LM4120 Precision Micropower Low Dropout Voltage Reference General Description Features The LM4120 is a precision low power low dropout bandgap voltage reference with up to 5 mA output current source and sink capability. Small SOT23-5 package Low dropout voltage: 120 mV Typ @ 1 mA High output voltage accuracy: 0.2% ± 5 mA Source and Sink current output: Supply current: 160 µA Typ. Low Temperature Coefficient: 50 ppm/˚C Enable pin Fixed output voltages: 1.8, 2.048, 2.5, 3.0, 3.3, 4.096 and 5.0V n Industrial temperature Range: −40˚C to +85˚C n (For extended temperature range, −40˚C to 125˚C, contact National Semiconductor) This series reference operates with input voltages as low as 2V and up to 12V consuming 160 µA (Typ.) supply current. In power down mode, device current drops to less than 2 µA. The LM4120 comes in two grades (A and Standard) and seven voltage options for greater flexibility. The best grade devices (A) have an initial accuracy of 0.2%, while the standard have an initial accuracy of 0.5%, both with a tempco of 50ppm/˚C guaranteed from −40˚C to +125˚C. The very low dropout voltage, low supply current and powerdown capability of the LM4120 makes this product an ideal choice for battery powered and portable applications. The device performance is guaranteed over the industrial temperature range (−40˚C to +85˚C), while certain specs are guaranteed over the extended temperature range (−40˚C to +125˚C). Please contact National for full specifications over the extended temperature range. The LM4120 is available in a standard 5-pin SOT-23 package. Functional Block Diagram n n n n n n n n Applications n n n n n n n n n n Portable, battery powered equipment Instrumentation and process control Automotive & Industrial Test equipment Data acquisition systems Precision regulators Battery chargers Base stations Communications Medical equipment Connection Diagram 10104702 Refer to the Ordering Information Table in this Data Sheet for Specific Part Number SOT23-5 Surface Mount Package 10104701 © 2005 National Semiconductor Corporation DS101047 www.national.com LM4120 Precision Micropower Low Dropout Voltage Reference March 2005 LM4120 Ordering Information Industrial Temperature Range (−40˚C to + 85˚C) Initial Output Voltage Accuracy at 25˚C And Temperature Coefficient 0.2%, 50 ppm/˚C max (A grade) 0.5%, 50 ppm/˚C max LM4120 Supplied as 1000 Units, Tape and Reel LM4120 Supplied as 3000 Units, Tape and Reel Top Marking LM4120AIM5-1.8 LM4120AIM5X-1.8 R21A LM4120AIM5-2.0 LM4120AIM5X-2.0 R14A LM4120AIM5-2.5 LM4120AIM5X-2.5 R08A LM4120AIM5-3.0 LM4120AIM5X-3.0 R15A LM4120AIM5-3.3 LM4120AIM5X-3.3 R16A LM4120AIM5-4.1 LM4120AIM5X-4.1 R17A LM4120AIM5-5.0 LM4120AIM5X-5.0 R18A LM4120IM5-1.8 LM4120IM5X-1.8 R21B LM4120IM5-2.0 LM4120IM5X-2.0 R14B LM4120IM5-2.5 LM4120IM5X-2.5 R08B LM4120IM5-3.0 LM4120IM5X-3.0 R15B LM4120IM5-3.3 LM4120IM5X-3.3 R16B LM4120IM5-4.1 LM4120IM5X-4.1 R17B LM4120IM5-5.0 LM4120IM5X-5.0 R18B SOT-23 Package Marking Information Only four fields of marking are possible on the SOT-23’s small surface. This table gives the meaning of the four fields. Field Information First Field: R = Reference Second and third Field: 21 = 1.800V Voltage Option 14 = 2.048V Voltage Option 08 = 2.500V Voltage Option 15 = 3.000V Voltage Option 16 = 3.300V Voltage Option 17 = 4.096V Voltage Option 18 = 5.000V Voltage Option Fourth Field: A-B = Initial Reference Voltage Tolerance A = ± 0.2% B = ± 0.5% www.national.com 2 Lead Temperature: If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Maximum Voltage on input or enable pins −0.3V to 14V Output Short-Circuit Duration Indefinite Power Dissipation +260˚C Vapor Phase (60 sec.) +215˚C Infrared (15 sec.) +220˚C Operating Range (Note 1) Storage Temperature Range −65˚C to +150˚C 350 mW Ambient Temperature Range −40˚C to +85˚C 2 kV 200V Junction Temperature Range −40˚C to +125˚C Power Dissipation (TA = 25˚C) (Note 2): MA05B package − θJA Soldering, (10 sec.) 280˚C/W ESD Susceptibility (Note 3) Human Body Model Machine Model Electrical Characteristics LM4120-1.8V, 2.048V and 2.5V Unless otherwise specified VIN = 3.3V, ILOAD = 0, COUT = 0.01µF, TA = Tj = 25˚C. Limits with standard typeface are for Tj = 25˚C, and limits in boldface type apply over the −40˚C ≤ TA ≤ +85˚C temperature range. Symbol VOUT Max (Note 5) Units Output Voltage Initial Accuracy LM4120A-1.800 LM4120A-2.048 LM4120A-2.500 ± 0.2 % LM4120-1.800 LM4120-2.048 LM4120-2.500 ± 0.5 % 14 50 ppm/˚c 0.0007 0.008 0.01 %/V 0 mA ≤ ILOAD ≤ 1 mA 0.03 0.08 0.17 1 mA ≤ ILOAD ≤ 5 mA 0.01 0.04 0.1 −1 mA ≤ ILOAD ≤ 0 mA 0.04 0.12 −5 mA ≤ ILOAD ≤ −1 mA 0.01 Parameter Conditions TCVOUT/˚C Temperature Coefficient −40˚C ≤ TA ≤ +125˚C ∆VOUT/∆VIN Line Regulation 3.3V ≤ VIN ≤ 12V ∆VOUT/∆ILOAD VIN−VOUT Load Regulation Dropout Voltage (Note 6) Min (Note 5) Typ (Note 4) ILOAD = 0 mA 45 65 80 ILOAD = +1 mA 120 150 180 ILOAD = +5 mA 180 210 250 VN Output Noise Voltage 0.1 Hz to 10 Hz (Note 8) 10 Hz to 10 kHz 36 IS Supply Current 160 ISS Power-down Supply Current VH 20 Enable = 0.4V −40˚C ≤ TJ ≤ +85˚C Enable = 0.2V 2.4 mV µVPP µVPP 250 275 1 2 Logic High Input Voltage %/mA µA µA V 2.4 3 www.national.com LM4120 Absolute Maximum Ratings (Note 1) LM4120 Electrical Characteristics LM4120-1.8V, 2.048V and 2.5V Unless otherwise specified VIN = 3.3V, ILOAD = 0, COUT = 0.01µF, TA = Tj = 25˚C. Limits with standard typeface are for Tj = 25˚C, and limits in boldface type apply over the −40˚C ≤ TA ≤ +85˚C temperature range. (Continued) Symbol VL Parameter Conditions Min (Note 5) Typ (Note 4) Logic Low Input Voltage 0.4 IH Logic High Input Current 7 IL Logic Low Input Current 0.1 Max (Note 5) Units V 0.2 VIN = 3.3V, VOUT = 0 15 µA µA 15 6 30 mA ISC Short Circuit Current Hyst Thermal Hysteresis (Note 7) −40˚C ≤ TA ≤ 125˚C 0.5 mV/V ∆VOUT Long Term Stability (Note 9) 1000 hrs. @ 25˚C 100 ppm VIN = 12V, VOUT = 0 17 6 30 Electrical Characteristics LM4120-3.0V, 3.3V, 4.096V and 5.0V Unless otherwise specified VIN = VOUT + 1V, ILOAD = 0, COUT = 0.01µF, TA = Tj = 25˚C. Limits with standard typeface are for Tj = 25˚C, and limits in boldface type apply over the −40˚C ≤ TA ≤ +85˚C temperature range. Symbol VOUT Max (Note 5) Units Output Voltage Initial Accuracy LM4120A-3.000 LM4120A-3.300 LM4120A-4.096 LM4120A-5.000 ± 0.2 % LM4120-3.000 LM4120-3.300 LM4120-4.096 LM4120-5.000 ± 0.5 % 14 50 ppm/˚c 0.0007 0.008 0.01 %/V 0 mA ≤ ILOAD ≤ 1 mA 0.03 0.08 0.17 1 mA ≤ ILOAD ≤ 5 mA 0.01 0.04 0.1 −1 mA ≤ ILOAD ≤ 0 mA 0.04 0.12 −5 mA ≤ ILOAD ≤ −1 mA 0.01 Parameter Conditions TCVOUT/˚C Temperature Coefficient −40˚C ≤ TA ≤ +125˚C ∆VOUT/∆VIN Line Regulation (VOUT + 1V) ≤ VIN ≤ 12V ∆VOUT/∆ILOAD VIN−VOUT www.national.com Load Regulation Dropout Voltage (Note 6) Min (Note 5) Typ (Note 4) ILOAD = 0 mA 45 65 80 ILOAD = +1 mA 120 150 180 ILOAD = +5 mA 180 210 250 4 %/mA mV 0.01µF, TA = Tj = 25˚C. Limits with standard typeface are for Tj = 25˚C, and limits in boldface type apply over the −40˚C ≤ TA ≤ +85˚C temperature range. (Continued) Symbol VN Parameter Conditions Min (Note 5) Typ (Note 4) Max (Note 5) Units Output Noise Voltage 0.1 Hz to 10 Hz (Note 8) 10 Hz to 10 kHz 20 µVPP 36 µVPP IS Supply Current 160 ISS Power-down Supply Current VH VL 250 275 Enable = 0.4V −40˚C ≤ TJ ≤ +85˚C Enable = 0.2V 1 2 Logic High Input Voltage 2.4 µA µA V 2.4 Logic Low Input Voltage 0.4 IH Logic High Input Current 7 IL Logic Low Input Current 0.1 V 0.2 VOUT = 0 15 µA µA 15 6 30 ISC Short Circuit Current Hyst Thermal Hysteresis (Note 7) −40˚C ≤ TA ≤ 125˚C 0.5 mV/V ∆VOUT Long Term Stability (Note 9) 1000 hrs. @ 25˚C 100 ppm VIN = 12V, VOUT = 0 17 6 mA 30 Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: Without PCB copper enhancements. The maximum power dissipation must be de-rated at elevated temperatures and is limited by TJMAX (maximum junction temperature), θJ-A (junction to ambient thermal resistance) and TA (ambient temperature). The maximum power dissipation at any temperature is: PDissMAX = (TJMAX − TA)/θJ-A up to the value listed in the Absolute Maximum Ratings. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. Note 4: Typical numbers are at 25˚C and represent the most likely parametric norm. Note 5: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate National’s Averaging Outgoing Quality Level (AOQL). Note 6: Dropout voltage is the differential voltage between VOUT and VIN at which VOUT changes ≤ 1% from VOUT at VIN = 3.3V for 1.8V, 2.0V, 2.5V and VOUT + 1V for others.For 1.8V option, dropout voltage is not guaranteed over temperature. A parasitic diode exists between input and output pins; it will conduct if VOUT is pulled to a higher voltage than VIN. Note 7: Thermal hysteresis is defined as the change in +25˚C output voltage before and after exposing the device to temperature extremes. Note 8: Output noise voltage is proportional to VOUT. VN for other voltage option is calculated using (VN(1.8V)/1.8) * VOUT. VN (2.5V) = (36µVPP/1.8) * 2.5 = 46µVPP. Note 9: Long term stability is change in VREF at 25˚C measured continuously during 1000 hrs. 5 www.national.com LM4120 Electrical Characteristics LM4120-3.0V, 3.3V, 4.096V and 5.0V Unless otherwise specified VIN = VOUT + 1V, ILOAD = 0, COUT = LM4120 LM4120 Typical Operating Characteristics Unless otherwise specified, VIN = 3.3V, VOUT = 2.5V, ILOAD = 0, COUT = 0.022µF, TA = 25˚C and VEN = VIN. Long Term Drift Typical Temperature Drift 10104712 10104713 Short Circuit Current vs Temperature Dropout Voltage vs Output Error 10104714 10104715 Dropout Voltage vs Load Current Line Regulation 10104733 www.national.com 10104717 6 Load Regulation GND Pin Current 10104719 10104718 GND Pin Current at No Load vs Temperature GND Pin Current vs Load 10104722 10104721 0.1Hz to 10Hz output Noise Output Impedance vs Frequency 10104723 10104724 7 www.national.com LM4120 LM4120 Typical Operating Characteristics Unless otherwise specified, VIN = 3.3V, VOUT = 2.5V, ILOAD = 0, COUT = 0.022µF, TA = 25˚C and VEN = VIN. (Continued) LM4120 LM4120 Typical Operating Characteristics Unless otherwise specified, VIN = 3.3V, VOUT = 2.5V, ILOAD = 0, COUT = 0.022µF, TA = 25˚C and VEN = VIN. (Continued) PSRR vs Frequency Start-Up Response 10104726 10104725 Enable Response Load Step Response 10104727 10104728 Load Step Response Line Step Response 10104729 www.national.com 10104730 8 Thermal Hysteresis Enable Pin Current 10104716 10104731 must be taken close to GND to turn the part off (see spec. table for thresholds). There is a minimum slew rate on this pin of about 0.003V/µS to prevent glitches on the output. All of these conditions can easily be met with ordinary CMOS or TTL logic. If the shutdown feature is not required, then this pin can safely be connected directly to the input supply. Floating this pin is not recommended. Pin Functions Output (Pin 5): Reference Output. Input (Pin 4):Positive Supply. Ground (Pin 2):Negative Supply or Ground Connection. Enable (Pin 3):Pulled to input for normal operation. Forcing this pin to ground will turn-off the output. REF (Pin 1):REF Pin. This pin should be left unconnected. Application Hints The standard application circuit for the LM4120 is shown in Figure 1. It is designed to be stable with ceramic output capacitors in the range of 0.022µF to 0.047µF. Note that 0.022µF is the minimum required output capacitor. These capacitors typically have an ESR of about 0.1 to 0.5Ω. Smaller ESR can be tolerated, however larger ESR can not. The output capacitor can be increased to improve load transient response, up to about 1µF. However, values above 0.047µF must be tantalum. With tantalum capacitors, in the 1µF range, a small capacitor between the output and the reference pin is required. This capacitor will typically be in the 50pF range. Care must be taken when using output capacitors of 1µF or larger. These application must be thoroughly tested over temperature, line and load. An input capacitor is typically not required. However, a 0.1µF ceramic can be used to help prevent line transients from entering the LM4120. Larger input capacitors should be tantalum or aluminium. The reference pin is sensitive to noise, and capacitive loading. Therefore, the PCB layout should isolate this pin as much as possible. The enable pin is an analog input with very little hysteresis. About 6µA into this pin is required to turn the part on, and it 10104732 FIGURE 1. INPUT CAPACITOR Noise on the power-supply input can effect the output noise, but can be reduced by using an optional bypass capacitor between the input pin and the ground. PRINTED CIRCUIT BOARD LAYOUT CONSIDERATION The mechanical stress due to PC board mounting can cause the output voltage to shift from its initial value. References in SOT packages are generally less prone to assembly stress than devices in Small Outline (SOIC) package. To reduce the stress-related output voltage shifts, mount the reference on the low flex areas of the PC board such as near to the edge or the corner of the PC board. 9 www.national.com LM4120 LM4120 Typical Operating Characteristics Unless otherwise specified, VIN = 3.3V, VOUT = 2.5V, ILOAD = 0, COUT = 0.022µF, TA = 25˚C and VEN = VIN. (Continued) LM4120 Typical Application Circuits Voltage Reference with Complimentary Output Voltage Reference with Negative Output 10104706 Precision High Current Low Droput Regulator 10104703 Precision High Current Low Dropout Regulator 10104707 Stacking Voltage References 10104704 Precision High Current Negative Voltage Regulator 10104708 Precision Voltage Reference with Force and Sense Output 10104705 10104709 www.national.com 10 LM4120 Typical Application Circuits Power Supply Splitter (Continued) Programmable Current Source 10104720 10104710 Precision Regulator with Current Limiting Circuit 10104711 11 www.national.com LM4120 Precision Micropower Low Dropout Voltage Reference Physical Dimensions inches (millimeters) unless otherwise noted National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 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