19-0850; Rev 4; 6/10
KIT
ATION
EVALU
BLE
AVAILA
2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
General Description
Features
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Optional Key Release Detection on All Keys
Monitor Up to 64 Keys
+1.62V to +3.6V Operation
Autosleep and Autowake to Minimize Current
Consumption
Under 1µA Sleep Current
FIFO Queues Up to 16 Debounced Key Events
Key Debounce Time User Configurable from 9ms
to 40ms
Low-EMI Design Uses Static Matrix Monitoring
Hardware Interrupt at the FIFO Level or at the End
of Definable Time Period
Up to Seven Open-Drain Logic Outputs Available
Capable of Driving LEDs
400kbps, 5.5V-Tolerant, 2-Wire Serial Interface
Selectable 2-Wire, Serial-Bus Timeout
Four I
2
C Address Choices
Small, 24-Pin TQFN Package (3.5mm x 3.5mm) , or
25-Pin WLP Package (2.31mm x 2.31mm)
MAX7359
The MAX7359 I
2
C interfaced peripheral provides micro-
processors with management of up to 64 key switches.
Key codes are generated for each press and release of
a key for easier implementation of multiple key entries.
Key inputs are monitored statically, not dynamically, to
ensure low-EMI operation. The switches can be metallic
or resistive (carbon) with up to 5kΩ of resistance.
The MAX7359 features autosleep and autowake to fur-
ther minimize the power consumption of the device.
The autosleep feature puts the device in a low-power
state (1µA typ) after a sleep timeout period. The
autowake feature configures the MAX7359 to return to
normal operating mode from sleep upon a key press.
The key controller debounces and maintains a FIFO of
key-press and release events (including autorepeat, if
enabled). An interrupt (INT) output can be configured to
alert key presses either as they occur, or at maximum rate.
Any of the column drivers (COL2/PORT2–COL7/PORT7)
or the
INT,
if not used, can function as a general-pur-
pose output (GPO).
The MAX7359 is offered in small, 24-pin TQFN (3.5mm x
3.5mm) and 25-bump WLP (2.31mm x 2.31mm) pack-
ages for cell phones, pocket PCs, and other portable
consumer electronic applications. The MAX7359 oper-
ates over the -40°C to +85°C temperature range.
Ordering Information
PART
MAX7359ETG+
MAX7359EWA+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 TQFN-EP*
25 WLP
Applications
Cell Phones
PDAs
Handheld Games
Portable Consumer Electronics
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Pin Configurations
AD0
COL0
13
12 COL1
11 COL2/PORT2
10 COL5/PORT5
SDA
SCL
GND
15
18
INT 19
17
16
14
INPUT
+1.62V TO +3.6V
V
CC
MAX7359
COL_
8
SWITCH
ARRAY,
UP TO 64
SWITCHES
V
CC
20
N.C. 21
COL7/PORT7 22
ROW0 23
ROW1 24
+
1
ROW2
2
ROW3
3
COL3/PORT3
4
COL4/PORT4
5
ROW4
EP*
6
ROW5
MAX7359
I.C.
Typical Application Circuits
TOP VIEW
9
8
7
COL6/PORT6
ROW7
ROW6
8
ROW_
SCL
SDA
INT
AD0
GND
TQFN
(3.5mm x 3.5mm)
*EP = EXPOSED PAD.
Typical Application Circuits continued at end of data sheet.
Pin Configurations continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
MAX7359
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
V
CC
..........................................................................-0.3V to +4V
COL2/PORT2–COL7/PORT7 ....................................-0.3V to +4V
SDA, SCL, AD0,
INT
.................................................-0.3V to +6V
All Other Pins ..............................................-0.3V to (V
CC
+ 0.3V)
DC Current on COL2/PORT2–COL7/PORT7 ......................25mA
GND Current .......................................................................80mA
Continuous Power Dissipation (T
A
= +70°C)
24-Pin TQFN (derate 15.4mW/°C above +70°C) ........1229mW
25-Bump WLP (derate 19.2mW/°C above +70°C)......1194mW
Junction-to-Case Thermal Resistance (
θ
JC
) (Note 1)
24-Pin TQFN.................................................................5.4°C/W
25-Bump WLP ...............................................................17°C/W
Junction-to-Ambient Thermal Resistance (
θ
JA
) (Note 1)
24-Pin TQFN...............................................................65.1°C/W
25-Bump WLP ...............................................................53°C/W
Operating Temperature Range (T
MIN
to T
MAX
) .....-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (TQFN only, soldering, 10s) ..............+300°C
Soldering Temperature (reflow) .......................................+260°C
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
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.
ELECTRICAL CHARACTERISTICS
(V
CC
= +1.62V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +2.5V, T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Operating Supply Voltage
SYMBOL
V
CC
All key switches open, oscillator running,
COL2–COL7 configured as key switches
Operating Supply Current
I
CC
N keys pressed
Sleep-Mode Supply Current
POR
POR Hysteresis
Key-Switch Source Current
Key-Switch Source Voltage
Key-Switch Resistance
Startup Time from Shutdown
Output Low Voltage
COL2/PORT2 to COL7/PORT7
INT
Output
Oscillator Frequency
Serial Bus Timeout
Input High Voltage
SDA, SCL, AD0
Input Low Voltage
SDA, SCL, AD0
Output Low Voltage SDA
Input Leakage Current
PORHYST
I
KEY
V
KEY
R
KEY
t
START
V
OLPORT
V
OLINT
F
OSC
t
OUT
V
IH
V
IL
V
OLPORT
I
SINK
= 10mA
V
CC
= 0V to +6V
-1
With bus timeout enabled
10
0.7 x
V
CC
0.3 x
V
CC
0.4
+1
I
SINK
= 10mA
I
SINK
= 10mA
64
40
Operating mode
(Note 4)
2
V
CC
rising
I
SL
1.0
42
20
0.42
35
0.55
5
2.4
0.2
0.5
CONDITIONS
MIN
1.62
25
(25 +
20 x N)
0.6
5
1.6
TYP
MAX
3.60
60
µA
UNITS
V
µA
V
mV
µA
V
kΩ
ms
V
V
kHz
ms
V
V
V
µA
SERIAL-INTERFACE SPECIFICATIONS
2
_______________________________________________________________________________________
2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
I
2
C TIMING CHARACTERISTICS
(V
CC
= +1.62V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +2.5V, T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Input Capacitance
(SCL, SDA, AD0)
SCL Serial-Clock Frequency
Bus Free Time Between a STOP
and a START Condition
Hold Time (Repeated) START
Condition
Repeated START Condition
Setup Time
STOP Condition Setup Time
Data Hold Time
Data Setup Time
SCL Clock Low Period
SCL Clock High Period
Rise Time of Both SDA and SCL
Signals, Receiving
Fall Time of Both SDA and SCL
Signals, Receiving
Fall Time of SDA Transmitting
Pulse Width of Spike Suppressed
Capacitive Load for Each Bus Line
SYMBOL
C
IN
f
SCL
t
BUF
t
HD, STA
t
SU, STA
t
SU, STO
t
HD, DAT
t
SU, DAT
t
LOW
t
HIGH
t
R
t
F
t
F, TX
t
SP
C
b
(Notes 4, 5)
(Notes 4, 5)
(Notes 4, 7)
(Notes 4, 8)
(Note 4)
(Note 6)
100
1.3
0.7
20 +
0.1C
b
20 +
0.1C
b
20 +
0.1C
b
300
300
250
50
400
(Notes 4, 5)
Bus timeout disabled
0
1.3
0.6
0.6
0.6
0.9
CONDITIONS
MIN
TYP
MAX
10
400
UNITS
pF
kHz
µs
µs
µs
µs
µs
ns
µs
µs
ns
ns
ns
ns
pF
MAX7359
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
All parameters are tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
All digital inputs at V
CC
or GND.
Guaranteed by design.
C
b
= total capacitance of one bus line in pF. t
R
and t
F
measured between +0.3V
CC
and +0.7V
CC
.
A master device must provide a hold time of at least 300ns for the SDA signal (referred to V
IL
of the SCL signal) to bridge
the undefined region of SCL’s falling edge.
Note 7:
I
SINK
≤
6mA.
Note 8:
Input filters on the SDA, SCL, and AD0 inputs suppress noise spikes less than 50ns.
_______________________________________________________________________________________
3
2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
MAX7359
Typical Operating Characteristics
(V
CC
= +2.5V, T
A
= +25°C, unless otherwise noted.)
GPO PORT OUTPUT LOW VOLTAGE
vs. SINK CURRENT
MAX7359 toc01
GPO PORT OUTPUT LOW VOLTAGE
vs. SINK CURRENT
MAX7359 toc02
GPO PORT OUTPUT LOW VOLTAGE
vs. SINK CURRENT
V
CC
= +3.6V
MAX7359 toc03
300
V
CC
= +2.4V
250
T
A
= +85°C
200
V
OL
(mV)
300
250
200
V
OL
(mV)
150
100
V
CC
= +3.0V
300
250
200
V
OL
(mV)
150
100
T
A
= +85°C
T
A
= +85°C
150
100
50
0
0
5
10
15
I
SINK
(mA)
20
25
30
T
A
= +25°C
T
A
= -40°C
50
0
0
5
10
15
I
SINK
(mA)
20
T
A
= +25°C
T
A
= -40°C
50
0
25
30
0
5
10
15
I
SINK
(mA)
20
T
A
= +25°C
T
A
= -40°C
25
30
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX7359 toc04
KEY-SWITCH SOURCE CURRENT
vs. SUPPLY VOLTAGE
COL0 = GND
KEY-SWITCH SOURCE CURRENT (µA)
T
A
= +85°C
21.5
MAX7359 toc05
SLEEP MODE SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SHUTDOWN SUPPLY CURRENT (µA)
MAX7359 toc06
40
AUTOSLEEP = OFF
35
SUPPLY CURRENT (µA)
22.0
2.0
1.5
30
T
A
= +85°C
21.0
T
A
= +25°C
20.5
T
A
= -40°C
1.0
25
T
A
= -40°C
T
A
= +25°C
15
1.6
2.0
2.4
2.8
3.2
3.6
SUPPLY VOLTAGE (V)
0.5
20
20.0
1.6
2.0
2.4
2.8
3.2
3.6
SUPPLY VOLTAGE (V)
0
1.6
2.1
2.6
3.1
3.6
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
2-Wire Interfaced Low-EMI
Key Switch Controller/GPO
Functional Block Diagram
MAX7359
MAX7359
64kHz
OSCILLATOR
COLUMN ENABLE
GPO ENABLE
CURRENT DETECT
CURRENT
SOURCE
COLUMN
DRIVES
INT
SDA
SCL
I
2
C
INTERFACE
CONTROL
REGISTERS
FIFO
KEY SCAN
COL0
COL1
COL2*
COL3*
COL4*
COL5*
COL6*
COL7*
ROW0
ROW1
ROW2
ROW3
ROW4
ROW5
ROW6
ROW7
ROW ENABLE
BUS
TIMEOUT
POR
OPEN-
DRAIN
ROW
DRIVES
*GPO
_______________________________________________________________________________________
5
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