General Description
The MAX6958/MAX6959 compact multiplexed com-
mon-cathode display drivers interface microprocessors
to seven-segment numeric LED digits, or discrete LEDs
through an SMBusTM- and I
2
C-compatible 2-wire serial
interface. The 2-wire serial interface uses fixed
0.8V/2.1V logic thresholds for compatibility with 2.5V
and 3.3V systems when the display driver is powered
from a 5V supply.
The MAX6958/MAX6959 drive up to four 7-segment
digits, with decimal points, plus four discrete LEDs, or
four 7-segment digits and eight discrete LEDs if the
digits' decimal points are not used, or up to 36 discrete
LEDs. The MAX6959 also includes two input ports, one
or both of which may be configured as a key-switch
reader, which automatically scans and debounces a
matrix of up to eight switches. Key-switch status is
obtained by polling internal status registers or by con-
figuring the MAX6959 interrupt output.
Other on-chip features include a hexadecimal font for
seven-segment displays, multiplex scan circuitry,
anode and cathode drivers, and static RAM that stores
each digit. The peak segment current for the display
digits is set internally to 23mA. Display intensity is
adjusted using a 64-step internal digital brightness con-
trol. The MAX6958/MAX6959 include a low-power shut-
down mode, a scan-limit register that allows the user to
display from one to four digits, and a test mode, which
forces all LEDs on. The LED drivers are slew-rate-limit-
ed to reduce EMI.
The MAX6958/MAX6959 are available in 16-pin PDIP
and QSOP packages and are fully specified over the
-40°C to +125°C automotive temperature range.
Applications
Features
o 400kbps 2-Wire Serial Interface
o 3V to 5.5V Operation
o Drive 4 Digits plus 4 or 8 Discrete LEDs
o Drive Common-Cathode LED Digits
o 23mA Constant-Current LED Segment Drive
o Hexadecimal Decode/No-Decode Digit Selection
o 64-Step Digital Brightness Control
o Slew-Rate-Limited Segment Drivers Reduced EMI
o Debounces Up to Eight Switches with n-Key
Rollover (MAX6959 Only)
o IRQ Output When a Key Input Is Debounced
(MAX6959 Only)
o 20µA Low-Power Shutdown (Data Retained)
o Automotive Temperature Range (-40°C to +125°C)
o Compact 16-Pin PDIP and QSOP Packages
MAX6958/MAX6959
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2634; Rev 0; 10/02
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Ordering Information continued at end of data sheet.
*EP = Exposed pad.
PART
TEMP
RANGE
SLAVE
ADDRESS
PIN-
PACKAGE
MAX6958AAEE
-40
°C to +125°C
0111000
16 QS O P - E P *
MAX6958AAPE
-40
°C to +125°C
0111000
16 DIP
V+
DIG0DIG3
SEG0SEG8
SDA
SCL
IRQ/SEG9
INPUT1
µC
SDA
SCL
IRQ
8
INPUT2
GND
8
8
8
8
5V
Key0
DIG0/SEG0
Key1
DIG1/SEG1
Key2
DIG2/SEG2
Key3
DIG3/SEG3
Key4
DIG4/SEG4
Key5
DIG5/SEG5
Key6
DIG6/SEG6
Key7
DIG7/SEG7
MAX6959
Typical Operating Circuit
SMBus is a trademark of Intel Corp.
Set-Top Boxes
Panel Meters
White Goods
Audio/Video Equipment
Vending Machines
Industrial Controls
Pin Configuration, Functional Diagram, and Typical
Application Circuit appear at end of data sheet.
MAX6958/MAX6959
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(V+ = 3V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 5V, T
A
= +25°C.) (Note 1)
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Voltage (with respect to GND)
V+, SCL, SDA .......................................................-0.3V to +6V
All Other Pins............................................-0.3V to (V+ + 0.3V)
Current
DIG0/SEG0DIG3/SEG3 Sink Current ..........................275mA
DIG0/SEG0SEG9 Source Current .................................30mA
SCL, SDA, INPUT1, INPUT2 ...........................................20mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin DIP (derate at 10.5mW/°C above +70°C) .........842mW
16-Pin QSOP (derate at 8.34mW/°C above +70°C).....667mW
Operating Temperature Range
MAX695_ (T
MIN
to T
MAX
) ...............................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Operating Supply Voltage
V+
3
5.5
V
T
A
= +25°C
20
50
Shutdown Supply Current
I
SHDN
Shutdown mode, all
digital inputs at V+
T
A
= T
MIN
to +85°C
125
µA
T
A
= +25°C
5.9
6.7
Operating Supply Current
I+
Intensity set to full,
no display load
connected, INPUT1
and INPUT2 open
circuit
T
A
= T
MIN
to T
MAX
7.5
mA
Display Scan Rate
f
SCAN
4 digits scanned
T
A
= T
MIN
to T
MAX
510
780
1050
Hz
Keyscan Debounce Time
t
DEBOUNCE
T
A
= T
MIN
to T
MAX
30.3
41
63
ms
T
A
= +25°C
-19
-23
-29
V
LED
= 2.4V,
V+ = 4.5V to 5.5V
T
A
= T
MIN
to T
MAX
-18
-30
T
A
= +25°C
-16
-29.5
Segment Drive Source Current
I
SEG
V
LED
= 2V,
V+ = 3V to 5.5V
T
A
= T
MIN
to T
MAX
-15.5
-30.5
mA
Segment Current Slew Rate
I
SEG
/
t
11
mA/µs
Segment Drive Current Matching
I
SEG
4
%
LOGIC INPUTS AND OUTPUTS
Input Leakage Current SCL
and SDA
I
IH
, I
IL
-1
+1
µA
Logic High Input Voltage SCL,
SDA
V
IH
2.1
V
Logic Low Input Voltage SCL,
SDA
V
IL
0.8
V
Input Leakage Current INPUT1,
INPUT2
I
INH
, I
INL
INPUT_ = V+
-1
+1
µA
Logic High Input Voltage INPUT1,
INPUT2
V
INH
0.7
V+
V
Logic Low Input Voltage INPUT1,
INPUT2
V
INL
0.3
V+
V
MAX6958/MAX6959
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
_______________________________________________________________________________________
3
Note 1: All parameters tested at T
A
=+25°C. Specifications over temperature are guaranteed by design.
Note 2: Guaranteed by design.
Note 3: A master device must provide a hold time of at least 300ns for the SDA signal (referred to V
IL
of the SCL signal) in order to
bridge the undefined region of SCL's falling edge.
Note 4: C
B
= total capacitance of one bus line in pF. t
R
and t
F
measured between 0.3V+ and 0.7V+.
Note 5: I
SINK
6mA. C
B
= total capacitance of one bus line in pF. t
R
and t
F
measured between 0.3V+ and 0.7V+.
Note 6: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.
DC ELECTRICAL CHARACTERISTICS (continued)
(V+ = 3V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 5V, T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Pullup to V+ INPUT1, INPUT2
I
PULLUP
26.5
µA
I
SINK
= 6mA, T
A
= -40
°C to +85°C
0.4
IRQ/SEG9, SDA Output Low
Voltage
V
OLBK
I
SINK
= 4mA, T
A
= T
MIN
to T
MAX
0.4
V
SDA Output Low Voltage
V
OL(SDA)
I
SINK
= 6mA
0.4
V
TIMING CHARACTERISTICS
(V+ = 3V to 5.5V, T
A
= T
MIN
to T
MAX
, Figure 1, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Serial Clock Frequency
f
SCL
400
kHz
Bus Free Time Between a STOP
and a START Condition
t
BUF
1.3
µs
Hold Time (Repeated) START
Condition
t
HD, STA
0.6
µs
Repeated START Setup Time
t
SU, STA
0.6
µs
STOP Condition Setup Time
t
SU, STO
0.6
µs
Data Hold Time
t
HD, DAT
(Note 3)
0.9
µs
Data Setup Time
t
SU, DAT
100
ns
SCL Clock Low Period
t
LOW
1.3
µs
SCL Clock High Period
t
HIGH
0.6
µs
Rise Time of Both SDA and SCL
Signals, Receiving
t
R
(Notes 2, 4)
20 +
0.1C
B
300
ns
Fall Time of Both SDA and SCL
Signals, Receiving
t
F
(Notes 2, 4)
20 +
0.1C
B
300
ns
Fall Time of SDA Transmitting
t
F
(Notes 2, 5)
20 +
0.1C
B
250
ns
Pulse Width of Spike Suppressed
t
SP
(Note 6)
50
ns
Capacitive Load for Each Bus
Line
C
B
400
pF
MAX6958/MAX6959
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
4
_______________________________________________________________________________________
Typical Operating Characteristics
(V+ = 5V, LED forward voltage = 2.4V, T
A
= +25°C, unless otherwise noted.)
SCAN RATE (f
SCAN
)
vs. TEMPERATURE
MAX6958/59 toc01
TEMPERATURE (
°C)
SCAN RATE (Hz)
100
80
40
60
0
20
-20
760
765
770
775
780
785
790
795
800
755
-40
120
5.5V
5V
3V
4.5V
KEYSCAN DEBOUNCE TIME (t
DEBOUNCE
)
vs. TEMPERATURE
MAX6958/59 toc02
TEMPERATURE (
°C)
KEYSCAN DEBOUNCE TIME (ms)
100
80
60
40
20
0
-20
40.5
41.0
41.5
42.0
42.5
40.0
-40
120
4.5V
5V
3V
5.5V
SCAN RATE (f
SCAN
)
vs. SUPPLY VOLTAGE
MAX6958/59 toc03
SUPPLY VOLTAGE (V)
SCAN RATE (Hz)
5.0
4.5
4.0
3.5
765
770
775
780
785
790
760
3.0
5.5
KEYSCAN DEBOUNCE TIME (t
DEBOUNCE
)
vs. SUPPLY VOLTAGE
MAX6958/59 toc04
SUPPLY VOLTAGE (V)
KEYSCAN DEBOUNCE TIME (ms)
5.0
4.5
4.0
3.5
40.6
40.8
41.0
41.2
41.4
41.6
41.8
42.0
42.2
40.4
3.0
5.5
SEGMENT SOURCE CURRENT
vs. SUPPLY VOLTAGE
MAX6958/59 toc05
SUPPLY VOLTAGE (V)
SEGMENT SOURCE CURRENT (mA)
5.25
5.00
4.75
5
10
15
20
25
0
4.50
5.50
V
LED
= 2.4V
SEGMENT SOURCE CURRENT
vs. SUPPLY VOLTAGE
MAX6958/59 toc06
SUPPLY VOLTAGE (V)
SEGMENT SOURCE CURRENT (mA)
4.5
4.0
3.5
5
10
15
20
25
0
3.0
5.0
5.5
V
LED
= 2V
WAVEFORM AT DIG0/SEG0,
FULL INTENSITY
MAX6958/59 toc07
V
DIG0
/
SEG0
1V/div
200
µs/div
INPUT PULLUP CURRENT
vs. TEMPERATURE
MAX6958/59 toc08
TEMPERATURE (
°C)
INPUT PULLUP CURRENT (
µ
A)
100
80
40
60
0
20
-20
5
10
15
20
25
30
35
40
45
0
-40
120
5.5V
5V
3V
4.5V
Detailed Description
The MAX6958/MAX6959 serially interfaced display dri-
vers drive up to: four 7-segment digits plus four dis-
crete LEDs if the decimal points are used, or four
7-segment digits plus eight discrete LEDs if the deci-
mal points are not used, or 36 discrete LEDs. Table 1
lists the display connection scheme.
The MAX6958/MAX6959 include the hexadecimal font
map for seven-segment displays. The seven-segment
LED digits can be controlled directly or programmed to
use the hexadecimal font. Direct segment control
allows the MAX6958/MAX6959 to drive bar graphs and
discrete LED indicators.
The MAX6958/MAX6959 use a multiplexing scheme that
minimizes the connections between the driver and LED
display. The MAX6958/MAX6959 can drive monocolor
and bicolor single-digit type displays, and monocolor
dual-digit displays. Dual-digit displays internally
wire together the equivalent segments for each digit,
requiring only eight segment pins instead of 16. The
MAX6958/MAX6959 can also drive multidigit LED dis-
plays that have the segments individually pinned for
each digit.
To connect four single-digit displays to the MAX6958/
MAX6959, connect cathode outputs DIG0/SEG0
DIG3/SEG3 to the cathodes of the four display digits as
shown in Table 1 (CC0CC3). Drive eight additional
LEDs with SEG0 to SEG7. Four of the eight LEDs can
be the decimal point (DP) segments of the four dis-
plays, and the other four can be discrete LED indica-
tors.
To connect two dual-digit displays to the MAX6958/
MAX6959, connect cathode outputs DIG0/SEG0 and
DIG1/SEG1 to the cathodes of the first dual digit.
Connect DIG2/SEG2 and DIG3/SEG3 to the cathodes
of the second dual digit. SEG0 to SEG3 can only drive
discrete LEDs, not digit DP segments. SEG4 to SEG7
can drive the DP segments if required. Bicolor single-
digit displays are connected and treated as dual-digit
displays, each digit being one of the two colors.
MAX6958/MAX6959
2-Wire Interfaced, 3V to 5.5V, 4-Digit,
9-Segment LED Display Drivers with Keyscan
_______________________________________________________________________________________
5
Pin Description
PIN
MAX6958
MAX6959
NAME
FUNCTION
1
1
SDA
Serial Data I/O
2
2
SCL
Serial Clock Input
3
--
SEG9
Segment Output. Segment driver sourcing current to a display anode.
--
3
IRQ/SEG9
Interrupt or Segment Output. May be segment driver sourcing current to a display
anode, or open-drain interrupt output, or open-drain logic output.
47, 1115
47, 1115
DIGX, SEGX
Digit and Segment Drivers. Digit X outputs sink current from the display common
cathode when acting as digit drivers. Segment X drivers source current to the display
anodes. Segment/digit drivers are high impedance when turned off.
8
8
GND
Ground
9, 10
--
N.C.
No Connect. Connect to V+ or leave open.
--
9
INPUT1
General-Purpose Input Port 1 with Internal Pullup. May be configured as general-
purpose logic input or keyscan input. Connect to V+ or leave open if unused.
--
10
INPUT2
General-Purpose Input Port 2 with Internal Pullup. May be configured as general-
purpose logic input or keyscan input. Connect to V+ or leave open if unused.
16
16
V+
Positive Supply Voltage
DIG0/SEG0 DIG1/SEG1
DIG2/SEG2
DIG3/SEG3
SEG 4
SEG 5
SEG 6
SEG 7
SEG 8
SEG 9/IRQ
LED Digit 0
CC0
SEG 0
SEG g
SEG f
SEG e
SEG d
SEG c
SEG b
SEG a
SEG 4
LED Digit 1
SEG 1
CC1
SEG g
SEG f
SEG e
SEG d
SEG c
SEG b
SEG a
SEG 5
LED Digit 2
SEG g
SEG f
CC2
SEG 2
SEG e
SEG d
SEG c
SEG b
SEG a
SEG 6
LED Digit 3
SEG g
SEG f
SEG 3
CC3
SEG e
SEG d
SEG c
SEG b
SEG a
SEG 7
Table 1. Standard Driver Connection to LED Displays
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