TS6001 A 7ppm/°C, 0.08% Precision +2.5V Voltage Reference in SOT23 FEATURES DESCRIPTION The TS6001 is a 3-terminal, series-mode 2.5-V precision voltage reference and is a pin-for-pin, identical to the MAX6025 voltage reference with improved electrical performance. The TS6001 consumes only 31μA of supply current at no-load, exhibits an initial output voltage accuracy of less than 0.08%, and a low output voltage temperature coefficient of 7ppm/°C. In addition, the TS6001’s output stage is stable for all capacitive loads to 2200pF and is capable of sinking and sourcing load currents up to 500µA. Improved Electrical Performance over MAX6025 Initial Accuracy: 0.08% (max) – TS6001A 0.16% (max) – TS6001B Temperature Coefficient: 7ppm/°C (max) – TS6001A 10ppm/°C (max) – TS6001B Quiescent Supply Current: 35μA (max) Low Supply Current Change with VIN: 0.1μA/V Output Source/Sink Current: ±500µA Low Dropout at 500μA Load Current: 75mV Load Regulation: 30ppm/mA Line Regulation: 10ppm/V Stable with CLOAD up to 2200pF APPLICATIONS Battery-Operated Equipment Data Acquisition Systems Hand-Held Equipment Smart Industrial Transmitters Industrial and Process-Control Systems Precision 3V/5V Systems Hard-Disk Drives Since the TS6001 is a series-mode voltage reference, its supply current is not affected by changes in the applied supply voltage unlike two-terminal shuntmode references that require an external resistor. The TS6001’s small form factor and low supply current operation all combine to make it an ideal choice in low-power, precision applications. The TS6001 is fully specified over the -40°C to +85°C temperature range and is available in a 3-pin SOT23 package. TYPICAL APPLICATION CIRCUIT Output Voltage Temperature Drift OUTPUT VOLTAGE - Volt 2.5010 THREE TYPICAL DEVICES DEVICE #1 2.5005 DEVICE #2 2.5000 DEVICE #3 2.4995 2.4990 -40 -15 10 35 60 85 TEMPERATURE DRIFT- °C Page 1 © 2014 Silicon Laboratories, Inc. All rights reserved. TS6001 ABSOLUTE MAXIMUM RATINGS IN to GND................................................................. -0.3V to +13.5V OUT to GND.................................................................... -0.3V to 7V Short Circuit to GND or IN (VIN < 6V) .............................. Continuous Output Short Circuit to GND or IN (VIN ≥ 6V) .............................. 60s Continuous Power Dissipation (TA = +70°C) 3-Pin SOT23 (Derate at 4.0mW/°C above +70°C) .......... 320mW Operating Temperature Range ................................. -40°C to +85°C Storage Temperature Range .................................. -65°C to +150°C Lead Temperature (Soldering, 10s)...................................... +300°C Electrical and thermal stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to any absolute maximum rating conditions for extended periods may affect device reliability and lifetime. PACKAGE/ORDERING INFORMATION ORDER NUMBER PART CARRIERQUANTITY MARKING TS6001AIG325 Tape & Reel ----- TS6001AIG325T Tape & Reel 3000 TS6001BIG325 Tape & Reel ----- Tape & Reel 3000 AAG AAH TS6001BIG325T Lead-free Program: Silicon Labs supplies only lead-free packaging. Consult Silicon Labs for products specified with wider operating temperature ranges. Page 2 TS6001 Rev. 1.0 TS6001 ELECTRICAL CHARACTERISTICS VIN = +5V, IOUT = 0, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. See Note 1. PARAMETER OUTPUT SYMBOL CONDITIONS TS6001A Output Voltage VOUT TA = +25°C TS6001B Output Voltage Temperature Coefficient (See Note 2) Line Regulation Load Regulation Dropout Voltage (See Note 3) OUT Short-Circuit Current Temperature Hysteresis (See Note 4) Long-Term Stability (See Note 5) DYNAMIC Noise Voltage Ripple Rejection Turn-On Settling Time Capacitive-Load Stability Range INPUT Supply Voltage Range Quiescent Supply Current Change in Supply Current TCVOUT (∆VOUT/VOUT) /∆VIN (∆VOUT/VOUT) /∆IOUT VIN -VOUT ISC ∆VOUT/ time eOUT ∆VOUT/ ∆VIN tR 0°C ≤ TA ≤ +85°C -40°C ≤ TA ≤ +85°C 0°C ≤ TA ≤ +85°C -40°C ≤ TA ≤ +85°C MIN TYP MAX UNITS 2.498 -0.08 2.496 -0.16 2.500 V % V % 2 2.5 3 4 2.502 0.08 2.504 0.16 7 10 10 15 10 30 30 70 75 4 4 240 320 150 TS6001A TS6001B (VOUT + 0.2V) ≤ VIN ≤ 12.6V Sourcing Sinking IOUT = 500μA VOUT Short to GND VOUT Short to IN 0 ≤ IOUT ≤ 500μA -500μA ≤ IOUT ≤ 0 2.500 ppm/°C ppm/V ppm/mA mV mA 100 ppm 168hr at TA = +25°C 75 ppm/ 168hr f = 0.1Hz to 10Hz f = 10Hz to 10kHz VIN = 5V ±100mV, f = 120Hz To VOUT = 0.1% of final value, COUT = 50 pF 50 75 82 340 μVP-P μVRMS dB μs COUT See Note 6 VIN IIN IIN/VIN Guaranteed by line-regulation test (VOUT + 0.2V) ≤ VIN ≤ 12.6V 0 VOUT + 0.2 31 0.1 2200 pF 12.6 35 2 V μA μA/V Note 1: All devices are 100% production tested at TA = +25°C and are guaranteed by characterization for TA = TMIN to TMAX, as specified. Note 2: Temperature Coefficient is measured by the “box” method; i.e., the maximum ∆VOUT is divided by the maximum ∆T. Note 3: Dropout voltage is the minimum input voltage at which VOUT changes ≤0.2% from VOUT at VIN = 5.0V. Note 4: Temperature hysteresis is defined as the change in the +25°C output voltage before and after cycling the device from +25°C to TMIN to +25°C and from +25°C to TMAX to +25°C. Note 5: Reference long-term drift or stability listed in the table is an intermediate result of a 1000-hour evaluation. Soldered onto a printed circuit board (pcb), voltage references exhibit more drift early in the evaluation because of assembly-induced differential stresses between the package and the pcb. Note 6: Not production tested; guaranteed by design. TS6001 Rev. 1.0 Page 3 TS6001 TYPICAL PERFORMANCE CHARACTERISTICS VIN = +5V; IOUT = 0mA; TA = +25°C, unless otherwise noted. Output Voltage Histogram Output Voltage Temperature Drift 9 2.5010 THREE TYPICAL DEVICES OUTPUT VOLTAGE - Volt 8 NUMBER OF UNITS 7 6 5 4 3 2 DEVICE #1 2.5005 DEVICE #2 2.5000 DEVICE #3 2.4995 1 0 2.4990 -0.02 0.02 0 0.04 -40 Long-Term Output Voltage Drift Line Regulation 85 120 OUTPUT VOLTAGE CHANGE - ppm OUTPUT VOLTAGE - Volt 60 TEMPERATURE DRIFT- °C THREE TYPICAL DEVICES DEVICE #1 2.5025 2.5000 DEVICE #2 2.4975 DEVICE #3 TA = -40°C 80 TA = +25°C 40 TA = +85°C 0 -40 2.4950 0 42 84 126 2 168 6 4 8 10 12 TIME - Hours SUPPLY VOLTAGE - Volt Dropout Voltage vs Source Current Load Regulation 0.4 14 160 OUTPUT VOLTAGE CHANGE - ppm DROPOUT VOLTAGE - V 35 10 OUTPUT VOLTAGE ERROR - % 2.5050 0.3 TA = +85°C 0.2 TA = +25°C TA = -40°C 0.1 0 0 200 400 600 800 SOURCE CURRENT- µA Page 4 -15 1000 80 TA = -40°C TA = +85°C 0 TA = +25°C -80 -160 -0.5 -0.25 0 0.25 0.5 LOAD CURRENT- mA TS6001 Rev. 1.0 TS6001 TYPICAL PERFORMANCE CHARACTERISTICS VIN = +5V; IOUT = 0mA; TA = +25°C, unless otherwise noted. Power Supply Rejection vs Frequency Supply Current vs Input Voltage 100 SUPPLY CURENT - µA POWER SUPPLY REJECTION – mV/V 40 VCC =+5.5V±0.25V 10 1 36 32 28 24 0.1 20 0.01 2 100 1k 10k 100k 6 4 8 10 12 14 1M INPUT VOLTAGE - Volt FREQUENCY - Hz Output Impedance vs Frequency Supply Current vs Temperature 10k VCC =+12.5V OUTPUT IMPEDANCE - Ω SUPPLY CURENT - µA 40 VCC =+7.5V 35 30 VCC = +2.5V, +5.5V 25 1k 100 10 1 0.1 20 -15 10 35 60 85 0.1 1 100 10k TEMPERATURE - °C FREQUENCY - Hz 0.1Hz to 10Hz Output Noise Power-On Transient Response OUTPUT 1V/DIV VOUT(N) 10µV/DIV 46µVPP 1s/DIV TS6001 Rev. 1.0 1M INPUT 2V/DIV -40 200µs/DIV Page 5 TS6001 TYPICAL PERFORMANCE CHARACTERISTICS IOUT 1mA/DIV Large-signal Load Transient Response IOUT = 0mA → 1mA → 0mA, AC-Coupled OUTPUT 200mV/DIV IOUT = 0µA → 50µA → 0µA, AC-Coupled OUTPUT 20mV/DIV IOUT 50µA/DIV VIN = +5V; IOUT = 0mA; TA = +25°C, unless otherwise noted. Small-signal Load Transient Response 10µs/DIV 10µs/DIV VIN 200mV/DIV Line Transient Response OUTPUT 100mV/DIV VIN =5V±0.25V, AC-Coupled 2µs/DIV Page 6 TS6001 Rev. 1.0 TS6001 PIN FUNCTIONS PIN 1 2 3 NAME IN OUT GND FUNCTION Supply Voltage Input +2.5V Output Ground DESCRIPTION/THEORY OF OPERATION The TS6001 incorporates a precision 1.25-V bandgap reference that is followed by an output amplifier configured to amplify the base bandgap output voltage to a 2.5-V output. The design of the bandgap reference incorporates proprietary circuit design techniques to achieve its low temperature coefficient of 7ppm/°C and initial output voltage accuracy less than 0.08%. The design of the output amplifier’s frequency compensation does not require a separate compensation capacitor and is stable with capacitive loads up to 2200pF. The design of the output amplifier also incorporates low headroom design as it can source and sink load currents to 500μA with a dropout voltage less than 100mV. APPLICATIONS INFORMATION Power Supply Input Bypass Capacitance If there are other analog ICs within 1 to 2 inches of the TS6001 with their own bypass capacitors to GND, the TS6001 would not then require its own bypass capacitor. If this is not the case, then it is considered good analog circuit engineering practice to place a 0.1µF ceramic capacitor in as close proximity to the TS6001 as practical with very short pcb track lengths. Output/Load Capacitance Considerations As mentioned previously, the TS6001 does not require a separate, external capacitor at VOUT for transient response stability as it is stable for capacitive loads up to 2200pF. For improved load regulation transient response, the use of a capacitor at VOUT helps to reduce output voltage overshoot/undershoot to transient load current conditions. Figure 1 illustrates the TS6001’s transient load regulation performance with CLOAD = 0pF to a 50-µA transient upon a 175-µA steady-state load current. Peak transients are approximately 20mV and the TS6001 settles in less than 8µs. As shown in Figure 2, adding a capacitive load reduces peak transients at the expense of settling time. In this case, the TS6001’s output was loaded with CLOAD = 1000pF and subjected to the same transient load current profile. Peak transients were reduced to less than 10mV and the TS6001 settled in less than 10µs. IOUT = 175µA → 225µA → 175µA OUTPUT 20mV/DIV OUTPUT 20mV/DIV IOUT 50µA/DIV IOUT 50µA/DIV IOUT = 175µA → 225µA → 175µA Figure 1: TS6001 Transient Load Regulation Response, CLOAD = 0pF TS6001 Rev. 1.0 Figure 2: TS6001 Transient Load Regulation Response, CLOAD = 1000pF Page 7 TS6001 Supply Current outputs of precision voltage references is illustrated in Figure 3. The TS6001 exhibits excellent dc line regulation as its supply current changes slightly as a function of the applied supply voltage. Because of a unique bias loop design, the change in its supply current as a function of supply voltage (its ∆IIN/∆VIN) is less than 0.1μA/V. Since the TS6001 is a series-mode reference, load current is drawn from the supply voltage only when required. In this case, circuit efficiency is maintained at all applied supply voltages. Reducing power dissipation and extending battery life are the net benefits of improved circuit efficiency. When the applied supply voltage is less than the minimum specified input voltage of the TS6001 (for example, during the power-up or “cold-start” transition), the TS6001 performs an internal calibration routine and can draw up to 200μA above its nominal, steady-state supply current. This internal calibration sequence also dominates the TS6001’s turn-on time. To ensure reliable power-up behavior, the input power source must have sufficient reserve power to provide the extra supply current drawn during the power-up transition. Voltage Reference Turn-On Time With a (VIN – VOUT) voltage differential larger than 200mV and ILOAD = 0mA, the TS6001’s typical combined turn-on and settling time to within 0.1% of its 2.5V final value is approximately 340μs. Output Voltage Hysteresis Reference output voltage thermal hysteresis is the change in the reference’s +25°C output voltage after temperature cycling from +25°C to +85°C to +25°C and from +25°C to -40°C to +25°C. Thermal hysteresis is caused by differential package stress impressed upon the TS6001’s internal bandgap core transistors and depends on whether the reference IC was previously at a higher or lower temperature. At 100ppm, the TS6001’s typical temperature hysteresis is equal to 0.25mV with respect to a 2.5V output voltage. Connecting Two or More TS6001s in Stacked VOUT Arrangements In many applications, it is desired to combine the outputs of two or more precision voltage references, especially if the combined output voltage is not available or is an uncommon output voltage. One such technique for combining (or “stacking”) the Page 8 Figure 3: Connecting Two TS6001-2.5s in a Stacked VREFOUT Arrangement In this example and powered by an unregulated supply voltage (VIN ≥ +5.2V), two TS6001-2.5 precision voltage references are used. The GND terminal of REFA is connected to the OUT terminal of REFB. This connection produces two output voltages, VREFOUT1 and VREFOUT2, where VREFOUT1 is the terminal voltage of REFB and VREFOUT2 is VREFOUT1 plus the OUT terminal voltage of REFB. By implementing this stacked arrangement with a pair of TS6001-2.5s, VREFOUT2 is 5V and VREFOUT1 is 2.5V. Although the TS6001-2.5s do not specifically require input bypass capacitors, it is good engineering practice to bypass both references from VIN to the global GND terminal (at REFB). If either or both reference ICs are required to drive a load capacitance, it is also good engineering practice to route the load capacitor’s return lead to each reference’s corresponding REF’s GND terminal. The circuit’s minimum input supply voltage, VIN, is determined by VREFOUT2 and REFB’s dropout voltage (75mV, typically). How to Configure the TS6001 into a GeneralPurpose Current Source In many low-voltage applications, a general-purpose current source is needed with very good line regulation. The TS6001-2.5 can be configured as a grounded-load, floating current source as shown Figure 4. In this example, the TS6001-2.5’s output voltage is bootstrapped across an external resistor (R1 + P1) which, in turn, sets the output current. The circuit’s total output current is IOUT = ISET+IQSC where IQSC is the TS6001 supply current (up to 35µA). For TS6001 Rev. 1.0 TS6001 improved output current accuracy, ISET should be at least 10 times IQSC. The circuit illustrated in Figure 5 avoids the need for multiple op amps and well-matched resistors by using an active integrator circuit. In this circuit, the voltage reference’s output is used as the input signal to the integrator. Because of op amp loop action, the integrator adjusts its output voltage to establish the correct relationship between the reference’s OUT and GND terminals (=VREF). In other words, the output voltage polarity of the integrator stage is opposite that of the reference’s output voltage. Figure 4: A Low-power, General-Purpose Current Source. A Negative, Precision Voltage Reference without Precision Resistors When using current-output DACs, it is oftentimes desired that the polarity of the output signal voltage is the same as the external reference voltage. There are two conventional techniques used to accomplish this objective: a) inverting the full-scale DAC output voltage or b) converting a current-output DAC into a voltage-switching DAC. In the first technique, an op amp and pair of precision resistors would be required because the DAC’s output signal voltage requires re-inversion to match the polarity of the external reference voltage. The second technique is a bit more involved and requires converting the current-output DAC into a voltage-switching DAC by driving the DAC’s VREF and IOUT terminals in reverse. Additional components required are two precision resistors, an op amp, and an external voltage reference, typically a 1.25-V reference. If the 1.25-V full-scale output voltage requires scaling to a 2.5-V or a 5-V full scale, then a second op amp and pair of precision resistors would be necessary to perform the amplification. To avoid the need for either re-inversion of the current-switching DAC’s output voltage or amplifying the voltage-switching DAC’s output voltage, it would then be desired to apply a negative voltage reference to the original current-switching DAC. In general, any positive voltage reference can be converted into a negative voltage reference using pair of matched resistors and an op amp configured for inverting mode operation. The disadvantage to this approach is that the largest single source of error in the circuit is the relative matching of the resistors used. TS6001 Rev. 1.0 Figure 5: How to Convert a VREF to a –VREF without Precision Resistors. The 2200pF capacitor at the output of the TS6001 is optional and the resistor in series with the output of the op amp should be empirically determined based on the amplifier choice and whether the amplifier is required to drive a large capacitive load. Rail-to-rail output op amps used for the integrator stage work best in this application; however, these types of op amps require a finite amount of headroom (in the millivolt range) when sinking load current. Therefore, good engineering judgment is always recommended when selecting the most appropriate negative supply for the circuit. How to Use the TS6001 in a High-Input Voltage Floating Current Source By adopting the technique previously shown in Figure 2, the basic floating current source circuit can be adapted to operate at much higher supply voltages beyond the supply voltage rating of the TS6001-2.5 by adding a discrete n-channel JFET. As shown in Figure 6, the JFET acts as a supply voltage regulator since its source voltage will always be 2.5V higher than VSY. The circuit minimizes reference IC self-heating because the JFET and the 2N3904 NPN transistor carry the load current. This circuit can operate up to +35V and is determined by the BVDS breakdown voltage of the external JFET. Page 9 TS6001 For example, if VSY is 0V, then the upper input supply voltage level for the circuit is 35V. With a 2.1kΩ load and the TS6001’s supply current of 35µA (max), this circuit supplies approximately a 1.23-mA current to the load. excellent load regulation while sourcing load currents up to 150mA. If the application circuit is designed to operate across a wide temperature range, it is recommended that circuit performance is thoroughly evaluated across the PNP transistor’s beta (β, or current gain) distribution. When the PNP transistor’s current gain is a minimum, the increase in base current must be absorbed by the TS6001 for a given load current. For higher output load currents, higher output power PNP transistors can be used so long as good thermal management techniques are applied and transistor current-gain vs ambient temperature behavior is evaluated. Figure 6: Using the TS6001-2.5 in a High-Input Voltage Floating Current Source. In many current source applications, the possibility of an output short-circuit condition - whether transient or sustained - exists. It is recommended to test thoroughly for either scenario to prevent the possibility that the TS6001 would be exposed to a total voltage from its IN terminal to GND terminal higher than its absolute maximum rating of 13.5V. Boosting the TS6001’s Output Current Drive While the TS6001 is capable of sourcing up to 500µA with excellent load regulation, there are applications where tight load regulation is required at much higher output load currents. By adding a general-purpose, industry-standard PNP transistor and one resistor to the TS6001’s basic configuration as shown in Figure 7, increasing a precision Figure 7: Boosting the TS6001’s Output Current with an External PNP Transistor. reference’s output source current drive is straightforward. Using a 2N2905 PNP transistor and a 1.5kΩ resistor, the TS6001 is able to maintain Page 10 TS6001 Rev. 1.0 TS6001 Generating Positive and Negative Low-Power Voltage References The circuit in Figure 8 uses a CD4049 hex inverter and a few external capacitors as the power supply to a dual-supply precision op amp to form a ±2.5V precision, bipolar output voltage reference around the TS6001. The CD4049-based circuit is a discrete charge pump voltage doubler/inverter that generates ±6V supplies for any precision, micropower op amp with VOS and TCVOS specifications consistent with the TS6001’s initial accuracy and output voltage drift performance. Figure 8: Generating Positive and Negative 2.5V References from a Single +3V or +5V Supply. TS6001 Rev. 1.0 Page 11 TS6001 PACKAGE OUTLINE DRAWING 3-Pin SOT23 Package Outline Drawing (N.B., Drawings are not to scale) Patent Notice Silicon Labs invests in research and development to help our customers differentiate in the market with innovative low-power, small size, analog-intensive mixed-signal solutions. Silicon Labs' extensive patent portfolio is a testament to our unique approach and world-class engineering team. The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice. Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. 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