TLV431AH6TA

TLV431 1.24V Cost effective shunt regulator Description The TLV431 is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 20mA. The output voltage may be set to any chosen voltage between 1.24 and 18 volts by selection of two external divider resistors. The TLV431 can be used as a replacement for zener diodes in many applications requiring an improvement in zener performance. The TLV431 is available in 2 grades with initial tolerances of 1% and 0.5% for the A and B grades respectively. TLV431_F (SOT23) REF 1 3 ANODE CATHODE 2 TLV431_H6 (SC70-6) CATHODE 1 N/C ‡ 2 REF 3 6 5 4 ANODE NC ‡ NC Features • • • Low Voltage Operation ........... VREF = 1.24V Temperature range -40 to 125°C Reference Voltage Tolerance at 25°C • 0.5%............TLV431B • 1%...............TLV431A Typical temperature drift • 4 mV (0°C to 70°C) • 6 mV (-40°C to 85°C) • 11mV (-40°C to 125°C) 80µA Minimum cathode current 0.25Ω Typical Output Impedance Adjustable Output Voltage ..... VREF to 18V Opto-coupler linearisation Linear regulators Improved Zener Variable reference TLV431_E5 (SOT23-5) N/C 1 5 ANODE N/C ‡ 2 CATHODE 3 4 REF • ‡ Connected internally to substrate; should be left floating or connected to anode • • • Applications • • • • Order Information TOL Order code TLV431AE5TA TLV431AFTA TLV431AH6TA TLV431BE5TA TLV431BFTA TLV431BH6TA Pack SOT23-5 SOT23 SC70-6 SOT23-5 SOT23 SC70-6 Part mark V1A V1A V1A V1B V1B V1B 1 Status Active Active Active Active Active Active Reel Size (inches) 7 7 7 7 7 7 Tape width (mm) 8 8 8 8 8 8 Quantity per reel 3000 3000 3000 3000 3000 3000 1% 0.5% Issue 1 - June 2008 © Zetex Semiconductors plc 2008 www.zetex.com TLV431 Absolute Maximum Ratings Cathode Voltage (VKA) ........................................................................... 20V Continuous Cathode Current (IKA) ........................................... -20 to 20mA Reference input current range (IREF).............................. -0.050 mA to 3mA Operating Junction Temperature............................................. -40 to 150°C Storage Temperature ............................................................... -55 to 150°C Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce device reliability. Unless otherwise stated voltages specified are relative to the ANODE pin. Package Thermal Data Package SOT23 SOT23-5 SC70-6 θJA 380°C/W 250°C/W 380oC/W PDIS TA =25°C, TJ = 150°C 330 mW 500 mW 330mW Recommended Operating Conditions Min VKA IKA TA Cathode Voltage Cathode Current Operating Ambient temperature range VREF 0.1 -40 Max 18 15 125 Units V mA °C Issue 1 - June 2008 © Zetex Semiconductors plc 2008 2 www.zetex.com TLV431 Electrical Characteristics Electrical characteristics over recommended operating conditions, IKA = 10mA, TA = 25°C, unless otherwise stated. Symbol Parameter Conditions VKA = VREF TA = 25°C VKA = VREF TA = 0 to 70°C VREF Reference voltage VKA = VREF TA = -40 to 85°C VKA = VREF TA = -40 to 125°C Deviation of reference voltage over full temperature range Ratio of change in reference voltage to the change in cathode voltage Reference Input Current IREF deviation over full temperature range TLV431A TLV431B TLV431A TLV431B TA = 0 to 70°C VKA = VREF TA = -40 to 85°C TA = -40 to 125°C 6V VKA from VREF to 18V R1 = 10kΩ R2 = OC TA = 0 to 70°C TA = -40 to 85°C TA = -40 to 125°C TA = 0 to 70°C VKA = VREF TA = -40 to 85°C TA = -40 to 125°C VKA = 18V VREF =0V VKA = VREF f = R3 ≥ IF(min) 15mA GND Figure 2. Using the TLV431 as the regulating element in an isolated PSU Printed circuit board layout considerations The TLV431 in the SOT23-5 package has the die attached to pin 2, which results in an electrical contact between pin 2 and pin 5. Therefore, pin 2 of the SOT23-5 package must be left floating or connected to pin 5. TLV431 in the SC70-6 package has the die attached to pin 2 and 5, which results in an electrical contact between pins 2, 5 and pin 6. Therefore, pins 2 and 5 must be left floating or connected to pin 6. Other applications of TLV431 R3 VIN VOUT R4 IB TLV431 ZXTP2039F Q1 R1 R1 ⎞ ⎛ VOUT = VREF ⎜1 + ⎟ R2 ⎠ ⎝ V C1 0.1µF REF R3 = VIN − (VOUT + VBE ) IB ⎞ ⎟ < IB ≤ 15mA ⎟ ⎠ R2 ISH ⎛ ISH ⎜ ⎜ hFE(min) ⎝ GND Figure 3. High current shunt regulator It may at times be required to shunt-regulate more current than the 15mA that the TLV431 is capable of. Figure 3 shows how this can be done using transistor Q1 to amplify the TLV431's current. Care needs to be taken that the power dissipation and/or SOA requirements of the transistor is not exceeded Issue 1 - June 2008 © Zetex Semiconductors plc 2008 9 www.zetex.com TLV431 ZXTN25020CFH VIN I OUT VOUT R3 IB V Q1 R1 ⎞ ⎛ VOUT = VREF ⎜1 + ⎟ R2 ⎠ ⎝ R1 R3 = VIN − ( VOUT + VBE ) IB +IK I TLV431 K REF C1 0.1µF R2 ⎛ IOUT(max) ⎜ ⎜ hFE(min) ⎝ ⎞ ⎟ < IB ≤ 15mA ⎟ ⎠ GND Figure 4. Basic series regulator A very effective and simple series regulator can be implemented as shown in Figure 4 above. This may be preferable if the load requires more current than can be provided by the TLV431 alone and there is a need to conserve power when the load is not being powered. This circuit also uses one component less than the shunt circuit shown in Figure 2 above. R1 ⎞ ⎛ VOUT = VREF ⎜1 + ⎟ R2 ⎠ ⎝ R3 = R1 VIN R3 ZXTN25020CFH IB Q1 Rs IOUT VOUT VREF VIN − ( VOUT + VBE ) IB +IK TLV431 V REF TLV431 C1 0.1µF ⎛ I OUT (max) ⎞ ⎜ ⎟ < I B ≤ 15mA ⎜h ⎟ ⎝ FE (min) ⎠ R2 RS = GND VREF IOUT (max) Figure 5. Series regulator with current limit Figure 5 adds current limit to the series regulator in Figure 4 using a second TLV431. For currents below the limit, the circuit works normally supplying the required load current at the design voltage. However should attempts be made to exceed the design current set by the second TLV431, the device begins to shunt current away from the base of Q1. This begins to reduce the output voltage and thus ensuring that the output current is clamped at the design value. Subject only to Q1's ability to withstand the resulting power dissipation, the circuit can withstand either a brief or indefinite short circuit. Issue 1 - June 2008 © Zetex Semiconductors plc 2008 10 www.zetex.com TLV431 AP1084 VIN VIN GND Volt Reg VREG VREF VOUT R1 VOUT R1 ⎞ ⎛ VOUT = VREF ⎜1 + ⎟ R2 ⎠ ⎝ VOUT ≥ (VREG + VREF ) TLV431 C1 0.1µF R2 (All features of the regulator such as short circuit protection, thermal shutdown, etc, are maintained.) GND Figure 6. Increasing output voltage of a fixed linear regulator One of the useful applications of the TLV431 is in using it to improve the accuracy and/or extend the range and flexibility of fixed voltage regulators. In the circuit in Figure 6 above, both the output voltage and its accuracy are entirely determined by the TLV431, R1 and R2. However the rest of the features of the regulator (up to 5A output current, output current limiting and thermal shutdown) are all still available. AP1117 VIN IB R3 Vin VR1 Vout GND VOUT R1 ⎞ ⎛ VOUT = VREF ⎜1 + ⎟ R2 ⎠ ⎝ VOUT ≥ (VREG + VREF ) 1.2V R1 VREF R3 = VIN − (VOUT − VREG ) IB TLV431 C1 0.1µF R2 0.1mA ≤ I B ≤ 15mA (All features of the regulator such as short circuit protection, thermal shutdown, etc, are maintained.) GND Figure 7. Adjustable linear voltage regulator Figure 7 is similar to Figure 6 with adjustability added. Note the addition of R3. This is only required for the AP1117 due to the fact that its ground or adjustment pin can only supply a few micro-Amps of current at best. R3 is therefore needed to provide sufficient bias current for the TLV431. Issue 1 - June 2008 © Zetex Semiconductors plc 2008 11 www.zetex.com V R3 V+ ISH R1 VIN R2 VREF Flag V+ Flag VIN TLV431 VTH GND 1.24 0 t 0.1mA ≤ I SH ≤ 18mA R1 ⎞ ⎛ VTH = VREF ⎜1 + ⎟ R2 ⎠ ⎝ R3 = V + − 1.24 I SH Figure 8. Using the TLV431 as a level detector In its open loop state, the TLV431 is analogous to a line-powered comparator with its noninverting input internally connected to a 1.24V reference voltage. This means the remaining inverting input can be used for comparator functions. Figure 8 above shows the TLV431 being used as a level comparator. Its output (Flag) is normally high and goes low when the input reaches or exceeds the threshold (VTH) determined by R1 and R2. Issue 1 - June 2008 © Zetex Semiconductors plc 2008 12 www.zetex.com TLV431 Package Outline - SOT23 E SOT23-5 e b 3 leads e1 L1 E1 D A A1 L c Dimension Table SOT23 Dim. Millimeters Min. A A1 b c D e 0.01 0.30 0.085 2.80 Max. 1.12 0.10 0.50 0.20 3.04 Min. 0.0004 0.012 0.003 0.110 Inches Max. 0.044 0.004 0.020 0.008 0.120 e1 E E1 L L1 Dim. Millimeters Min. Max. Min. Inches Max. 1.90 NOM 2.10 1.20 0.25 0.45 2.64 1.40 0.60 0.62 - 0.075 NOM 0.083 0.047 0.0098 0.018 0.104 0.055 0.0236 0.024 - 0.95 NOM 0.037 NOM Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Dimension table - SOT23-5 Dim. Millimeters Min. A A1 A2 b C D 0.9 0.00 0.90 0.20 0.09 2.70 Max. 1.45 0.15 1.3 0.50 0.26 3.10 Min. 0.0354 0.00 0.0354 0.0078 0.0035 0.1062 Inches Max. 0.0570 0.0059 0.0511 0.0196 0.0102 0.1220 E E1 e e1 L ao Dim. Millimeters Min. 2.20 1.30 Max. 3.20 1.80 Min. 0.0866 0.0511 Inches Max. 0.1181 0.0708 0.95 REF 1.90 REF 0.10 0 0.60 30 0.0374 0.0748 0.0039 0 0.0236 30 Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Issue 1 - June 2008 © Zetex Semiconductors plc 2008 13 www.zetex.com TLV431 Package outline - SC70-6 Dim. Millimeters Min. Max. 1.10 0.10 1.00 0.30 0.25 Min. Inches Max. 0.0433 0.0039 0.0394 0.0118 0.0098 Dim. Millimeters Min. Max. Min. Inches Max. A A1 A2 b C D 0.80 0 0.80 0.15 0.08 0.0315 0 0.0315 0.006 0.0031 E E1 e e1 L ao 2.10 BSC 1.25 BSC 0.65 BSC 1.30 BSC 0.26 0 0.46 8 0.0826 BSC 0.0492 BSC 0.0255 BSC 0.0511 BSC 0.0102 0 0.0181 8 2.00 BSC 0.0787 BSC Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Issue 1 - June 2008 © Zetex Semiconductors plc 2008 14 www.zetex.com TLV431 Intentionally left blank Issue 1 - June 2008 © Zetex Semiconductors plc 2008 15 www.zetex.com TLV431 Definitions Product change Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. Customers are solely responsible for obtaining the latest relevant information before placing orders. Applications disclaimer The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoever is assumed by Zetex with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. 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Samples may be available “Active” Product status recommended for new designs “Last time buy (LTB)” Device will be discontinued and last time buy period and delivery is in effect “Not recommended for new designs” Device is still in production to support existing designs and production “Obsolete” Production has been discontinued Datasheet status key: “Draft version” This term denotes a very early datasheet version and contains highly provisional information, which may change in any manner without notice. “Provisional version” This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance. However, changes to the test conditions and specifications may occur, at any time and without notice. “Issue” This term denotes an issued datasheet containing finalized specifications. However, changes to specifications may occur, at any time and without notice. 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