MAX6954AAX-T Maxim Integrated Products, MAX6954AAX-T Datasheet - Page 6

• Manufacturer Part Number: MAX6954AAX-T
• Description: LED Drivers 7-, 14-, 16-Segment LED Display Driver,
• Manufacturer: Maxim Integrated Products

Specifications of MAX6954AAX-T

• 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

4-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan
The MAX6954 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 MAX6954 for monocolor and
bicolor displays.
The MAX6954 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: £, €, ¥, °, µ, ±,
↑, and ↓. Seven bits represent the 104-character font
6
34, 35, 36
16, 18
19, 21
22–31
SSOP
7–15,
1, 2,
_______________________________________________________________________________________
17
20
32
33
—
—
3
4
5
6
38, 39, 40
17, 18, 20 12, 13, 15
21, 23, 24 16, 18, 19
16, 25
26–35
7–15,
PDIP
1, 2,
PIN
19
22
36
37
—
3
4
5
6
33, 34, 35
T Q F N - EP
Detailed Description
36, 37,
11, 20
21–30
2–10,
38
39
40
14
17
31
32
—
1
O S C _O U T
O0–O18
NAME
P0–P4
BLINK
DOUT
GND
OSC
ISET
N.C.
CLK
DIN
CS
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 and port P4 as IRQ output.
Chip-Select Input. Serial data is loaded into the shift register while CS is low. The
most recent 16 bits of data latch on CS’s rising edge.
Serial-Data Output. The data into DIN is valid at DOUT 15.5 clock cycles later. Use
this pin to daisy-chain several devices or allow data readback. Output is push-pull.
S er i al - C l ock Inp ut. On C LK’ s r i si ng ed g e, d ata shi fts i nto the i nter nal shi ft r eg i ster . On
C LK’ s fal l i ng ed g e, d ata i s cl ocked out of D OU T. C LK i s acti ve onl y w hi l e C S i s l ow .
Serial-Data Input. Data from DIN loads into the internal 16-bit shift register on CLK’s
rising edge.
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
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
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 MAX6954s. Output is push-pull.
Not Connected Internally
Exposed Pad (TQFN package only). Internally connected to GND. Connect to a
large ground plane to maximize thermal performance.
map; an 8th bit is used to select whether the decimal
point (DP) is lit. Seven-segment LED digits may be con-
trolled directly or use the hexadecimal font. Direct seg-
ment control allows the MAX6954 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 37–40.)
The MAX6954 communicates through an SPI-compati-
ble 4-wire serial interface. The interface has three
FUNCTION
Pin Description
Serial Interface
SET
from OSC
SET
to set