MAX6950CEE+ Maxim Integrated Products, MAX6950CEE+ Datasheet - Page 12

• Manufacturer Part Number: MAX6950CEE+
• Description: IC DRVR DSPL LED SRL 16-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6950CEE+

• Display Type: LED
• Configuration: 7 Segment
• Interface: 3-Wire Serial
• Digits Or Characters: 5 Digits
• Current - Supply: 10mA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP Exposed Pad, 16-eQSOP , 16-HQSOP
• Number Of Digits: 5
• Number Of Segments: 40
• Low Level Output Current: 400 mA
• High Level Output Current: - 50 mA
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Supply Current: 15 mA
• Maximum Power Dissipation: 667 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The allowed range of the frequency at the OSC pin, f
is 1MHz to 8MHz, which allows the blink frequency to be
adjusted over a wide range. The internal oscillator may
be accurate enough for many applications using a single
device. If an exact or synchronized blink rate is required,
then OSC should be driven by an external clock.
The display scan rate (defined in the Electrical
Characteristics table) is calculated by dividing f
4000 for the MAX6950 (scanning a full five digits), or by
6400 for the MAX6951 (scanning a full eight digits). The
display scan rate is the refresh rate for all the digits of the
display. With f
for 200µs.
There is a fail-safe circuit in the MAX6950/MAX6951 to
ensure the display multiplexing works if the OSC is con-
figured incorrectly. This ensures that the driver cannot
remain stuck on a single digit, forcing a peak current con-
tinuously through segments. The fail-safe circuit detects
that f
tions to guarantee a minimum effective clock of typically
75.5kHz. The scan rate for eight digits is about 11Hz in
fail-safe mode, and appears to flicker to most observers.
A flickering display is a good indication that there is a
problem with the multiplex clock. The clock failure detec-
tion works regardless of the clock source being the inter-
nal RC oscillator or external clock drive.
Serially Interfaced, +2.7V to +5.5V,
5- and 8-Digit LED Display Drivers
Table 13. Intensity Register Format
12
15/16 (max on)
DUTY CYCLE
1/16 (min on)
______________________________________________________________________________________
OSC
10/16
11/16
12/16
13/16
14/16
15/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
is too slow, and generates extra clock transi-
OSC
TYPICAL SEGMENT
at 4MHz, each display digit is enabled
CURRENT (mA)
12.5
17.5
22.5
27.5
32.5
37.5
37.5
2.5
7.5
10
15
20
25
30
35
5
CODE (HEX)
ADDRESS
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
OSC
OSC
by
,
D7
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
The RC oscillator uses an external resistor R
also sets the peak segment current) and an external
capacitor C
ommended values of R
4MHz, which makes the slow and fast blink frequency
0.5Hz and 1Hz, respectively.
The OSC inputs of multiple MAX6950/MAX6951 drivers
can be connected together to an external clock to make
the devices blink at the same frequency. Segment blink-
ing may be synchronized across multiple MAX6950/
MAX6951s so that all drivers blink not only at the same
frequency, but also in phase. When the control register is
written with the T bit set (Table 9), the OSC divider chain
is cleared and the display multiplexing sequence reset.
To synchronize several drivers, it is necessary to write
this register in all drivers at the same time. In practice,
adequate synchronization can be achieved by writing to
multiple drivers in quick succession.
When the global blink timing synchronization bit is set,
the multiplexing and blink counter is cleared on the ris-
ing edge of CS. By setting the T bit in multiple
MAX6950/MAX6951s at the same time (or in quick suc-
cession), the blink timing can be synchronized across
all the devices. Note that the display multiplexing
D6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D5
Multiple MAX6950/MAX6951 Drivers
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Synchronization of Blinking Across
SET
D4
to set the oscillator frequency. The rec-
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D3
SET
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
and C
D2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
SET
D1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
set the oscillator at
D0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
SET
CODE
(which
0xXA
0xXB
0xXC
0xXD
0xX0
0xX1
0xX2
0xX3
0xX4
0xX5
0xX6
0xX7
0xX8
0xX9
0xXE
0xXF
HEX