Electronic Components Datasheet Search |
|
LM2647 Datasheet(PDF) 5 Page - Texas Instruments |
|
|
LM2647 Datasheet(HTML) 5 Page - Texas Instruments |
5 / 43 page LM2647 www.ti.com SNVS210E – MAY 2004 – REVISED JUNE 2005 Pin Description (continued) Pin 20, LDRV2: Gate drive pin for the Channel 2 bottom FET (Low-side drive). The bottom gate driver is interlocked with the top gate driver to prevent shoot-through/cross-conduction. It is always latched high when a fault condition is asserted by the IC. Pin 21, V5: Upper rail of the lower FET drivers of both channels. Also used to charge up the bootstrap capacitors of the upper FET drivers. This is connected to an external 5V supply. The 5V rail may be the same as the rail used to provide power to the VDD pin (Pin 5), but the VDD pin will then require to be well-decoupled so that it does not interact with the V5 pin. A low-pass RC filter consisting of a ceramic 0.1µF capacitor (preferably 0.22µF) and a 10 Ω resistor will suffice as shown in the Typical Applications circuit. Pin 22, VIN: The input to both the Buck regulator power stages. It also is used by the internal ramp generator to implement the line feedforward feature. The VIN pin is also used with the SENSE pin voltage to predict the CCM (continuous conduction mode) duty cycle and to thereby set the minimum allowed DCM duty cycle to 85% of the CCM value (in SKIP mode, see Pin 10). This is a high input impedance pin, drawing only about 100µA (typical) from the input rail. Pin 23, LDRV1: LDRV pin of Channel 1. See Pin 20. Pin 24, PGND1: PGND pin for Channel 1.See Pin 19. Pin 25, BOOT1: Boot pin of Channel 1. See Pin 18. Pin 26, HDRV1: HDRV pin of Channel 1. See Pin 17. Pin 27, SW1: SW pin of Channel 1. See Pin 16. Pin 28, ILIM1: Channel 2 Current Limit pin. See Pin 15. These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) Voltages from the indicated pins to SGND/PGND unless otherwise indicated (2): VIN 30V V5 7V VDD 7V BOOT1, BOOT2 36V BOOT1 to SW1, BOOT2 to SW2 7V SW1, SW2 30V ILIM1, ILIM2 30V SENSE1, SENSE2, FB1, FB2 7V PGOOD 7V EN 7V Power Dissipation (TA = 25°C) (3) 1.0W Junction Temperature +150°C ESD Rating (Note 4) 2kV Ambient Storage Temperature Range -65°C to +150°C Soldering Dwell Time, Temperature Wave 4 sec, 260°C Infrared 10 sec, 240°C Vapor Phase 75 sec, 219°C (1) Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is guaranteed. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics table. (2) PGND1, PGND2 and SGND are all electrically connected together on the PCB. (3) The maximum allowable power dissipation is calculated by using PDmax = (TJMAX - TA) /θJA , where TJMAX is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction-to-ambient thermal resistance of the specified package. The 1.0W rating of the TSSOP-28 package for example results from using 125°C, 25°C, and 97°C/W for TJMAX, TA, and θJA respectively. The 2.85W rating of the 28-pin LLP package results from using 125°C, 25°C, and 35°C/W for TJMAX, TA, and θJA respectively. The rated power dissipation should be derated by 10mW/°C above 25°C ambient for the TSSOP package and 29mW/°C above 25°C ambient for the LLP package. The θJA value above represents the worst-case condition with no heat sinking. Heat sinking will permit more power to be dissipated at higher ambient temperatures. For detailed information on soldering plastic TSSOP and LLP packages, refer to http://www.national.com/packaging/. Copyright © 2004–2005, Texas Instruments Incorporated Submit Documentation Feedback 5 Product Folder Links: LM2647 |
Similar Part No. - LM2647 |
|
Similar Description - LM2647 |
|
|
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 |