S9318 Datasheet, PDF (2/6 Pages) Summit Microelectronics, Inc. – Nonvolatile DACPOT™ Electronic Potentiometer With Up/Down Counter Interface

PIN NAMES
Symbol
INC
UP/DN
VH
GND
V_OUT
VL
CS
V_DD
Description
Increment Input, High to Low
Edge Trigger
Up/Down Input controlling relative
V_OUT movement
V+ reference input
Analog and Digital Ground
Trimmed Voltage Output
V- reference input
Active low chip select input
Supply Voltage (2.7V to 5.5V)
PINOUT
INC 1
UP/DN 2
VH 3
GND 4
S9318
8 VDD
7 CS
6 VL
5 VOUT
2016 ILL1.1
Analog Section
The S9318 is an 8-bit, voltage output digital-to-analog
converter (DAC). The DAC consists of a resistor network
that converts an 8-bit value into equivalent analog output
voltages in proportion to the applied reference voltage.
Reference Inputs
The voltage differential between the VL and VH inputs
sets the full-scale output voltage range. VL must be equal
to or greater than ground (i.e. a positive voltage). VH must
be greater than VL and less than or equal to VDD. See
table on page 3 for guaranteed operating limits.
Output Buffer Amplifier
The voltage output is a precision unity-gain follower that
can slew up to 1V/µs.
Digital Interface
The interface is designed to emulate a simple up/down
counter, but instead of a parallel count output, a
ratiometric voltage output is provided.
Chip Select (CS) is an active low input. Whenever CS is
high the S9318 is in standby mode and consumes the
least power. This mode is equivalent to a potentiometer
that is adjusted to the required setting. When CS is low the
S9318 will recognize transitions on the INC input and will
move the VOUT either toward the VH reference or toward
the VL reference depending upon the state of the UP/DN
input.
The host may exit an adjustment routine in two ways:
deselecting the S9318 while INC is low will not perform a
store operation (a subsequent power cycle will recall the
original data); deselecting the S9318 while INC is high will
store the current VOUT setting into nonvolatile memory.
Increment (INC) is an edge triggered input. Whenever
CS is low and a high to low transition occurs on the INC
input, the VOUT voltage will either move toward VH or VL
depending upon the state of the UP/DN input.
UP/Down (UP/DN) is an input that will determine the VOUT
movement relative to VH and VL. When CS is low, UP/DN
is high and there is a high to low transition on INC, the
VOUT voltage will move (1/256^th x VH-VL) toward VH.
When CS and UP/DN are low, and there is a high to low
transition on INC, the VOUT will move (1/256^th x VH-VL)
toward VL.
2016-04 4/24/99
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