ISL22416 Datasheet, PDF (9/14 Pages) Intersil Corporation – Single Digitally Controlled Potentiometer XDCP

Typical Performance Curves (Continued)
300
250
200
150
50k
100
10k
50
0
16
36
56
76
96
TAP POSITION (DECIMAL)
FIGURE 11. TC FOR RHEOSTAT MODE IN ppm
ISL22416
INPUT
OUTPUT
WIPER AT MID POINT (POSITION 40h)
R_TOTAL = 9.5kΩ
FIGURE 12. FREQUENCY RESPONSE (2.6MHz)
SIGNAL AT WIPER
(WIPER UNLOADED)
WIPER MID POINT MOVEMENT
FROM 3Fh TO 40h
FIGURE 13. MIDSCALE GLITCH, CODE 3Fh TO 40h
Pin Description
Potentiometer Pins
RH AND RL
The high (RH) and low (RL) terminals of the ISL22416 are
equivalent to the fixed terminals of a mechanical
potentiometer. RH and RL are referenced to the relative
position of the wiper and not the voltage potential on the
terminals. With WR set to 127 decimal, the wiper will be
closest to RH, and with the WR set to 0, the wiper is closest
to RL.
RW
RW is the wiper terminal and is equivalent to the movable
terminal of a mechanical potentiometer. The position of the
wiper within the array is determined by the WR register.
SCL
SIGNAL AT WIPER
(WIPER UNLOADED MOVEMENT
FROM 7Fh TO 00h)
FIGURE 14. LARGE SIGNAL SETTLING TIME
SHDN
The SHDN pin forces the resistor to end-to-end open circuit
condition on RH and shorts RW to RL. When SHDN is
returned to logic high, the previous latch settings put RW at
the same resistance setting prior to shutdown. This pin is
logically ANDed with SHDN bit in ACR register. SPI interface
is still available in shutdown mode and all registers are
accessible. This pin must remain HIGH for normal operation.
RH
RW
RL
FIGURE 15. DCP CONNECTION IN SHUTDOWN MODE
9
FN6227.2
September 9, 2009