Data Sheet

ADR3625

APPLICATIONS INFORMATION

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Rev. 0 | 17 of 21

BASIC VOLTAGE REFERENCE CONNECTION

The basic configuration for the ADR3625 reference is shown in

Figure 48. For detailed information on connecting the bypass ca-

pacitors, see the Input and Output Capacitors section.

Figure 48. Basic Reference Connection

INPUT AND OUTPUT CAPACITORS

Input Capacitors

A 1 μF to 10 μF electrolytic or ceramic capacitor can be connected

to the input to improve transient response in applications where

the supply voltage can fluctuate. It is recommended to connect an

additional 0.1 μF ceramic capacitor in parallel to reduce supply

noise.

Output Capacitors

A COUT is required for stability and to filter out low level voltage

noise. The minimum value of COUT is 0.1 μF and can go as high as

10 μF for stability.

An additional 1 μF to 10 μF electrolytic or ceramic capacitor can be

added in parallel to improve transient performance in response to

sudden changes in load current.

The larger the output capacitor, the lower the bandwidth of the

output is, thus lowering the noise. However, increasing the output

capacitor increases the settling time and decreases the response

rate.

The ADR3625 is stable with a variety of capacitor types, includ-

ing ceramic, electrolytic (including polymer), tantalum, and film.

Small surface-mount capacitors have low effective series resistance

(ESR) and take up little board space. Place and connect the output

capacitor as close as possible to the VOUT FORCE pin. Use low

ESR capacitors.

START-UP TIME

The start-up time is determined by the output capacitance and

output load current. Figure 49 shows an example of the start-up

response when stepping the supply voltage and Figure 50 shows

an example of the start-up response when stepping the enable

voltage.

Figure 49. Star-Up Response (Input)

Figure 50. Start-Up Response (Enable)