Document
SEMICONDUCTOR
AS1431 Precision Adjustable Shunt Reference
Description
The AS1431 is a three-terminal adjustable shunt regulator providing a highly accurate 0.4% bandgap reference. The adjustable shunt regulator is ideal for a wide variety of linear applications that can be implemented using external components to obtain adjustable currents and voltages. In the standard shunt configuration, the combination of low temperature coefficient (TC), sharp turn-on characteristics, low output impedance and programmable output voltage make this precision reference a perfect zener diode replacement. The AS1431 is characterized to operate over the full automotive temperature range of Ð55 to 125¡C and is now available in the SOT-23 (5L) package.
Features
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Temperature-compensated: 30 ppm/¡C Trimmed 0.4% bandgap reference Internal amplifier with 150 mA capability Temperature range: Extended to Ð55 to125¡C Low frequency dynamic output impedance: < 150 m½ Low output noise Robust ESD protection
Pin Configuration Ñ
Top view
TO-92 (LP)
CATHODE CATHODE ANODE ANODE REFERENCE ANODE N/C
2 3 4 1
SOIC (D)
8 7 6 5
REFERENCE ANODE ANODE N/C
SOT-89 (S) SOT-23/5L (DBV)
N/C N/C CATHODE ANODE CATHODE REFERENCE ANODE REFERENCE
Ordering Information
AS1431 D R4 D 7
Circuit Type: Precision Adjustable Shunt Regulator Temperature Range: D = –55°C to +125°C Bandgap Tolerance: R4 = ±0.4% Packaging Option: A = Ammo Pack B = Bulk T = Tube 7 = Tape and Reel (7" Reel Dia) 13 = Tape and Reel (13" Reel Dia) Package Style: D = SOIC DBV = SOT-23/5L LP = TO-92 S = SOT-89
ASTEC Semiconductor
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AS1431
Functional Block Diagram
Precision Adjustable Shunt Reference
CATHODE (K)
REFERENCE (R)
+ Ð
2.5 V
ANODE (A)
Absolute Maximum Ratings
Parameter Cathode-Anode Reverse Breakdown Anode-Cathode Forward Current Operating Cathode Current Reference Input Current Continuous Power Dissipation at 25¡C TO-92 8L SOIC SOT-89 SOT-23/5L Junction Temperature Storage Temperature Lead Temperature Soldering 10 Seconds TJ TSTG TL Symbol VKA IAK IKA IREF PD 775 750 1000 200 150 Ð65 to 150 300 mW mW mW mW ¡C ¡C ¡C Rating 37 1 250 10 Units V A mA mA
Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Recommended Conditions
Parameter Cathode Voltage Cathode Current Symbol VKA IK Rating VREF to 20 10 Unit V mA
Typical Thermal Resistances
Package TO-92 SOIC SOT-89 θJA 160¡C/W 175¡C/W 110¡C/W θJC 80¡C/W 45¡C/W 8¡C/W 150¡C/W Typical Derating 6.3 mW/¡C 5.7 mW/¡C 9.1 mW/¡C 1.7 mW/¡C
SOT-23/5L 575¡C/W
ASTEC Semiconductor
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Precision Adjustable Shunt Reference
Electrical Characteristics
AS1431
Electrical Characteristics are guaranteed over full junction temperature range (Ð55 to 125¡C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. The conditions are: VKA = VREF and IK = 10 mA unless otherwise stated. Parameter Reference Voltage Symbol VREF TC ÆVREF IREF ÆIREF IK(min) IK(off) ZKA VREF = 0 V, VKA = 36 V f ² 1 kHz IK = 1 to 100 mA ÆVK = 3 V to 36 V R1 = 10 k ½; R2 = ° Over temp. Ð2 Test Condition TA = 25¡C Over temp. ÆVREF with Temp* Ratio of Change in VREF to Cathode Voltage Reference Input Current IREF Temp Deviation Min IK for Regulation Off State Leakage Dynamic Output Impedance Min. 2.490 2.470 0.06 Ð1.1 0.7 0.4 0.4 0.04 0.15 1.9 1.2 1 500 0.2 Typ. 2.500 Max. 2.510 2.530 0.16 Unit V V mV/¡C mV/V µA µA mA nA ½ Circuit 1 1 1 2 2 2 1 3 1
*Calculating Average Temperature Coefficient (TC)
Average Temperature Coefficient
ppm 0 0 % 0 • TC in mV/°C = ∆VREF –10 5000 0.5 ∆T • TC in %/°C = mV ∆VREF (mV) ∆TA ∆VREF VREF at 25°C ∆TA ∆VREF –55 –25 0 25 50 75 Temperature (°C) 100 125 • TC in ppm/°C = VREF at 25°C ∆TA
X 100
–20
X 106
0.06 mV/°C 0.002%/°C 24 ppm/°C
ASTEC Semiconductor
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AS1431
Test Circuits
VIN VKA = VREF VIN
Precision Adjustable Shunt Reference
VKA
VIN
VKA
IREF
IK
IK R1 IREF (VREF) R2
IK (OFF)
Figure 1a. Test Circuit 1
Figure 1b. Test Circuit 2
Figure 1c. Test Circuit 3
ASTEC Semiconductor
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Precision Adjustable Shunt Reference
Typical Performance Curves
AS1431
Low Current Operating Characteristics
900 800 700 IK – Cathode Current (mA) 600 IK – Cathode Current (µA) 500 400 300 200 100 0 –100 –200 –1.0 0 1.0 2.0 3.0 125°C 25°C –55°C VKA = VREF Temperature Range: –55 to 125°C 150 125 100 75 50 25 0 –25 –50 –75 –100 –2
High Current Operating Characteristics
VKA = VREF Temperature Range: –55 to 125°C
–1
0
1
2
3
VKA – Cathode Voltage (V)
VKA – Cathode Voltage (V)
Figure 2
Figure 3
Off State Leakage
100 VKA = 36 V VREF = 0 V IZ off – Off State Cathode Current (nA) VREF – Reference Voltage (V) 10 2.53 2.52 2.51 2.50
Reference Voltage v.