MAX6955AAX Maxim Integrated Products, MAX6955AAX Datasheet - Page 6

• Manufacturer Part Number: MAX6955AAX
• Description: LED Drivers Integrated Circuits (ICs)
• Manufacturer: Maxim Integrated Products

Specifications of MAX6955AAX

• Number Of Digits: 16
• Number Of Segments: 128
• Low Level Output Current: 935000 uA
• High Level Output Current: 55000 uA
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Supply Current: 30000 uA
• Maximum Power Dissipation: 941 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-36
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan
The MAX6955 is a serially interfaced display driver that
can drive up to 16 digits 7-segment, 8 digits 14-seg-
ment, 8 digits 16-segment, 128 discrete LEDs, or a
combination of these display types. Table 1 shows the
drive capability of the MAX6955 for monocolor and
bicolor displays.
The MAX6955 includes 104-character ASCII font maps
for 14-segment and 16-segment displays, as well as
the hexadecimal font map for 7-segment displays. The
characters follow the standard ASCII font, with the addi-
tion of the following common symbols: £, A , ¥, °, µ, ±, ↑,
and ↓. Seven bits represent the 104-character font
map; an 8th bit is used to select whether the decimal
6
SSOP
34, 35
22–31
16, 18
19, 21
7–15,
1, 2,
_______________________________________________________________________________________
17
20
32
33
36
—
—
3
4
5
6
PIN
TQFN-EP
12, 13, 15
16, 18, 19
36, 37,
33, 34
11, 20
21–30
2–10,
14
17
31
32
38
39
40
35
—
1
OSC_OUT
O0–O18
Detailed Description
P4/IRQ
NAME
P0–P3
BLINK
GND
ISET
OSC
AD0
SDA
AD1
N.C.
SCL
V+
EP
General-Purpose I/O Ports (GPIOs). GPIO can be configured as logic inputs or open-drain
outputs. Enabling key scanning configures some or all ports P0–P3 as key-switch matrix inputs
with internal pullup (Key_A through Key_D).
Address Input 0. Sets device slave address. Connect to GND, V+, SCL, or SDA to give four
logic combinations. See Table 5.
I
I
Address Input 1. Sets device slave address. Connect to GND, V+, SCL, or SDA to give four
logic combinations. See Table 5.
Digit/Segment Drivers. When acting as digit drivers, outputs O0 to O7 sink current from the
display common cathodes. When acting as segment drivers, O0 to O18 source current to the
display anodes. O0 to O18 are high impedance when not being used as digit or segment
drivers.
Ground
Segment Current Setting. Connect ISET to GND through series resistor R SET to set the peak
current.
Positive Supply Voltage. Bypass V+ to GND with a 47µF bulk capacitor and a 0.1µF ceramic
capacitor.
Multiplex Clock Input. To use internal oscillator, connect capacitor C SET from OSC to GND.
To use external clock, drive OSC with a 1MHz to 8MHz CMOS clock.
Blink Clock Output. Output is open drain.
Clock Output. OSC_OUT is a buffered clock output to allow easy blink synchronization of
multiple MAX6955s. Output is push-pull.
General-Purpose I/O Port. Also functions as IRQ output when key scanning is enabled.
Not Internally Connected
Exposed Paddle. Internally connected to GND. Connect to a large ground plane to improve
thermal performance.
2
2
C-Compatible Serial Data I/O
C-Compatible Serial Clock Input
point (DP) is lit. Seven-segment LED digits can be con-
trolled directly or use the hexadecimal font. Direct seg-
ment control allows the MAX6955 to be used to drive
bar graphs and discrete LED indicators.
Tables 2, 3, and 4 list the connection schemes for 16-,
14-, and 7-segment digits, respectively. The letters in
Tables 2, 3, and 4 correspond to the segment labels
shown in Figure 1. (For applications that require mixed
display types, see Tables 38–41.)
The MAX6955 operates as a slave that sends and
receives data through an I
face. The interface uses a serial data line (SDA) and a
FUNCTION
2
C-compatible 2-wire inter-
Pin Description
Serial Interface
Serial Addressing