PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4040 TCN4040 PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE FEATURES GENERAL DESCRIPTION ■ ■ ■ ■ ■ ■ ■ For applications in tight quarters, the TCN4040 precision voltage reference is available in a space-saving 3mm x 1.3mm SOT-23B-3 surface mount package. The TCN4040 eliminates the need for an external stabilizing capacitor while maintaining stability with any capacitive load. The minimum operating current is 60µA. The maximum operating current is 15mA. To ensure that the prime parts have an accuracy of better than ±0.5% (C grade) at 25°C, the TCN4040 uses fuse and zener-zap reverse breakdown voltage trim during wafer sort. Low dynamic impedance and bandgap reference temperature drift curvature correction maintain stable reverse breakdown voltage accuracy over a wide range of operating temperatures (– 40°C to + 85°C) and currents from (60µA to 15mA). The TCN4040 also is available in both adjustable and 1.2V versions. Small Packages ....... SOT-23B-3, TO-92, and SO-8 Output Capacitor Not Required Handles Capacitive Loads Fixed Reverse Breakdown Voltage of 2.5V Low Output Noise Wide Operating Current Range (60µA to 15mA) – 40°C to + 85°C Operating Temperature Range APPLICATIONS ■ ■ ■ ■ ■ ■ ■ ■ Portable, Battery-Powered Equipment Data Acquisition Systems Instrumentation Process Control Energy Management Product Testing Automotive Precision Audio Components ORDERING INFORMATION Output Voltage (V) Part No. Voltage Tolerance Temp. Coefficient Grade Package TCN4040C-2.5ENB 2.5 SOT-23B-3* ±0.5%, 100ppm/°C Max (C Grade) TCN4040C-2.5EOA 2.5 8-Pin SOIC ±0.5%, 100ppm/°C Max (C Grade) TCN4040C-2.5EZB 2.5 TO-92 ±0.5%, 100ppm/°C Max (C Grade) TCN4040D-2.5EOA 2.5 8-Pin SOIC ±1.0%, 150ppm/°C Max (D Grade) TCN4040D-2.5ENB 2.5 SOT-23B-3* ±1.0%, 150ppm/°C Max (D Grade) TCN4040D-2.5EZB 2.5 TO-92 ±1.0%, 150ppm/°C Max (D Grade) TCN4040E-2.5ENB 2.5 SOT-23B-3* ±2.0%, 150ppm/°C Max (E Grade) TCN4040E-2.5EZB 2.5 TO-92 ±2.0%, 150ppm/°C Max (E Grade) NOTE: *SOT-23B-3 is equivalent to the JEDEC (TO-236) PIN CONFIGURATION SOT-23B-3* (TOP VIEW) 8-Pin SOIC NC 1 TO-92-3 1 2 3 NC 8 + 1 NC 2 7 NC NC 3 6 NC – 4 5 NC TCN4040EOA 2 3 + – TCN4040ENB NOTE: *SOT-23B-3 is equivalent to the JEDEC (TO-236) TCN4040-01 6/16/97 1 specifications to its devices. TelCom Semiconductor reserves the right to make changes in the circuitry and TCN4040EZB NC + – PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4040 ABSOLUTE MAXIMUM RATINGS* (Note 1) ESD Susceptibility Human Body Model (Note 3) ................................ 2kV Machine Model (Note 3) .....................................200V Reverse Current. ....... ...............................................20mA Forward Current ....... ................................................10mA Power Dissipation (TA = 25°C) (Note 2) SOT-23B-3 Package ...................................... 230mW TO-92 Package .............................................. 440mW SO-8 Package ................................................470mW Storage Temperature ........................... – 65°C to + 150°C Lead Temperature (Soldering, 10 seconds) EOA ................................................................ +260°C ENB ................................................................ +300°C EZB ................................................................. +300°C *Functional operation above the absolute maximum stress rating is not implied. OPERATING RATINGS (NOTES 1 AND 2) Temperature Range (TMIN ≤ TA ≤ TMAX) ..................... – 40°C ≤ TA ≤ +85°C Reverse Current TCN4040-2.5 ...................................... .60µA to 15mA NOTES: 1. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is 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. 2. The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature), θJA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDMAX = (TJMAX – TA) /θJA or the number given in Absolute Maximum Ratings, whichever is lower. For the TCN4040, TJMAX = 125°C, and the typical thermal resistance (θJA), when board mounted, is 185°C/W for the M package, 326°C/W for the SOT-23B-3 package, and 180° C/W with 0.4” lead length and 170°C/W with 0.125” lead length for the TO-92-3 package. 3. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. ELECTRICAL CHARACTERISTICS: Boldface type specifications apply for TA = TJ = TMIN to TMAX. All other specifications; TA = TJ = 25°C. TCN4040CEOA TCN4040CENB TCN4040CEZB TCN4040DEOA TCN4040DENB TCN4040DEZB TCN4040EENB TCN4040EEZB Symbol Parameter Test Conditions Min Typ Max Min Typ Max VR IR =100µA Notes 4, 5 IR =100µA Notes 4, 5, 6 Notes 4, 5 — 2.500 — — 2.500 — — 2.500 — — — — — 45 ±25 ±49 65 70 ±150 — — — — — — 45 ±12 ±29 60 65 ±100 IRMIN ∆VR/∆T ∆VR/∆IR Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR =10mA IR =1mA IR =100µA Notes 4, 5 IRMIN ≤ IR ≤ 1mA Notes 4, 5 1mA ≤ IR =12mA ZR Reverse Dynamic Impedance TCN4040-01 6/16/97 IR =1mA, f = 120Hz, IAC = 0.1 IR Notes 4, 5 — — — — — ±20 ±15 ±15 ±20 ±15 ±15 Min Typ 45 ±20 ±15 ±15 Max Unit — V ±50 mV 65 70 ±150 µA ±74 ppm/°C — — 0.4 0.8 1.0 — — 0.4 1.0 1.2 — — 0.4 1.0 1.2 mV — — — 2.3 6.0 8.0 0.9 — — — 2.3 8.0 10.0 1.1 — — — 2.3 8.0 10.0 1.1 mV 0.3 2 0.3 0.3 Ω PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4040 ELECTRICAL CHARACTERISTICS (Cont.): Boldface type specifications apply for TA = TJ = TMIN to TMAX. All other specifications; TA = TJ = 25°C. TCN4040CEOA TCN4040CENB TCN4040CEZB Symbol Parameter eN Test Conditions Wideband Noise IR =100µA, 10Hz ≤ f ≤ 10kHz Notes 4, 5 Reverse Breakdown t =1000hrs Voltage Long Term T = 25°C ±0.1°C Stability IR =100µA Notes 4, 5 ∆VR Min Typ Max — 35 — 120 TCN4040DEOA TCN4040DENB TCN4040DEZB TCN4040EENB TCN4040EEZB Min Typ Max Min Typ Max Unit — — 35 — — 35 — µVmsec — — 120 — — 120 — ppm/°C NOTES: 4. Typicals are at TJ = 25°C and represent most likely parametric norm. 5. Limits are 100% production tested at 25°C. 6. The boldface (over-temperature) limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from – 40°C to the reference point of 25°C, and VR is the reverse breakdown voltage. The total over-temperature tolerance for the different grades is shown below: C-grade: ±1.15% = ±0.5% ±100ppm/°C x 65°C D-grade: ±1.98% = ±1.0% ±150ppm/°C x 65°C E-grade: ±2.98% = ±2.0% ±150ppm/°C x 65°C PIN DESCRIPTION Pin No. (SOT-23B-3) Pin No. TO-92 Pin No. 8-Pin SOIC 1 1 1 2 3 2 3 2 3 Symbol NC NC NC + – – NC NC NC + 4 5 6 7 8 TCN4040-01 6/16/97 3 Description No connection No connection No connection Positive terminal Negative terminal Negative terminal No connection No connection No connection Positive terminal PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4040 APPLICATIONS INFORMATION RS is determined by the supply voltage, (VS), the load and operating current, (IL and IQ), and the TCN4040’s reverse breakdown voltage, VR. Available in a space saving SOT-23B-3 surface mount package, the TCN4040 is a precision micro-power curvature-corrected bandgap shunt voltage reference. The TCN4040 is designed for stable operation without an external capacitor connected between the “+” pin and the “–” pin. The TCN4040 also remains stable, however, if a bypass capacitor is used. The minimum operating current increase is 60mA and the maximum operating current is 15mA. The TCN4040, in the SOT-23B-3 package has a parasitic Schottky diode between pin 3 (–) and pin 1. (Die attach interface contact). Therefore, pin 1 of the SOT-23B-3 package must be left floating or connected to pin 3. In a conventional shunt regulator application, an external series resistor (RS) is connected between the supply voltage and the TCN4040 (Figure 1). RS determines the current that flows through the load (IL) and the TCN4040 (IQ). Even when the supply voltage is at its minimum, and the load current is at its maximum value, RS should be small enough to supply at least the minimum acceptable IQ to the TCN4040 since load current and supply voltage may vary. Conversely, when the supply voltage is at its maximum and IL is at its minimum, RS should be large enough that the current flowing through the TCN4040 is less than 15mA. TCN4040-01 6/16/97 VS – VR RS = IL + IQ VS RS IQ + IL IL VR IQ TCN4040 Figure 1. Shunt Regulator 4 PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4041 TCN4041 PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE FEATURES GENERAL DESCRIPTION ■ ■ ■ ■ For applications in tight quarters, the TCN4041 precision voltage reference is available in a space-saving 3mm x 1.3mm SOT-23B-3 surface mount package. The TCN4041 eliminates the need for an external stabilizing capacitor while maintaining stability with any capacitive load. The minimum operating current is for both the TCN40411.2V and the TCN4041-ADJ. Both versions have a maximum operating current of 12mA. To ensure that the prime parts have an accuracy of better than ±0.5% (C grade) at 25°C, the TCN4041 uses fuse and zener-zap reverse breakdown voltage trim during wafer sort. Low dynamic impedance and bandgap reference temperature drift curvature correction maintain stable reverse breakdown voltage accuracy over a wide range of operating temperatures (– 40°C to + 85°C) and currents from (60µA to 12mA). The TCN4041 is available in small SOT-23, TO-92, and SO-8 packages. ■ ■ ■ Small Packages ....... SOT-23B-3, TO-92, and SO-8 Output Capacitor Not Required Handles Capacitive Loads Adjutable Voltage and Fixed Reverse Breakdown Voltage of 1.2V Low Output Noise Wide Operating Current Range (60µA to 15mA) – 40°C to + 85°C Operating Temperature Range APPLICATIONS ■ ■ ■ ■ ■ ■ ■ ■ Portable, Battery-Powered Equipment Data Acquisition Systems Instrumentation Process Control Energy Management Product Testing Automotive Precision Audio Components ORDERING INFORMATION Output Voltage (V) Part No. Package Voltage Tolerance Temp. Coefficient Grade SOT-23B-3* ±0.5%, 100ppm/°C Max (C Grade) ADJ SOT-23B-3* ±0.5%, 100ppm/°C Max (C Grade) 1.2 8-Pin SOIC ±0.5%, 100ppm/°C Max (C Grade) TCN4041C-ADJEOA ADJ 8-Pin SOIC ±0.5%, 100ppm/°C Max (C Grade) TCN4041C-1.2EZB 1.2 TO-92 ±0.5%, 100ppm/°C Max (C Grade) TCN4041C-ADJEZB ADJ TO-92 ±0.5%, 100ppm/°C Max (C Grade) TCN4041D-2.5EOA 2.5 8-Pin SOIC ±1.0%, 150ppm/°C Max (D Grade) TCN4041D-4.1EOA 4.1 8-Pin SOIC ±1.0%, 150ppm/°C Max (D Grade) TCN4041D-1.2ENB 1.2 SOT-23B-3* ±1.0%, 150ppm/°C Max (D Grade) TCN4041D-ADJENB ADJ SOT-23B-3* ±1.0%, 150ppm/°C Max (D Grade) TCN4041D-1.2EZB 1.2 TO-92 ±1.0%, 150ppm/°C Max (D Grade TCN4041D-ADJEZB ADJ TO-92 ±1.0%, 150ppm/°C Max (D Grade) TCN4041E-1.2ENB 1.2 SOT-23B-3* ±2.0%, 150ppm/°C Max (E Grade) TCN4041E-1.2EZB 1.2 TO-92 ±2.0%, 150ppm/°C Max (E Grade) TCN4041C-1.2ENB 1.2 TCN4041C-ADJENB TCN4041C-1.2EOA NOTE: *SOT-23B-3 is equivalent to the JEDEC (TO-236) TCN4041-01 6/19/97 1 specifications to its devices. TelCom Semiconductor reserves the right to make changes in the circuitry and PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4041 ABSOLUTE MAXIMUM RATINGS* (Note 1) Human Body Model (Note 3) ................................ 2kV Machine Model (Note 3) .....................................200V Reverse Current. ....... ...............................................20mA Forward Current ....... ................................................10mA Power Dissipation (TA = 25°C) (Note 2) SOT-23B-3 Package ...................................... 230mW TO-92 Package .............................................. 440mW SO-8 Package ................................................470mW Storage Temperature ........................... – 65°C to + 150°C Lead Temperature (Soldering, 10 seconds) EOA ................................................................ +260°C ENB ................................................................ +300°C EZB ................................................................. +300°C ESD Susceptibility *Functional operation above the absolute maximum stress rating is not implied. OPERATING RATINGS (NOTES 1 AND 2) Temperature Range (TMIN ≤ TA ≤ TMAX) ..................... – 40°C ≤ TA ≤ +85°C Reverse Current TCN4041-1.2 ....................................... 60µA to 12mA TCN40401-ADJ .................................... 68µA to12mA Output Voltage Range TCN4041-ADJ ....................................... 1.24V to 10V NOTES: 1. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is 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. 2. The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature), θJA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDMAX = (TJMAX – TA) /θJA or the number given in Absolute Maximum Ratings, whichever is lower. For the TCN4041, TJMAX = 125°C, and the typical thermal resistance (θJA), when board mounted, is 185°C/W for the M package, 326°C/W for the SOT-23B-3 package, and 180° C/W with 0.4” lead length and 170°C/W with 0.125” lead length for the TO-92-3 package. 3. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. ELECTRICAL CHARACTERISTICS: Boldface type specifications apply for TA = TJ = TMIN to TMAX. All other specifications; TA = TJ = 25°C. All other specifications; TA = TJ = 25°C. The grades C, D, and E designate initial Reverse Breakdown Voltage tolerances of ±0.5%, ±1.0%, and ±2.0%, respectively. TCN4041CEOA TCN4041CENB TCN4041CEZB TCN4041DEOA TCN4041DENB TCN4041DEZB TCN4041EENB TCN4041EEZB Symbol Parameter Test Conditions Min Typ Max Min Typ Max VR IR =100µA Notes 4, 5 IR =100µA Notes 4, 5, 6 Notes 4, 5 — 1.225 — — 2.500 — — 2.500 ±6 45 ±12 ±24 65 70 ±160 — — — — — — 60 65 ±100 — — — — — IRMIN ∆VR/∆T ∆VR/∆IR Reverse Breakdown Voltage Reverse Breakdown Voltage Tolerance Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient Reverse Breakdown Voltage Change with Operating Current Change IR =10mA IR =1mA IR =100µA Notes 4, 5 IRMIN ≤ IR ≤ 1mA Notes 4, 5 1mA ≤ IR =12mA ZR Reverse Dynamic Impedance TCN4041-01 6/19/97 IR =1mA, f = 120Hz, IAC = 0.1 IR Notes 4, 5 — — — — — ±14 45 ±20 ±15 ±15 ±20 ±15 ±15 Min Typ 45 ±20 ±15 ±15 Max Unit — V ±25 mV 65 70 ±150 µA ±36 ppm/°C — — 0.7 1.5 2.0 — — 0.4 2.0 2.5 — — 0.4 2.0 2.5 mV — — — 2.5 6.0 8.0 1.5 — — — 2.3 8.0 10.0 2.0 — — — 2.3 8.0 10.0 2.0 mV 0.5 2 0.3 0.3 Ω PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4041 ELECTRICAL CHARACTERISTICS (Cont.): Boldface type specifications apply for TA = TJ = TMIN to TMAX. All other specifications; TA = TJ = 25°C. The grades C, D, and E designate initial Reverse Breakdown Voltage tolerances of ±0.5%, ±1.0%, and ±2.0%, respectively. TCN4041CEOA TCN4041CENB TCN4041CEZB Symbol Parameter eN Test Conditions Wideband Noise ∆VR IR =100µA, 10Hz ≤ f ≤ 10kHz Notes 4, 5 Reverse Breakdown t =1000hrs Voltage Long Term T = 25°C ±0.1°C Stability IR =100µA Notes 4, 5 Min Typ Max — 20 — 120 TCN4041DEOA TCN4041DENB TCN4041DEZB TCN4041EENB TCN4041EEZB Min Typ Max Min Typ Max Unit — — 20 — — 20 — µVmsec — — 120 — — 120 — ppm/°C NOTES: 4. Typicals are at TJ = 25°C and represent most likely parametric norm. 5. Limits are 100% production tested at 25°C. 6. The boldface (over-temperature) limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from – 40°C to the reference point of 25°C, and VR is the reverse breakdown voltage. The total over-temperature tolerance for the different grades is shown below: C-grade: ±1.15% = ±0.5% ±100ppm/°C x 65°C D-grade: ±1.98% = ±1.0% ±150ppm/°C x 65°C E-grade: ±2.98% = ±2.0% ±150ppm/°C x 65°C 7. When VOUT ≤ 1.6V, the TCN4041-ADJ in the SOT-23B package must operate at reduced IR. This is caused by the series resistance of the die attach between the die (-) output and the package (-) output pin. See the Output Saturation (SOT23-B only) curve in the Typical Characteristics section. 8. Reference voltage and temperature coefficient will change with output voltage. See Typical Characteristics curves. PIN CONFIGURATION SOT-23B-3* (TOP VIEW) NC TO-92-3 8-Pin SOIC 1 NC 1 2 3 3 2 – + TCN4041EZB-1.2V TCN4041ENB-1.2V 1 2 3 NC 1 8 + NC 2 7 NC NC 3 6 NC – 4 5 NC TCN4041EOA-1.2V 1 NC + – NC TCN4041-ADJ 2 3 + – 1 8 + NC 2 7 NC NC 3 6 NC – 4 5 NC TCN4041ENB-ADJ NOTE: *SOT-23B-3 is equivalent to the JEDEC (TO-236) TCN4041-01 6/19/97 TCN4041EOA-ADJ 3 PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4041 PIN DESCRIPTION Pin No. (SOT-23B-3) Pin No. TO-92 Pin No. 8-Pin SOIC 1 1 1 2 3 2 3 2 3 Symbol NC NC NC + – – NC NC NC + 4 5 6 7 8 No connection No connection No connection Positive terminal Negative terminal Negative terminal No connection No connection No connection Positive terminal Output voltage on the TCN4041-ADJ can be adjusted to any value between 1.24V and 10V. It is a function of the internal reference voltage (VREF) and the ratio of the external feedback resistors (see Figure 2). The output can be found with the equation (where VOUT is the desired output voltage): APPLICATIONS INFORMATION Available in space-saving SOT-23B-3 surface mount packages, the TCN4041 is a precision micro-power curvature-corrected bandgap shunt voltage reference. It is designed for stable operation without an external capacitor connected between the “+” pin and the “-” pin. The TCN4041 also remains stable, however, if a bypass capacitor is used. The device is available in either a fixed 1.2V or an adjustable reverse breakdown voltage. The minimum operating current is 60mA, and the maximum operating current is 12mA for both options. TCN4041s in the SOT-23 package have pin 1 connected as the (-) output. (Die attach interface contact). Therefore, pin 1 of the TCN4041-1.2 must be left floating or connected to pin 3, and pin 1 on the TCN4041-ADJ is the (-) output. In a conventional shunt regulator application, an external series resistor (RS) is connected between the supply voltage and the TCN4041 (Figure 1). RS determines the current that flows through the load (IL) and the TCN4041 (IQ). Even when the supply voltage is at its minimum, and the load current is at its maximum value, RS should be small enough to supply at least the minimum acceptable IQ to the TCN4041 since load current and supply voltage may vary. Conversely, when the supply voltage is at its maximum and IL is at its minimum, RS should be large enough that the current flowing through the TCN4041 is less than 12mA. RS is determined by the supply voltage, (VS), the load and operating current, (IL and IQ), and the TCN4041’s reverse breakdown voltage, VR. VOUT = VREF (R2/R1 + 1) Equation 1. The value of the internal VREF is a function of VO. The “corrected” VREF can be determined by (where VO is the desired output voltage): VREF’ = VOUT ∆VREF/∆VOUT) +VY Equation 2. ∆VREF/∆VOUT is typically -1.3mV/V, and VY = 1.240V. Replace the value of VREF’ in Equation 1 with the value determined using Equation 2. The actual output voltage can deviate from that predicted by the typical ∆VREF/∆VO in Equation 2. The worst case ∆VREF/∆VOUT for C-grade parts is – 2.5mV/V and VY = 1.246V; for D-grade, the worst case is – 3.0mV/V and VY = 1.248V. The difference in output voltage resulting from typical worst case values are shown in the following example: Let VO = +9V. Using the typical value of ∆VREF/∆VOUT, VREF is 1.228; choosing a value of R1 = 10kΩ, R2 = 63.272kW. The output voltage, when using worst case ∆VREF/∆VOUT for C-grade and D-grade parts, is 8.965V and 8.946V, respectively. This could result in errors as large as 0.39% for C-grade, and 0.59% for D-grade parts. However, resistor values resulting from the typical value of ∆VREF/∆VOUT will work most of the time, requiring no additional adjustments. VS - VR RS = IL + IQ TCN4041-01 6/19/97 Description 4 PRELIMINARY INFORMATION PRECISION MICROPOWER SHUNT VOLTAGE REFERENCE TCN4041 VS VS RS RS IQ + IL IL VR VOUT IQ R1 R2 TCN4041 Figure 1. Shunt Regulator TCN4041-01 6/19/97 TCN4041-ADJ Figure 2. Adjustable Shunt 5