 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SC4612HEVB Datasheet(PDF) 9 Page - Semtech Corporation |
|
||||||||||||||||||||||||||||||
SC4612HEVB Datasheet(HTML) 9 Page - Semtech Corporation |
|
|
9 / 18 page  SC4612H 9 EN pin is used to set the Soft Start duration. . . . . . . . . . . . . . . . . . . . . . () 6 SS SS 10 25 C 5 . 0 t − ⋅ ⋅ ≈ Startup is inhibited until VDD input reaches the UVLO threshold (typically 4.5V). Once VDD rises above UVLO, the external soft start capacitor begins to charge from an internal 25uA current source. When the SS/EN pin reaches approximately 0.8V, top side switching is enabled. However, a top side pulse will not occur until SS/EN has charged up to the level appropriate for the existing output voltage (a pre bias condition). Once the first top side gate pulse actually occurs, the bottom side driver is enabled and the remainder of the startup is fully synchronous. In the event of an over current during startup, the SC462H behaves in the same manner as an over current in steady state (see Over Current Protection). Oscillator Frequency Selection: The internal oscillator sawtooth signal is generated by charging an external capacitor with an internal 00μA current source. Under Voltage Lock Out Under Voltage Lock Out (UVLO) circuitry senses the VDD through a voltage divider. If this signal falls below 4.5V (typical) with a 400mV hysteresis (typical), the output drivers are disabled. During the thermal shutdown, the output drivers are disabled. General Description The SC462H is a versatile voltage mode synchronous rectified buck PWM convertor, with an input supply (VIN) ranging from 4.5V to 40V designed to control and drive N-channel MOSFETs. The power dissipation is controlled by allowing high speed and integration with the high drive currents to ensure low MOSFET switching loss. The synchronous buck configuration also allows converter sinking current from load without losing output regulation. The internal reference is trimmed to 500mV with ± % accuracy, and the output voltage can be adjusted by an external resistor divider. A fixed oscillator frequency (up to .2MHz) can be programmed by an external capacitor for design optimization. Other features of the SC462H include: Wide input power voltage range (from 4.5V to 40V), low output voltages, externally programmable soft- start, hiccup over current protection, wide duty cycle range, thermal shutdown, and -40 to 25°C junction operating temperature range. Theory of Operation Supplies: Two pins (VDD and DRV) are used to power up the SC462H. If input supply (Vin) is less than 0V, tie DRV and VDD together. This DRV supply should be bypassed with a low ESR 2.2uF (or greater) ceramic capacitor directly at the DRV to GND pins of the SC462H. The DRV supply also provides the bias for the low and the high side MOSFET gate drive. The maximum rating for DRV supply is 0V and for applications where input supply is below 0V, it should be connected directly to VDD. The internal pass transistor will regulate the DRV from an external supply connected to VDD to produce 7.8V typical at the DRV pin. Soft Start / Shut down: The SC462H performs a “pre-bias” type startup. This ensures that a pre-charged output capacitor will not cause the SC462H to turn on the bottom FET during startup to discharge it, as a normal synchronous buck controller would do. An external capacitor on the SS/ Applications Information |
Similar Part No. - SC4612HEVB |
|
Similar Description - SC4612HEVB |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
