MAX6969AUG-T Maxim Integrated Products, MAX6969AUG-T Datasheet - Page 7

• Manufacturer Part Number: MAX6969AUG-T
• Description: LED Drivers 16-Port, 5.5V LED Dr iver, 16-Segment Any
• Manufacturer: Maxim Integrated Products

Specifications of MAX6969AUG-T

• Number Of Segments: 32
• Low Level Output Current: 60000 uA
• Operating Supply Voltage: 3 V to 5.5 V
• Maximum Supply Current: 25000 uA
• Maximum Power Dissipation: 975 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-24
• Minimum Operating Temperature: - 40 C

The MAX6969 LED driver comprises a 4-wire serial
interface driving 16 constant-current-sinking, open-
drain output ports. The outputs drive LEDs in either
static or multiplex applications (Figure 1). The constant-
current outputs are guaranteed for current accuracy
not only with chip-supply voltage variations (5V ±10%
and 3V to 5.5V), but also over a realistic range of driver
output voltage drop (0.5V to 2.5V). The drivers use cur-
rent-sensing feedback circuitry (not simple current mir-
rors) to ensure very small current variations over the full
allowed range of output voltage (see the Typical
Operating Characteristics).
The 4-wire serial interface comprises a 16-bit shift reg-
ister and a 16-bit transparent latch. The shift register is
written through a clock input, CLK, and a data input,
DIN, and the data propagates to a data output, DOUT.
The data output allows multiple drivers to be cascaded
and operated together. The contents of the 16-bit shift
register are loaded into the transparent latch through a
latch-enable input, LE. The latch is transparent to the
shift register outputs when high, and latches the current
state on the falling edge of LE.
Figure 2. 4-Wire Serial-Interface Timing Diagram
DOUT
OUT_
CLK
DIN
OE
LE
16-Port, 5.5V Constant-Current LED Driver
_______________________________________________________________________________________
Detailed Description
t
DS
D15
t
DH
t
CL
t
OEL
D14
t
f
t
t
CH
OEW
80%
20%
Each driver output is an open-drain, constant-current
sink that should be connected to the cathode of either
a single LED or a series string of multiple LEDs. The
LED anode can be connected to a supply voltage of up
to 5.5V, independent of the MAX6969 supply, V+. The
constant-current capability is up to 55mA per output,
set for all eight outputs by an external resistor, R
An internal reset circuit clears the internal registers of
the MAX6969 on power-up. All outputs (OUT0–OUT15)
initialize to high impedance, regardless of the initial
logic levels of the CLK, DIN, OE, and LE inputs.
The serial interface on the MAX6969 is a 4-wire serial
interface using four inputs (DIN, CLK, LE, OE) and a
data output (DOUT). This interface is used to write dis-
play data to the MAX6969. The serial-interface data
word length is 16 bits, D0–D15. See Figure 2.
The functions of the five interface pins are as follows.
DIN is the serial-data input, and must be stable when it
is sampled on the rising edge of CLK. Data is shifted in,
MSB first. This means that data bit D15 is clocked in
first, followed by 15 more data bits finishing with the
LSB, D0.
t
OEH
D1
t
r
t
DO
t
CP
Initial Power-Up and Operation
.
D0
t
LS
4-Wire Serial Interface
D7
t
LW
SET
.
7