NCP102 Low Dropout Linear Regulator Controller

Size: px

Start display at page:

Download "NCP102 Low Dropout Linear Regulator Controller"

Cornelia Hood
6 years ago
Views:

Low Dropout Linear Regulator Controller The NCP is a low dropout linear regulator controller for applications requiring highcurrent and ultra low dropout voltages.

1 Low Dropout Linear Regulator Controller The NCP is a low dropout linear regulator controller for applications requiring highcurrent and ultra low dropout voltages. The use of an external NChannel MOSFET allows the user to adapt the device to a multitude of applications depending on system requirements for current and dropout voltage. An extremely accurate.8 (±%) reference allows the implementation of sub voltage supplies. The reference is guaranteed over the complete supply and temperature ranges. Other features of the NCP are a dedicated enable input, internally compensated error amplifier and an adjustable softstart. A minimum drive capability of ± provides fast transient response. The drive current is internally limited to protect the controller in case of an external MOSFET failure. The NCP is packaged in a space saving TSOP. Features 4. to. Supply oltage Range.8 (±%) oltage Reference (Temperature and Process) Programmable Regulator Output oltage Down to.8 Drive Current Capability of > ± MLCC and POSCAP Compatible Programmable SoftStart Enable Active High Space Saving TSOP Package RoHS Compliant PbFree Package Applications Desktop and Laptops Computer Peripherals such as Graphics Cards Sub Power Supplies EN GND TSOP (SOT) SN SUFFIX CASE 8G = Device Code A = Assembly Location Y = Year W = Work Week = PbFree Package PIN CONNECTIONS FB 4 SOFTS (Top iew) CC DR ORDERING INFORMATION MARKING DIAGRAM AYW (Note: Microdot may be in either location) Device Package Shipping CHIP ENABLE EN GND FB U CC NCP DR SOFTS 4 CC C CC RG X R in C in OUT C OUT NCPSNTG TSOP (PbFree) /Tape & Reel For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8/D. C SOFTS C FB C OUT R Figure. Typical Application Semiconductor Components Industries, LLC, 8 January, 8 Rev. Publication Order Number: NCP/D

2 CC ULO CC EN CC I EN I SOFTS SOFTS GND FB DR Figure. Representative Block Diagram PIN FUNCTION DESCRIPTION Pin Symbol Name Description EN Enable Input (Active High). Pull the EN pin below.8 to disable the regulator and enter the standby mode operation. GND Ground FB Inverting input of the error amplifier. The output voltage is sampled by means of a resistor divider and applied to this pin for regulation. 4 SOFTS Programmable softstart. An internal current source charges the capacitor connected to this pin. The softstart period ends once the voltage of the softstart capacitor reaches.8. DR Gate drive for external NChannel MOSFET. It is also the buffered output of the error amplifier. CC Power supply voltage input. Operating voltage range is from 4. to.. A decoupling capacitor to GND should be used. A minimum of. F is recommended.

3 MAXIMUM RATINGS (T A = C, unless otherwise noted) Rating Symbol alue Unit Main Supply Input oltage Main Supply Input Current Enable oltage Enable Current SoftStart oltage SoftStart Current Drive oltage Drive Current Feedback oltage Feedback Current Thermal Resistance, JunctiontoAmbient (. sq in Printed Circuit Copper Clad) (. sq in Printed Circuit Copper Clad) CC. to I CC EN. to 9.7 I EN SOFTS. to 9.7 I SOFTS DR. to 9.7 I DR FB. to 9.7 I FB R JA Power Dissipation (T A = C, oz Cu,. sq in Printed Circuit Copper Clad) P D.4 W Storage Temperature Range T stg to C Operating Junction Temperature Range T J 4 to C Reflow Temperature seconds T reflow C Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.. This device series contains ESD protection and exceeds the following tests: Human Body Model (HBM) ±. k per JEDEC standard: JESDA4 Machine Model (MM) ± per JEDEC standard: JESDA. Latchup current maximum rating: ± per JEDEC standard: JESD78. C/W

4 ELECTRICAL CHARACTERISTICS ( CC =, EN =, DR = FB, SS = open, C CC =. F. For typical values T J = C. For min/max values, T J = 4 C to C, unless otherwise noted) Parameter Condition Min Typ Max Unit POWER SUPPLY Supply oltage CC 4.. Supply Current CC = CC = I CC I CC CC Startup oltage CC increasing CC(on) CC Turn Off oltage CC decreasing CC(off) CC Hysteresis CC(on) CC(off) CC(hys)..4. Standby Current EN =, CC = EN =, CC = I CC(off) I CC(off) ERROR AMPLIFIER Input Bias Current FB =. I FB.. A Open Loop DC Gain (Note ) A v 7 db Unity Gain Bandwidth FB = DR BW.7 MHz Power Supply Rejection Ratio (Note ) CC =, Hz PSRR db DRIE Sink Current Source Current Output oltage Drive Current Under Fault Conditions T J = C Low State High State DR =, FB = DR =., CC = FB = DR =, FB =. DR =., CC =, FB =. I DR =, FB = I DR =, FB =., CC = 9. DR =, FB =. DR = open, FB =. I DR(SNK). I DR(SNK). I DR(SRC). I DR(SRC). DR(low) DR(high) 9. I DR(MAX) I DR(MAX) SOFTSTART Source Current SOFTS = I SOFTS. 4.. A ENABLE Source Current I EN. A Input Threshold oltage On State Off State EN Increasing EN Decreasing EN(on).7 EN(off). Threshold oltage Hysteresis EN(on) EN(off) EN(hys) m REFERENCE Reference oltage CC =, CC = REF Guaranteed by design

5 TYPICAL CHARACTERISTICS I CC, SUPPLY CURRENT () Operating CC = CC, SUPPLY OLTAGE () Minimum Operating..8.7 Standby Figure. Supply Current vs. Junction Temperature Startup Threshold Figure 4. Supply oltage Thresholds vs. Junction Temperature A OL, OPEN LOOP OLTAGE GAIN (db) Gain Phase f, FREQUENCY (khz) T J = C CC = Figure. Error Amplifier Open Loop oltage Gain/Phase vs. Frequency PHASE ( ) I DR(SNK), DRIE SINK CURRENT () CC =, DR =, FB = CC =, DR =., FB = Figure. Drive Sink Current vs. Junction Temperature I DR(SRC), DRIE SOURCE CURRENT () 8 CC =, FB =. CC =, FB = Figure 7. Drive Source Current vs. Junction Temperature I DR(MAX), MAXIMUM DRIE CURRENT () DR =, FB =. DR = open, FB =. 7 Figure 8. Drive Current Under Fault Conditions vs. Junction Temperature

6 TYPICAL CHARACTERISTICS I SOFTS, SOFTSTART CHARGE ( A) Figure 9. SoftStart Charge Current vs. Junction Temperature EN, ENABLE THRESHOLD OLTAGE () On State Off State. 7 Figure. Enable Threshold oltages vs. Junction Temperature.9 REF, REFERENCE OLTAGE ().88 CC = Figure. Reference oltage vs. Junction Temperature

7 DETAILED OPERATING DESCRIPTION The NCP is a low dropout linear regulator controller for applications requiring highcurrent and ultra low dropout voltages. The use of an external NChannel MOSFET allows the user to adapt the device to a multitude of applications depending on system requirements for current and dropout voltage. An extremely accurate.8 (±%) reference allows the implementation of sub voltage supplies. The reference is guaranteed over the complete supply and temperature ranges. Other features of the NCP are a dedicated enable input, internally compensated error amplifier and an adjustable softstart. A minimum drive capability of ± provides fast transient response. The drive current is internally limited to protect the controller in case of an external MOSFET failure. The NCP is packaged in a space saving TSOP. SUPPLY OLTAGE The NCP supply voltage range is between 4. and.. The controller is enabled once the supply voltage exceeds its minimum supply threshold, typically 4.. The minimum operating voltage is reduced to 4. (typical) once the controller is enabled to provide noise immunity. A bypass capacitor is required on the CC pin to provide charge storage during power up and transient events. A minimum of. F is recommended. DRIE OUTPUT A powerful error amplifier (EA) capable of driving an external MOSFET is built into the NCP. The output of the error amplifier is connected to the DR pin. It has a minimum drive current capability of ± providing a fast transient response. The EA is biased directly from CC. The DR voltage follows CC up and it is internally clamped to 9.7 (typ.). This allows the use of external MOSFETs with a maximum gate voltage of. The DR current is provided directly from CC. Therefore, the CC capacitor should be large enough to maintain a constant CC during power up and transients. Otherwise, the supply voltage may collapse reaching the controller undervoltage lockout threshold. INTERNAL REFERENCE The internal.8 reference facilitates the implementation of sub supplies required in modern computing equipment. The internal reference is trimmed during manufacturing to obtain better than ±% accuracy over the complete operating range. The output voltage, out, is programmed using a resistor divider (R and R) as shown in Figure. The resistor divider senses the output voltage and compares it to the internal.8 reference. Equation relates the output voltage to the internal reference voltage and external resistors R and R. out REF R R (eq. ) R ERROR AMPLIFIER The NCP has a wide bandwidth error amplifier. It allows the user to implement a wide bandwidth feedback loop resulting in better transient response and lower system cost. It requires the user to compensate the system. A narrow bandwidth error amplifier usually does not require external compensation but it requires more output capacitance to meet typical transient requirements. The output of the error amplifier is available for frequency compensation. A capacitor (C COMP ) can be placed between the DR and FB pins. In most cases the resistor is not needed. The uncompensated error amplifier dominant pole is approximately. Hz. Any external capacitance between the DR and FB pins reduces the dominant pole frequency due to the Miller multiplication effect. Equation relates the dominant pole frequency to C COMP. f pole.7 C COMP.84 (eq. ) EXTERNAL ENABLE The EN input allows the NCP to be remotely enabled. An internal A (typ.) current source pulls up the EN voltage. The EN pin is internally pulled to CC or 9., whichever is lower. The controller is enabled once the EN pin voltage exceeds.8 (typ.). The controller is disabled by pulling down on the EN pin. Figure shows the relationship between enable and softstart. EN SOFTS out t SOFTS Figure. Relationship Between Enable and SoftStart The EN pin can be connected to CC if the enable feature is not used. If connected to CC and CC is higher than 9. a resistor in series should be used to limit the current into the EN pin as the pin is internally clamped to 9.. A minimum of 4 k is recommended. 7

8 SOFTSTART Softstart reduces inrush current and overshoot of the output voltage. The adjustable softstart built into the NCP allows the user to select the optimum softstart time for the application. The softstart time is set with a capacitor from the SOFTS pin to ground. Softstart is achieved by controlling the slope of the DR voltage based on the slope of the softstart capacitor voltage, C SOFTS. The capacitor is charged to CC with a constant 4. A (typ.) current source, I SOFTS. This results in a linear charge of the softstart capacitor and thus the output voltage. The softstart period, t SOFTS, ends once the capacitor voltage reaches.8 (typ). The softstart capacitor is calculated using Equation. t SOFT S c SOFT S.8 I SOFT S (eq. ) The softstart capacitor is internally pulled to GND when CC is not within its operating range or the controller is disabled using the EN pin. POWER SEQUENCING Power sequencing can be easily implemented using the SOFTS and EN pins. This is achieved by directly connecting the SOFTS pin of the master controller to the EN pin of the slave controller. If CC is above 9. a resistor divider is required to limit the voltage on the EN pin because the pin is internally clamped to 9.. Figure shows the timing waveforms of the master and slave controllers. out (master) SoftStart (master) out (slave) SoftStart (slave) Figure. Powerup Sequencing Waveforms Power sequencing will affect the softstart time calculated using Equation because the softstart capacitor charge current is now increased by the enable charge current. The softstart time is calculated using Equation by replacing I SOFTS with the sum of I EN and I SOFTS. APPLICATION INFORMATION ON Semiconductor provides an electronic design tool, a demonstration board and an application note to facilitate design using the NCP and to reduce development cycle time. All the tools can be downloaded at The electronic design tool allows the user to easily determine most of the system parameters of a linear regulator. The tool also evaluates the frequency response of the system. The demonstration board is designed to generate a. / A voltage supply from a.8 supply. The circuit schematic is shown in Figure 4 and the regulator design is described in Application Note AND8. R8 ENABLE k MMBT94 Q J C R p k TP R7 k TP U EN CC GND DR FB SOFTS 4 NCP TP4 C. CC in J TP TP. C NTD4N R J Open Q Q TPa C4 p R TP7 R R k C C7 C C8 TPa C. C TP out J TP TP8 TP9 TP TP R4 k J4 GND Figure 4. Circuit Schematic J 8

9 PACKAGE DIMENSIONS S L A 4 B TSOP CASE 8G ISSUE M NOTES:. DIMENSIONING AND TOLERANCING PER ANSI Y4.M, 98.. CONTROLLING DIMENSION: MILLIMETER.. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH THICKNESS. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. 4. DIMENSIONS A AND B DO NOT INCLUDE MOLD FLASH, PROTRUSIONS, OR GATE BURRS.. (.) G H D C K J M MILLIMETERS INCHES DIM MIN MAX MIN MAX A B C D G H....4 J...4. K L M S SOLDERING FOOTPRINT* SCALE : mm inches *For additional information on our PbFree strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. The products described herein (NCP), may be covered by one or more of the following U.S. patents: 7,7,47. There may be other patents pending. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Typical parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box, Denver, Colorado 87 USA Phone: 77 or 8448 Toll Free USA/Canada Fax: 77 or Toll Free USA/Canada orderlit@onsemi.com N. American Technical Support: 8898 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: Japan Customer Focus Center Phone: ON Semiconductor Website: Order Literature: For additional information, please contact your local Sales Representative NCP/D

NCP A Low Dropout Linear Regulator

NCP A Low Dropout Linear Regulator 1.5 A Low Dropout Linear Regulator The NCP566 low dropout linear regulator will provide 1.5 A at a fixed output voltage. The fast loop response and low dropout voltage make this regulator ideal for applications