SC4437 Wide Input Voltage Range Precision Voltage Reference POWER MANAGEMENT Features n n n n n n n n n Description VIN Voltage Range: VOUT + 0.9V to 28V VOUT: Fixed 3.3V VOUT High Accuracy ( ±1% ) over -40°C to 125°C VOUT Low Temperature Coefficient Output Current up to 20mA Low (< 160µA) Quiescent Current Stable without Compensation Capacitor Available with Compact, Surface Mount SOT-23 Package Pb-Free, Halogen Free, RoHS/WEEE compliant product Applications n n n n n n n 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 flexibility 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. 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 µF September 21, 2009 OUT IN 3.3V CO (optional) GND 1 www.semtech.com SC4437 Pin Configuration Ordering Information Device Package SC4437SK-3.3TRT 3-Lead Plastic SOT-23 SC4437EVB 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 θJA = 202°C/W Marking Information © 2009 Semtech Corp. 2 www.semtech.com SC4437 Recommended Operating Conditions Absolute Maximum Ratings VIN Voltage ……………………………………………… 30V VIN Voltage …………………… …………………… 4.2 to 28V Reverse Voltage …………………………………………-15V Maximum Output Current ………………………………… 20mA Output Short Circuit Duration ………………… Indefinite(1) Temperature Range ……………………………-40˚C to 125˚C Lead Temperature (Soldering) 10 seconds (2) ………… 260°C ESD Rating ……………………………………… … …… 2kV Thermal Information Thermal Resistance, Junction to Ambient(3) ……… 202 °C/W Maximum Junction Temperature …………………… +150°C Storage Temperature Range(4) ………………-65°C to +150°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) For VIN ≤ 10 V. (2) Compatible for Wave Soldering and IR Reflow. (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 specified temperature range, the output may drift. Electrical Characteristics Unless specified: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1µF, CO = 0µF, -40°C< TA =TJ < 125°C Parameter Symbol Conditions Min VIN Refer to Line Regulation Spec. 4.2 Typ Max Units 28 V INPUT Input Voltage Range Drop Out Voltage VIN-VOUT IOUT = 0 0.6 0.9 V IOUT = 10mA, TA = 25°C 0.9 1.28 V 1.38 V IOUT = 10mA Leakage Current for Input Voltage Reverse Connection IREV Quiescent Current IQ VIN = -15V 2 6 µΑ TA = 25°C 110 180 µΑ 220 µΑ OUTPUT Output Voltage Output Voltage Accuracy VOUT TJ =25°C 3.3 % 0°C≤TJ < 100°C, 0mA<IOUT ≤ 20mA, 4.2V ≤VIN ≤28V VOUT + 0.9V ≤ VIN ≤ VOUT +2.5V Line Regulation dVOUT/dVIN TA = 25°C VOUT + 2.5V ≤ VIN ≤ 28V © 2009 Semtech Corp. TA = 25°C 3 -1 100 50 V 1 % 500 ppm/V 3300 ppm/V 100 ppm/V 300 ppm/V www.semtech.com SC4437 Electrical Characteristics (continued) Unless specified: VIN= VOUT + 2.5V, IOUT = 0, CIN= 0.1µF, CO = 0µF, -40°C< TA =TJ < 125°C Parameter Symbol Conditions TA = 25°C IOUT = 100µA Load Regulation dVOUT/dILOAD Min TA = 25°C IOUT = 10mA TA = 25°C IOUT = 20mA Typ Max Units 3000 4000 ppm/mA 6000 ppm/mA 150 ppm/mA 250 ppm/mA 100 ppm/mA 150 ppm/mA 120 ppm/°C 100 75 Output Voltage Temperature Coefficient dVOUT/dT 0°C≤ TJ < 105°C 80 Output Short Circuit Current ISC Short VOUT to GND, TA = 25°C 55 TON VIN > VOUT + 2.5V, VOUT settles to ±0.05% of final value mA DYNAMIC Turn-On Settling Time 3 (1) ms NOTES: (1) Guaranteed by design. © 2009 Semtech Corp. 4 www.semtech.com SC4437 Pin Descriptions Pin # Pin Name 1 VIN Input supply voltage for the precision voltage reference. 2 VOUT Output voltage. 3 GND Ground connection for the circuit. © 2009 Semtech Corp. Pin Function 5 www.semtech.com SC4437 Typical Waveforms Minimum Input - Output Voltage Differential Supply Current vs Input Voltage Minimum Input-Output Voltage Differential 150 140 130 120 110 100 90 80 70 60 50 Supply Current (µA) 20 Load Current (mA) Supply Current vs Input Voltage 15 125 °C -55 °C 10 5 25 °C 0 0 0.5 1 1.5 Input-Output Voltage (V) 2 125 °C 25 °C -55 °C 0 Load Regulation - Sourcing Output Voltage - 3.3V (mV) Output Voltage - 3.3V (mV) 0 25 °C 125 °C -20 -55 °C -30 5 10 15 Output Current (mA) 20 Load Regulation, Sinking Load Regulation, Sourcing 0 10 15 Input Voltage (V) Load Regulation - Sinking 10 -10 5 180 130 80 30 25 °C -55 °C -20 20 Line Regulation 125 °C 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Output Current (mA) 2 Power Supply Rejection Ratio vs Frequency Line Regulation Power Supply Rejection Ratio vs Frequency 100 25 °C 3.3 3.29 PSRR (dB) Output Voltage (V) 3.31 125 °C -55 °C 3.28 10 3.27 1 3.26 0 5 © 2009 Semtech Corp. 10 15 Input Voltage (V) 20 0.1 6 1 10 100 Frequency (KHz) 1000 www.semtech.com SC4437 Typical Waveforms (Continued) Output Impedance Start Up with Input Voltage 20 V Output Impedance (Ohm) Output Impedance vs Frequency 1000 100 No Output Cap 10 1 ȝF Output Cap 1 0.01 0.1 1 10 100 Frequency (KHz) 1000 Output Noise Performance 10 Hz to 100 kHz Output Noise Waveform 0.1Hz to 10 Hz Noise Density uV/(Hz^0.5) Noise Density VS Frequency 1.000 0.100 0.01 0.1 1 10 100 Frequency (kHz) 1 mA Transient Response without Output Cap © 2009 Semtech Corp. 1 mA Transient Response with 1 µF Output Cap 7 www.semtech.com SC4437 Block Diagram VIN VOUT GND © 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 µA). improve the dynamic response under load transient. In order to obtain optimum performance under load transient, it is recommended that a 0.1 µ F ceramic capacitor placed at the input and a 1 µF (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 µA), protecting both the battery and the device itself. Load Transient Responses The following figure shows the circuit setup to test the 1 mA load transient response. 3.3V Precision Reference Over Wide Input Voltage Range, Load Conditions and Operating Temperatures 2.3V SC4437 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 specification. 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 125°C, 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 © 2009 Semtech Corp. 5.8V OUT IN CIN 0.1 µF 1 kȍ GND 3.3V CO (optional) 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 1µF capacitance, the transient response is improved significantly. The figure below shows the 1mA transient response with 1 µF capacitance at the output. 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 10 100 Frequency (kHz) Start Up With the input voltage 5.8V, the device shows very small start up overshoot, as shown by the figure below. Low Noise Operation The SC4437 is a low noise reference. The noise is measured with high gain amplification and band filtering. Without any output capacitor the noise level is measured to be around 0.7 µV/√Hz from 0 to 100 kHz. With output capacitor the noise level will be significantly lower. The following figure 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 . © 2009 Semtech Corp. 10 www.semtech.com SC4437 Outline Drawing – SOT-23 3L D A DIM e1 A A1 A2 b c D E E1 e e1 L L1 N 0 aaa bbb 3 B E E1 1 2 bxN e bbb .035 .000 .035 .012 .003 .110 .082 .047 .015 0° .037 - .114 .093 .051 .075 .037 .020 .022 3 - .044 .004 .040 .020 .007 .120 .104 .055 .024 8° .004 .008 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 C A B A2 A DIMENSIONS MILLIMETERS INCHES MIN NOM MAX MIN NOM MAX aaa C 3X SEATING PLANE A1 C H GAUGE PLANE SEATING PLANE C SIDE VIEW 0 c 0.25 L L1 SEE DETAIL A DETAIL A NOTES: 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. © 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 © 2009 Semtech Corp. 12 www.semtech.com