LED1 Code (dec#)

0

16

32

48

64

80

96

112

128

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

D001

TA = -40°C

TA = +25°C

TA = +85°C

LED2 Code (dec#)

0

16

32

48

64

80

96

112

128

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

D002

TA = -40°C

TA = +25°C

TA = +85°C

SCL

SDA_IN

SDA_OUT

t 5

t 1

t 4

t 3

t

2

7

LM3644, LM3644TT

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SNVSA52E – AUGUST 2014 – REVISED SEPTEMBER 2016

Product Folder Links: LM3644 LM3644TT

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Copyright © 2014–2016, Texas Instruments Incorporated

7.6 Timing Requirements

MIN

NOM

MAX

UNIT

t1

SCL clock period

2.4

µs

t2

Data in set-up time to SCL high

100

ns

t3

Data out stable After SCL low

0

ns

t4

SDA low set-up time to SCL Low (start)

100

ns

t5

SDA high hold time after SCL high (stop)

100

ns

7.7 Switching Characteristics

over operating free-air temperature range (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

ƒSW

Switching frequency

2.5 V

≤ VIN ≤ 5.5 V

–6%

4

6%

MHz

Figure 1. I2C-Compatible Interface Specifications

7.8 Typical Characteristics

Ambient temperature is 25°C, input voltage is 3.6 V, HWEN = VIN, CIN = COUT = 2 × 10 µF and L = 1 µH, unless otherwise

noted .

Figure 2. LED1 Flash Current vs Brightness Code

Figure 3. LED2 Flash Current vs Brightness Code