LED dedicated drive control circuit
TM1638
1. An overview
TM1638 is an LED Controller driven on a 1/16 to 14/16 duty factor. 10 segment output lines,
8 grid output lines, 8 segment/key scan output lines, one display memory, control circuit,
key scan circuit are all incorporated into a single chip to build a highly reliable peripheral
device for a single chip microcomputer. Serial data is fed to TM1638 via a three-line
serial interface. Housed in a SOP28 package, TM1638 pin assignments and application
circuit are optimized for easy PCB Layout and cost saving advantages.
2. FEATURES
•
•
•
•
•
•
•
•
CMOS Technology
Display Mode 10 segments × 8-bit
Key Scanning (8 × 3bit)
8-Step Dimming Circuitry
Serial interface (CLK, STB, DIO)
Oscillatory Manners: RC Oscillation（450KHz±5%）
Built-in power-on reset circuit
Available in SOP28 package
3. The pin definitions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
K1
K2
K3
VDD
SEG1/KS1
SEG2/KS2
SEG3/KS3
SEG4/KS4
SEG5/KS5
SEG6/KS6
SEG7/KS7
SEG8/KS8
SEG9
SEG10
STB
CLK
DIO
GND
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GND
GRID7
GRID8
VDD
28
27
26
25
24
23
22
21
20
19
18
17
16
15
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LED dedicated drive control circuit
TM1638
4. The pin function:
Symbol
DIO
Description
PIN Name
Data I/O
This pin outputs serial data at the falling edge of
the shift clock. This pin inputs serial data at the
rising edge of the shift clock (starting from the
lower bit) (N-Channel, open-drain)
Serial Interface Strobe Pin
The data input after the STB has fallen
is processed as a command. When t
his pin is "HIGH", CLK is ignored.
STB
Chip Select
CLK
Clock input
K1 ~ K3
Key scan
data input
SEG1/KS1 ~
SEG8/KS8
Output (above)
Segment output (also used as key source)
(P-Channel, open drain)
SEG9 ~ SEG10
Output (above)
Segment output
(P-Channel, open drain)
GRID1 ~ GRID8
Output (above)
Grid Output Pins
(N-Channel, open drain)
VDD
Power Supply
5V ± 10%
GND
Ground Pin
This pin reads serial data at the rising
edge and outputs data at the falling edge.
The data sent to these pins are latched at
the end of the display cycle
Note: DIO port is N-channel open drain output. When read data with MCU it require an external
1K-10K pull-up resistor (10K is recomended).
Chip circuit
10K
DIO
CT
GND
Figure (1)
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LED dedicated drive control circuit
TM1638
5. Display memory address:
Data transmitted from an external device to TM1628 via the serial interface are stored in the Display RAM
and are assigned addresses from 00H-0FH. The RAM addresses of TM1638 are given below in 16 bits unit.
LED display data write time, in accordance with the address from the show from low to high, the data byte from low to high operation.
S
EG
1
0
S
E
G9
S
E
G8
S
E
G7
S
E
G6
S
E
G5
S
E
G4
S
E
G3
S
E
G2
S
E
G1
xxHL (low nibble)
X
X
xxHL (low nibble)
xxHU (high nibble)
B0 B
1 B
2 B
3 B
4 B5 B6 B7 B0
0
0H
L
00
H
U
0
2H
L
02
H
U
0
4H
L
04
H
U
0
6H
L
06
H
U
0
8H
L
08
H
U
0
AH
L
0A
H
U
0
CH
L
0C
H
U
0
EH
L
0E
H
U
B1 B2
01
H
L
03
H
L
05
H
L
07
H
L
09
H
L
0B
H
L
0D
H
L
0F
H
L
B
3
X
X
X
X
xxHU (high nibble)
B
4
B5 B6 B
7
01
H
U
03
H
U
05
H
U
07
H
U
09
H
U
0B
H
U
0D
H
U
0F
H
U
G
RI
D1
G
RI
D2
G
RI
D3
G
RI
D4
G
RI
D5
G
RI
D6
G
RI
D7
G
RI
D8
Figure (2)
LED display when writing data follow from low address to high address, from low to high byte
operation, In the use of no use to the SEG output BIT in the corresponding address bit write 0
6. Key scan and key scan data register:
Key scan matrix of 8 × 3bit, as shown in Figure (3) as follows:
K3
K2
K1
KS1
KS2
KS3
KS4
KS5
KS6
KS7
KS8
Figure (3)
Key scan data storage address is as follows, starting reading key command to start reading the key data
BYTE1-BYTE4 bytes, reading it started from the low output; chip pins K and KS corresponding button is
pressed, the corresponding BIT bit is 1 within the byte.
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LED dedicated drive control circuit
B
0
K
3
B
1
B
2
K
2
K
1
KS
1
KS
3
KS
5
KS
7
B
3
X
B
4
K
3
B
5
B6
K
2
K1
K
S2
K
S4
K
S6
K
S8
TM1638
B
7
X
BY
T
E1
BY
T
E2
BY
T
E3
BY
T
E4
Figure (4)
▲Note: 1.TM1638 can read up to 4 bytes, more is not allowed to read.
2.The data byte can only be read sequentially from BYTE1-BYTE4. For example:
hardware KS8 and K2 corresponding button is pressed, then you want to read this key data,
you must need to read the first 4 bytes of the first 5BIT bit, can read data; When K1 and KS8,
K2 and KS8, K3 and KS8 three keys pressed simultaneously, the read data at this time
BYTE4 B4, B5, B6 bits are 1
7. Instruction:
Command to set the display mode and the LED status of the drive.
In the DIO input after the STB falling edge of the rst byte as a command.
After decoding, to take up B7, B6 two bits to
Distinguish between dierent instructions.
Instruction
B7
B6
0
1
1
0
Data Command set
Display control Command set
1
1
Address Command set
If the instructions or data transmission STB is set high, the serial communication
is initialized, and the instruction or data being transmitted invalid (instruction or
data prior to transmission remain valid).
7.1 Data Command Set
The command to set the data write and read, B1 and B0 bits are not allowed to set 01 or 11
M
S
B
LS
B
B
7
B6
B5
B4
0
0
0
0
0
0
1
1 Unrelated
1 items,
1
fill in 0
1
1
B
3
B
2
0
1
0
1
B
1
B0
0
1
0 Set up Data read Write data to the display register
0 and write mode Read the key scan data
Set up Address Automatic address increased
increasing mode
Fixed address
Normal mode
Test mode
(Internal use)
Test mode
Function
Explain
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LED dedicated drive control circuit
TM1638
7.2 Address Command Set
MS
B
L
S
B
B7
B6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
B
5
B
4
Unrelated
items,
fill in 0
B
3
B
2
B1
B0
Show Address
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
00
H
01
H
02
H
03
H
04
H
05
H
06
H
07
H
08
H
09
H
0A
H
0B
H
0C
H
0D
H
0E
H
0F
H
Address Setting Commands are used to set the address of the display memory.
The address is considered valid if it has a value of 00H to 0FH. If the address
is set to 10H or higher, the data is ignored until a valid address is set. When
power is turned ON, the address is set at 00H. Please refer to the diagram above.
7.3 Display Control Command Set
M
S
B
B
7
1
1
1
1
1
1
1
1
1
1
LS
B
B6
B5
B4
0
0
0
0 Unrelated
0 items,
0 fill in 0
0
0
0
0
B
3
0
1
B
2
B
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
B0
Function
Explain
Set the pulse width to 1/16
0
Set the pulse width to 2/16
1
Set the pulse width to 4/16
0
1 Set the number Set the pulse width to 10/16
0 of extinction Set the pulse width to 11/16
Set the pulse width to 12/16
1
Set
the pulse width to 13/16
0
Set the pulse width to 14/16
1
Display off
Display switch
Display on
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LED dedicated drive control circuit
TM1638
8. Serial data transfer formats:
Read and receive a BIT at the rising edge of the clock operation.
8.1 Reception (Data / Command Write)
CLK
1
2
3
4
5
6
7
8
DIO
B0
B1
B2
B3
B4
B5
B6
B7
STB
Figure (5)
8.2 Transmission (Data / Read)
CLK
1
2
``````
8
DIO
B0
B1
``````
B7
B0
B1
B2
B3
STB
Data Read Command is Set
Data Reading starts
Twait
Figure (6)
Note: It must be noted that when the data is read, the waiting time(t ) wait
between the rising of the eighth clock that has set the command and the
falling of the first clock that has read the data is greater or equal to 1µ s.
9. Display and Buttons:
(1) Display:
1. Common cathode LED:
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
1
1
1
1
GRID1
1
1
1
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
A DPY
a
B
C f g b
D
c
Ee
d
F
[LEDgn]
G
GRID1
Figure (7)
Figure 7 shows the common cathode LED connection diagram, if the digital display to "0",
Then you need to GRID1 low when so SEG1, SEG2, SEG3, SEG4, SEG5, SEG6 is high, SEG7 low,
See Figure (2) shows the address table, just inside the 00H address unit write data 3FH
You can make digital tube displays "0."
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LED dedicated drive control circuit
S
EG
8
0
B
7
SE
G
7
0
B6
S
E
G6
1
B
5
S
EG
5
1
B
4
SE
G
4
1
B3
S
E
G3
1
B
2
S
EG
2
1
B
1
SE
G
1
1
B0
TM1638
0
0
H
2. Common anode LED:
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GRID7
1
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GRID7
1
1
1
SEG1
1
1
A DPY
a
B
f
b
C
g
D
c
Ee
d
F
[LEDgn]
G
SEG1
1
Figure (8)
Figure 8 shows the LED common anode connection diagram, if the digital display to "0", then you need to
GRID1, GRID2, GRID3, GRID4, GRID5, GRID6 time to SEG1 low to high, low, when in GRID7 so SEG1 low.
To address unit 00H, 02H, 04H, 06H, 08H, 0AH which were written data 01H, all the rest of the address unit
write data 00H.
S
EG
8
0
0
0
0
0
0
0
B
7
SE
G
7
0
0
0
0
0
0
0
B6
S
E
G6
0
0
0
0
0
0
0
B
5
S
EG
5
0
0
0
0
0
0
0
B
4
SE
G
4
0
0
0
0
0
0
0
B3
S
E
G3
0
0
0
0
0
0
0
B
2
S
EG
2
0
0
0
0
0
0
0
B
1
SE
G
1
1
1
1
1
1
1
0
B0
0
0
H
0
2
H
0
4
H
0
6
H
0
8
H
0
A
H
0
C
H
Note:SEG1-10 are P-Channel open drain output, GRID1-8 are N-Channel open drain output,
SEG1-10 can only access the LED anode , GRID can only access the LED cathode, can not reverse.
(2) Keyboard scan:
You can follow the Figure (9) observed with an oscilloscope and SEG2/KS2 SEG1/KS1 the
output waveform, SEGN / KSN is shown in Figure (10).
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LED dedicated drive control circuit
K1
K2
K3
VDD
SEG1/KS1
SEG2/KS2
SEG3/KS3
SEG4/KS4
SEG5/KS5
SEG6/KS6
SEG7/KS7
SEG8/KS8
SEG9
SEG10
vcc
Connected Oscilloscope probe 1
Connected Oscilloscope probe 2
R1
1k
R2
1k
TM1638
STB
CLK
DIO
GND
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GND
GRID7
GRID8
VDD
Waveform when IC scans the keyboard SEGN / KSN :
SEG1/KS1
SEG2/KS2
SEG3/KS3
SEGN/KSN
Tdisp=500us
Figure (10)
Tsp and the oscillation frequency of the IC work, improve our TM1638 after several oscillation frequency
is not exactly the same. 500uS only a reference to the actual measurement shall prevail.
.
General use diagram (11), to meet key design requirements.
K1
S1
S3
K2
S2
S4
K3
S6
S5
SGE1/KS1 SGE1/KS2 SGE1/KS3
Figure (11)
When S1 is pressed, the first byte B0 read "1." If multiple keys are pressed, it will read more than one "1",
When the S2, S3 is pressed, the first byte in the B1, B3 read "1."
Note: The use of composite key considerations:
SEG1/KS1-SEG10/KS10 display and key scanning is re-used. In Figure (12) as an example, display
the desired light D1, D2 off,need to SEG1 to "1", SEG2 "0" state, if S1, S2 are pressed simultaneously,
the equivalent of SEG1, SEG2 is short, then D1, D2 are illuminated.
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LED dedicated drive control circuit
SGE1/KS1
TM1638
S1
SGE2/KS2
1
D1
1
S2
D2
K1
GRID1
Figure (12)
Solution:
1. the hardware, you can press the keys will need to set the K-line in a different figure above (13), the
SGE1/KS1
1
1
S1
D1
D2
S2
GRID1
GRID2
K1
K2
Figure (13)
2. in SEG1-SEG N series resistance shown in the above (14), the resistance of 510 ohms resistance should be
chosen, resulting in too large Key failure, is too small to show interference may not solve the problem.
SGE1/KS1
510
S1
510
S2
D1
D2
1
1
SGE2/KS2
K1
GRID1
Figure (14)
3. or series diode as shown in Figure (15) below.
SGE1/KS1
S1
SGE2/KS2
D1
1
1
S2
D2
K1
GRID1
Figure (15)
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LED dedicated drive control circuit
：transmission:
10. Application of the serial data
TM1638
10.1 Address increasing mode
Use address auto-increment mode, set the address is actually transmitted data stream to set the
starting address stored. Start address command word has been sent, "STB" do not set high data
transmission followed up 16BYTE, data transfer is completed before the "STB" is set high.
CLK
DIO
Command1
Command2
Command3
Data1
Data2
```````
Data n
Command4
STB
Command1: Display Mode Setting command
Command2: Data Setting Command
Command3: Set the display address
Data1 ~ n: Transfer Display Data (up to 16 bytes)
Command4: Display Control Command
10.2 Fixed Address Mode
Use a fixed address mode, set the address is actually a set of its need to send the address of
1BYTE data storage. Address to send completed, "STB" do not set high, followed by transfer 1BYTE data,
data transfer is completed before the "STB" is set high. And then re-set the first two address data
needs to be stored up to 16BYTE data transfer is completed, "STB" is set high.
CLK
DIO
Command1
Command2
Command3
Data1
Command4
Data2
```````
Command5
STB
Command1: Display Mode Setting command
Command2: Data Setting Command
Command3: Set the display address 1
Data1: display data transmitted within 1 to Command3 address
Command4: Set the display address 2
Data2: display data transmitted within 2 to Command4 address
Command5: Display Control Commands
10.3 Read Timing button
CLK
DIO
Command1
Data1
Data2
Data3
Data4
STB
Command1: Set the display mode
Data1 ~ 4: read the key data
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LED dedicated drive control circuit
TM1638
10.4 Programming Flow Chart
The use of automatic address programming flow chart 1:
Start
Set the read key data
Command (42H)
Initialization
No
Read 1BTYE in
Allow
Set command to write data memory,
The use of automatic address 1 (40H)
Set from the beginning to
Address (0C0H)
The key value stored on the
Register in the MCU
No
Transmission of data
Read 4BYTE
It?
Yes
16BYTE data
Send finished?
A button is pressed
Next?
No
Yes
Yes
Mass display control command set
Maximum brightness (8FH)
Button handler
Order
End
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LED dedicated drive control circuit
TM1638
Fixed address programming flow chart:
Start
Send command for Disp
max.brightness (8FH)
Initialization
Read Key data
Command (42H)
Write memory command to
the dataFixed address (44H)
No
Read 1BTYE in
Allow
Set Address
to (0C0H)
Key will be stored in
Register in the MCU
Send 1BYTE
Data
Read 4BYTE
It?
Yes
Re-set Address
to(0C1H)
A button is pressed
Next?
Button handler
Order
No
After the pass ... ...
Some of the data
Yes
Send 1BYTE
Data
End
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LED dedicated drive control circuit
TM1638
11. Application circuit:
11.1 TM1638 with common anode LED displays, as shown in Figure (16):
KS1
S1
KS2
S2
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED1
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED2
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED3
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
KS3
S3
SG1
SG2
SG3
KS4
S4
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED6
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED5
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED4
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
KS5
SG6
SG5
SG4
KS6
S5
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED7
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED8
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED9
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
S6
SG7
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
LED10
DPY
a
a
b
c f
b
g
d
e e
c
d
f
dp
g
dp
SG10
SG8
SG9
KS7
S7
KS8
S8
K1
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S19
S20
S21
S22
S23
S24
K2
VCC
K3
10K
R1
10K
R2
VCC
VCC
C5
100μF
C4
104
Note: The capacitors conected betwen GND and
VDD pins must be located as close as possible
to the TM1638 chip.
K1
K2
K3
VDD
SEG1 SEG1/KS1
SEG2 SEG2/KS2
SEG3 SEG3/KS3
SEG4 SEG4/KS4
SEG5 SEG5/KS5
SEG6 SEG6/KS6
SEG7 SEG7/KS7
SEG8 SEG8/KS8
SEG9 SEG9
SEG10 SEG10
STB
CLK
DIO
GND
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GND
GRID7
GRID8
VDD
R3
10K
C3
GR1
GR2
GR3
GR4
GR5
GR6
104
C2
C1
104
GR7
GR8
TM1638
Figure (16)
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104
STB
CLK
DIO
LED dedicated drive control circuit
TM1638
11.2 TM1638 with common cathode LED display, as shown in Figure (17):
DVD
GR1
GR2
GR3
GR4
GR5
GR6
GR7
GR8
SG1
SG2
SG3
SG4
SG5
SG6
SG7
SG8
1
2
3
4
5
6
7
8
dts
DDD
a
b
c
d
e
f
g
h
VCD
MP3 PBC
VCC
R3
VCC
10K
R2
10K
C1
100uF
C2
104
K1
K2
K3
VDD
SG1
SEG1/KS1
SG2
SEG2/KS2
SG3
SEG3/KS3
SG4
SEG4/KS4
SG5
SEG5/KS5
SG6
SEG6/KS6
SG7
SEG7/KS7
SG8
SEG8/KS8
SG9
SEG9
SG10
SEG10
VCC
Note: The capacitors conected betwen GND and
VDD pins must be located as close as possible
to the TM1638 chip.
R1
10K
K1
K2
K3
STB
CLK
DIO
GND
GRID1
GRID2
GRID3
GRID4
GRID5
GRID6
GND
GRID7
GRID8
VDD
C3
C4
C5
GR1
GR2
GR3
GR4
GR5
GR6
101
101
101
GR7
GR8
TM1638
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
S2
S5
S8
S11
S14
S17
S20
S23
S3
S6
S9
S12
S15
S18
S21
S24
S25
S26
S27
S28
S29
S30
S31
S32
K1
K2
K3
Figure (17)
Note: 1. VDD, GND filter capacitor between the PCB board layout should be
placed as close to the TM1638 chip, enhanced filtering effect.
2. The three 100pF capacitors connected to the DIO, CLK, STB communication port
can reduce the interference of the communication port.
3. Due to Blu-ray turn-on voltage of digital blood pressure is about 3V,
so TM1638 power supply should be used in 5V.
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STB
CLK
DIO
LED dedicated drive control circuit
TM1638
12. Electrical characteristics:
Absolute maximum ratings (Ta=25C, Vss=0V)
Symbol
Parameter
Ratings
Unit
V
Logic supply voltage
Vdd
Logic input voltage
VI1
LED Seg drive output current
IO1
-50
mA
LED Grid drive output current
IO2
+200
mA
Power dissipation
PD
400
-0.5 ~ +7.0
-0.5 ~ VDD + 0.5
V
mW
Operating temperature
Topt
-40 ~ +80
C
Storage temperature
Tstg
-65 ~ +150
C
Recommended operating range (Ta = -20 ~ +70 C, Vss = 0 V)
Parameter
Symbol
Typ
Min
Max
Vdd
High level input voltage
ViH
0.7 Vdd
-
Low level input voltage
ViL
0
-
Test Conditions
V
5
Power supply voltage
Unit
Vdd
0.3 Vdd
V
V
Electrical Characteristics (Ta = -20 ~ +70 C, VDD = 4.5 ~ 5.5 V, Vss = 0 V
Parameter
Min
Typ
Max
I
oh
1
-2
0
25
-4
0
mA
Se
g
1~
Se
g1
1
，
V
o=v
dd
-2
V
I
oh
2
-2
0
30
-5
0
mA
Se
g
1~
Se
g1
1
，
V
o=v
dd
-3
V
IOL1
80
Unit
High-Level
Output Current
Low-Level
Output Current
Test Conditions
Symbol
140
-
mA
G
ri
d1
~
Gr
id
6
V
o=
0
.3
V
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LED dedicated drive control circuit
Low-level output current
Segment High-Level
Output Current
Tolerance
Idout
4
-
-
I
t
ol
sg
-
-
5
Output pull-down
resistor
-
-
High-Level
Input Voltage
VIH
0.
7
VD
D
-
Low-Level
Input Voltage
VIL
-
-
VH
-
0.35
Dynamic current
consumption
µA
±1
-
-
IDDdyn
Vo=0.4V, dout
VO=VD
D– 3V
，
S
eg
1～Se
g1
1
kΩ
Ii
Hysteresis voltage
%
10
RL
Input Current
mA
TM1638
K1 ~ K3
VI = VDD / VSS
V
C
L
K，D
I
N，S
TB
0.
3
VD
D
V
C
L
K，D
I
N，S
TB
-
V
CLK, DIN, STB
mA
5
no load, display off
Switching Characteristics (Ta = -20 ~ +70 C, VDD = 4.5 ~ 5.5 V)
Parameter
Symbol
Oscillation frequency
Fosc
Transmission
Delay Time
Min
Typ
Max
Unit
Test Conditions
-
500
-
KHz
R = 16.5 K
t
P
LZ
-
-
30
0
n
s
C
LK→ D
OU
T
t
P
ZL
-
-
10
0
n
s
CL=15
pF
,R
L=1
0KΩ
TT
ZH1
-
-
2
μs
S
eg
1
～Se
g
11
CL=
3
00
pF
Rise Time
G
ri
d1
～G
ri
d
4
Se
g1
2
/G
ri
d
7
～
S
eg
1
4/
Gr
i
d5
T
T
ZH
2
-
-
0.
5
μs
Fall Time
TTHZ
-
-
120
µs
CL = 300pF, Segn, Gridn
Maximum clock
frequency
Fmax
1
-
-
MHz
50% duty cycle
Input capacitance
CI
-
-
15
pF
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LED dedicated drive control circuit
TM1638
Timing Characteristics (Ta = -20 ~ +70 C, VDD = 4.5 ~ 5.5 V)
Typ
Symbol
Min
Clock pulse width
PWCLK
400
ns
Strobe pulse width
PWSTB
1
µs
Data setup time
tSETUP
100
ns
Data hold time
tHOLD
100
ns
tCLK-STB
1
µs
CLK↑→STB↑
tWAIT
1
µs
CLK↑→CLK↓
Parameter
CLK －＞　STB time
Waiting time
Max
Unit
Test Conditions
Timing Waveform:
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LED dedicated drive control circuit
TM1638
13. Package size
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This application document was last updated :2011 -4-9
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