Tunable First-Order Resistorless All-Pass Filter with Low Output Impedance

Table 1

Comparison of single active element based proposed and existing first-order circuits.

Ref no.	Active element	No. of passive components	Resistorless	High input impedance	Low output impedance	Supply voltages	Matching condition required	Tunable	Highest operating frequency
[9]	CCII	5	No	Yes	No	—	Yes	No	~10 KHz
[10]	FDCCII	3	No	Yes	Yes	±3.3 V	Yes	No	1.59 MHz
[11]	CCII	3	No	Yes	No	—	Yes	No	—
[12]	UVC	3	No	Yes	Yes	±2.5 V	Yes	Yes	1.17 MHz
[13]	CBTA/; CCCDBA	3	No	No	Yes	±2.5 V	No	No	119 KHz
[14]	DDCC	2	No	No	No	±2.5 V	No	No	1.59 MHz
[15]	DXCCII	2/3	No	Yes	Yes	±2.5 V	No	No	25 MHz
[16]	CCIII	4	No	No	No		Yes	No	1 KHz
[17]	DXCCII	4	No	Yes	No	±1.25 V	Yes	No	1.59 MHz
[18]	VD-DIBA	1	Yes	Yes	Yes	—	No	No	318 KHz
[19]	ICCII	2	No	No	No	±2.5 V	Yes	No	370 KHz
[20]	CCII	3	No	Yes	No	±2.5 V	Yes	No	1 MHz
[21]	CCII	3	No	No	No	—	Yes	No	159 KHz
[22]	FDCCII	2	No	Yes	Yes	±3 V	No	No	3.11 MHz
Proposed	DDDXCCII	1	Yes	No	Yes	±1.25 V	No	Yes	4–6 MHz