus an additional current which is proportional to the voltage applied to the PLLFLTR pin ...
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... For V high current efficiency generally improves with larger MOSFETs, while for V increase to the point that the use of a higher R with lower C CC Kool registered trademark of Magnetics, Inc. LTC1709-8/LTC1709-9 Pin Connection). Consequently, logic-level CC , reverse transfer capacitance C DS(ON) V OUT ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO synchronous MOSFET losses are greatest at high input voltage when the top switch duty factor is low or during a short-circuit when the synchronous switch is on close to 100% of the period. The term ( generally given for a MOSFET in the ...
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... The input supply current should be measured while the controller is operating in continuous mode at maximum V and the power dissipation calculated in order to IN prevent the maximum junction temperature from being exceeded. LTC1709-8/LTC1709-9 pin from the V supply pin. The INTV CC IN pin regulator can supply up to 50mA CC ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO EXTV Connection CC The LTC1709 contains an internal P-channel MOSFET switch connected between the EXTV When the voltage applied to EXTV CC internal regulator is turned off and an internal switch closes, connecting the EXTV pin to the INTV CC thereby supplying internal and MOSFET gate driving power to the IC ...
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... The LTC1709-8 has an output voltage range of 1.30V to 3.5V in 50mV and 100mV steps. The LTC1709-9 has an output voltage range of 1.10V to 1.85V in 25mV steps. Between the ATTENOUT pin and ground is a variable resistor, R1, whose value is controlled by the five VID input pins (VID0 to VID4) ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO Each VID digital input is pulled 40k resistor in series with a diode from V . Therefore, it must be BIAS grounded to get a digital low input, and can be either floated or connected get a digital high input. The BIAS series diode is used to prevent the digital inputs from ...
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... LTC1709 PLLIN pin must be driven from a low impedance SS source such as a logic gate located close to the pin. ) EXTERNAL = SS OSC PLLIN Figure 7. Phase-Locked Loop Block Diagram LTC1709-8/LTC1709 equal to the capture range 0.5 f (150kHz-300kHz greater than the oscil- PLLIN , current is sourced continuously, ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO The loop filter components ( current pulses from the phase detector and provide a stable input to the voltage controlled oscillator. The filter components C and R determine how fast the loop LP LP acquires lock. Typically R =10k and ...
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... AC filtered closed loop response test point. The DC step, rise time, and settling at this test point truly reflects the closed loop response. Assuming a predominantly second order system, phase margin and/or damping factor can be LTC1709-8/LTC1709-9 current has two components: the first is the current typically results in a small IN to 20m of ESR ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO estimated using the percentage of overshoot seen at this pin. The bandwidth can also be estimated by examining the rise time at the pin. The I external components TH shown in the Figure 1 circuit will provide an adequate starting point for most applications. ...
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... The output capacitor ripple current is calculated by using the inductor ripple already calculated for each inductor and multiplying by the factor obtained from Figure 3 A 300 pF along with the calculated duty factor. The output ripple in LTC1709-8/LTC1709 013 ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO continuous mode will be highest at the maximum input voltage since the duty factor is < 50%. The maximum output current ripple is: V OUT COUT COUTMAX 300 kHz RMS V 20 ...
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... Figure 11 graphically illustrates the principle SW1 L1 R SENSE1 D1 SW2 L2 R SENSE2 CIN I COUT Figure 11. Single and 2-Phase Current Waveforms LTC1709-8/LTC1709-9 V OUT C OUT + SINGLE PHASE DUAL PHASE SW1 V SW2 CIN I COUT R L 170989 F10 ...
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... LTC1709-8/LTC1709 APPLICATIO S I FOR ATIO The worst-case RMS ripple current for a single stage design peaks at an input voltage of twice the output voltage. The worst-case RMS ripple current for a two stage design results in peak outputs of 1/4 and 3/4 of input voltage. When the RMS current is calculated, higher effective duty factor results and the peak current levels are divided as long as the currents in each stage are balanced ...
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... Plastic SSOP (0.209) (LTC DWG # 05-08-1640 – 8 0.65 (0.0256) BSC 0.25 – 0.38 (0.010 – 0.015) LTC1709-8/LTC1709-9 12.67 – 12.93* (0.499 – 0.509 7.65 – 7.90 (0.301 – 0.311 1.73 – 1.99 (0.068 – ...
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... LTC1709-8/LTC1709-9 U TYPICAL APPLICATIO 1 RUNN/SS 2 0.1 F SENSE1 1000pF 3 SENSE1 2.7k 4 EAIN 10k 5 INTV PLLFLTR CC 6 51k PLLIN 15k 7 NC 47k 3.3nF 100pF 9 SGND SENSE2 1000pF 14 SENSE2 15 ATTENOUT 470pF 16 ATTENIN 17 VID0 18 VID1 Figure 12. 1.3V to 2.5V/20A CPU Power Supply with Active Voltage Positioning ...