ESMT

Elite Semiconductor Memory Technology Inc.

Publication Date: Jan. 2018

Revision: 1.8

18/24



Second-Order Filter Configuration

AD22650 can be used like a standard OPAMP. Several filter topologies can be implemented by using

AD22650, both single-ended and differential input configuration, see figure 6. For inverting input

configuration, the overall gain is

1

2

R

R



, the high-pass filter

’s cutoff frequency is

3

1

2

1

C

R



, the

low-pass filter

’s cutoff frequency is

2

1

3

2

2

1

C

C

R

R



, The detail component values are listed on table

2.

R2

R3

C3

IN

OUT

(a) Inverting Input

R1

C1

C2

R2

R3

C3

IN-

OUT

(b) Differential Input

R1

C1

C2

C3

IN+

R1

C1

R2

R3

Figure 6. Second-order Active Low-Pass Filter

Gain

(V/V)

High

Pass

(Hz)

Low

Pass

(kHz)

C1 (pF)

C2 (pF)

C3 (

μF)

R1 (k

Ω)

R2 (k

Ω)

R3 (k

Ω)

-1

1.6

40

100

680

10

10

10

24

-1.5

1.3

40

68

680

15

8.2

12

30

-2

1.6

60

33

150

6.8

15

30

47

-2

1.6

30

47

470

6.8

15

30

43

-3.33

1.2

30

33

470

10

13

43

43

-10

1.5

30

22

1000

22

4.7

47

27

Table 2. Second-order Low-Pass Filter Specifications



Over-Temperature Protection

AD22650 provide an over-temperature protection to limit the junction temperature to 150℃. As junction

temperature exceeds 150℃, internal thermal sensor will turn off the drivers immediately. The drivers will

turn on again if the junction temperature is smaller than 130℃. A 20℃ hysteresis is designed to lower

the average junction temperature during continuous thermal overload conditions, increasing lifetime of

the chip.