MAX7314ATG Maxim Integrated Products, MAX7314ATG Datasheet - Page 19

• Manufacturer Part Number: MAX7314ATG
• Description: Communication ICs - Various
• Manufacturer: Maxim Integrated Products
• Type: Hot Insertion Protectionr

Specifications of MAX7314ATG

• Mounting Style: SMD/SMT
• Operating Supply Voltage: 2.5 V, 3.3 V
• Supply Type: Analog
• Package / Case: TQFN-24 EP
• Data Rate: 400 Kbps
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2 V
• Supply Current: 0.057 mA
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 12. PWM Intensity Settings (Blink Enabled)
I/O ports P0–P15, interrupt output INT/O16, RST input,
BLINK input, and serial interface SDA, SCL, AD0 remain
high impedance with up to 6V asserted on them when
the MAX7314 is powered down (V+ = 0V). The MAX7314
can therefore be used in hot-swap applications.
The open-drain output architecture allows the ports to
level translate the outputs to higher or lower voltages
than the MAX7314 supply. An external pullup resistor
can be used on any output to convert the high-imped-
ance logic-high condition to a positive voltage level.
The resistor can be connected to any voltage up to
5.5V. For interfacing CMOS inputs, a pullup resistor
value of 220kΩ is a good starting point. Use a lower
resistance to improve noise immunity, in applications
where power consumption is less critical, or where a
faster rise time is needed for a given capacitive load.
INTENSITY
GLOBAL)
SETTING
OUTPUT
(OR
0xC
0xD
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
0x8
0x9
0xA
0xB
0xE
0xF
Static low
PWM DUTY CYCLE
REGISTER BIT = 0
10/16
11/16
12/16
13/16
14/16
15/16
LOW
TIME
Applications Information
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
OUTPUT BLINK
18-Port GPIO with LED Intensity Control,
______________________________________________________________________________________
PHASE X
Interrupt, and Hot-Insertion Protection
Output Level Translation
Static low
HIGH
15/16
14/16
13/16
12/16
11/16
10/16
TIME
9/16
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
impedance
Static high
PWM DUTY CYCLE
15/16
14/16
13/16
12/16
11/16
10/16
LOW
TIME
9/16
8/16
7/16
6/16
5/16
4/16
3/16
2/16
1/16
Hot Insertion
OUTPUT BLINK
REGISTER = 1
PHASE X
impedance
Static high
HIGH
10/16
11/16
12/16
13/16
14/16
15/16
TIME
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
P hase 0: LE D on at hi g h i ntensi ty
P hase 1: LE D on at hi g h i ntensi ty
P hase 1: LE D on at l ow i ntensi ty
Phase 0: LED on continuously
Phase 1: LED off continuously
P hase 0: LE D on at l ow i ntensi ty
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:
where:
R
LED (Ω).
V
V
V
sinking I
I
For example, to operate a 2.2V red LED at 14mA from a
5V supply, R
LED
SUPPLY
LED
OL
LED
REGISTER BIT = 0
REGISTER BIT = 1
BLINK PHASE 0
BLINK PHASE 1
is the desired operating current of the LED (A).
is the output low voltage of the MAX7314 when
Output is half intensity during both blink phases
is the forward voltage of the LED (V).
is the resistance of the resistor in series with the
LED
EXAMPLES OF LED BLINK BEHAVIOR
R
is the supply voltage used to drive the LED (V).
(LED IS ON WHEN OUTPUT IS LOW)
LED
(V).
LED
= (V
= (5 - 2.2 - 0.25) / 0.014 = 182Ω.
SUPPLY
- V
P hase 0: LE D on at hi g h i ntensi ty
P hase 1: LE D on at l ow i ntensi ty
P hase 1: LE D on at hi g h i ntensi ty
Phase 0: LED off continuously
Phase 1: LED on continuously
P hase 0: LE D on at l ow i ntensi ty
LED
Driving LED Loads
REGISTER BIT = 1
REGISTER BIT = 0
BLINK PHASE 0
BLINK PHASE 1
- V
OL
) / I
LED
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