MAX5415 Maxim, MAX5415 Datasheet - Page 8

• Manufacturer Part Number: MAX5415
• Description: Dual / 256-Tap / Low-Drift / Digital Potentiometers in 14-Pin TSSOP
• Manufacturer: Maxim

have been shifted in, they are latched into the appropri-
ate potentiometer control register when CS transitions
from low to high. Note that if CS is not kept low during
the entire data stream, the data will be corrupted and
the device will need to be reloaded.
The first bit A0 (address bit) is used to address one or
the other of the potentiometers for programming.
Potentiometer control register A is selected for writing
when A0 is ‘zero,’ and potentiometer control register B
is selected when A0 is ‘one.’
The MAX5413/MAX5414/MAX5415 feature POR circuit-
ry that sets the wiper to the midscale position at power-
up.
The MAX5413/MAX5414/MAX5415 are intended for a
variety of circuits where accurate, fine-tuning adjustable
resistance is required, such as in adjustable voltage or
adjustable gain circuit configurations. It is primarily used
in either a potentiometer divider or a variable-resistor
configuration.
Dual, 256-Tap, Low-Drift, Digital Potentiometers
in 14-Pin TSSOP
Figure 2. Potentiometer Serial Data Timing Circuit
Figure 3. Detailed Serial Interface Timing Diagram
8
SCLK
DIN
CS
_______________________________________________________________________________________
t
CSO
Applications Information
t
CSS
t
DS
t
DH
CS
SCLK
TIME
DIN
1ST CLOCK PULSE
MSB
A0
t
CL
D7
t
CH
D6
D5
• • •
• • •
• • •
D4
Figure 5 shows the MAX5413/MAX5414/MAX5415 being
used with a MAX4250 low-noise op amp to fine tune a
current-to-voltage converter. Pins H
MAX5413/MAX5414/MAX5415 are connected to the
node between R3 and R2, and pin L
ground. Circuit space is minimized due to both devices’
packaging.
Figure 6 shows how to use the MAX5413/MAX5414/
MAX5415 to digitally adjust the gain of a noninverting op
amp configuration. In Figure 6a, connect the MAX5413/
MAX5414/MAX5415 as a variable resistor in series with a
resistor to ground to form the adjustable gain control of a
noninverting amplifier.
Similarly, Figure 6b shows how to use the MAX5413/
MAX5414/MAX5415 as a 3-terminal potentiometer. In
this application, the MAX5413/MAX5414/MAX5415 low
5ppm/°C ratiometric tempco allows for a very stable
adjustable gain configuration over temperature.
D3
Adjustable Current-to-Voltage Converter
D2
D1
9TH CLOCK PULSE
t
CP
POT REGISTER LOADED
LSB
D0
Adjustable Gain Amplifier
t
CSH
t
X
CS1
X
is connected to
and W
t
CSW
X
of the