AP431_10

AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Features • Precision reference voltage • • • • • • • • • • AP431: 2.495V ± 1% • AP431A: 2.495V ± 0.5% Sink current capability: 200mA Minimum cathode current for regulation: 300μA Equivalent full-range temp coefficient: 30 ppm/oC Fast turn-on response Low dynamic output impedance: 0.2Ω Programmable output voltage to 36V Low output noise Lead Free packages: SOT25, SC59, SC59R, SOT89-3L and TO92-3L SOT23, SOT23R, SOT25, SC59, SC59R, SOP-8L, SOT89-3L, TO92-3L: Available in “Green” Molding Compound (No Br, Sb) Lead Free Finish/ RoHS Compliant (Note 1) Description The AP431 and AP431A are 3-terminal adjustable precision shunt regulators with guaranteed temperature stability over the applicable extended commercial temperature range. The output voltage may be set at any level greater than 2.495V (VREF) up to 36V merely by selecting two external resistors that act as a voltage divider network. These devices have a typical output impedance of 0.2Ω. Active output circuitry provides very sharp turn-on characteristics, making these devices excellent improved replacements for Zener diodes in many applications. The precise (+/-) 1% Reference voltage tolerance of the AP431/AP431A make it possible in many applications to avoid the use of a variable resistor, consequently saving cost and eliminating drift and reliability problems associated with it. • Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html. Typical Application Circuit VIN VOUT + Cin AP431 R1 + Cout R2 VOUT = (1+R1/R2)VREF Precision Regulator AP431/AP431A Document number: DS31002 Rev. 15 - 2 1 of 16 www.diodes.com June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Pin Assignments (1) SOT25 (2) SOP-8L (Top View) NC NC CATHODE 1 2 3 4 REF 5 ANODE (Top View) CATHODE ANODE ANODE NC 1 2 3 4 8 7 6 5 REF ANODE ANODE NC (3) SC59 (4) SC59R (Top View) 3 REF ANODE 1 2 CATHODE (Top View) 3 ANODE 1 2 REF CATHODE (5) SOT23 (6) SOT23R (Top View) 3 ANODE 1 2 CATHODE REF ANODE (Top View) 3 1 2 REF CATHODE (7) SOT89-3L (8) TO92-3L (Top View) (Top View) + 3 Cathode 2 Anode 1 REF 1 2 3 REF Anode Cathode AP431/AP431A Document number: DS31002 Rev. 15 - 2 2 of 16 www.diodes.com + + June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Functional Block Diagram REF (R) + Cathode (C) Anode (A) VREF Symbol Cathode (C) REF (R) Anode (A) Absolute Maximum Ratings Symbol Vcv ICC IREF TOP TST Parameter Cathode Voltage Continuous Cathode Current Reference Input Current Operating Temperature Storage Temperature SOT23(R) SOT25 SC59(R) SOP-8L SOT89-3L TO92-3L Rating +36 -10 to +250 10 -20 to +85 -65 to +150 400 550 400 600 800 780 Unit V mA mA o C o C mW mW mW mW mW mW PD Power Dissipation (Notes 2, 3) Notes: 2. TJ, max =150°C. 3. Ratings apply to ambient temperature at 25°C. AP431/AP431A Document number: DS31002 Rev. 15 - 2 3 of 16 www.diodes.com June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Electrical Characteristics (TA = 25oC, V+ = +5.0V, unless otherwise stated) Symbol VREF VREF ΔVREF ΔVKA IREF αIREF IKA(MIN) IKA(OFF) |ZKA| Parameter Reference voltage Deviation of Reference input voltage over temperature (Note 4) Ratio of the change in Reference voltage to the change in Cathode voltage Reference input current Deviation of Reference input current over temperature Minimum Cathode current for regulation Off-state current Dynamic output impedance (Note 5) Test Conditions AP431 VKA = VREF, I KA = 10mA (Fig.1) AP431A VKA = VREF, IKA = 10mA, Ta = Full range (Fig.1) VKA = VREF to10V IKA = 10mA (Fig. 2) VKA = 10V to 36V R1 = 10KΩ,R2 = ∞ IKA= 10mA (Fig. 2) R1 = 10KΩ,R2 = ∞ IKA = 10mA Ta = Full range (Fig. 2) VKA = VREF (Fig.1) VKA = 36V, VREF = 0V (Fig. 3) V KA = VREF V KA = VREF ΔIKA = 0.1mA ~ 15mA Frequency ≤ 1KHz (Fig.1) Min Typ. Max 2.470 2.520 2.495 2.482 2.507 ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ 8.0 -1.4 -1 1.4 0.4 0.19 0.1 0.2 20 -2.0 -2 3.5 1.2 0.5 1.0 0.5 Unit V mV mV/V mV/V μA μA mA μA Ω VMAX VDEV = VMAX - VMIN VMIN TI Temperature T2 Notes: 4. Deviation of reference input voltage, VDEV, is defined as the maximum variation of the reference over the full temperature range. The average temperature coefficient of the reference input voltage αVREF is defined as: α VREF VDEV ) ⋅10 6 VREF (25°C) = T2 − T1 ( ……………………..………..…………….. ( ppm °C ) Where: T2 – T1 = full temperature change. αVREF can be positive or negative depending on whether the slope is positive or negative. Notes: 5. The dynamic output impedance, RZ, is defined as: Z KA = Δ V KA Δ IKA When the device is programmed with two external resistors R1 and R2 (see Figure 2.), the dynamic output impedance of the overall circuit, is defined as: Z KA = ' Δv ≈ Z KA Δi (1 + R1 ) R2 June 2010 © Diodes Incorporated AP431/AP431A Document number: DS31002 Rev. 15 - 2 4 of 16 www.diodes.com AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Test Circuits Input IN IN VKA IKA R1 VREF R2 IREF VREF IKA VKA VKA IZ(OFF) Note:VKA=VREF(1+R1/R2)+IREFxR1 Fig 1. Test Circuit for VKA= VREF Fig 2. Test Circuit for VKA > VREF Fig 3. Test Circuit for Off-State Current AP431/AP431A Document number: DS31002 Rev. 15 - 2 5 of 16 www.diodes.com June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Typical Performance Characteristics Cathode Current vs Cathode Voltage 100 VKA =Vref Ta=25oC Cathode Current (uA) 600 VKA =Vref Ta=25oC Cathode Current (uA) vs Cathode Voltage Cathode Current (mA) 400 0 200 0 -100 -1.5 0.5 -0.5 1.5 Cathode Voltage (v) 2.5 -200 -1 -0.5 0 0.5 1.5 1 Cathode Voltage(v) 2 2.5 Reference Voltage vs Free-Air Temperature Reference Input Current (uA) 2500 Reference Voltage (mV) 2495 2490 2485 2480 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 Free-Air Temperature (oC) Reference Input Current vs Free Temperature 2 1.8 1.6 1.4 1.2 1 -50 R1=10K IKA=10mA -25 0 25 50 75 Free-Air Temperature (oC) 100 125 Change in Reference Voltage vs Cathode Voltage Change in Reference Voltage (mv) 0 -2 -4 -6 -8 -10 -12 0 5 10 15 20 Cathode Voltage (V) 25 30 IKA=10mA Ta=25oC AP431/AP431A Document number: DS31002 Rev. 15 - 2 6 of 16 www.diodes.com June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Typical Performance Characteristics (Continued) Small-Signal Voltage Amplification vs Frequency 60 AV-Small Signal Voltage Amplification (dB) 50 IKA=10mA TA=25oC 15KΩ 9μF Output IKA 232Ω 40 30 20 Test Circuit for Voltage Amplification 10 0 1K 10K 100K 1M 10M f-Frequency-Hz Reference Impedance vs Frequency 100 I KA=10mA o TA =25 C | ZKA | Reference Impedance (Ω) 10 50Ω + 1 0.1 1K 10K 100K 1M 10M f-Frequency-Hz AP431/AP431A Document number: DS31002 Rev. 15 - 2 7 of 16 www.diodes.com 8.25KΩ + - + GND 1KΩ Output I KA GND Test Circuit for Reference Impedance June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Typical Performance Characteristics (Continued) Pulse Response 6 TA=25oC Input 220Ω Output 5 Input and Output Voltage-V 4 Pulse Generator f=100kHz 50Ω 3 Output GND 2 Test Circuit for Pulse Response 1 0 -1 0 1 2 3 t-Time-μS 4 5 6 7 STABILITY BOUNDARY CONDITIONS† 100 90 80 IKA-Cathode Current-mA 70 60 Stable 50 40 30 20 10 0 0.001 0.01 0.1 1 CL-Load Capacitance-µF 10 CL R2 150? I KA CL A VKA=Vref B VKA=5V C VKA=10V D VKA=15V B TA=25oC + - VBATT Stable C A Test Circuit for Curve A D R1=10K? I KA 150? + - VBATT + The areas under the curves represent conditions that may cause the device to oscillate. For curves B, C, and D, R2 and V+ were adjusted to establish the initial VKA and IKA conditions with CL=0.VBATT and CL were then adjusted to determine the ranges of stability. Test Circuit for Curve B, C, and D AP431/AP431A Document number: DS31002 Rev. 15 - 2 8 of 16 www.diodes.com June 2010 © Diodes Incorporated AP431/AP431A ADJUSTABLE PRECISION SHUNT REGULATOR Application Examples V IN VIN R CL R R1A R1B V IN I OUT R2A R2B O N OFF + LED on when Low Limit < VIN < High Limit Low Limit ≈ VREF (1+R1B/R2B) High Limit ≈ VREF (1+R1A/R2A) Delay = RC x ln ( VIN V IN -V ) I OUT = V REF / RCL REF Fig. 4 Voltage Monitor V IN I OUT V IN Fig. 5 Delay Timer Fig. 6 Current Limiter or Current Source V OUT V IN PULSE R 1 V OUT R 1 RS R 2 R 2 I OUT = V REF / RS V OUT = (1 + R1/R2) x VREF LIMIT (1 + R1/R2) x VREF Fig. 7 Constant-Current Sink Fig. 8 Higher-Current Shunt Regulator Fig. 9 Crow Bar VIN R1A R1B Output ON when Low Limit