REF35120 datasheet(16/27 Pages) TI

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9.4 Device Functional Modes

9.4.1 Basic Connections

Figure 9-1 shows the typical connections for the REF35. TI recommends a supply bypass capacitor (CIN)

ranging from 0.1 μF to 10 μF. A 1 μF to 10 μF output capacitor (CL) must be connected from REF to GND. The

equivalent series resistance (ESR) value of CL must be between TBD mΩ to TBD mΩ to ensure output stability.

VIN

CIN

GND

VREF

Optional

AVDD

REF

REF35

Figure 9-1. Basic Connections

9.4.2 Start-Up

Figure 9-2 shows the start-up behavior of REF35205 device with 1 μF load capacitance. REF35 device ensures

the output voltage settles to the expected output voltage within specified accuracy without oscillations. The

start-up time is dependent on the output voltage variant, output capacitance and NR pin capacitance. Higher

capcitance leads to longer start-up time.

Figure 9-2. REF35205 Start-up Behavior, CREF = 1 μF

9.4.3 Output Transient Behavior

The REF35 output buffer is capable of sourcing 10 mA load current as well as sink 5 mA of load current. The

output stage is designed using class B architecture to achieve low quiescent current. This architecture has a

cross over dead band close to no load condition. Any load transient where the load current is close to dead band

will require wider settling time. The settling time will be higher for large output capacitor. For larger load steps

e.g. ADC reference drive the settling time will be faster.

Figure 9-3 and Figure 9-4 show the output settling behavior for light load transient and high load transient

respectively.

REF35

SNAS809 – DECEMBER 2021

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REF35120 датащи(PDF) 16 Page - Texas Instruments