MAX5389 MAXIM [Maxim Integrated Products], MAX5389 Datasheet - Page 9

• Manufacturer Part Number: MAX5389
• Description: Dual, 256-Tap, Volatile, Low-Voltage Linear Taper Digital Potentiometer
• Manufacturer: MAXIM [Maxim Integrated Products]

The MAX5389 dual, 256-tap, volatile, low-voltage linear
taper digital potentiometer offers three end-to-end resis-
tance values of 10kI, 50kI, and 100kI. The potenti-
ometer consists of 255 fixed resistors in series between
terminals H_ and L_. The potentiometer wiper, W_, is
programmable to access any one of the 256 tap points
on the resistor string. On power-up, the wiper position is
set to midscale (tap 128).
The potentiometers are programmable independent of
each other. The MAX5389 features an up/down interface.
Logic inputs CS_, UD_, and INC_ determine the wiper
position of the device (Table 1). With CS_ low and UD_
high, a high-to-low (falling edge) transition on INC_
increments the internal counter which moves the wiper,
W_, closer to H_. When both CS_ and UD_ are low, the
falling edge of INC_ decrements the internal counter
Figure 2. Up/Down Interface Timing Diagram
INC_
UD_
CS_
W_
_______________________________________________________________________________________
Detailed Description
t
DI
t
CI
Dual, 256-Tap, Volatile, Low-Voltage
Linear Taper Digital Potentiometer
Up/Down Interface
t
ID
t
IW
t
IL
and moves the tap point, W_ closer to L_, (Figure 2). The
wiper performs a make-before-break transition ensuring
that W_ is never disconnected from the resistor string
during a transition from one tap point to another. When
the wiper is at either end of the resistor array additional
transitions in the direction of the end point do not change
the counter value.
Table 1. Up/Down Control Table
X = Don’t care.
↑ = Low-to-high transition.
↓ = High-to-low transition.
t
IH
CS_
H
L
L
L
L
t
IC
UD_
H
H
X
L
L
INC_
á
á
â
â
X
No change
No change
No change
Decrement
Increment
W_
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