MAX7316 View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX7316
Maxim Integrated
MAX7316 Datasheet PDF : 24 Pages
| |||
10-Port I/O Expander with LED Intensity
Control, Interrupt, and Hot-Insertion Protection
Table 12. PWM Intensity Settings (Blink Enabled)
OUTPUT
(OR
GLOBAL)
INTENSITY
SETTING
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
0x8
0x9
0xA
0xB
0xC
0xD
0xE
0xF
PWM DUTY CYCLE
OUTPUT BLINK
PHASE X
REGISTER BIT = 0
PWM DUTY CYCLE
OUTPUT BLINK
PHASE X
REGISTER BIT = 1
EXAMPLES OF LED BLINK BEHAVIOR
(LED IS ON WHEN OUTPUT IS LOW)
BLINK PHASE 0
REGISTER BIT = 0
BLINK PHASE 0
REGISTER BIT = 1
LOW
TIME
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
10/16
11/16
12/16
13/16
14/16
15/16
Static low
HIGH
TIME
LOW
TIME
HIGH
TIME
BLINK PHASE 1
REGISTER BIT = 1
BLINK PHASE 1
REGISTER BIT = 0
15/16
15/16
1/16
14/16
13/16
12/16
11/16
10/16
9/16
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
14/16
13/16
12/16
11/16
10/16
9/16
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
10/16
11/16
12/16
13/16
14/16
15/16
Phase 0: LED on at low intensity Phase 0: LED on at high intensity
Phase 1: LED on at high intensity Phase 1: LED on at low intensity
Output is half intensity during both blink phases
Phase 0: LED on at high intensity Phase 0: LED on at low intensity
Phase 1: LED on at low intensity Phase 1: LED on at high intensity
Static low
Static high Static high
impedance impedance
Phase 0: LED on continuously
Phase 1: LED off continuously
Phase 0: LED off continuously
Phase 1: LED on continuously
Driving LED Loads
When driving LEDs, a resistor in series with the LED
must be used to limit the LED current to no more than
50mA. Choose the resistor value according to the fol-
lowing formula:
RLED = (VSUPPLY - VLED - VOL) / ILED
where:
RLED is the resistance of the resistor in series with the
LED (Ω).
VSUPPLY is the supply voltage used to drive the LED (V).
VLED is the forward voltage of the LED (V).
VOL is the output low voltage of the MAX7316 when
sinking ILED (V).
ILED is the desired operating current of the LED (A).
For example, to operate a 2.2V red LED at 14mA from a
5V supply, RLED = (5 - 2.2 - 0.25) / 0.014 = 182Ω.
Driving Load Currents Higher than 50mA
The MAX7316 can be used to drive loads drawing more
than 50mA, like relays and high-current white LEDs, by
paralleling outputs. Use at least one output per 50mA of
load current; for example, a 5V 330mW relay draws
66mA and needs two paralleled outputs to drive it.
Ensure that the paralleled outputs chosen are controlled
by the same blink phase register, i.e., select outputs
from the P0 through P7 range. This way, the paralleled
outputs are turned on and off together. Do not use out-
put O8 as part of a load-sharing design. O8 cannot be
switched at the same time as any of the other outputs
because it is controlled by a different register.
______________________________________________________________________________________ 19
Share Link: