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TL431ACLP

Programmable shunt ref, 2.495V-36V, ±0.5%, 0.2Ω Zka, TO-92

18000

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جزء الشركة المصنعة ： جزء الشركة المصنعة

TL431ACLP

الحزمة ： الحزمة

TO-92-3 (5.2 x 4.2 x 4.2mm, 2.54mm pitch, through-hole)

العلامة التجارية ： العلامة التجارية

فئات المنتجات:：فئات المنتجات

الدوائر المتكاملة الدوائر المتكاملة, المتحكمات الدقيقة والمعالجات

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SII9396SCNUC-BAR

IS43TR16256BL-125KBLI

الوصف

نظرة عامة على المنتج

The TL431ACLP is a precision programmable shunt voltage reference from Texas Instruments with 2.495V to 36V adjustable output, ±0.5% initial accuracy, and 1mA to 100mA cathode current range in a TO-92 through-hole package.

المواصفات الرئيسية

Reference Voltage (Vref)	2.495V typical (2.470V to 2.520V for A-grade)
Adjustable Output Range	Vref to 36V
Initial Accuracy (A-grade)	±0.5% at 25°C
Cathode Current (IKA)	1mA to 100mA
Dynamic Impedance	0.2Ω typical (below Vref)
Reference Input Current	2µA typical
Temperature Coefficient	30ppm/°C typical (C-grade: 0-70°C)
Cathode-Anode Voltage (Max)	37V
درجة حرارة التشغيل	0°C to +70°C (C-grade)
الحزمة	TO-92-3 (5.2 x 4.2mm, through-hole)

الميزات

Programmable shunt voltage reference
2.495V to 36V output range
±0.5% initial accuracy (A-grade)
0.2Ω dynamic impedance
Low reference pin current: 2µA typical
Wide cathode current range: 1mA to 100mA
Direct replacement for TL431, LM431, etc.
Low temperature drift: 30ppm/°C typical

التطبيقات

Switch-mode power supply feedback
Precision voltage reference
Shunt regulator
Voltage monitoring and comparison
OVP and OCP circuits

مقدمة المنتج:TL431ACLP مقدمة المنتج

The TL431ACLP from Texas Instruments is a three-terminal programmable shunt voltage reference that functions as a precision zener diode with adjustable breakdown voltage from 2.495V to 36V. When the reference pin (REF) voltage exceeds 2.495V, the cathode (KA) conducts, pulling current away from the load. This negative feedback action is used in SMPS feedback loops: the output voltage is divided down by two resistors to the REF pin, and the TL431 shunts current through an optocoupler LED to the primary side, closing the regulation loop. The ±0.5% initial accuracy (A-grade) and 30ppm/°C temperature drift provide precision regulation over temperature. The 0.2Ω dynamic impedance means the cathode voltage changes only 0.2mV per mA of cathode current change, providing excellent load regulation. The C-grade is specified for 0°C to +70°C, and the LP suffix denotes the TO-92 through-hole package.

مبدأ العمل:TL431ACLP مبدأ العمل

The TL431ACLP operates as a precision shunt regulator with an internal 2.495V bandgap reference and an open-collector error amplifier. The REF pin is connected to the internal reference comparator’s non-inverting input. When VREF exceeds the internal 2.495V reference, the error amplifier drives the output transistor (between cathode and anode) to conduct more current. This increased cathode current flows through an external series resistor, dropping more voltage and reducing VREF back toward 2.495V. For a simple shunt regulator, VOUT = VREF × (1 + R1/R2) + IREF × R1 ≈ 2.495 × (1 + R1/R2), where R1 is the upper divider resistor (VOUT to REF) and R2 is the lower divider resistor (REF to ANODE). For VOUT = 5V, R1/R2 ≈ 1.0, so R1 = R2 = 10kΩ. The minimum cathode current of 1mA is required for proper regulation; below this, the device may not regulate accurately. In an SMPS application, the cathode connects through a resistor and optocoupler LED to the output rail; the REF pin monitors the divided output voltage; and the anode connects to the output ground. When the output rises, the TL431 conducts more, increasing optocoupler LED current, which reduces the primary-side PWM duty cycle, bringing the output back to the setpoint.

وصف الدبوس:TL431ACLP تعريف الدبوس ووظائفه

دبوس	الاسم	النوع	الوصف
1	REF	المدخلات	Reference input pin. The device regulates to maintain 2.495V at this pin relative to Anode (±0.5% for A-grade). Input bias current is 2µA typical. Connect a voltage divider from Cathode to REF to Anode to set the desired output voltage. The reference voltage is internally trimmed to 2.495V at 25°C with 10ppm/°C typical drift.
2	الأنود	الطاقة	Anode (ground reference) pin. Connects to the most negative point in the circuit. All voltages are referenced to this pin. Maximum anode-cathode voltage is 37V. This pin carries the full operating current minus the cathode current.
3	القطب السالب	المخرجات	Cathode (output) pin. Draws current to regulate the voltage at the REF pin to 2.495V. Operating cathode current range is 1mA to 100mA. Minimum operating current (Imin) is 0.5mA typical (1mA max) to maintain regulation. Dynamic impedance is 0.2Ω typical above Imin.

TL431ACLP pin assignment (TO-92-3, flat face toward you, pins down): Pin 1 (left) = REF, Pin 2 (center) = Anode, Pin 3 (right) = Cathode. In SOT-23-3 (DBZR) package: Pin 1 = REF, Pin 2 = Anode, Pin 3 = Cathode. In SOIC-8: Pin 1-4 = NC, Pin 5 = Cathode, Pin 6 = NC, Pin 7 = REF, Pin 8 = Anode. For basic shunt regulator, connect REF to Cathode for 2.495V fixed output, or use voltage divider for higher output voltages (Vout = 2.495V × (1 + R1/R2)).

Application Scenarios:In which products and applications isTL431ACLP مستعمل

SMPS Feedback: Output voltage divided to REF; cathode drives optocoupler LED; regulates isolated 5V/12V/24V outputs
Adjustable Zener: R1/R2 sets VOUT from 2.495V to 36V; replaces fixed zener with precision, adjustable voltage
Voltage Monitor: REF monitors divided rail voltage; cathode pulls down enable pin when voltage exceeds threshold
OVP Circuit: Cathode triggers SCR gate when REF exceeds 2.495V; crowbar protects downstream circuitry
Current Source: Series resistor + TL431 creates precision constant-current sink; I = VREF/R2

Alternative Models:What chips are recommended as replacements for TL431ACLP

الطراز	الشركة المصنعة	الفرق الرئيسي	الحزمة	Specs
KA431AZTA	أونسمي	Direct compatible replacement with identical 2.495V reference and 1-100mA cathode current range	TO-92-3	2.495V/1-100mA
LM431ACM	TI	Direct equivalent in SOIC-8 surface-mount for compact power supply feedback loops	SOIC-8	2.495V/A-grade
TLV431ACDBZR	TI	Low-voltage 1.24V reference version with 80µA minimum cathode current for low-power designs	SOT-23-3	1.24V/80µA min
ATL431LIBQDBZR	TI	Ultra-low-power 25µA min cathode current version for battery-powered and standby circuits	SOT-23-3	2.5V/25µA min
LM4040C10IDBZR	TI	Fixed 10V precision shunt reference with 0.1% tolerance for high-accuracy voltage regulation	SOT-23-3	10V fixed/0.1%

TL431ACLP is an adjustable 2.495-36V shunt voltage regulator in TO-92-3 with ±1% A-grade reference tolerance and 1-100mA cathode current. The KA431 and LM431 are direct pin-compatible replacements. TLV431 offers a 1.24V low-voltage reference, while ATL431 provides ultra-low 25µA minimum cathode current for battery applications. LM4040 provides fixed-voltage precision references.