3BHB系列电压
3BHB系列电压基准具有集成的低输出阻抗缓冲器（ADC驱动缓冲器）；因此，驱动高精度、高通量SAR ADC的REF引脚时不需要外部缓冲器，如图49所示。3BHB004692R0002的ADC驱动缓冲器能够在1µs内补充47µF电容器上70 pC的电荷，而不允许电容器上的电压在18位精度下下降超过1 LSB。 x在生产过程中在多个温度下进行微调，最大漂移仅为3±4±3±2±1 1输出阻抗（ü）频率（Hz） 带隙电压参考30版权所有 续）0°C至70°C之间的参考电压和缓冲电压，同时在820µa的典型静态电流下运行。基准漂移保证在0°C和70°C之间。REF62xx可在-55°C至125°C的温度下运行，而不会损坏。图50比较了常规电压基准（REF20xx）和带集成ADC驱动缓冲器（ 的电压基准的输出阻抗。图51比较了常规电压基准和REF62xx的突发模式、基准稳定性能。图 3BHB004692R0002驱动REF引脚 输出阻抗比较1 LSB=19.07µV，与ADS8851在1 MSPS图51。参考压降k版权所有 9.3.2温度漂移REF62xx系列设计用于最小漂移误差，定义为输出电压随温度的变化。
输出电容值范围
稳定性3BHB系列电压基准电压稳定，输出电容值范围为10µF至47µF。在10µF的低输出电容值下，需要20 mΩ至100 mΩ的有效串联电阻（ESR）才能稳定；而在47µF的较高值下，需要5 mΩ至100 mΩ的ESR。图52中的阴影区域显示了REF62xx设备的稳定运行区域。图52.稳定输出电容器范围FILT引脚需要1µF值的电容器，以确保稳定性和噪声性能。通过增加PCB迹线长度，可以轻松实现低ESR（5 mΩ至20 mΩ），从而无需使用分立电阻器。可以有意添加更高的ESR值（大于20 mΩ，但小于100 mΩ），以增加REF62xx的输出带宽。较高的ESR提高了REF62xx的瞬态性能，但由于带宽增加，噪声性能恶化。9.4设备功能模式当REF62xx的EN引脚被拉高时，设备处于激活模式。设备必须处于活动模式才能正常运行。要将REF62xx置于关闭模式，将ENABLE引脚拉低。在关机模式下，设备的输出变为高阻抗，设备的静态电流降至1µA（典型值）。有关逻辑高电压电平和逻辑低电压电平，请参阅电气特性表中的启用引脚电压参数。
3BHB series voltage
3BHB series voltage reference has integrated low output impedance buffer (ADC drive buffer); Therefore, when driving the REF pin of high-precision and high-throughput SAR ADC, no external buffer is required, as shown in Figure 49. The ADC drive buffer of 3BHB004692R0002 can supplement the charge of 70 pC on the 47 µ F capacitor within 1 µ s, without allowing the voltage on the capacitor to drop more than 1 LSB with 18 bit accuracy. X Fine adjustment is carried out at multiple temperatures during production, and the maximum drift is only 3 ± 4 ± 3 ± 2 ± 1 1 Output impedance (U) Frequency (Hz) Band gap voltage reference 30 Copyright continued) Reference voltage and buffer voltage between 0 ° C and 70 ° C, while operating at 820 µ a typical static current. The reference drift is guaranteed to be between 0 ° C and 70 ° C. The REF62xx can operate at temperatures from - 55 ° C to 125 ° C without damage. Figure 50 compares the conventional voltage reference (REF20xx) with the drive buffer with integrated ADC (output impedance of voltage reference. Figure 51 compares the burst mode and reference stability performance of conventional voltage reference and REF62xx. Figure 3BHB004692R0002 compares the output impedance of drive REF pin 1 LSB=19.07 µ V with ADS8851 in 1 MSPS Figure 51. Refer to Voltage Drop k Copyright 9.3.2 Temperature Drift REF62xx series is designed for minimum drift error, which is defined as the change of output voltage with temperature.
Output capacitance value range
Stability The voltage reference voltage of 3BHB series is stable, and the output capacitance value range is 10 µ F to 47 µ F. Under the low output capacitance value of 10 µ F, an effective series resistance (ESR) of 20 m Ω to 100 m Ω is required to be stable; At a higher value of 47 µ F, an ESR of 5 m Ω to 100 m Ω is required. The shaded area in Figure 52 shows the stable operation area of the REF62xx device. Figure 52. Stable output capacitor range The FILT pin requires a capacitor with a value of 1 µ F to ensure stability and noise performance. By increasing the PCB trace length, it is easy to achieve low ESR (5 m Ω to 20 m Ω) without using discrete resistors. A higher ESR value (greater than 20 m Ω, but less than 100 m Ω) can be intentionally added to increase the output bandwidth of REF62xx. The higher ESR improves the transient performance of REF62xx, but the noise performance deteriorates due to the increase of bandwidth. 9.4 Device function mode When the EN pin of REF62xx is pulled up, the device is in the active mode. The device must be in active mode to function properly. To place REF62xx in OFF mode, pull down the ENABLE pin. In the shutdown mode, the output of the device becomes high impedance, and the static current of the device drops to 1 µ A (typical value). For the logic high voltage level and logic low voltage level, refer to the Enable Pin Voltage parameter in the Electrical Characteristics table.
