基于ATL431的2.5V 低静态电流可调节精密并联稳压器

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基于ATL431的2.5V 低静态电流可调节精密并联稳压器

　　1 特性

　　可调节稳压输出：2.5V 至 36V

　　超低工作电流

　　IKA(min) = 35µA(最大值)

　　IREF = 150nA(最大值)

　　内部补偿确保稳定性

　　无需容性负载即可保持稳定

　　25°C 温度下的基准电压容差

　　0.5% (ATL43xB)

　　1% (ATL43xA)

　　温度漂移典型值

　　5mV(–40°C 至 85°C);“I”版本

　　6mV(–40°C 至 125°C);“Q”版本

　　扩展级阴极电流范围：35µA 至 100mA

　　低输出阻抗：0.3Ω(最大值)

　　ATL431AQ、ATL431BI 和 ATL431BQ 目前均为预览状态

　　ATL432AI、ATL432AQ、ATL432BI 和 ATL432BQ 目前均为预览状态

　　2 应用

　　反激式开关模式电源 (SMPS) 中的二次侧稳压

　　工业、计算、消费类和便携式产品

　　可调节电压和电流基准

　　电源管理

　　电源隔离

　　齐纳二极管替代产品

　　3 说明

　　ATL431 和 ATL432 为三引脚可调节分流稳压器，在适用的汽车级、商业级和工业级温度范围内均可满足规定的热稳定性。 这两款稳压器均可通过两个外部电阻将输出电压设置为 Vref(约为 2.5V)至 36V 范围内的任意值。 其输出阻抗典型值均为 0.05Ω。此类器件的有源输出电路具有出色的导通特性，因此成为了许多应用中齐纳二极管的绝佳替代产品，例如板载稳压器、可调节电源和开关电源。

　　ATL43X 的阴极电流范围相比其上一代产品 TL43X 有 20 倍以上的提升。 另外稳定性也有所提高，可支持范围更为宽泛的负载电容类型和容值。

ATL431 和 ATL432 这两款器件的功能完全相同，只是引脚分配和订货编号有所不同。 ATL43X 提供 A 和 B 两个等级，25°C 温度下的初始容差分别为 1% 和 0.5%。 此外，这两款器件的输出温度漂移较低，可确保在整个温度范围内保持出色的稳定性。

TI产品现货库存在线购买：https://www.iczoom.com/brand/509-c-1-20.html

　　ATL43xxI 器件的额定工作温度范围为 –40°C 至 85°C;ATL43xxQ 器件的额定工作温度范围为 –40°C 至 125°C。

　　ATL43x is a low power counterpart to TL431 and TLV431, having lower minimum cathode current (Ik(min) = 35 µA vs 0.1/1.0 mA). Like TL431, ATL43x is used in conjunction with it's key components to behave as a single voltage reference, error amplifier, voltage clamp or comparator with integrated reference.

　　ATL43x can be operated and adjusted to cathode voltages from 2.5 V to 36 V, making this part optimum for a wide range of end equipments in industrial, auto, telecom & computing. In order for this device to behave as a shunt regulator or error amplifier, > 35 µA (Imin(max)) must be supplied in to the cathode pin. Under this condition, feedback can be applied from the Cathode and Ref pins to create a replica of the internal reference voltage.

　　Various reference voltage options can be purchased with initial tolerances (at 25°C) of 0.5% and 1.0%. These reference options are denoted by B (0.5%) and A (1.0%) after the ATL43x.

　　The ATL43xxI devices are characterized for operation from –40°C to 85°C, and the ATL43xxQ devices are characterized for operation from –40°C to 125°C.

　　ATL43x consists of an internal reference and amplifier that outputs a sink current based on the difference between the reference pin and the virtual internal pin. The sink current is produced by an internal Darlington pair.

　　When operated with enough voltage headroom (≥ 2.5 V) and cathode current (IKA), ATL43x forces the reference pin to 2.5 V. However, the reference pin can not be left floating, as it needs Iref ≥ 0.1 µA (please see the Functional Block Diagram). This is because the reference pin is driven into an NPN, which needs base current in order operate properly.

　　When feedback is applied from the Cathode and Reference pins, ATL43x behaves as a Zener diode, regulating to a constant voltage dependent on current being supplied into the cathode. This is due to the internal amplifier and reference entering the proper operating regions. The same amount of current needed in the above feedback situation must be applied to this device in open loop, servo or error amplifying implementations in order for it to be in the proper linear region giving ATL43x enough gain.

　　Unlike many linear regulators, ATL43x is internally compensated to be stable without an output capacitor between the cathode and anode; however, if it is desired to use an output capacitor Figure 15 through Figure 22 can be used as a guide to assist in choosing the correct capacitor to maintain stability.