REF1112 SBOS283 – SEPTEMBER 2003 µA, 1.25V 10ppm/°C, 1µ Shunt Voltage Reference FEATURES APPLICATIONS z MICRO-PACKAGE: SOT23-3 z BATTERY-POWERED INSTRUMENTS z WIDE CURRENT RANGE: 1µ µA to 5mA z PORTABLE DEVICES z HIGH INITIAL ACCURACY: 0.2% z MEDICAL EQUIPMENT z EXCELLENT SPECIFIED DRIFT PERFORMANCE: z CURRENT SOURCES z CALIBRATORS z MICROPOWER CURRENT AND VOLTAGE REFERENCE 30ppm/°C (max) from 0°C to +70°C 50ppm/°C (max) from –40°C to +85°C VS DESCRIPTION IREF + ILOAD The REF1112 is a two-terminal shunt reference designed for power and space-sensitive applications. The REF1112 features an operating current of 1µA in a SOT23-3 package and is an improved, lower power pin-compatible drop-in replacement for designs currently using the REF1004 and LT1004. The REF1112 is specified from –40°C to +85°C with operation extending from –40°C to +125°C. RBIAS ILOAD VOUT IREF RLOAD The REF1112 complements other 1µA components from Texas Instruments including the OPA349 and the TLV240x low power operational amplifiers, and the TLV349x micropower voltage comparator. RBIAS = VS − VD ILOAD + IREF VO 1 3 NC GND 2 SOT23 NC indicates pin should be left unconnected. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2003, Texas Instruments Incorporated www.ti.com ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY Reverse Breakdown Current ............................................................ 10mA Forward Current ............................................................................... 10mA Operating Temperature ................................................. –55°C to +125°C Storage Temperature .................................................... –65°C to +150°C Junction Temperature .................................................................. +150°C Lead Temperature (soldering, 10s) ............................................... +300°C Electrostatic discharge can cause damage ranging from performance degradation to complete device failure. Texas Instruments recommends that all integrated circuits be handled and stored using appropriate ESD protection methods. (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet published specifications. PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR(1) SPECIFIED TEMPERATURE RANGE PACKAGE MARKING SOT23-3 DBZ –40°C to +125°C R11A REF1112AIDBZT Tape and Reel, 250 " " " " REF1112AIDBZR Tape and Reel, 3000 REF1112 " ORDERING NUMBER TRANSPORT MEDIA, QUANTITY NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com. PRELIMINARY ELECTRICAL CHARACTERISTICS Boldface limits apply over the specified temperature range, TA = –40°C to +125°C. At TA = +25°C, IREF = 1.2µA, and CLOAD = 10nF, unless otherwise noted. REF1112 - 1.25V PARAMETER CONDITIONS REVERSE BREAKDOWN VOLTAGE TEMPERATURE COEFFICIENT MIN TYP MAX UNITS 1.2475 -0.2 1.25 1.2525 + 0.2 V % 10 15 15 30 50 ppm/°C ppm/°C ppm/°C 1 1.2 µA 30 100 ppm/mA 0.037 0.125 Ω IREF = 1.2µA 1.2µA < IREF < 5mA 0°C to +70°C –40°C to +85°C –40°C to +125°C MINIMUM OPERATING CURRENT REVERSE BREAKDOWN VOLTAGE CHANGE WITH CURRENT 1.2µA < IREF < 5mA REVERSE DYNAMIC IMPEDANCE 1.2µA < IREF < 5mA LOW-FREQUENCY NOISE(1) 0.1Hz < IREF < 10Hz THERMAL HYSTERESIS(2) 25 µVPP 100 ppm 60 ppm/kHr LONG-TERM STABILITY +25°C ± 0.1°C TEMPERATURE CHARACTERISTICS Specified Range Operating Range Storage Range Thermal Resistance θJA –40 –55 –65 SOT23-3 Surface-Mount +125 +125 +150 135 °C °C °C °C/W (1) Peak-to-peak noise is measured with a 2-pole high-pass filter at 0.1Hz and a 4-pole low-pass chebyshev filter at 10Hz. (2) Thermal hysteresis is defined as the change in output voltage after operating the device at 25°C, cycling the device through the specified temperature range, and returning to 25°C. REF1112 2 www.ti.com SBOS283 TYPICAL CHARACTERISTICS At TA = +25°C, IREF = 10µA and CL = 10nF, unless otherwise specified. REVERSE CHARACTERISTICS 10K FORWARD CHARACTERISTICS 1.0 -40°C ≤ TA ≤ 125°C TA = 25°C 0.8 Voltage Regulation Region 100 Forward Voltage (V) Reverse Current (µA) 1K 10 1 0.6 Behaves as standard silicon diode 0.4 0.2 0.1 0.01 0.00 0.0 0.25 0.50 0.75 1.00 1.25 1.50 0.001 0.01 Reverse Voltage (V) 10 REVERSE VOLTAGE CHANGE vs CURRENT TEMPERATURE DRIFT 1.255 Output Voltage Change (mV) 0.5 1.254 Reverse Voltage (V) 0.1 1.0 Forward Current (mA) 1.253 1.252 1.251 1.250 -40°C ≤ TA ≤ 125°C 0.4 0.3 0.2 0.1 1.249 1.248 −55 0.0 −35 −15 5 25 45 65 85 105 0.001 125 0.01 Temperature (°C) 1 10 REVERSE DYNAMIC IMPEDANCE REVERSE DYNAMIC IMPEDANCE 100 10k -40°C ≤ TA ≤ 125°C TA = +25°C f = 10Hz 10 Dynamic Impedance (Ω) Dynamic Impedance (Ω) 0.1 Reverse Current (mA) 1 0.1 1k IREF = 10µA 100 10 IREF = 5mA 1 0.1 0.01 0.01 0.001 0.01 0.1 1 10 Reverse Current (mA) REF1112 SBOS283 1 10 100 1k Frequency (Hz) 10k 100k 3 www.ti.com TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, IREF = 10µA and CL = 10nF, unless otherwise specified. TEMPERATURE DRIFT DISTRIBUTION REVERSE BREAKDOWN VOLTAGE DISTRIBUTION 50 25 0°C to +70°C 40 Distribution (%) Distribution (%) 20 15 10 30 20 10 5 0 0 1.2475 1.2500 1.2525 0 5 10 Reverse Breakdown Voltage (V) 15 20 25 30 35 Drift (ppm/°C) TEMPERATURE DRIFT DISTRIBUTION LOW-FREQUENCY NOISE, 0.1 to 10Hz 25 −40°C to +85°C 15 10µV/div Distribution (%) 20 10 5 0 0 5 10 15 20 25 30 Drift (ppm/°C) 35 40 45 50 1.0s/div RESPONSE TIME RESPONSE TIME CLOAD = 0.01µF CLOAD = 0.1µF 2V 2V 1V VIN VOUT 0V VIN VOUT 375kΩ VOUT 0.01µF 5V Voltage (V) Voltage (V) 1V 0V IREF 375kΩ VOUT 0.1µF 5V VIN VIN 0V 0V 10ms/div 25ms/div REF1112 4 www.ti.com SBOS283 APPLICATIONS INFORMATION . VS The REF1112 is a two-terminal bandgap reference diode designed for high accuracy with outstanding temperature characteristics at low operating currents. Precision thin-film resistors result in 0.2% initial voltage accuracy and 50ppm/°C maximum temperature drift. The REF1112 is specified from –40°C to +85°C, with operation from –40°C to +125°C, and is offered in a SOT23-3 package. Typical connections for the REF1112 are shown in Figure 1. A minimum 1µA bias current is required to maintain a stable output voltage and can be provided with a resistor connected to the supply voltage. IBIAS depends on the values selected for RBIAS and VS, and will vary as a sum of the minimum operating current and the load current. To maintain stable operation, the value of RBIAS must be low enough to maintain the minimum operating current at the minimum and maximum load and supply voltage levels. 10kΩ ISET ISET = 0.1µF VREF RSET RSET FIGURE 2. REF1112 Provides a Stable Current Source. 3V 795kΩ VS VREF RBIAS 3V 250kΩ TLV2401 VOUT = 1V IBIAS = IREF + ILOAD 0.1µF VREF 1µF REF1112 1MΩ ILOAD 0.1µF IREF IBIAS = VS - VREF RBIAS FIGURE 3. MicroPOWER 3µA 1V Voltage Reference. FIGURE 1. Typical Connections. 3V A 0.1µF load capacitor is recommended to maintain stability under varying load conditions. A minimum 0.01µF load capacitor is required for stable operation. Start-up time for the REF1112 will be affected, depending on the value of load capacitance and the bias currents being used. A 1µF power supply bypass capacitor is recommended to minimize supply noise within the circuit. The REF1112 shunt voltage reference provides a versatile function for low power and space-conservative applications. The REF1112 can be configured with an additional diode and NPN transistor to provide a temperature compensated current reference as shown in Figure 2. The REF112 can be scaled to provide extremely low power reference voltages. Figure 3 shows the REF1112 used as a 1V out, 3µA voltage reference, and in Figure 4 a 2.5V reference on 1µA. RSET VOUT = 2.5V 0.1µF 0.1µF FIGURE 4. 2.5V Reference on 1µA. REF1112 SBOS283 RLOAD 5 www.ti.com For applications requiring a stable voltage reference capable of sinking higher than 5mA of current, a REF1112 combined with an OPA347 can sink up to 10mA of current. This configuration is shown in Figure 5, and through appropriate selection of R1 and R2, can be used to provide a wide range of stable reference voltages. The REF1112 is also useful for level shifting, and as shown in Figure 6, can be used to achieve the full input range of an ADC. VS RSET IBIAS 2.5V R1 10kΩ 10kΩ 0.01µF OPA347 1.25V 0.1µF VOUT = 1.25 (1 + R1 / R2) R2 10kΩ FIGURE 5. Adjustable Voltage Shunt Reference VS VREF VOUT +V 1.25V ADC 0.1µF VIN V FIGURE 6. REF1112 Provides a Level Shift to Achieve Full ADC Input Range. REF1112 6 www.ti.com SBOS283 MECHANICAL DATA MPDS108 – AUGUST 2001 DBZ (R-PDSO-G3) PLASTIC SMALL-OUTLINE 3,04 2,80 2,05 1,78 0,60 0,45 1,03 0,89 1,40 1,20 2,64 2,10 0,51 0,37 1,12 0,89 0,100 0,013 0,55 REF 0,180 0,085 4203227/A 08/01 NOTES: A. B. C. D. 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