MAX6952EAX Maxim Integrated Products, MAX6952EAX Datasheet - Page 14

• Manufacturer Part Number: MAX6952EAX
• Description: LED Drivers 5 x 7 Matrix LED Dis play Driver, 4-Digit
• Manufacturer: Maxim Integrated Products

Specifications of MAX6952EAX

• Number Of Digits: 4
• Number Of Segments: 140
• Low Level Output Current: 500000 uA
• High Level Output Current: 50000 uA
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Supply Current: 16000 uA
• Maximum Power Dissipation: 941.2 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-36
• Minimum Operating Temperature: - 40 C

• If OSC is driven with an accurate frequency, blink
The scan-limit register sets how many monocolor digits
are displayed, either two or four. A bicolor digit is con-
nected as two monocolor digits.
The multiplexing scheme drives digits 0 and 1 at the
same time, then digits 2 and 3 at the same time. To
increase the effective brightness of the displays, drive
only two digits instead of four. By doing this, the aver-
age segment current doubles, but also doubles the
number of MAX6952s required to drive a given number
of digits.
Because digit 1 is driven at the same time as digit 0
(and digit 3 is driven at the same time as digit 2), only 1
bit is used to set the scan limit. The bit is clear if one or
two digits are to be driven, and set if three or four digits
are to be driven (Table 20). Change the scan-limit
register only when the MAX6952 is in shutdown mode.
Display brightness is controlled digitally by four pulse-
width modulators, one for each display digit. Each digit is
controlled by a nibble of one of the two intensity registers,
Intensity10 and Intensity32. The modulator scales the
average segment current in 16 steps from a maximum of
15/16 down to 1/16 of the peak current. The minimum
interdigit blanking time is, therefore, 1/16 of a cycle. The
maximum duty cycle is 15/16. (Tables 21 and 22).
4-Wire Interfaced, 2.7V to 5.5V,
4-Digit 5
Table 15. Memory Mapping of User-Defined Font Register 0x05
Table 16. Font Pointer Address Behavior
14
can be used as a seconds counter or similar.
ADDRESS CODE
FONT POINTER ADDRESS
______________________________________________________________________________________
(HEX)
0x85
0x05
0x05
0x80 to 0xF6
0xF8 to 0xFF
0xF7
✕
7 Matrix LED Display Driver
REGISTER
0x00–0x7F
0x00–0x7F
0x80–0xFF
Scan-Limit Register
DATA
Intensity Registers
Valid range to set the font address pointer. Pointer autoincrements after a font data read or
write, while pointer address remains in this range.
Font address resets to 0x80 after a font data read or write to this pointer address.
Invalid range to set the font address pointer. Pointer is set to 0x80 if address.
OR WRITE
SPI READ
Read
Write
Write
A write to the no-op register is ignored.
The RC oscillator uses an external resistor RSET and an
external capacitor C
f
R
mended values of R
4MHz, which makes the blink frequencies 0.5Hz and
1Hz. The recommended value of R
peak current to 40mA, which makes the segment cur-
rent adjustable from 2.5mA to 37.5mA in 2.5mA steps:
I
f
Where:
K
K
R
C
C
pF, typically 2pF
The recommended value of R
recommended value of C
SEG
OSC
OSC
SET
I
F
SET
SET
STRAY
Selecting External Components R
= 2144
= 6000
Read 7-bit user-definable font data entry from current font
address. MSB of the register data is clear. Font address
pointer is incremented after the read.
Write 7-bit user-definable font data entry to current font
address. Font address pointer is incremented after the
write.
Write font address pointer with the register data.
. The allowed range of f
= K
= K
= external capacitor in pF
also sets the peak segment current. The recom-
= external resistor in kΩ
C
I
= stray capacitance from OSC pin to GND in
SET
F
/ R
/ (R
ACTION
SET
SET
to Set Oscillator Frequency and
mA
✕
C
SET
SET
SET
FUNCTION
to set the oscillator frequency,
and C
SET
+ C
is 26pF.
STRAY
OSC
SET
SET
Segment Current
) MHz
No-Op Register
set the oscillator to
is 1MHz to 8MHz.
is 53.6kΩ and the
SET
also sets the
SET
and