LT3640EFE LINER [Linear Technology], LT3640EFE Datasheet
LT3640EFE
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LT3640EFE Summary of contents
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FEATURES n High Voltage Buck Regulator 36V Operating Range 1.3A Output Current n OVLO Protects Input to 55V n Low Voltage Synchronous Buck Regulator: 2.5V to 5.5V Input Voltage Range 1A Output Current n Synchronizable, Adjustable 350kHz to ...
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... JA EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LT3640EFE#PBF LT3640EFE#TRPBF LT3640IFE#PBF LT3640IFE#TRPBF LT3640EUFD#PBF LT3640EUFD#TRPBF LT3640IUFD#PBF LT3640IUFD#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER V Undervoltage Lockout Threshold IN V Undervoltage Release Threshold IN V Overvoltage Lockout Threshold IN V Overvoltage Release Threshold IN Quiescent Current from V IN EN/UVLO Threshold Voltage EN/UVLO ...
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LT3640 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER SS1, SS2 Charge Current SS1 to FB1 Offset Voltage SS2 to FB2 Offset Voltage RST1 Threshold as Percentage RST2 Threshold as Percentage ...
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TYPICAL PERFORMANCE CHARACTERISTICS HV Channel Effi ciency (2MHz 3.3V) OUT1 12V 16V 24V 0.2 0.4 0.6 0.8 1.0 1.2 V CURRENT (A) OUT1 ...
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LT3640 TYPICAL PERFORMANCE CHARACTERISTICS FB2 Voltage vs SS2 700 600 500 400 300 200 100 0 0 400 6000 800 1000 200 SS2 VOLTAGE (mV) 3640 G10 LV Channel Peak Current Limit vs Duty Cycle 2.0 1.5 1.0 0.5 0.0 ...
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TYPICAL PERFORMANCE CHARACTERISTICS Full Frequency Waveforms SW1 10V/DIV I L1 0.5A/DIV SW2 5V/DIV I L2 0.5A/DIV 3640 G18 200ns/DIV V = 12V IN1 IN2 OUT1 V = 3.3V/0. 1.8V/0.5A OUT1 OUT2 Watchdog Upper Boundary Period ...
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LT3640 PIN FUNCTIONS (FE/QFN) FB2 (Pin 1/Pin 26): The low voltage converter regulates the FB2 pin to 600mV. Connect the feedback resistor divider tap to this pin to set output voltage. PGOOD (Pin 2/Pin 27): Open-drain logic output that starts ...
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BLOCK DIAGRAM 2μA EN/ 100k UVLO 5.5V 2μA SS1 R2 FB1 V OUT1 + R1 – + – A8 2μA SS2 R4 FB2 V OUT2 R3 PGOOD 2μA CPOR POR TIMER + – ENABLE – S ...
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LT3640 TIMING DIAGRAMS FB RST WDI WDO t < t OPERATION The LT3640 is a dual channel, constant-frequency, current mode monolithic buck switching regulator with power-on reset and watchdog timer. Both channels are synchronized to a single oscillator with frequency ...
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OPERATION when the V pin voltage is above 2.3V, the EN2 pin is IN2 pulled high and the FB1 pin voltage is above 1.165V. The internal top power MOSFET is turned on each cycle at the beginning of each oscillator ...
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LT3640 APPLICATIONS INFORMATION Setting the Output Voltages The internal reference voltage is 1.265V for the high volt- age channel, and 600mV for the low voltage channel. The output voltages are set by resistor dividers according to the following formulas: ⎛ ...
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APPLICATIONS INFORMATION The maximum V should not exceed the absolute maxi- IN mum rating. For fi xed frequency operation, the maximum V is: IN ⎛ ⎞ OUT − ⎝ ⎜ ⎠ ⎟ ...
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LT3640 APPLICATIONS INFORMATION the ripple current is determined, the inductance for the high voltage channel is: ⎛ V OUT − 1 ⎝ ⎜ V ≈ • OUT 1 D Δ ...
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APPLICATIONS INFORMATION ring to twice its nominal value, possibly exceeding the LT3640’s voltage rating. This situation can be easily avoided (see the Linear Technology Application Note 80). Output Capacitors and Output Ripple The output capacitor has two essential functions. In ...
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LT3640 APPLICATIONS INFORMATION BST and SW Pin Considerations The high voltage channel requires an external capacitor between the BST and SW pins and an external boost diode from a voltage source to the BST pin. In most cases, a 0.22μF ...
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APPLICATIONS INFORMATION In the event of V undervoltage lockout lockout or the EN/UVLO pin being driven below 1.26V, the soft-start latch is set, triggering a start-up sequence. A latch is set to discharge the SS2 pin at power-up. ...
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LT3640 APPLICATIONS INFORMATION Reverse Protection In battery charging applications or in battery back-up systems, the output will be held high when the input to the LT3640 is absent. If the V pin is fl oated and the LT3640 is IN ...
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APPLICATIONS INFORMATION pull-ups eliminate the need for external pull-ups when the rise time of these pins is not critical. The open-drain confi guration allows wired-OR connections. The two power-on reset timers share one oscillator. The power-on reset timeout period, t ...
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LT3640 APPLICATIONS INFORMATION Figure 9a shows the power-on reset timing. Having FB1 or FB2 high starts the CPOR oscillator. After t responding RST is released. When both RST1 and RST2 are released, the CWDT oscillator starts. Figure 9b shows the ...
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TYPICAL APPLICATIONS 34V L1: VISHAY IHLP-2020 L2: VISHAY IHLP-1616 D1: DIODES B240A D2: CENTRAL SEMI CMDSH- 34V OUT1 100k 100k L1: VISHAY IHLP-2020 L2: VISHAY IHLP-1616 D1: DIODES B240A D2: CENTRAL SEMI ...
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LT3640 PACKAGE DESCRIPTION 4.75 (.187) 6.60 ±0.10 4.50 ±0.10 SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 0.50 – 0.75 (.0035 – .0079) (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. ...
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PACKAGE DESCRIPTION 4.50 ± 0.05 3.10 ± 0.05 2.50 REF 2.65 ± 0.05 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 5.00 ± ...
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LT3640 TYPICAL APPLICATION 34V 4.7μF RELATED PARTS PART NUMBER DESCRIPTION LT1933 500mA (I ), 500kHz Step-Down Switching Regulator in SOT-23 OUT LT1936 36V, 1. 500kHz, High Effi ciency Step-Down DC/DC OUT Converter LT1940 Dual ...