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| SC4437 Wide Input Voltage Range Precision Voltage Reference POWER MANAGEMENT Features VIN Voltage Range: VOUT + 0.9V to 28V VOUT: Fixed 3.3V VOUT High Accuracy ( 1% ) over -40C to 125C VOUT Low Temperature Coe cient Output Current up to 20mA Low (< 160A) Quiescent Current Stable without Compensation Capacitor Available with Compact, Surface Mount SOT-23 Package Pb-Free, Halogen Free, RoHS/WEEE compliant product Description The SC4437 is a low power precision series bandgap reference device. It accepts wide input voltage range VOUT + 0.9V to 28V and generates stable output voltage with superior accuracy and low drift over operating temperatures. The SC4437 is ideal for battery powered systems where there can be wide variations in supply voltage and a need to minimize power dissipation. The SC4437 is able to supply up to 20mA output current with excellent line and load regulation characteristics. The output compensation capacitor is optional. It provides user the exibility of compact, low cost design or further noise performance enhanced design. The SC4437 is available in a compact 3-lead surface mount SOT-23 package. Applications Bias Supplies High Accuracy Micropower Supplies Data Acquisition Systems Medical Devices Portable Battery Powered Equipment Test Equipment Automotive and Industrial Typical Application Circuit SC4437 VIN up to 28V CIN 0.1 F IN GND OUT 3.3V CO (optional) September 21, 2009 1 www.semtech.com SC4437 Pin Con guration Ordering Information Device SC4437SK-3.3TRT SC4437EVB Package 3-Lead Plastic SOT-23 Evaluation Board TOP VIEW IN 1 3 GND OUT 2 Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Pb-Free, Halogen Free, RoHS/WEEE compliant product. 3-LEAD PLASTIC SOT-23 JA = 202C/W Marking Information (c) 2009 Semtech Corp. 2 www.semtech.com SC4437 Absolute Maximum Ratings VIN Voltage ...................................................... 30V Reverse Voltage ................................................-15V Output Short Circuit Duration ..................... Indefinite(1) Lead Temperature (Soldering) 10 seconds (2) ............ 260C ESD Rating ............................................. ... ...... 2kV Recommended Operating Conditions VIN Voltage ........................ ........................ 4.2 to 28V Maximum Output Current ....................................... 20mA Temperature Range .................................-40 C to 125 C Thermal Information Thermal Resistance, Junction to Ambient(3) ......... 202 C/W Maximum Junction Temperature ........................ +150C Storage Temperature Range(4) ..................-65C to +150C Exceeding the above speci cations may result in permanent damage to the device or device malfunction. Operation outside of the parameters speci ed in the Electrical Characteristics section is not recommended. NOTES: (1) For VIN 10 V. (2) Compatible for Wave Soldering and IR Re ow. (3) Calculated from package in still air, mounted to 3" x 4.5", 4 layer FR4 PCB per JESD51 standards. (4) If the part is stored outside of the speci ed temperature range, the output may drift. Electrical Characteristics Unless speci ed: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1F, CO = 0F, -40C< TA =TJ < 125C Parameter INPUT Input Voltage Range Symbol Conditions Min Typ Max Units VIN Refer to Line Regulation Spec. IOUT = 0 4.2 0.6 0.9 28 0.9 1.28 1.38 2 110 6 180 220 V V V V Drop Out Voltage VIN-VOUT IOUT = 10mA, TA = 25C IOUT = 10mA Leakage Current for Input Voltage Reverse Connection Quiescent Current OUTPUT Output Voltage Output Voltage Accuracy IREV IQ VIN = -15V TA = 25C VOUT % TJ =25C 0CTJ < 100C, 0mA V % ppm/V ppm/V ppm/V ppm/V Line Regulation dVOUT/dVIN VOUT + 2.5V VIN 28V (c) 2009 Semtech Corp. 3 www.semtech.com SC4437 Electrical Characteristics (continued) Unless speci ed: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1F, CO = 0F, -40C< TA =TJ < 125C Parameter Symbol Conditions IOUT = 100A TA = 25C Min Typ 3000 Max 4000 6000 Units ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/mA ppm/C mA Load Regulation dVOUT/dILOAD IOUT = 10mA TA = 25C 100 150 250 IOUT = 20mA Output Voltage Temperature Coe cient Output Short Circuit Current DYNAMIC Turn-On Settling Time TON dVOUT/dT ISC 0C TJ < 105C TA = 25C 75 100 150 80 55 120 Short VOUT to GND, TA = 25C VIN > VOUT + 2.5V, VOUT settles to 0.05% of nal value 3 (1) ms NOTES: (1) Guaranteed by design. (c) 2009 Semtech Corp. 4 www.semtech.com SC4437 Pin Descriptions Pin # 1 2 3 Pin Name VIN VOUT GND Pin Function Input supply voltage for the precision voltage reference. Output voltage. Ground connection for the circuit. (c) 2009 Semtech Corp. 5 www.semtech.com SC4437 Typical Waveforms Minimum Input - Output Voltage Di erential 20 Minimum Input-Output Voltage Differential Supply Current vs Input Voltage Supply Current vs Input Voltage 150 140 130 120 110 100 90 80 70 60 50 0 5 Load Current (mA) 15 125 C -55 C 10 5 0 0 0.5 1 1.5 Input-Output Voltage (V) 2 Supply Current (A) 125 C 25 C -55 C 25 C 10 15 Input Voltage (V) 20 Load Regulation - Sourcing Load Regulation, Sourcing Output Voltage - 3.3V (mV) Load Regulation - Sinking Load Regulation, Sinking Output Voltage - 3.3V (mV) 10 0 25 C -10 -20 -55 C -30 0 5 10 15 Output Current (mA) 20 125 C 180 130 80 30 -20 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Output Current (mA) 2 125 C 25 C -55 C Line Regulation Line Regulation 3.31 Output Voltage (V) Power Supply Rejection Ratio vs Frequency Power Supply Rejection Ratio vs Frequency 100 3.3 25 C PSRR (dB) 3.29 3.28 3.27 3.26 0 5 125 C -55 C 10 1 10 15 Input Voltage (V) 20 0.1 1 10 100 Frequency (KHz) 1000 (c) 2009 Semtech Corp. 6 www.semtech.com SC4437 Typical Waveforms (Continued) Output Impedance Output Impedance vs Frequency 1000 Start Up with Input Voltage 20 V Output Impedance (Ohm) 100 No Output Cap 10 1 F Output Cap 1 0.01 0.1 1 10 100 Frequency (KHz) 1000 Output Noise Performance 10 Hz to 100 kHz Noise Density VS Frequency Noise Density uV/(Hz^0.5) Output Noise Waveform 0.1Hz to 10 Hz 1.000 0.100 0.01 0.1 1 Frequency (kHz) 10 100 1 mA Transient Response without Output Cap 1 mA Transient Response with 1 F Output Cap (c) 2009 Semtech Corp. 7 www.semtech.com SC4437 Block Diagram VIN VOUT GND (c) 2009 Semtech Corp. 8 www.semtech.com SC4437 Applications Information Advantage Over Shunt References The SC4437 is a low power precision series voltage reference. The series reference has major advantages over shunt references when the load current has variations and the reference is powered by a battery. A shunt reference requires a resistance to connect the input and the output. This resistance will be designed to consume the maximum load current. When the actual load current is smaller than the maximum load current, the difference will be consumed by the reference. This behavior not only reduce efficiency but also increase the thermal stress on the device, thus is not desirable. On the contrary, the series reference consumes the same current as the load. When there is no load current required, the device itself consumes very little current (in the scale of 10s of A). Precision Reference Over Wide Input Voltage Range, Load Conditions and Operating Temperatures SC4437 1k OUT GND 3.3V CO (optional) improve the dynamic response under load transient. In order to obtain optimum performance under load transient, it is recommended that a 0.1 F ceramic capacitor placed at the input and a 1 F (and up) ceramic capacitor placed at the output. Reverse Battery Connection Protection The SC4437 has reverse battery connection protection. When the input and ground is reversely connected, the leakage current from the input is very small (maximum 6 A), protecting both the battery and the device itself. Load Transient Responses The following gure shows the circuit setup to test the 1 mA load transient response. 3.3V 2.3V 5.8V IN CIN 0.1 F The SC4437 can maintain 1% precision regulation over wide load range, operating temperature condition and input voltage range. To provide 3.3V output voltage, the load can range from 0 to 20mA; the temperature can range from -40 C to 125 C; the input voltage can range from V OUT + 0.9V to 28V, depending on the load and temperature conditions. The input voltage range should be selected based on the drop out voltage speci cation. Although the SC4437 can maintain tight regulation over wide operating conditions, attention should be paid to the thermal stress of the device. For example, with the input voltage of 28V and the load current of 20mA, the power consumption on the device is P = (28V-3.3V)*0.02A = 0.494W With the thermal resistance of 202 C/W, the power consumption on the chip gives an ambient to junction temperature increase of 99.8 C. If the ambient temperature is higher than 25 C, then the junction temperature will be higher than 125C, thus should be avoided. Input and Output Capacitances The SC4437 is stable with or without output capacitors under all load conditions. Adding output capacitances can Without output capacitance, the transient response is shown below. The high overshoot is due to the high resistance at high frequency without output capacitance. With 1F capacitance, the transient response is improved signi cantly. The gure below shows the 1mA transient response with 1 F capacitance at the output. (c) 2009 Semtech Corp. 9 www.semtech.com SC4437 Applications Information (continued) Noise Density uV/(Hz^0.5) Noise Density VS Frequency 1.000 0.100 0.01 0.1 1 Frequency (kHz) 10 100 Start Up With the input voltage 5.8V, the device shows very small start up overshoot, as shown by the gure below. Low Noise Operation The SC4437 is a low noise reference. The noise is measured with high gain ampli cation and band ltering. Without any output capacitor the noise level is measured to be around 0.7 V/Hz from 0 to 100 kHz. With output capacitor the noise level will be signi cantly lower. The following gure shows the noise measurement result under room temperature without output capacitor from 10Hz to 100kHz and the scope picture of noise measurement result from 0.1 Hz to 10 Hz . (c) 2009 Semtech Corp. 10 www.semtech.com SC4437 Outline Drawing - SOT-23 3L D e1 3 B A DIM A A1 A2 b c D E E1 e e1 L L1 N 0 aaa bbb DIMENSIONS MILLIMETERS INCHES MIN NOM MAX MIN NOM MAX .035 .000 .035 .012 .003 .110 .082 .047 .037 .044 .004 .040 .020 .007 .120 .104 .055 1.12 0.89 0.10 0.01 0.88 0.95 1.02 0.51 0.30 0.18 0.08 2.80 2.90 3.04 2.10 2.37 2.64 1.20 1.30 1.40 1.90 BSC 0.95 BSC 0.40 0.50 0.60 (0.55) 3 0 8 0.10 0.20 E1 E .015 1 2 bxN e bbb CAB 0 .114 .093 .051 .075 .037 .020 .022 3 .004 .008 .024 8 A A2 3X aaa C SEATING PLANE A1 C H SEATING PLANE C GAUGE PLANE 0.25 L L1 DETAIL A 0 c SIDE VIEW NOTES: SEE DETAIL A 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. (c) 2009 Semtech Corp. 11 www.semtech.com SC4437 Land Pattern - SOT-23 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 (c) 2009 Semtech Corp. 12 www.semtech.com |
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