ld7552 Leadtrend Technology, ld7552 Datasheet
ld7552
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ld7552 Summary of contents
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... General Description The LD7552 is a low cost, low startup current, current mode PWM controller with green-mode power-saving operation. The integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation and the small package provide the users a high efficiency, minimum external component counts, and low cost solution for AC/DC power applications ...
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... CS Current sense pin, connect to sense the MOSFET current 7 VCC Supply voltage pin 8 OUT Gate drive output to drive the external MOSFET Leadtrend Technology Corporation LD7552-DS-00 February, 2005 YY: Year code (D: 2004, E: 2005…..) WW: week code TOP MARK PP: production code YYWWPP ...
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... Storage Temperature Range Package thermal resistance (DIP-8) Package thermal resistance (SOP-8) Lead temperature (LD7552IS & LD7552IN, Soldering, 10sec) Lead temperature (LD7552BS & LD7552BN, Soldering, 10sec) Caution: Stresses beyond the ratings specified in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied ...
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... Input impedance Delay to Output Oscillator (RT pin) Frequency Green Mode Frequency Temp. Stability Voltage Stability Gate Drive Output (OUT Pin) Output Low Level Output High Level Rising Time Falling Time Leadtrend Technology Corporation LD7552-DS-00 February, 2005 =15.0V) CC CONDITIONS V =0V COMP V =3V COMP V =open COMP ...
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... Temperature (°C) Fig. 1 UVLO (Off) vs. Temperature 72.0 71.0 70.0 69.0 68.0 67.0 66.0 -40 - Temperature (°C) Fig. 3 Frequency vs. Temperature 75.9 75.6 75.3 75.0 74.7 74.4 -40 - Temperature (°C) Fig. 5 Duty-Cycle (max.) vs. Temperature Leadtrend Technology Corporation LD7552-DS-00 February, 2005 17.0 16.8 16.4 16.0 15.6 15.2 14.8 14.4 14 100 120 18.2 18.0 17.8 17.6 17.4 17.2 17 100 120 60 80 100 120 5 LD7552 -40 - ...
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... Under Voltage Lockout (UVLO) An UVLO comparator is included to detect the voltage on the Vcc pin to ensure the supply voltage enough to power on the LD7552 PWM controller and in addition to drive the power MOSFET. As shown in Fig hysteresis is provided to prevent the shutdown from the voltage dip during startup ...
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... On/Off Control The LD7552 can be controlled to turn off by pulling COMP pin to lower than 1.2V. The gate output pin of LD7552 will be disabled immediately under such condition. The off mode can be released when the pull-low signal is removed. Dual-Oscillator Green-Mode Operation ...
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... What LD7552 used to implement the power-saving operation is Leadtrend Technology’s own IP approach, as shown in the block diagram, 2 oscillators are implemented in LD7552. The first oscillator is to take care the normal switching frequency, which can be set by the RT pin through an external resistor. Under this operation mode, as shown in Fig ...
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... Package Information SOP-8 Symbols θ Leadtrend Technology Corporation LD7552-DS-00 February, 2005 Dimensions in Millimeters MIN MAX 4.801 5.004 3.810 3.988 1.346 1.753 0.330 0.508 1.194 1.346 0.178 0.229 0.102 0.254 5.791 6.198 0.406 1.270 0° ...
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... Important Notice Leadtrend Technology Corp. reserves the right to make changes or corrections to its products at any time without notice. Customers should verify the datasheets are current and complete before placing order. Leadtrend Technology Corporation LD7552-DS-00 February, 2005 Dimension in Millimeters ...