LT3837EFE#PBF Linear Technology, LT3837EFE#PBF Datasheet
LT3837EFE#PBF
Specifications of LT3837EFE#PBF
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LT3837EFE#PBF Summary of contents
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... Instrumentation Power Supplies n Isolated Medical Supplies L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6498466, 5841643. TYPICAL APPLICATION 9V –18V to 3.3V at 10A Isolated Converter 22 ...
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... Operating Junction Temperature Range (Notes ........................................ –40°C to 125°C Storage Temperature Range .................. –65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LT3837EFE#PBF LT3837EFE#TRPBF LT3837IFE#PBF LT3837IFE#TRPBF LEAD BASED FINISH TAPE AND REEL LT3837EFE LT3837EFE#TR Consult LTC Marketing for parts specifi ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are 27.4k 90k, unless otherwise specifi ed. PGDLY ENDLY PARAMETER Feedback Amplifi er Voltage Gain Soft-Start Charging Current Soft-Start Discharge Current Control Pin Threshold ( Gate ...
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LT3837 TYPICAL PERFORMANCE CHARACTERISTICS V Shutdown Current CC vs Temperature UVLO 14V – 100 –25 0 TEMPERATURE (°C) 3837 G01 SENSE ...
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TYPICAL PERFORMANCE CHARACTERISTICS Feedback Amplifi er Source and Sink Current vs Temperature 70 SOURCE CURRENT SINK CURRENT 1. – 100 –25 0 TEMPERATURE (°C) ...
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LT3837 TYPICAL PERFORMANCE CHARACTERISTICS PG Delay Time vs Temperature 300 250 R PGDLY 200 150 R PGDLY 100 50 0 –50 – TEMPERATURE (°C) PIN FUNCTIONS SG (Pin 1): Synchronous gate drive output. This pin pro- vides an ...
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PIN FUNCTIONS V (Pin 9): Pin used for frequency compensation for the C switcher control loop the output of the feedback amplifi er and the input to the current comparator. Switcher frequency compensation components are normally placed on ...
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LT3837 BLOCK DIAGRAM 1.237V REFERENCE ( DISABLE + 0.8V – UVLO 10 OSC 7 OSCILLATOR SYNC PGDLY 15 ENDLY 4 8 CLAMPS 0.7 + 1.3 – 1.25V 3V INTERNAL REGULATOR S ...
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FLYBACK FEEDBACK AMPLIFIER LT3837 FEEDBACK AMP 1.237V – + COLLAPSE DETECT ENABLE TIMING DIAGRAM PRIMARY SIDE MOSFET DRAIN VOLTAGE PG VOLTAGE SG VOLTAGE V FLBK – ...
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LT3837 OPERATION The LT3837 is a current mode switcher controller IC designed specifi cally for use in an isolated fl yback topology employing synchronous rectifi cation. The LT3837 operation is similar to traditional current mode switchers. The major difference is ...
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OPERATION Minimum Output Switch On-Time (t The LT3837 affects output voltage regulation via fl yback pulse action. If the output switch is not turned on, there is no fl yback pulse and output voltage information is not available. This causes ...
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LT3837 OPERATION LOAD COMP – CMP CMP Figure 1. Load Compensation Diagram Figure 1 shows the block diagram of the load compensa- tion ...
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APPLICATIONS INFORMATION Primary Winding Feedback The previous work was developed using a separate wind- ing for voltage feedback possible to use the primary winding as the feedback winding as well. This can simplify the design of the transformer. ...
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LT3837 APPLICATIONS INFORMATION ratio of between the two windings. Also keep the secondary MOSFET R small to improve cross regulation. DS(ON) Leakage Inductance Transformer leakage inductance (on either the primary or secondary) causes a spike after the primary side switch ...
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APPLICATIONS INFORMATION tight coupling usually increases primary-to-secondary capacitance and limits the primary-to-secondary break- down voltage isn’t always practical. Primary Inductance The transformer primary inductance the peak-to-peak ripple current ratio (X) in the trans- former relative to ...
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LT3837 APPLICATIONS INFORMATION Setting Feedback Resistive Divider Use the equation developed in the Operation section for the feedback divider recommended that the Thevenin impedance of the resistors on the FB Pin is roughly 3k for bias current cancellation ...
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APPLICATIONS INFORMATION 5. Verify this result by connecting a resistor of this value from the R pin to ground. CMP 6. Disconnect the ground short to C requisite 0.1μF fi lter capacitor to ground. Measure the output impedance R = ...
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LT3837 APPLICATIONS INFORMATION Enable Delay Time (ENDLY) Enable delay time provides a programmable delay between turn-off of the primary gate drive node and the subsequent enabling of the feedback amplifi er. As discussed earlier, this delay allows the feedback amplifi ...
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APPLICATIONS INFORMATION dropping the voltage on UVLO. In this manner, hysteresis is produced. Referring to Figure 4, the voltage hysteresis at V equal to the change in bias current times R procedure is to select the desired V hysteresis, V ...
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LT3837 APPLICATIONS INFORMATION Minimum Load Considerations At light loads, the LT3837 derived regulator goes into forced continuous conduction mode. The primary side switch always turns on for a short time as set by the t resistor. If this produces more ...
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APPLICATIONS INFORMATION If the output load current is relatively constant, the feedback resistive divider is used to compensate for these losses. Otherwise, use the LT3837 load compensation circuitry (see Load Compensation). If multiple output windings are used, the fl yback ...
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LT3837 APPLICATIONS INFORMATION With C determined, calculate the primary-side power MILLER MOSFET power dissipation δ • R DPRI RMS PRI ( ) ...
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... LTC SwitcherCAD™ terrifi c free circuit simulation tool that is available at www.linear.com. Final optimization of output ripple must be done on a dedicated PC board. Parasitic inductance due to poor layout can signifi cantly impact ripple. Refer to the PC Board Layout section for more details. SwitcherCAD is a trademark of Linear Technology Corporation. LT3837 ( ) ...
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LT3837 APPLICATIONS INFORMATION IC Thermal Considerations Take care to ensure that the LT3837 junction temperature does not exceed 125°C. Power is computed from the aver- age supply current, the sum of quiescent supply current (I in the specifi cations) plus ...
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APPLICATIONS INFORMATION VCC LT3825 GND LT3825 CC SG GND TYPICAL APPLICATION 36V 10k MMBT3904 10μF 0.1μF 7.5V 100k 1% 29. UVLO PGDLY 3.01k 17.4k t SYNC ON 1% ...
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LT3837 PACKAGE DESCRIPTION 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 (.0035 – .0079) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. DIMENSIONS ARE IN 3. DRAWING NOT TO SCALE ...
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... Text Change to Applications Information Changes to Related Parts Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. LT3837 ...
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... Limited Only by External Components, Ideal for 24V Nominal IN OUT Input Voltage 2.5V ≤ V ≤ 32V, Current Mode Control, 200kHz to 2.5MHz, IN 3mm × 3mm DFN-8, MSOP-8E and ThinSOT are trademarks of Linear Technology Corporation. SENSE www.linear.com ● ® ≤ 36V, Burst Mode Operation IN 3837fc LT 1209 REV C • ...