SC4212

SC4212 Very Low Input /Very Low Dropout 1Amp Regulator With Enable Description The SC4212 is a high performance positive voltage regu lator designed for applications requiring very low input voltage and very low dropout voltage at up to 1 Ampere. It operates with a VIN as low as 1.5V, with output voltage programmable as low as 0.5V. The SC4212 features ultra low dropout, ideal for applications where VOUT is very close to VIN. Additionally, the SC4212 has an enable pin to further reduce power dissipation while shutdown. The SC4212 provides excellent regulation over variations in line, load and temperature. The SC4212 is available in a 3 x 3 MLPD-8 package. The output voltage can be set via external divider or to a f ixed setting of 0.5V depending upon how the FB pin is configured. POWER MANAGEMENT Features „ „ „ „ „ „ „ „ „ Input voltage as low as 1.5V 400mV dropout @ 1A Adjustable output from 0.5V Over current and over temperature protection Enable pin 10μA quiescent current in shutdown Low reverse leakage (output to input) Full industrial temperature range Available in MLPD-8 Pb-free package, fully WEEE and RoHS compliant Applications „ „ „ „ „ „ „ Telecom/Networking cards Motherboards/Peripheral cards Industrial Applications Wireless infrastructure Set top boxes Medical equipment Notebook computers Typical Application Circuit SC4212 SC4212 VIN VIN ENABLE C1 VIN EN VOUT FB GND C1 C2 R2 VOUT ENABLE VIN EN VOUT FB GND R1 C2 VOUT VOUT = 0.5V VOUT = 0.5(R1 + R 2) (Volts ) R2 April 27, 2010 1 SC4212 Pin Configuration Ordering Information Part Number NC EN VIN NC 1 8 Package 3mm x 3mm x 1mm MLPD-8 Evaluation Board TOP VIEW GND FB VOUT NC SC4212MLTRT(1)(2) SC4212EVB 2 7 3 T 6 Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Pb-free product. This product is fully WEEE and RoHS compliant. 4 5 3mm x 3mm x 1mm MLPD-8 θJA = 36.3°C/W Marking Information Marking for the 3 x 3mm MLPD 8ld Lead Package: y yww = Datecode ( Example : 0952 ) x xxx = Semtech Lot No. ( Example : E901 ) 2 SC4212 Absolute Maximum Ratings VIN to GND ............………………………...… -0.3V to 7V EN, FB, VOUT …………………..….... -0.3V to VIN +0.3V ESD Rating …......………………...……………… 3.5kV (2) Thermal Information Thermal Resistance, Junction to Ambient(1) .. 36.3°C/W Thermal Resistance, Junction to Case............. 3.77°C/W Operation Ambient Temperature Range...-40 to +85°C Operation Junction Temperature Range ..-40 to+125°C Storage Temperature …………………......-65 to +150°C Peak IR Reflow Temperature (10s to 30s)……........+260° Recommended Operating Conditions Supply Input Voltage ………………......… 1.5 to 5.5V Maximum Output Current ……………...……........... 1A Junction Temperature …………….....… -40 to +125°C Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES: (1)Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. (2)Tested according to JEDEC standard JESD22-A114-B. Electrical Characteristics Unless specified otherwise: FB = VOUT, EN = VIN =, 1.5V to 5.5V, IOUT = 10μA to 1A, TA = +25°C for Typ, -40 to +85 °C for Min and Max, TJ < 125°C. Parameter Input Supply Input Supply Voltage Quiescent Current Output Output Voltage(1) Line Regulation(1) Load Regulation(1) Minimum Load Current(3) Current Limit Symbol Conditions Min Typ Max Units VIN IQ VIN = 3.3V, IOUT = 0A VIN = 5.5V, EN = 0V 1.5 5.5 3 15 V mA µA VOUT VIN = 3.3V, IOUT = 10mA, TA = 25°C 1.5V < VIN < 5.5V, IOUT = 10mA -2% -3% VOUT +2% +3% V %/V %/A µA A REG(LINE) REG(LOAD) IOUT ICL IOUT = 10mA IOUT = 10mA to1A VIN = VOUT + 0.5V 1.10 IOUT = 500mA, TA = 25°C 0.20 0.50 0.40 1.50 10 1.5 100 250 300 200 400 500 Dropout Voltage(1)(2) VDO IOUT = 500mA IOUT = 1A, TA = 25°C IOUT = 1A mV 3 SC4212 Electrical Characteristics (continued) Parameter Feedback VIN = 3.3V, FB = VOUT , IOUT = 10mA, TA = 25°C 0.495 0.490 FB = VREF 0.500 80 0.505 0.510 200 nA V Symbol Conditions Min Typ Max Units Reference Voltage(1) Feedback Pin Current Enable Enable Input High Current VREF IFB IEN VIH VIL EN = 0V, VIN = 3.3V VIN = 3.3V VIN = 3.3V 1.6 1.5 10.0 µA Enable Input Threshold Over Temperature Protection High Trip Level Hysteresis 0.5 V TOT TOT_HYS 160 10 °C °C Notes: (1) Low duty cycle pulse testing with Kelvin connections required. (2) VDO = VIN - VOUT when VOUT decreases by 1.5% of its nominal output voltage when VIN = VOUT + 0.8V. (3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement. 4 SC4212 Typical Characteristics Stability Curve, COUT = 10µF Stability Curve, COUT = 100µF Typixcal Droop Voltage at Vin = 1.5 V 450 400 D roop Volta ge (m V) Dropout Voltage (mV) Droop Voltage (mV) Dropout Voltage (mV) IOUT (A) Typical Dropout Voltage at VIN = 1.5 V Typixcal Droop Voltage at Vin = 5.0 V 350 300 250 200 150 100 50 0 Typical Dropout Voltage at VIN = 5.0 V IOUT (A) 350 300 250 200 150 100 50 0 0.0 VIN = 1.5V TA = 125°C TA = 125°C TA = 25°C TA = 25°C TA = -40°C TA = -40°C 0.1 0.2 0.3 IOUT (A) ReferenceIout (A) Vs Temperature 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.1 0.2 VIN = 5.5V 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 IOUT (A) Reference Iout (A) Vs Temperature 506 505 504 503 502 501 500 499 498 -50 -25 Reference Voltage vs. Junction Temperature 505 504 503 Reference Voltage (mV) Reference Voltage vs. Junction Temperature Reference Voltage (mV) 502 501 500 499 498 497 496 0 25 Tj (ºC) 50 75 100 125 495 -50 -25 0 25 TJ (ºC) 50 75 100 125 Temperature (ºC) Temperature (ºC) 5 SC4212 Pin Descriptions Pin # 1,4,5 2 Pin Name NC EN Pin Function No connect. Enable Input. Pulling this pin below 0.5V turns the regulator off, reducing the quiescent current to a fraction of its operating value. The device will be enabled if this pin is left open. Connect to VIN if the enable feature is not being used. Input voltage pin. For regulation at full load, the input to this pin must between ( VOUT + 0.5V ) and 5.5V. Minimum VIN = 1.5V . A large bulk capacitance should be placed close to this pin to ensure that the input supply does not sag below 1.5V. Also a minimum of 4.7µF ceramic capacitor should be placed directly at this pin. This pin is the power output of this device. A minimum 10µF capacitor should be placed directly at this pin. When this pin is connected to the VOUT pin , the output voltage will be set to 0.5V . If external feedback resistors are used , the output voltage will be determined by the resistor ratio (See Application Circuits on page1): 0.5 ⋅ (R 1 + R 2 ) VOUT = R2 Volts R1: The resistor connected from VOUT to FB. R2: The resistor connected from FB to GND. 3 VIN 6 VOUT 7 FB 8 T 5 GND Thermal Pad Reference ground. The GND pin and the thermal pad must be connected together at the IC. Thermal pad for heatsinking purposes. Not connected internally. Connect to ground plane using multiple vias. 4 3 2 1 Block Diagram VIN RSENSE VPUMP VOUT FB 0.5V VIN VIN 1.5uA EN Thermal Shutdown VOUT VIN Reverse Voltage Shutdown + + + - Reference GND 6 SC4212 Applications Information Introduction The SC4212 is intended for applications where high current capability and very low dropout voltage are required. It provides a very simple, low cost solution that uses very little PCB real estate. Additional features include an enable pin to allow for a very low power consumption standby mode, and a fully adjustable output. Component Selection Input capacitor: A large bulk capacitance of ≥ 10 µF should be placed close to the input supply pin of the SC4212 to ensure that VIN does not sag below 1.5V. Also a minimum 4.7μF ceramic capacitor is recommended to be placed directly next to the VIN pin. This allows for the device being some distance fromany bulk ca pacitance on the rail. Additionally, input droop due to load transients is reduced, improving load transient response. Additional capacitance may be added if re quired by the application. Output capacitor: A minimum bulk capacitance of ≥ 10μF, along with a 0.1μF ceramic decoupling capacitor is recommended. Increasing the bulk capacitance will improve the overall transient response.The use of mul tiple lower value ceramic capacitors in parallel to achieve the desired bulk capacitance will not cause stability issues. Although designed for use with ceramic output capacitors, the SC4212 is extremely tolerant of output capacitor ESR values and thus will also work comfortably with tantalum output capacitors. Noise immunity: In very electrically noisy environments, it is recommended that 0.1 μF ceramic capacitors be placed from VIN to GND and VOUT to GND as close to the device pins as possible. External voltage selection resistors: T he use of 1% resistors designed for a current flow ≥ 10 µA is recom mended to ensure a well-regulated output (thus R2 ≤ 50k Ω). Enable: Pulling the EN pin below 0.5V turns the regula tor off, reducing the quiescent current to a fraction of its operating value. A pull up resistor up to 400kΩ should be connected from the EN pin to the VIN pin in application where an input voltage of < 1.9V is required. For applications with input voltages higher than 1.9V, the EN pin could be left open or connected to VIN. Thermal Considerations The power dissipation in the SC4212 is approximately equal to the product of the output current and the input to output voltage differential: PO = (VIN − VOUT) ⋅ I OUT The absolute worst-case dissipation is given by: PO(MAX) = (VIN (MAX) − VOUT(MIN) ) ⋅ I OUT(MAX) + VIN (MAX) ⋅ I Q(MAX) For a typical scenario, VIN = 3.3V ± 5%, VOUT = 2.8V and IOUT = 1A, therefore: VIN(MAX) = 3.465V, VOUT(MIN) = 2.744V and IQ(MAX) = 3mA Thus PD(MAX) = 0.731W. Using this figure, and assuming TA(MAX) = 70°C, we can calculate the maximum thermal impedance allowable to maintain TJ ≤ 125°C:  TJ(MAX) − TA(MAX)   125°C − 70°C  = R TH(J − A)(MAX) =  = 75 °C W    0.731W  PO(MAX)    This should be achievable with the 3mm x 3mm MLPD-8 package using PCB copper area to aid in conducting the heat away, such as one square inch of copper connected to the ground pins of the device. Internal ground/power planes and air flow will also assist in removing heat. For higher ambient tempertures it may be necessary to use additional copper area. 7 SC4212 Outline Drawing — 3mm x 3mm MLPD-8 Land Pattern — 3mm x 3mm MLPD-8 K Y DIM G Z C G H K P X Y Z DIMENSIONS INCHES MILLIMETERS (.116) .087 .067 .102 .026 .016 .030 .146 (2.95) 2.20 1.70 2.58 0.65 0.40 0.75 3.70 (C) H X P NOTES: 1. 2. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. 3. 8 SC4212 © Semtech 2010 All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent or other industrial or intellectual property rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected operation resulting from misuse, neglect improper installation, repair or improper handling or unusual physical or electrical stress including, but not limited to, exposure to parameters beyond the specified maximum ratings or operation outside the specified range. SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFESUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF SEMTECH PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE UNDERTAKEN SOLELY AT THE CUSTOMER’S OWN RISK. Should a customer purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages and attorney fees which could arise. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 9