MAX1365 Datasheet, PDF (13/25 Pages) Maxim Integrated Products – Stand-Alone, 4.5-/3.5-Digit Panel Meters with 4-20mA Output

Stand-Alone, 4.5-/3.5-Digit Panel Meters
with 4–20mA Output
A
F
D
G
DIGIT 4
A
A
A
A
BF _G B F _G BF _G BF _G B
CE
CE
CE
CE
C
DP
DP
DP
DP
DP
D
D
D
D
DIGIT 3
DIGIT 2
DIGIT 1
DIGIT 0
Figure 2. Segment Connection for the MAX1365 (4.5 Digits)
A
F
D
G
DIGIT 4
A
A
A
BF _G B F _G BF _G B
CE
CE
CE
C
DP
DP
DP
DP
D
D
D
DIGIT 3
DIGIT 2
DIGIT 1
Figure 3. Segment Connection for the MAX1367 (3.5 Digits)
The MAX1365/MAX1367 use a multiplexing scheme to
drive one digit at a time. The scan rate is fast enough to
make the digits appear to be lit. Figure 5 shows the
data-timing diagram for the MAX1365/MAX1367 where
T is the display scan period (typically around 1/512Hz
or 1.9531ms). T_ON in Figure 5 denotes the amount of
time each digit is on and is calculated as follows:
T_ON
=
T
5
=
1.95312ms
5
=
390.60µs
Decimal-Point Control
The MAX1365/MAX1367 allow for full decimal-point
control and feature leading-zero suppression.
Use the DPON, DPSET1, and DPSET2 bits in the con-
trol register to set the value of the decimal point (Tables
2 and 3). The MAX1365/MAX1367 overrange and
underrange display is shown in Table 4.
Leading-Zero Suppression
The MAX1365/MAX1367 include a leading-zero sup-
pression circuitry to turn off unnecessary zeros. For
example, when DPSET1 and DPSET2 = [0,0], 0.0 is dis-
played instead of 000.0 (MAX1365). This feature saves
a substantial amount of power by not lighting unneces-
sary LEDs.
Interdigit Blanking
The MAX1365/MAX1367 also include an interdigit-
blanking circuitry. Without this feature, it is possible to
Table 1. LED Priority Table
HOLD
1
0
0
X = Don’t care.
PEAK
X
1
0
DISPLAY VALUES FORM
Hold value
Peak value
Latest ADC result
Table 2. Decimal-Point Control Table—
MAX1365
DPON DPSET1 DPSET2
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
DISPLAY
OUTPUT
18888
18888
18888
18888
1888.8
188.88
18.888
1.8888
ZERO INPUT
READING
0
0
0
0
0.0
0.00
0.000
0.0000
Table 3. Decimal-Point Control Table—
MAX1367
DPON DPSET1 DPSET2
1
0
0
1
0
1
1
1
0
1
1
1
DISPLAY
OUTPUT
1888.
188.8
18.88
1.888
ZERO INPUT
READING
0.
0.0
0.00
0.000
Table 4. LED During Overrange and
Underrange Conditions
CONDITION
Overrange
Underrange
MAX1367
1---
-1---
MAX1365
1----
-1----
see a faint digit next to a digit that is completely on.
The interdigit-blanking circuitry prevents ghosting over
into the next digit for a short period of time. The typical
interdigit blanking time is 4µs.
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