Improper handling or cleaning may increase droop. Con-
tamination from handling parts and circuit boards can be
removed with cleaning solvents and de-ionized water.
APPLICATIONS INFORMATION
BASIC CIRCUIT CONNECTION
Basic Layout
Pinout
As with any precision circuit, careful layout will ensure best
performance. Make short, direct interconnections and avoid
stray wiring capacitance—especially at the analog and
digital input pins.
The pinout for the DIP and SOIC package of the ACF2101 is
different. The pinouts for the different packages are shown in
several figures in this data sheet.
Figures 1a and 1b illustrate the basic connections needed for
operation. Figures 1c and 1d illustrate the addition of
external integration capacitors and input guards.
Power Supplies
The ACF2101 can operate from supplies that range from
+4.5V and –10V to ±18V. Since the output voltage
integrates negatively from ground, a positive supply of +5V
is sufficient to attain specified performance. Using +5V and
–15V power supplies reduces power dissipation by one-half
of that at ±15V.
Leakage currents between printed circuit board traces can
easily exceed the input bias current of the ACF2101. A
circuit board “guard” pattern reduces leakage effects by
surrounding critical high impedance input circuitry with a
low impedance circuit connection at the same potential.
Leakage will flow harmlessly to the low impedance node.
Figure 2a and 2b show printed circuit patterns that can be
used to guard critical pins. Note that traces leading to these
pins should also be guarded.
Power supply connections should be bypassed with good
high-frequency capacitors, such as 1µF solid tantalum
capacitors, positioned close to the power supply pins.
Top View
ACF2101BU
Top View
ACF2101BP
Input
Input
1
2
Sw In B
In B
Sw In A 24
In A 23
Cap A 22
Com A 21
Gnd A 20
Out A 19
18
1
2
3
4
5
6
7
8
9
Out A
Gnd A
Com A
Cap A
In A
24
VOUT
23
22
3
Cap B
Com B
Gnd B
Out B
4
21
V+
5
20
1µF
Input
Input
6
Sw In A
Sw In B
In B
V+ 19
V– 18
17
VOUT
VOUT
7
1µF
8
17
V–
9
16
Cap B
16
10
11
15
10 Com B
11 Gnd B
12 Out B
15
14
14
1µF
1µF
12 V–
V+ 13
SOIC
13
DIP
+
+
VOUT
V–
V+
These points must be connected to a
common ground point or a ground plane.
These points must be connected to a
common ground point or a ground plane.
FIGURE 1b. Basic Circuit Connections, DIP.
FIGURE 1a. Basic Circuit Connections, SOIC package.
®
7
ACF2101
BB [ BURR-BROWN CORPORATION ]
