LM4132 SOT-23 Precision Low Dropout Voltage Reference General Description Features The LM4132 family of precision voltage references performs comparable to the best laser-trimmed bipolar references, but in cost effective CMOS technology. The key to this break through is the use of EEPROM registers for correction of curvature, tempco, and accuracy on a CMOS bandgap architecture that allows package level programming to overcome assembly shift. The shifts in voltage accuracy and tempco during assembly of die into plastic packages limit the accuracy of references trimmed with laser techniques. Unlike other LDO references, the LM4132 is capable of delivering up to 20mA and does not require an output capacitor or buffer amplifier. These advantages and the SOT23 packaging are important for space-critical applications. Series references provide lower power consumption than shunt references, since they do not have to idle the maximum possible load current under no load conditions. This advantage, the low quiescent current (60µA), and the low dropout voltage (400mV) make the LM4132 ideal for batterypowered solutions. n n n n n n n n n n The LM4132 is available in five grades (A, B, C, D and E) for greater flexibility. The best grade devices (A) have an initial accuracy of 0.05% with guaranteed temperature coefficient of 10ppm/˚C or less, while the lowest grade parts (E) have an initial accuracy of 0.5% and a tempco of 30ppm/˚C. Output initial voltage accuracy 0.05% Low temperature coefficient 10ppm/˚C Low Supply Current, 60µA Enable pin allowing a 3µA shutdown mode 20mA output current Voltage options 1.8V, 2.048V, 2.5V, 3.0V, 3.3V, 4.096V Custom voltage options available (1.8V to 4.096V) VIN range of VREF + 400mV to 5.5V @ 10mA Stable with low ESR ceramic capacitors SOT23-5 Package Applications n n n n n n n n n n n Instrumentation & Process Control Test Equipment Data Acquisition Systems Base Stations Servo Systems Portable, Battery Powered Equipment Automotive & Industrial Precision Regulators Battery Chargers Communications Medical Equipment Typical Application Circuit 20151301 *Note: The capacitor CIN is required and the capacitor COUT is optional. © 2006 National Semiconductor Corporation DS201513 www.national.com LM4132 SOT-23 Precision Low Dropout Voltage Reference August 2006 LM4132 Connection Diagram Top View 20151302 SOT23-5 Package NS Package Number MF05A Ordering Information Input Output Voltage Accuracy at 25˚C And Temperature Coefficient LM4132 Supplied as 1000 units, Tape and Reel LM4132 Supplied as 3000 units, Tape and Reel Part Marking 0.05%, 10 ppm/˚C max (A grade) LM4132AMF-1.8 LM4132AMFX-1.8 R4AA LM4132AMF-2.0 LM4132AMFX-2.0 R4BA LM4132AMF-2.5 LM4132AMFX-2.5 R4CA LM4132AMF-3.0 LM4132AMFX-3.0 R4DA LM4132AMF-3.3 LM4132AMFX-3.3 R4EA 0.1%, 20 ppm/˚C max (B grade) 0.2%, 20 ppm/˚C max (C grade) 0.4%, 20 ppm/˚C max (D grade) 0.5%, 30 ppm/˚C max (E grade) LM4132AMF-4.1 LM4132AMFX-4.1 R4FA LM4132BMF-1.8 LM4132BMFX-1.8 R4AB LM4132BMF-2.0 LM4132BMFX-2.0 R4BB LM4132BMF-2.5 LM4132BMFX-2.5 R4CB LM4132BMF-3.0 LM4132BMFX-3.0 R4DB LM4132BMF-3.3 LM4132BMFX-3.3 R4EB LM4132BMF-4.1 LM4132BMFX-4.1 R4FB LM4132CMF-1.8 LM4132CMFX-1.8 R4AC LM4132CMF-2.0 LM4132CMFX-2.0 R4BC LM4132CMF-2.5 LM4132CMFX-2.5 R4CC LM4132CMF-3.0 LM4132CMFX-3.0 R4DC LM4132CMF-3.3 LM4132CMFX-3.3 R4EC LM4132CMF-4.1 LM4132CMFX-4.1 R4FC LM4132DMF-1.8 LM4132DMFX-1.8 R4AD LM4132DMF-2.0 LM4132DMFX-2.0 R4BD LM4132DMF-2.5 LM4132DMFX-2.5 R4CD LM4132DMF-3.0 LM4132DMFX-3.0 R4DD LM4132DMF-3.3 LM4132DMFX-3.3 R4ED LM4132DMF-4.1 LM4132DMFX-4.1 R4FD LM4132EMF-1.8 LM4132EMFX-1.8 R4AE LM4132EMF-2.0 LM4132EMFX-2.0 R4BE LM4132EMF-2.5 LM4132EMFX-2.5 R4CE LM4132EMF-3.0 LM4132EMFX-3.0 R4DE LM4132EMF-3.3 LM4132EMFX-3.3 R4EE LM4132EMF-4.1 LM4132EMFX-4.1 R4FE Pin Descriptions Pin # Name Function 1 N/C No connect pin, leave floating 2 GND Ground 3 EN Enable pin www.national.com 4 VIN Input supply 5 VREF Reference output 2 Lead Temperature If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Infrared (15sec) Maximum Voltage on any input Vapor Phase (60 sec) 260˚C 215˚C 220˚C ESD Susceptibility (Note 3) Human Body Model -0.3 to 6V Output short circuit duration (soldering, 10sec) 2kV Indefinite Power Dissipation (TA = 25˚C) (Note 2) Storage Temperature Range Operating Ratings 350mW Maximum Input Supply Voltage −65˚C to 150˚C 5.5V Maximum Enable Input Voltage VIN Maximum Load Current 20mA Junction Temperature Range (TJ) −40˚C to +125˚C Electrical Characteristics LM4132-1.8 (VOUT = 1.8V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Typ Min (Note Max (Note 4) 5) (Note 4) LM4132A-1.8 (A Grade - 0.05%) -0.05 0.05 LM4132B-1.8 (B Grade - 0.1%) -0.1 0.1 LM4132C-1.8 (C Grade - 0.2%) -0.2 0.2 LM4132D-1.8 (D Grade - 0.4%) -0.4 0.4 LM4132E-1.8 (E Grade - 0.5%) -0.5 0.5 LM4132A-1.8 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-1.8 20 LM4132C-1.8 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current Supply Current in Shutdown 60 100 µA EN = 0V 3 7 µA 120 ppm / mA ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V 30 ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 ∆VREF VIN - VREF ppm / ˚C 20 LM4132E-1.8 IQ_SD % Temperature Coefficient LM4132D-1.8 IQ Unit Output Voltage Initial Accuracy ppm / V ppm Dropout Voltage (Note 9) ILOAD = 10mA 230 VN Output Noise Voltage 0.1 Hz to 10 Hz 170 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level 65 3 400 mV µVPP %VIN www.national.com LM4132 Absolute Maximum Ratings (Note 1) LM4132 Electrical Characteristics LM4132-2.0 (VOUT = 2.048V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Typ Min (Note Max (Note 4) 5) (Note 4) LM4132A-2.0 (A Grade - 0.05%) -0.05 0.05 LM4132B-2.0 (B Grade - 0.1%) -0.1 0.1 LM4132C-2.0 (C Grade - 0.2%) -0.2 0.2 LM4132D-2.0 (D Grade - 0.4%) -0.4 0.4 LM4132E-2.0 (E Grade - 0.5%) -0.5 0.5 LM4132A-2.0 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-2.0 20 LM4132C-2.0 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current 60 100 7 Supply Current in Shutdown EN = 0V 3 ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V 30 ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 ∆VREF VIN - VREF ppm / ˚C 20 LM4132E-2.0 IQ_SD % Temperature Coefficient LM4132D-2.0 IQ Unit Output Voltage Initial Accuracy µA µA ppm / V 120 ppm / mA ppm Dropout Voltage (Note 9) ILOAD = 10mA 175 VN Output Noise Voltage 0.1 Hz to 10 Hz 190 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level www.national.com 65 4 400 mV µVPP %VIN over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Min (Note 4) Typ (Note 5) (A Grade - 0.05%) -0.05 0.05 LM4132B-2.5 (B Grade - 0.1%) -0.1 0.1 LM4132C-2.5 (C Grade - 0.2%) -0.2 0.2 LM4132D-2.5 (D Grade - 0.4%) -0.4 0.4 LM4132E-2.5 (E Grade - 0.5%) -0.5 0.5 Temperature Coefficient LM4132A-2.5 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-2.5 20 LM4132C-2.5 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current 60 100 µA 3 7 µA 120 ppm / mA EN = 0V ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V 50 ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 VIN - VREF ppm / ˚C 20 Supply Current in Shutdown ∆VREF % LM4132A-2.5 LM4132E-2.5 IQ_SD Unit Output Voltage Initial Accuracy LM4132D-2.5 IQ Max (Note 4) ppm / V ppm Dropout Voltage (Note 9) ILOAD = 10mA 175 VN Output Noise Voltage 0.1 Hz to 10 Hz 240 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level 65 5 400 mV µVPP %VIN www.national.com LM4132 Electrical Characteristics LM4132-2.5 (VOUT = 2.5V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply LM4132 Electrical Characteristics LM4132-3.0 (VOUT = 3.0V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Min Typ (Note 4) (Note 5) (A Grade - 0.05%) -0.05 0.05 LM4132B-3.0 (B Grade - 0.1%) -0.1 0.1 LM4132C-3.0 (C Grade - 0.2%) -0.2 0.2 LM4132D-3.0 (D Grade - 0.4%) -0.4 0.4 LM4132E-3.0 (E Grade - 0.5%) -0.5 0.5 Temperature Coefficient LM4132A-3.0 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-3.0 20 LM4132C-3.0 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current 60 100 µA 7 µA 120 ppm / mA EN = 0V 3 ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V 70 ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 VIN - VREF ppm / ˚C 20 Supply Current in Shutdown ∆VREF % LM4132A-3.0 LM4132E-3.0 IQ_SD Unit Output Voltage Initial Accuracy LM4132D-3.0 IQ Max (Note 4) ppm / V ppm Dropout Voltage (Note 9) ILOAD = 10mA 175 VN Output Noise Voltage 0.1 Hz to 10 Hz 285 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level www.national.com 65 6 400 mV µVPP %VIN over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Min Typ Max (Note 4) (Note 5) (Note 4) LM4132A-3.3 (A Grade - 0.05%) -0.05 0.05 LM4132B-3.3 (B Grade - 0.1%) -0.1 0.1 LM4132C-3.3 (C Grade - 0.2%) -0.2 0.2 LM4132D-3.3 (D Grade - 0.4%) -0.4 0.4 LM4132E-3.3 (E Grade - 0.5%) -0.5 0.5 LM4132A-3.3 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-3.3 20 LM4132C-3.3 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current 60 100 µA 3 7 µA 120 ppm / mA Supply Current in Shutdown EN = 0V ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V 85 ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 ∆VREF VIN - VREF ppm / ˚C 20 LM4132E-3.3 IQ_SD % Temperature Coefficient LM4132D-3.3 IQ Unit Output Voltage Initial Accuracy ppm / V ppm Dropout Voltage (Note 9) ILOAD = 10mA 175 VN Output Noise Voltage 0.1 Hz to 10 Hz 310 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level 65 7 400 mV µVPP %VIN www.national.com LM4132 Electrical Characteristics LM4132-3.3 (VOUT = 3.3V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply LM4132 Electrical Characteristics LM4132-4.1 (VOUT = 4.096V) Limits in standard type are for TJ = 25˚C only, and limits in boldface type apply over the junction temperature (TJ) range of -40˚C to +125˚C unless otherwise specified. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25˚C, and are provided for reference purposes only. Unless otherwise specified VIN = 5V and ILOAD = 0 Symbol VREF TCVREF / ˚C (Note 6) Parameter Conditions Typ Min (Note Max (Note 4) 5) (Note 4) LM4132A-4.1 (A Grade - 0.05%) -0.05 0.05 LM4132B-4.1 (B Grade - 0.1%) -0.1 0.1 LM4132C-4.1 (C Grade - 0.2%) -0.2 0.2 LM4132D-4.1 (D Grade - 0.4%) -0.4 0.4 LM4132E-4.1 (E Grade - 0.5%) -0.5 0.5 LM4132A-4.1 0˚C ≤ TJ ≤ + 85˚C 10 -40˚C ≤ TJ ≤ +125˚C 20 LM4132B-4.1 20 LM4132C-4.1 20 -40˚C ≤ TJ ≤ +125˚C 30 Supply Current 60 100 3 7 Supply Current in Shutdown EN = 0V ∆VREF/∆VIN Line Regulation VREF + 400mV ≤ VIN ≤ 5.5V ∆VREF/∆ILOAD Load Regulation 0mA ≤ ILOAD ≤ 20mA 25 Long Term Stability (Note 7) 1000 Hrs 50 Thermal Hysteresis (Note 8) -40˚C ≤ TJ ≤ +125˚C 75 ∆VREF VIN - VREF ppm / ˚C 20 LM4132E-4.1 IQ_SD % Temperature Coefficient LM4132D-4.1 IQ Unit Output Voltage Initial Accuracy 100 µA µA ppm / V 120 ppm / mA ppm Dropout Voltage (Note 9) ILOAD = 10mA 175 VN Output Noise Voltage 0.1 Hz to 10 Hz 350 400 ISC Short Circuit Current 75 mA VIL Enable Pin Maximum Low Input Level 35 %VIN VIH Enable Pin Minimum High Input Level 65 mV µVPP %VIN Note 1: Absolute Maximum Ratings indicate limits beyond which damage may occur to the device. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see Electrical Characteristics. 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. θJ-A for SOT23-5 package is 220˚C/W, TJMAX = 125˚C. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. Note 4: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control. Note 5: Typical numbers are at 25˚C and represent the most likely parametric norm. Note 6: Temperature coefficient is measured by the "Box" method; i.e., the maximum ∆VREF is divided by the maximum ∆T. Note 7: Long term stability is VREF @ 25˚C measured during 1000 hrs. Note 8: Thermal hysteresis is defined as the change in +25˚C output voltage before and after cycling the device from (-40˚C to 125˚C). Note 9: Dropout voltage is defined as the minimum input to output differential at which the output voltage drops by 0.5% below the value measured with a 5V input. www.national.com 8 LM4132 Typical Performance Characteristics for 1.8V Output Voltage vs Temperature Load Regulation 20151364 20151367 Line Regulation 0.1-10Hz Noise Spectrum 20151379 20151368 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151376 20151373 9 www.national.com LM4132 Typical Performance Characteristics for 2.048V Output Voltage vs Temperature Load Regulation 20151304 20151303 Line Regulation 0.1 - 10 Hz Noise 20151314 20151309 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151340 www.national.com 20151315 10 LM4132 Typical Performance Characteristics for 2.5V Output Voltage vs Temperature Load Regulation 20151354 20151355 Line Regulation 0.1 - 10 Hz Noise 20151321 20151356 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151357 20151358 11 www.national.com LM4132 Typical Performance Characteristics for 3.0V Output Voltage vs Temperature Load Regulation 20151365 20151369 Line Regulation 0.1-10 Hz Noise Spectrum 20151380 20151370 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151374 www.national.com 20151377 12 LM4132 Typical Performance Characteristics for 3.3V Output Voltage vs Temperature Load Regulation 20151366 20151371 Line Regulation 0.1-10 Hz Noise Spectrum 20151381 20151372 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151378 20151375 13 www.national.com LM4132 Typical Performance Characteristics for 4.096V Output Voltage vs Temperature Load Regulation 20151360 20151359 Line Regulation 0.1 - 10 Hz Noise 20151319 20151361 Output Voltage Noise Spectrum Power Supply Rejection vs Frequency 20151362 www.national.com 20151363 14 LM4132 Typical Performance Characteristics Dropout vs Load to 0.5% Accuracy Supply Current vs Input Voltage 20151308 20151353 Enable Threshold Voltage and Hysteresis Shutdown IQ vs Temperature 20151310 20151317 Typical Long Term Stability Ground Current vs Load Current 20151330 20151318 15 www.national.com LM4132 Typical Performance Characteristics (Continued) Typical Thermal Hysteresis Turn-On Transient Response 20151352 20151331 Line Transient Response VIN = 4V to 5.5V Load Transient Response ILOAD = 0 to 10mA 20151350 www.national.com 20151351 16 Thermal hysteresis is defined as the change in output voltage at 25oC after some deviation from 25oC. This is to say that thermal hysteresis is the difference in output voltage between two points in a given temperature profile. An illustrative temperature profile is shown in Figure 1. THEORY OF OPERATION The foundation of any voltage reference is the band-gap circuit. While the reference in the LM4132 is developed from the gate-source voltage of transistors in the IC, principles of the band-gap circuit are easily understood using a bipolar example. For a detailed analysis of the bipolar band-gap circuit, please refer to Application Note AN-56. SUPPLY AND ENABLE VOLTAGES To ensure proper operation, VEN and VIN must be within a specified range. An acceptable range of input voltages is VIN > VREF + 400mV (ILOAD ≤ 10mA) The enable pin uses an internal pull-up current source (IPULL_UP ) 2µA) that may be left floating or triggered by an external source. If the part is not enabled by an external source, it may be connected to VIN. An acceptable range of enable voltages is given by the enable transfer characteristics. See the Electrical Characteristics section and Enable Transfer Characteristics figure for more detail. Note, the part will not operate correctly for VEN > VIN. 20151338 FIGURE 1. Illustrative Temperature Profile This may be expressed analytically as the following: COMPONENT SELECTION A small ceramic (X5R or X7R) capacitor on the input must be used to ensure stable operation. The value of CIN must be sized according to the output capacitor value. The value of CIN must satisfy the relationship CIN ≥ COUT. When no output capacitor is used, CIN must have a minimum value of 0.1µF. Noise on the power-supply input may affect the output noise. Larger input capacitor values (typically 4.7µF to 22µF) may help reduce noise on the output and significantly reduce overshoot during startup. Use of an additional optional bypass capacitor between the input and ground may help further reduce noise on the output. With an input capacitor, the LM4132 will drive any combination of resistance and capacitance up to VREF/20mA and 10µF respectively. The LM4132 is designed to operate with or without an output capacitor and is stable with capacitive loads up to 10µF. Connecting a capacitor between the output and ground will significantly improve the load transient response when switching from a light load to a heavy load. The output capacitor should not be made arbitrarily large because it will effect the turn-on time as well as line and load transients. While a variety of capacitor chemistry types may be used, it is typically advisable to use low esr ceramic capacitors. Such capacitors provide a low impedance to high frequency signals, effectively bypassing them to ground. Bypass capacitors should be mounted close to the part. Mounting bypass capacitors close to the part will help reduce the parasitic trace components thereby improving performance. Where VHYS = Thermal hysteresis expressed in ppm VREF = Nominal preset output voltage VREF1 = VREF before temperature fluctuation VREF2 = VREF after temperature fluctuation. The LM4132 features a low thermal hysteresis of 75 ppm (typical) from -40˚C to 125˚C after 8 temperature cycles. TEMPERATURE COEFFICIENT Temperature drift is defined as the maximum deviation in output voltage over the operating temperature range. This deviation over temperature may be illustrated as shown in Figure 2. SHORT CIRCUITED OUTPUT The LM4132 features indefinite short circuit protection. This protection limits the output current to 75mA when the output is shorted to ground. 20151339 FIGURE 2. Illustrative VREF vs Temperature Profile TURN ON TIME Turn on time is defined as the time taken for the output voltage to rise to 90% of the preset value. The turn on time depends on the load. The turn on time is typically 33.2µs when driving a 1µF load and 78.8µs when driving a 10µF load. Some users may experience an extended turn on time (up to 10ms) under brown out conditions and low temperatures (-40˚C). Temperature coefficient may be expressed analytically as the following: 17 www.national.com LM4132 THERMAL HYSTERESIS Application Information LM4132 Application Information (Continued) TD = Temperature drift VREF = Nominal preset output voltage VREF_MIN = Minimum output voltage over operating temperature range VREF_MAX = Maximum output voltage over operating temperature range Where: VREF is in volts (V) and VERROR is in milli-volts (mV). Voltage error (mV) to percentage error (percent): ∆T = Operating temperature range. The LM4132 features a low temperature drift of 10ppm (max) to 30ppm (max), depending on the grade. LONG TERM STABILITY Long-term stability refers to the fluctuation in output voltage over a long period of time (1000 hours). The LM4132 features a typical long-term stability of 50ppm over 1000 hours. The measurements are made using 5 units of each voltage option, at a nominal input voltage (5V), with no load, at room temperature. Where: VREF is in volts (V) and VERROR is in milli-volts (mV). PRINTED CIRCUIT BOARD and LAYOUT CONSIDERATIONS References in SOT packages are generally less prone to PC board mounting than devices in Small Outline (SOIC) packages. To minimize the mechanical stress due to PC board mounting that can cause the output voltage to shift from its initial value, mount the reference on a low flex area of the PC board, such as near the edge or a corner. The part may be isolated mechanically by cutting a U shape slot on the PCB for mounting the device. This approach also provides some thermal isolation from the rest of the circuit. EXPRESSION OF ELECTRICAL CHARACTERISTICS Electrical characteristics are typically expressed in mV, ppm, or a percentage of the nominal value. Depending on the application, one expression may be more useful than the other. To convert one quantity to the other one may apply the following: ppm to mV error in output voltage: Bypass capacitors must be mounted close to the part. Mounting bypass capacitors close to the part will reduce the parasitic trace components thereby improving performance. Where: VREF is in volts (V) and VERROR is in milli-volts (mV). Bit error (1 bit) to voltage error (mV): VREF is in volts (V), VERROR is in milli-volts (mV), and n is the number of bits. mV to ppm error in output voltage: www.national.com 18 LM4132 Typical Application Circuits 20151326 FIGURE 3. Voltage Reference with Complimentary Output 20151327 FIGURE 4. Precision Voltage Reference with Force and Sense Output 20151328 FIGURE 5. Programmable Current Source 19 www.national.com LM4132 SOT-23 Precision Low Dropout Voltage Reference Physical Dimensions inches (millimeters) unless otherwise noted SOT23-5 Package NS Package Number MF05A 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. BANNED SUBSTANCE COMPLIANCE National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C2) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/quality/green. Lead free products are RoHS compliant. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560