19
LTC1060
1060fb
Output Offsets
The DC offset at the filter bandpass output is always equal
to V
OS3
. The DC offsets at the remaining two outputs
(Notch and LP) depend on the mode of operation and
external resistor ratios. Table 5 illustrates this.
It is important to know the value of the DC output offsets,
especially when the filter handles input signals with large
dynamic range. As a rule of thumb, the output DC offsets
increase when:
1. The Q’s decrease.
2. The ratio (f
CLK
/f
0
) increases beyond 100:1. This is
done by decreasing either the (R2/R4) or the
R6/(R5 + R6) resistor ratios.
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
N Package
20-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
LTC1060 OFFSETS
U
PACKAGE DESCRIPTIO
.255 ± .015*
(6.477 ± 0.381)
1.040*
(26.416)
MAX
12
3
4
5
6
7
8
910
19 1112
131416
1517
18
20
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
N20 1002
.020
(0.508)
MIN
.120
(3.048)
MIN
.125 – .145
(3.175 – 3.683)
.065
(1.651)
TYP
.045 – .065
(1.143 – 1.651)
.018 ± .003
(0.457 ± 0.076)
.005
(0.127)
MIN
.100
(2.54)
BSC
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325
+.035
–.015
+0.889
–0.381
8.255
()
Table 5
V
OSN
V
OSBP
V
OSLP
MODE PIN 3 (18) PIN 2 (19) PIN 1 (20)
1,4 V
OS1
[(1/Q) + 1 + ||H
OLP
||] – V
OS3
/Q V
OS3
V
OSN
– V
OS2
1a V
OS1
[1 + (1/Q)] – V
OS3
/Q V
OS3
V
OSN
– V
OS2
1b V
OS1
[(1/Q) + 1 + R2/R1] – V
OS3
/Q V
OS3
~ (V
OSN
– V
OS2
) (1 + R5/R6)
1c V
OS1
[(1/Q) + 1 + R2/R1] – V
OS3
/Q V
OS3
(R5 + R6)
(R5 + 2R6)
~(V
OSN
– V
OS2
)
2, 5 [V
OS1
(1 + R2/R1 + R2/R3 + R2/R4) – V
OS3
(R2/R3)] V
OS3
V
OSN
– V
OS2
• [R4/(R2 + R4)] + V
OS2
[R2/(R2 + R4)]
2a
V
OS3
(R5 + R6)
(R5 + 2R6)
~(V
OSN
– V
OS2
)
2b
V
OS3
~ (V
OSN
– V
OS2
) (1 + R5/R6)
3, 4a V
OS2
V
OS3
R4
R1
V
OS1
1 + – V
OS2
+
R4
R2
+
R4
R3
R4
R2
– V
OS3
R4
R3
R4(1 + k)
R2 + R4(1 + k)
+ V
OS2
;k = •
R2
R2 + R4(1 + k)
R6
R5 + R6
[V
OS1
(1 + R2/R1 + R2/R3 + R2/R4) – V
OS3
(R2/R3)]
R4k
R2 + R4k
+ V
OS2
;k = •
R2
R2 + R4k
R6
R5 + R6
[V
OS1
(1 + R2/R1 + R2/R3 + R2/R4) – V
OS3
(R2/R3)]
