㆔合微科股½㈲限公司
SAMHOP Microelectronics Corp.
The information in this document is subject to change without notice.
c
SAMHOP Microelectronics Corp. All Rights Reserved.
台北縣新店市民權路
100
號
7
樓
7F,No.100,Min-Chyuan Road, Hsintien, Taipei Hsien, Taiwan, R.O.C.
TEL: 886-2-2218-3978/2820 FAX: 886-2-2218-3320
Email : info@samhop.com.tw
Page 1
SAMHOP Microelectronics Corp.
8-BIT CONSTANT CURRENT LED DRIVER
GENERAL DESCRIPTION
The SM16705P/F/FN are specifically designed for
LED display constant current drivers.
This constant current output circuits is able to setup
by external resistor (I
OUT
= 5 ~ 90mA).
This IC is monolithic integrated circuit designed to be
used together with Bi-CMOS process.
The devices consist of 8bit shift register, latch, AND-
GATE and Constant Current Drivers.
FEATURES
* Constant Current Output :
can setup all output current with one resistor
for 5 to 90mA.
* Maximum Clock Frequency :
f
CLK
= 25 (MHz)
(Cascade Connect Operate,
Topr = 25
o
C)
* 5V CMOS Compatible Input
* 16 pin DIP, SOP or SSOP package
* Constant Output Current Matching :
Output-GND
Voltage
≧
0.4V
≧
0.7V
Current
Matching
±6.0%
±6.0%
Output Current
5 ~ 40mA
5 ~ 90mA
PIN ASSIGNMENTS
GND
SERIAL-IN
CLOCK
LATCH
OUT0
OUT1
OUT2
OUT3
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
R-EXT
SERIAL-OUT
ENABLE
OUT7
OUT6
OUT5
OUT4
Part Number
SM16705P
SM16705F
SM16705FN
Package Type
16pin DIP
16pin SOP
16pin SSOP
SM16705
Page 2
V.2.10
SAMHOP Microelectronics Corp.
8-BIT CONSTANT CURRENT LED DRIVER
PIN DESCRIPTION
Pin NO.
1
2
3
I
I
I/O
Pin Name
GND
SERIAL-IN
CLOCK
GND terminal
Terminal of serial-data input to the shift register.
Input terminal of a clock for shift register on rising edge.
Input terminal of data strobe. Latches pass data with
"H" level input of LATCH-terminal, and hold data with
"L" level input.
Constant Current-sinking output terminals.
Input terminal of output enable. All outputs (OUT0~7) do
off with "H" level input of ENABLE-terminal and do on
with "L" level input.
Output terminal of serial-data for next SERIAL-IN terminal.
An external resistor at this terminal establishes all of the
output current.
Supply voltage terminal.
Function Description
4
I
LATCH
5~12
O
OUT0~7
13
I
ENABLE
14
15
16
O
I/O
SERIAL-OUT
R-EXT
VDD
Page 3
V.2.10
SAMHOP Microelectronics Corp.
8-BIT CONSTANT CURRENT LED DRIVER
TRUTH TABLE
CLOCK
UP
UP
UP
DOWN
DOWN
LATCH
H
L
H
X
X
ENABLE
L
L
L
L
H
SERIAL-IN
D
n
D
n + 1
D
n + 2
D
n + 3
D
n + 3
OUT0 … OUT5 … OUT7
D
n
… D
n - 5
… D
n - 7
No change
D
n + 2
… D
n - 3
… D
n - 5
D
n + 2
… D
n - 3
… D
n - 5
Off
SERIAL-OUT
D
n - 8
D
n - 7
D
n - 6
D
n - 5
D
n - 5
Note : 1.OUT0~7=on when Dn="H" ; OUT0~7=off when Dn="L".
2. In order to ensure that the level of the power supply voltage is correct, an external resistor
must be connected betwen R-EXT and GND.
EQUIVALENT CIRCUIT OF INPUTS AND OUTPUTS
1. ENABLE terminal
V
DD
R
IN
(Up)
2. LATCH terminal
V
DD
ENABLE
LATCH
R
IN
(Down)
GND
GND
3. CLOCK, SERIAL-IN terminal
V
DD
CLOCK,
SERIAL-IN
GND
4. SERIAL-OUT terminal
V
DD
SERIAL-OUT
GND
Page 4
V.2.10
SAMHOP Microelectronics Corp.
8-BIT CONSTANT CURRENT LED DRIVER
BLOCK DIAGRAM
OUT0
R-EXT
I-REG.
OUT1
OUT7
ENABLE
Q
ST D
Q
ST D
Q
ST D
LATCH
SERIAL-IN
CLOCK
D Q
CK
D Q
CK
D Q
CK
D Q
CK
SERIAL-
OUT
TIMING DIAGRAM
CLOCK
SERIAL-IN
LATCH
ENABLE
OUT0
OUT1
OUT2
OUT7
SERIAL-OUT
.....
5V
0V
5V
0V
5V
0V
5V
0V
On
Off
On
Off
On
Off
On
Off
5V
0V
Note : Latches are level sensitive, not rising edges sensitive and not synchronous CLOCK.
Input of LATCH-terminal to H Level, data passes latches, and input of LATCH -terminal to L level, data
hold latches.
Input of ENABLE-terminal to H Level, all output (OUT0 ~ 7) do off.
Page 5
V.2.10
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