MAX6955 Maxim, MAX6955 Datasheet - Page 5

• Manufacturer Part Number: MAX6955
• Description: 2-Wire Interfaced / 2.7V to 5.5V LED Display Driver with I/O Expander and Key Scan
• Manufacturer: Maxim

(V+ = 3.3V, LED forward voltage = 2.4V, Typical Application Circuit, T
110
105
100
4.4
4.2
4.0
3.8
3.6
95
90
85
80
45
40
35
30
25
20
15
10
5
0
-40
-40
2.5
DEAD CLOCK OSCILLATOR FREQUENCY
INTERNAL OSCILLATOR FREQUENCY
V
V
CC
CC
-10
-10
3.0
2-Wire Interfaced, 2.7V to 5.5V LED Display
= 5.5V
= 3.3V
V
vs. SUPPLY VOLTAGE
GPIO SINK CURRENT
CC
vs. TEMPERATURE
vs. TEMPERATURE
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
3.5
= 2.5V
20
20
_______________________________________________________________________________________
4.0
50
50
Driver with I/O Expander and Key Scan
R
C
R
C
OUTPUT = LOW
V
4.5
80
SET
SET
PORT
SET
SET
80
= 56kΩ
= 56kΩ
= 22pF
= GND
= 0.6V
110
5.0
110
5.5
1.02
1.00
0.98
0.96
0.94
0.92
4.4
4.2
4.0
3.8
3.6
0.5
0.4
0.3
0.2
0.1
0
2.5
2.5
-40
INTERNAL OSCILLATOR FREQUENCY
V
V
CC
CC
PORT INPUT PULLUP CURRENT
SEGMENT SOURCE CURRENT
3.0
3.0
-10
= 5.5V
= 3.3V
vs. SUPPLY VOLTAGE
vs. SUPPLY VOLTAGE
vs. TEMPERATURE
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
3.5
3.5
20
4.0
4.0
A
50
Typical Operating Characteristics
= +25°C, unless otherwise noted.)
V
R
C
OUTPUT = HIGH
V
CC
4.5
4.5
SET
SET
PORT
= 2.5V
80
V
= 56kΩ
= 22pF
LED
= 1.4V
5.0
5.0
= 1.8V
110
5.5
5.5
OSC_OUT
KEY_A
OSC
O18
IRQ
0V
0V
O0
0V
0V
0V
0V
R
C
INTERNAL OSCILLATOR WAVEFORM
SET
SET
WAVEFORM AT PINS O0 AND O18,
= 56kΩ
= 22pF
AT OSC AND OSC_OUT PINS
KEY-SCAN OPERATION
MAXIMUM INTENSITY
(KEY_A AND IRQ)
OSC_OUT: 2V/div
OSC: 500mV/div
KEY_A: 1V/div
IRQ: 2V/div
100ns/div
200µs/div
400µs/div
1V/div
MAX6954 toc03
MAX6954 toc09
MAX6954 toc06
5