MAX6947ATE+T Maxim Integrated Products, MAX6947ATE+T Datasheet - Page 13

• Manufacturer Part Number: MAX6947ATE+T
• Description: IC LED DRIVER LINEAR 16-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Linear (I²C Interface)r

Specifications of MAX6947ATE+T

• Constant Current: Yes
• Topology: Open Drain, PWM
• Number Of Outputs: 10
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: RGB, White LED
• Frequency: 400kHz
• Voltage - Supply: 2.25 V ~ 3.6 V
• Voltage - Output: 7V
• Mounting Type: Surface Mount
• Package / Case: 16-TQFN Exposed Pad
• Operating Temperature: -40°C ~ 125°C
• Current - Output / Channel: 20mA
• Internal Switch(s): Yes
• Number Of Segments: 3
• Low Level Output Current: 21.12 mA
• Operating Supply Voltage: 2.25 V to 3.6 V
• Maximum Supply Current: 60 uA
• Maximum Power Dissipation: 1176 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Details

In shutdown mode, all ports configured as constant-
current outputs (output register set to a value between
0x02 and 0xFE) are switched off, and these outputs go
high impedance as if their registers were set to value
0xFF. Ports configured as logic inputs or outputs (out-
put registers set to value 0x00 or 0x01) are unaffected
(Table 4). This means that any ports used for GPIOs
are still fully operational in shutdown mode, and port
inputs can be read and output ports can be toggled at
any time using the serial interface. Use the MAX6946/
MAX6947 for a mix of logic inputs, logic outputs, and
PWM LED drivers, and only the LED drivers turn off
automatically in shutdown.
Put the MAX6946/MAX6947 into shutdown mode by
clearing the run bit (bit D0) in the configuration register
(0x10) (Table 2). Exit shutdown by setting the run bit high
through the serial interface or by using the Reset Run
option (see the Reset Run Option section). Configure
and control the MAX6946/MAX6947 normally through the
serial interface in shutdown mode. All registers are
accessible in shutdown mode, and shutdown mode
does not change any register values.
Figure 4. Ramp-Up Behavior
Figure 5. Ramp-Down, Hold-Off, and Fade-Off Behavior
FULL CURRENT/
HALF CURRENT
0
10-Port, Constant-Current LED Driver and
I/O Expander with PWM Intensity Control
______________________________________________________________________________________
1/4s 1/2s
1/8s
1/16s
FULL CURRENT/
HALF CURRENT
ZERO TO 4s HOLD-OFF DELAY BEFORE FADE-OFF
1s
0
Shutdown Mode
1/4s 1/2s
1/8s
1/16s
2s
EXIT SHUTDOWN COMMAND
ZERO TO 4s CURRENT RAMP-UP AFTER CS RUN
1s
ZERO TO 8s CURRENT RAMP-DOWN
2s
Changing a port from static logic-low (0x00) or static
logic-high (0x01) to a constant-current value
(0x02–0xFE) in shutdown mode turns that output off
(logic-high or high impedance) like any other constant-
current outputs in shutdown. The new constant-current
output starts just like any other constant-current outputs
when exiting shutdown.
Changing a port from a constant-current value
(0x02–0xFE) to static logic-low (0x00) or static logic-
high (0x01) in shutdown causes that output to set to the
value as a GPIO output. The new GPIO output is unaf-
fected just like any other GPIO output when exiting
shutdown.
The MAX6946/MAX6947 provide controls that allow the
output currents to ramp down into shutdown (ramp-
down), and ramp up again out of shutdown (ramp-up)
(Figures 4 and 5). Ramp-down comprises a programma-
ble hold-off delay that also maintains the outputs at full
current for a time before the programmed fade-off time.
After the hold-off delay, the output currents ramp down.
4s
1/4s 1/2s
1/8s
1/16s
ZERO TO 4s CURRENT FADE-OFF AFTER HOLD-OFF DELAY
Ramp-Up and Ramp-Down Controls
1s
4s
2s
4s
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