ISSI IS31FL3745 User Manual

18×8 DOTS MATRIX LED DRIVER EVALUATION BOARD GUIDE

DESCRIPTION

The IS31FL3745 is a general purpose 18×n (n=1~8)
LED Matrix programmed via 1MHz I2C compatible
interface. Each LED can be dimmed individually with
8-bit PWM data and 8-bit DC scaling data which
allowing 256 steps of linear PWM dimming and 256
steps of DC current adjustable level.

Additionally each LED open and short state can be
detected, IS31FL3745 store the open or short
information in Open-Short Registers. The Open-Short
Registers allowing MCU to read out via I2C compatible
interface. Inform MCU whether there are LEDs open or
short and the locations of open or short LEDs.

FEATURES

 Supply voltage range: 2.7V to 5.5V
 18 Current sink (Maximum)
 Support 18 × n (n=1~8) LED matrix configurations
 Individual 256 PWM control steps
 Individual 256 DC current steps
 Global 256 current setting
 SDB rising edge reset I2C module
 Programmable H/L logic:1.4/0.4, 2.4/0.6
 29kHz PWM frequency
 State lookup registers
 Individual open and short error detect function
 180 degree phase delay operation to reduce power

noise

 De-Ghost
 Cascade for synchronization of chips

QUICK START

RECOMMENDED EQUIPMENT

 5.0V, 2A power supply

ABSOLUTE MAXIMUM RATINGS

 ≤ 5.5V power supply

Caution: Do not exceed the conditions listed above, otherwise
the board will be damaged.

PROCEDURE

The IS31FL3745 evaluation board is fully assembled
and tested. Follow the steps listed below to verify
board operation.

Caution: Do not turn on the power supply until all connections
are completed.

1) Short JP1 (OPEN=EXT CTRL) to enable the
control of on board MCU (default status).

2) Connect the 5V DC power to VCC / GND in CON4,
or plug in the USB power input to micro-USB
(CON5).

3) Turn on the power supply, pay attention to the
supply current. If the current exceeds 1A, please
check for circuit fault.

EVALUATION BOARD OPERATION

The IS31FL3745 evaluation board has six display
modes. Press MODE button to switch configurations.

1) (Default mode) Rainbow #1.

2) Rainbow #2.

3) Purple breath.

4) Change colors.

5) White.

Note: IS31FL3745 solely controls the FxLED function on the
evaluation board.

Figure 1: Photo of IS31FL3745-CLS4 Evaluation Board

ORDERING INFORMATION

Part No. Temperature Range Package

IS31FL3745-CLS4-EB -40°C to +125°C (Industrial) WLCSP-36, Lead-free

Table 1: Ordering Information

For pricing, delivery, and ordering information, please contacts ISSI’s analog marketing team at

[e-mail] or [phone]

Integrated Silicon Solution, Inc. – ams.issi.com 1

Rev. A, 03/11/2019

18×8 DOTS MATRIX LED DRIVER EVALUATION BOARD GUIDE

SOFTWARE SUPPORT

EXT CTRL (JP1) default setting is close circuit. If it is
set to open, the on-board MCU will configure the I2C
pins and SDB pin to High Impedance and sleep.
External I2C and SDB signals can be connected to
TP4 to control the IS31FL3745 LED driver.

SDB

VCC

GND

Figure 2: Photo of Arduino UNO connected to Evaluation

Board

SDA

SCL

The steps listed below are an example using the
Arduino for external control.

The Arduino hardware consists of an Atmel
microcontroller with a bootloader allowing quick
firmware updates. First download the latest Arduino
Integrated Development Environment IDE (1.6.12 or
greater) from www.arduino.cc/en/Main/Software. Also
download the W ire.h library from
www.arduino.cc/en/reference/wire and verify that
pgmspace.h is in the directory …program
Files(x86)/Arduino/hardware/tools/avr/avr/include/avr
/. Then download the latest IS31FL3745 test firmware
(sketch) from the ISSI website

http://ams.issi.com/US/product-analog-fxled-driver.shtml.

1) Open EXT CTRL (JP1).

2) Connect the 5 pins from Arduino board to
IS31FL3745 EVB:

a) Arduino 5V pin to IS31FL3745 EVB VCC.
b) Arduino GND to IS31FL3745 EVB GND.
c) Arduino SDA (A4) to IS31FL3745 EVB SDA.
d) Arduino SCL (A5) to IS31FL3745 EVB SCL.
e) If Arduino use 3.3V MCU VCC, connect

3.3V to IS31FL3745 EVB SDB, if Arduino
use 5.0V MCU VCC, connect 5.0V or 3.3V
to EVB SDB.

(Arduino UNO MCU VCC is 5V, so SDB can
be 5V or 3.3V)

3) Use the test code in appendix Ⅰ or download the
test firmware (sketch) from the ISSI website,

a .txt file and copy the code to Arduino IDE,
compile and upload to Arduino.

4) Run the Arduino code for desired mode setting by
Arduino code.

Please refer to the datasheet to get more information about
IS31FL3745.

Integrated Silicon Solution, Inc. – ams.issi.com 2

Rev. A, 03/11/2019

18×8 DOTS MATRIX LED DRIVER EVALUATION BOARD GUIDE

U1

RSET

R5
10KR6100K

PVCC

C1

A3

100nF

C2

100nF

R4

100K

AD1

R3
100K

PVCC

PVCC

F5

VDD

SDA

D3

SDA

SCL

E3

SCL

SDB

E5

SDB

F3

RSET

D4

AD1

AD2

E4

AD2

SYNC

F2

SYNC

F4

GND

31FL3745

SW8
SW7
SW6
SW5
SW4
SW3
SW2
SW1

CS18
CS17
CS16
CS15
CS14
CS13
CS12
CS11
CS10

SW08

B6

SW07

C1

SW06

A6

SW05

B1

SW04

A5

SW03

A1

SW02

A4

SW01

A2

CS18

B5

CS17

B4

CS16

C5

CS15

C6

CS14

C4

CS13

D6

CS12

D5

CS11

E6

CS10

F6

CS09

F1

CS9

CS08

E1

CS8

CS07

E2

CS7

CS06

D1

CS6

CS05

D2

CS5

CS04

C2

CS4

CS03

C3

CS3

CS02

B3

CS2

CS01

B2

CS1

3V

R10
10K

K1

MCU

U3

1

VBAT

2

PC13-ANTI_TAMP

3

PC14-OSC32_IN

4

PC15-OSC32_OUT

OSCI

5

OSC_IN

OSCO

6

OSC_OUT

7

NRST

GND

8

VSSA

3V

9

VDDA

10

PA0

PA0-WKUP/ADC_IN0/TIM2_CH1_ETR

11

PA1/ADC_IN1/TIM2_CH2

12

PA2/USART2_TX/ADC_IN2/TIM2_CH3

13

PA3/USART2_RX/ADC_IN3/TIM2_CH4

14

CS

PA4/SPI1_NSS/ADC_IN4

15

SCK

PA5/SPI1_SCK/ADC_IN5

16

MISO

PA6/SPI1_MISO/ADC_IN6/TIM3_CH1

17

MOSI

PA7/SPI1_MOSI/ADC_IN7/TIM3_CH2

18

PB0/ADC_IN8/TIM3_CH3

19

PB1/ADC_IN9/TIM3_CH4

20

PB2/BOOT1

21

PB10/I2C2_SCL/USART3_TX

22

PB11/I2C2_SDA/USART3_RX

23

VSS_1

3V

24

VDD_1

STM32F103C8T6

C5
1μF

PB7/I2C1_SDA/TIM4_CH2
PB6/I2C1_SCL/TIM4_CH1

PA12/CANTX/USBDP/TIM1_ETR
PA11/CANRX/USBDM/TIM1_CH4

PA10/USART1_RX/TIM1_CH3

PA9/USART1_TX/TIM1_CH2

PB15/SPI2_MOSI/TIM1_CH3N
PB14/SPI2_MISO/TIM1_CH2N

PB13/SPI2_SCK/TIM1_CH1N

PB12/SPI2_NSS/TIM1_BKIN

VDD_3

VSS_3
PB9/TIM4_CH4
PB8/TIM4_CH3

BOOT0

PB4/JNTRST

PB3/JTDO
PA15/JTDI

PA14/JTCK/SWCLK

VDD_2

VSS_2

PA13/JTMS/SWDIO

PA8/TIM1_CH1/MCO

3V

48

GND

47
46
45
44

SDA

43

SCL

42
41

PB5

40
39
38

CLK

37

3V

36

GND

35

DIO

34

USB_DP2

33

USB_DM2

32
31
30
29

SDB

28

INTB

27
26
25

R1 4.7K
R2 4.7K

3V

SINK09

SINK01

SW06
SW02

SW01
SW05

CON1

CON2

CON3

1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16

1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16

1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16

IO

P1

SW8

1 2

SW4

3 4
5 6
7 8
9 10

SW3

11 12

SW7

13 14

SW11

15 16

Header 8X2

P2

1 2
3 4
5 6

CS18

7 8

CS16 CS17

9 10

CS14 CS15

11 12

CS12 CS13

13 14

CS10 CS11

15 16

Header 8X2

P3

CS8 CS9

1 2

CS6 CS7

3 4

CS4 CS5

5 6

CS2 CS3

7 8
9 10
11 12
13 14
15 16

Header 8X2

SW10
SW6
SW2

SW1
SW5
SW9

CS1

SINK08
SINK06SINK07
SINK04SINK05
SINK02SINK03

SW08
SW04

SW03
SW07

SINK18
SINK16SINK17
SINK14SINK15
SINK12SINK13
SINK10SINK11

GND

1

GND

2

GND

3

SDB

4

PVCC

5

DIO

6

GND

7

CLK

8

3V

9

SYNC

10

PVCC

11

SCL

12

SDA

13

AD2

14

AD1

15

PVCC

16

PVCC

17

PVCC

18

PVCC

19

CON4

SDB

MISO1SDB
MOSI35V
SCK5SCL
CS7SDA
PA09GND

TP4

PA0

R8 100K
R9 1K

2
4

PVCC

SCL

6

SDA

8

GND

10

3V

GND

MISO
MOSI
SCK
CS
PA0

2
1

JP1

CS01

CS01 20R

CS02

CS02 20R

CS03

CS03 20R

CS04

CS04 20R

CS05

CS05 20R

CS06

CS06 20R

CS07

CS07 20R

CS08

CS08 20R

CS09

CS09 20R

CS10

CS10 20R

CS11

CS11 20R

CS12

CS12 20R

CS13

CS13 20R

CS14

CS14 20R

CS15

CS15 20R

CS16

CS16 20R

CS17

CS17 20R

CS18

CS18 20R

*Note1

Y1 8M

1

GND

OSCI

2

OSCO

C3
33p

OSCI

GND

SINK01
SINK02
SINK03
SINK04
SINK05
SINK06
SINK07
SINK08
SINK09
SINK10
SINK11
SINK12
SINK13
SINK14
SINK15
SINK16
SINK17
SINK18

4

3

OSCO

3V Power

PVCC

U2

1

VIN

VOUT

3

C6
1μF

EN

2

GND

BP

LDO

3V

5

C8
1μF

C7

4

10nF

Micro USB

PVCC

C4
33p

USB_DM2

R11 22R

USB_DP2

R12 22R

R13

3V

1.5K

D1

C9A
10μF

DFL240

C9B

D2

10μF

DFL240

1

VCC

2

USB_DM
USB_DP

USB_DM

3

USB_DP

4

NC

5

GND

Con5

Figure 3: IS31FL3745 Application Schematic

CS18
CS17

D6
RGB4P

D5
RGB4P

D4
RGB4P

D3
RGB4P

D2
RGB4P

D1
RGB4P

D12
RGB4P

D11
RGB4P

D10
RGB4P

D9
RGB4P

D8
RGB4P

D7
RGB4P

D18
RGB4P

D17
RGB4P

D16
RGB4P

D15
RGB4P

D14
RGB4P

D13
RGB4P

D24
RGB4P

D23
RGB4P

D22
RGB4P

D21
RGB4P

D20
RGB4P

D19
RGB4P

D30
RGB4P

D29
RGB4P

D28
RGB4P

D27
RGB4P

D26
RGB4P

D25
RGB4P

D36
RGB4P

D35
RGB4P

D34
RGB4P

D33
RGB4P

D32
RGB4P

D31
RGB4P

D42
RGB4P

D41
RGB4P

D40
RGB4P

D39
RGB4P

D38
RGB4P

D37
RGB4P

D48
RGB4P

D47
RGB4P

D46
RGB4P

D45
RGB4P

D44
RGB4P

D43
RGB4P

CS16

CS15
CS14
CS13

CS12
CS11
CS10

CS9
CS8
CS7

CS6
CS5
CS4

CS3
CS2
CS1

SW1 SW2 SW3 SW4 SW5 SW6

SW7 SW8

Figure 4: FxLED_6x8_ARRAY Schematic

Integrated Silicon Solution, Inc. – ams.issi.com 3

Rev. A, 03/11/2019

18×8 DOTS MATRIX LED DRIVER EVALUATION BOARD GUIDE

BILL OF MATERIALS

IS31FL3745

Name Symbol Description Qty Supplier Part No.

LED Driver U1 Matrix LED Driver 1 ISSI IS31FL3745

LDO U2 3.0V LDO 1 SGMICRO SGM2019-3.0YN5G

MCU U3 Microcontroller 1 STM STM32F103C8T6

Crystal Y1 Crystal, 8MHz 1 HLX HC-49S

Diode D1,D2 Diode, SMD 2 DIODES DFLS240

CS01,CS02,
CS04,CS05,

Resistor

CS07,CS08,
CS10,CS11,
CS13,CS14,

CS16,CS17

RES,20R,1/10W,±5%,SMD 12 Yageo RC0603JR-0720RL

CS03,CS06,

Resistor

Resistor R1,R2 RES,4.7k,1/10W,±5%,SMD 2 Yageo RC0603JR-074K7L

Resistor R3,R4,R6,R8 RES,100k,1/10W,±5%,SMD 4 Yageo RC0603JR-07100KL

Resistor R5,R10 RES,10k,1/10W,±5%,SMD 2 Yageo RC0603JR-0710KL

Resistor R9 RES,1k,1/10W,±5%,SMD 1 Yageo RC0603JR-071KL

Resistor R11, R12 RES,22R,1/10W,±5%,SMD 2 Yageo RC0603JR-0722RL

Resistor R13 RES,1.5k,1/10W,±5%,SMD 1 Yageo RC0603JR-071K5L

Capacitor C1,C2 CAP,100nF,16V,±20%,SMD 2 Yageo CC0603MRX7R7BB104

Capacitor C3,C4 CAP,33pF,50V,±5%,SMD 2 Yageo CQ0603JRNPO9BN360

Capacitor C5,C6,C8 CAP, 1µF,16V,±10%,SMD 1 Yageo CC0603KRX7R7BB105

Capacitor C7 CAP,10nF,16V,±10%,SMD 1 Yageo CC0603KPX7R7BB103

Capacitor C9A,C9B CAP,10µF,16V,±20%,SMD 2 Yageo CC0805KKX7R7BB106

Button K1 Button SMD 1

Bill of Materials, refer to Figure 3 above.

CS09,CS12,

CS15,CS18

RES,20R,1/10W,±5%,SMD
(Note 1)

6 Yageo RC0603JR-0720RL

FxLED 6x11 ARRAY

Name Symbol Description Qty Supplier Part No.

Diode D1~D48 RGB LED, SMD 48 Everlight 9-237/R6GHBHC-A01/2T

Bill of Materials, refer to Figure 4 above.

Note 1: The value of these resistors on the evaluation board is 20Ω. For PVCC=5V and red LED application, prefer 51Ω for these resistors as
shown in datasheet Figure 1.

Integrated Silicon Solution, Inc. – ams.issi.com 4

Rev. A, 03/11/2019