LTC3736-2 Linear Technology, LTC3736-2 Datasheet
LTC3736-2
Related parts for LTC3736-2
LTC3736-2 Summary of contents
Page 1
... An internal soft-start, which can be lengthened externally, smoothly ramps the output voltage during start-up. The LTC3736-2 is available in the tiny thermally enhanced (4mm × 4mm) QFN and 24-lead narrow SSOP packages. , LTC and LT are registered trademarks of Linear Technology Corporation trademark of Linear Technology Corporation ...
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... LTC3736 ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (V ) ........................ – 0.3V to 10V IN PLLLPF, RUN/SS, SYNC/FCB TRACK, SENSE1 , SENSE2 , IPRG1, IPRG2 Voltages ................. – 0. Voltages .................. – 0.3V to 2.4V FB1 FB2 TH1 TH2 SW1, SW2 Voltages ............ – PACKAGE/ORDER I FOR ATIO TOP VIEW 1 SW1 ...
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... FB Note 4: Dynamic supply current is higher due to gate charge being delivered at the switching frequency. Note 5: The LTC3736-2 is tested in a feedback loop that servos I specified voltage and measures the resultant V Note 6: Peak current sense voltage is reduced dependent on duty cycle to a percentage of value as shown in Figure 1. ...
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... LTC3736 TYPICAL PERFOR A CE CHARACTERISTICS Efficiency and Power Loss vs Load Current 100 V = 2.5V OUT 95 90 EFFICIENCY 100 LOAD CURRENT (mA) Load Step (Pulse-Skipping Mode) V OUT AC-COUPLED 100mV/DIV I L 2A/DIV V = 3.3V 100µs/DIV 1.8V OUT I = 300mA TO 3A LOAD ...
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... TEMPERATURE (°C) 37362 G13 Undervoltage Lockout Threshold vs Temperature 2.50 2.45 2.40 2.35 2.30 2.25 2.20 2.15 2. 100 –60 –40 37362 G15 LTC3736-2 www.DataSheet4U.com = 25°C unless otherwise noted. Regulated Feedback Voltage vs Temperature 0.606 0.605 0.604 0.603 0.602 0.601 0.600 0.599 0.598 0.597 0.596 0.595 0.594 –60 –40 –20 0 ...
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... LTC3736 TYPICAL PERFOR A CE CHARACTERISTICS Shutdown Quiescent Current vs Input Voltage 20 RUN/ INPUT VOLTAGE ( CTIO S (QFN/SSOP Package (Pins 1, 8/Pins 4, 11): Current Threshold and TH1 TH2 Error Amplifier Compensation Point. Nominal operating range on these pins is from 0 ...
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... SEC EXTSS – PHASE SYNC DETECT DETECTOR CLK1 VOLTAGE SLOPE CONTROLLED CLK2 COMP OSCILLATOR – – V FB1 FCB FCB + + 0.54V + – V FB2 LTC3736-2 www.DataSheet4U.com (Pins 24, 7/Pins 3, 10): Feedback Pins. Receives INTSS SLOPE1 SLOPE2 UV1 PGOOD OV1 SHDN 37362 FD OV2 UV2 37362fa 7 ...
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... LTC3736 CTIO AL DIAGRA CLK1 – ICMP + IPRG1 OV1 8 W (Controller 1) RS1 SWITCHING LOGIC ANTISHOOT AND THROUGH OV1 BLANKING CIRCUIT SC1 FCB IREV1 SLOPE1 SW1 + SENSE1 SHDN + EAMP – SC1 + V FB1 OVP IREV1 RICMP – 0.68V IPROG1 www.DataSheet4U.com SENSE1 ...
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... THROUGH OV2 BLANKING SC2 CIRCUIT FCB IREV2 SLOPE2 SW2 + SENSE2 SHDN + EAMP – SC2 SCP TRACK + V FB2 OVP IREV2 – 0.68V FCB LTC3736-2 www.DataSheet4U.com SENSE2 TG2 MP2 PGND SW2 L2 V OUT2 + SENSE2 C BG2 OUT2 MN2 PGND – R2B V FB2 + R2A ...
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... Shutdown, Soft-Start and Tracking Start-Up (RUN/SS and TRACK Pins) The LTC3736-2 is shut down by pulling the RUN/SS pin low. In shutdown, all controller functions are disabled and the chip draws only 9µA. The TG outputs are held high (off) and the BG outputs low (off) in shutdown. Releasing RUN/SS allows an internal 0.7µ ...
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... OUT1 850kHz. In other words, the LTC3736-2’s PLL is guaran- teed to lock to an external clock source whose frequency is between 250kHz and 850kHz. Dropout Operation When the input supply voltage (V pin has risen 13 ...
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... EMI and power losses in the input capacitor and input power supply. With 2-phase operation, the two controllers of the LTC3736-2 are operated 180 degrees out of phase. This effectively interleaves the current pulses coming from the topside MOSFET switches, greatly reducing the time where they overlap and add together ...
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... U OPERATIO (Refer to Functional Diagram) Figure 2 shows example waveforms for a single phase dual controller versus a 2-phase LTC3736-2 system. In this case, 2.5V and 1.8V outputs, each drawing a load current of 2A, are derived from a 7V (e.g., a 2-cell Li-Ion battery) input supply. In this example, 2-phase operation would reduce the RMS input capacitor current from 1 ...
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... V = 2.5V) is required for applications GS that work close to this voltage. When these MOSFETs are used, make sure that the input supply to the LTC3736-2 is less than the absolute maximum MOSFET V which is typically 8V. The P-channel MOSFET’s on-resistance is chosen based on the required load current. The maximum average ...
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... LTC3736-2 applications. Selecting the N-channel MOSFET is typically easier, since for a given • off delays are much smaller than for a P-channel MOSFET. Table 1. Selected P-Channel MOSFETs Suitable for LTC3736-2 Applications • r • R PART NUMBER Si7540DP equation TOP ...
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... N-channel MOSFET from turning on and storing charge during the dead time, which could cost as much efficiency Schottky diode is generally a good size for most LTC3736-2 applications, since it conducts a relatively small average current. Larger diodes result in additional transition losses due to their larger junction capacitance ...
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... The output ripple is highest at maximum input voltage since I RIPPLE . IN Setting Output Voltage The LTC3736-2 output voltages are each set by an external feedback resistor divider carefully placed across the out- put, as shown in Figure 5. The regulated output voltage is determined by: V OUT To improve the frequency response, a feedforward capaci- tor may be used ...
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... LTC3736-2. Pulling the RUN/SS pin below 0.65V puts the LTC3736-2 into a low quiescent current shutdown mode (I RUN/SS has been pulled all the way to ground, there will be a delay before the LTC3736-2 comes out of shutdown and is given by ...
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... FCB, is shown in Figure 8 and specified in the Electrical Characteristics table. Note that the LTC3736-2 can only be synchronized to an external clock whose frequency is within range of the LTC3736-2’s internal VCO, which is nominally 200kHz to 1MHz. This is guaranteed, over temperature and variations between 300kHz and 750kHz. A simplified block diagram is shown in Figure 9 ...
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... LTC3736 APPLICATIO S I FOR ATIO SYNC/ FCB EXTERNAL OSCILLATOR PLLLPF pin. If the external and internal frequencies are the same but exhibit a phase difference, the current sources turn on for an amount of time corresponding to the phase difference. The voltage on the PLLLPF pin is adjusted until the phase and frequency of the internal and external oscillators are identical ...
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... Maximum Sense Voltage for Low Input Supply Minimum On-Time Considerations Minimum on-time, t time that the LTC3736-2 is capable of turning the top P-channel MOSFET on and then off determined by internal timing delays and the gate charge required to turn on the top MOSFET. Low duty cycle and high frequency ...
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... L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, five main sources usually account for most of the losses in LTC3736-2 circuits: 1) LTC3736-2 DC bias current, 2) MOSFET gate charge current and 4) transition losses. 1) The V ...
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... It is most important to keep the ground paths with high switch- ing currents away from each other. The PGND pins on the LTC3736-2 IC should be shorted together and connected to the common power ground connection (away from the switching currents). ...
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... LTC3736 APPLICATIO S I FOR ATIO BOLD LINES INDICATE HIGH, SWITCHING CURRENT LINES. KEEP LINES TO A MINIMUM LENGTH MP1 MN1 MP2 MN2 Figure 14. Branch Current Waveforms www.DataSheet4U.com L1 V OUT1 + C R OUT1 OUT2 + C R OUT2 L2 37362 F14 ...
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... FB2 8 MP2 I TH2 6 10 Si3447BDV R ITH2 TRACK SW2 22k PGND FB2B TRACKA TRACKB 118k 59k 118k L1, L2: VISHAY IHLP-2525CZ-01 D1, D2: OPTIONAL LTC3736-2 www.DataSheet4U.com L1 1.5µH V OUT1 2.5V 6A MN1 + Si7540DP C OUT1 150µF MN2 C OUT2 Si7540DP 150µ OUT2 1. 1.5µH 37362 F15 L1 1.5µ ...
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... LTC3736-2 U TYPICAL APPLICATIO S R FB1A 59k C ITH1 1nF C LP 10nF V IN 3.3V R 10Ω VIN C IN 22µF C ITH2 C 1nF VIN 1µF R FB2A 59k Figure 17. 2-Phase, Synchronizable, Dual Output Synchronous DC/DC Converter 26 C FF1 100pF R FB1B 187k CLK IN MP1 ITH1 + SW1 SENSE1 22k ...
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... TOP MARK (NOTE 5) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 4. EXPOSED PAD SHALL BE SOLDER PLATED 5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6. DRAWING NOT TO SCALE LTC3736-2 www.DataSheet4U.com 7.90 – 8.50* (.311 – .335 7.40 – 8.20 (.291 – .323) 2 ...
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... LTC3736-2 U TYPICAL APPLICATIO 2-Phase, 750kHz, Dual Output Synchronous DC/DC Converter R FB1A 59k C ITH1A 100pF C ITH1 1000pF 22µF C 1000pF VIN 1µ 10nF R FB2A 59k RELATED PARTS PART NUMBER DESCRIPTION LTC1735 High Efficiency Synchronous Step-Down Controller TM LTC1778 No R Synchronous Step-Down Controller ...