Datasheet

7Maxim Integrated
Digitally-Programmed, Dual
2nd-Order Continuous Lowpass Filter
MAX270/MAX271
Pin Description (continued)
MAX271
X = Pin has no function in this mode.
Note: All digital input levels are TTL and CMOS compatible, unless otherwise noted.
PIN NAME FUNCTION, FP MODE (MODE = GND OR V-) FUNCTION, FP MODE (MODE = GND OR V+)
1 T/H OUT Track-and-Hold Output
2 V+ Positive Supply Voltage
3 OUTA Filler A Signal Output
4
SHDN
—
SHUTDOWN Control. A low level disconnects outputs
and places device into shutdown mode
5 INA Filter A Signal Input
6 V- Negative Supply Voltage
7 INB Filter B Signal Input
8 MODE
Selects FP mode when connected to GND or V- and pin-strap mode when connected to V+.
9 OUTB Filter B Signal Output
10 GND Ground
11
T/H A/B
—
Track-and-Hold Input Control. A high/low level internally
connects OUTNOUTB to input of Track-and-Hold
12
WR
WRITE Control Input. A low level writes data
D0-D6 program memory addressed by A1, A0
(or performs function as described for address
inputs). High level latches data.
—
13 T/H EN X
Track-and-Hold Output Control. Low level disconnects
T/H OUT. Connect pin high for normal operation
14
CS
Chip Select Input. Must be low for WR input to
be recognized.
—
15, 16 A1, A0
Address and FP Control Inputs.
0, 0 Programs f
C
, filter A
0, 1 Programs f
C
, filter B
1,0 Controls T/H functions:
D0 performs T/H En pin function
D1 performs T/H A/B pin function.
1,1 Controls device shutdown:
D0 performs SHDN pin function
Note: The WR pin must be strobed low to initiate
a program/function (Figure 2).
—
17-23 D0–D6
7-bit Data Inputs. Allows programming of
128 cutoff frequencies (also performs control
functions as described above).
7-bit Data Inputs. Program memory latches are trans-
parent in this mode. Connect pins high or low to
program filters A and B simultaneously to the same f
C
.
24
T/H
Track-and-Hold Control. Low level causes T/H OUT to track selected filter output. Filter output level held at
T/H OUT synchronous with T/H rising transition.