T6327A

tm
TE
CH
T6327A
Low-Dropout, Constant-Current
White LED with Dimming Control
FEATURES
GENERAL DESCRIPTION
• Up to 350mA LED Bias Current
• Constant Current Option :
- 20/60/100/120/175/210/240/260
/300/350 mA
- RSET : external resistor to set output current
• Simple LED Dimming Control
• Build in Morse Code S.O.S Signal
and Single Flash Loop Flicker Function
• Low Dropout Voltage
• Low 0.05uA Shutdown Current
• 2.7V to 6V Supply Voltage Range
• TO-252 and SOP-8 lead-free Package
• ESD Human Body Mode Over 5KV
• Build in Thermal Protect 160 °C
The T6327A low-dropout bias supply for
white LEDs is a high-performance alternative
to the simple ballast resistors used in
conventional white LED designs. The T6327A
with internal LED dimming function. The
T6327A Build in Morse Code S.O.S Signal
and Single Flash Loop Flicker Function,
significantly lower dropout voltage, and in
some applications, significantly improved
efficiency. The T6327A is available in TO-252
and SOP-8 lead-free package.
PART NUMBER EXAMPLES
T 6 3 2 7 A -3 0 2 0 A W G
a
b
c
d e f
APPLICATIONS
a : Device Number
• Handheld Electronics
• Flash Light
• Lighting
b : Dimming step
3=3step, 2=2step, 1=1step
c : Output current
020=20mA, 060=60mA, 100=100mA,
120=120mA, 175=175mA, ,210=210mA,
240=240mA, 260=260mA, ,300=300mA,
350=350mA, none=external resistor
d : Flicker Function
A=S.O.S, B=flash/1Hz, C=flash/4Hz,
e : package
W=TO-252, D=SOP-8
f : G=lead-free
TM Technology Inc. reserves the right
P. 1
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
PIN ARRANGEMENT(Top view)
VSS
6
1
2
3
4
5
LED
RSET/NC
VSS
SET
VDD
TEST
VSS
1
8
RSET/NC
2
7
SET
LED2
3
6
VDD
LED1
4
5
VSS
TO-252
SOP-8
PIN DESCRIPTION
SYMBOL
TO-252
SOP-8
TSET
-
1
RSET/NC
4
8
VSS
VDD
LED
SET
3
1
5
2
2,5
6
3,4
7
DESCRIPTION
Test pin, initial pull low, if pull high active test mode
NC: No connection for internal resistor
RSET : external resistor to set output current
RSET terminal is used to connect an external resistor to set output current.
Ground
Power supply
LED Cathode Connection.
Control dimming and flicker mode
TM Technology Inc. reserves the right
P. 2
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Value
Unit
Voltage on any pin relative to GND
VIN
-0.3 to 7
V
Operating Temperature Rang
TA
-40 to +85
°C
TLEAD
300
°C
TS
-65 to +150
°C
SOP-8
800
TO-252
1600
Maximum Soldering Temperature (at leads, 10 sec)
Storage Temperature Rang
Continuous Power Dissipation ( TA = +70°C )
mW
Electrical Characteristics
(Typical values are at TA =25°C)
Symbol
Description
Conditions
VDD
Operating voltage range
power supply input
RSET
RSET bias voltage
ISET=400uA, no loading
ISET
SET input current range
ILED
Maximum LED sink current
VDD = 4.5V
VLED =3.5V
Min. Typ. Max
2.7
T6327A-350
T6327A-300
T6327A-260
T6327A-240
T6327A-210
T6327A-175
T6327A-120
T6327A-100
T6327A-060
T6327A-020
ILSD
LED leakage current in
shutdown
tSH
SET pin Signal pulse width
VIH
Input high voltage
VSET >VIH for enable, VDD=5V
VIL
Input low voltage
VSET <VIL for disable, VDD=5V
TTP
Thermal Protect
V
0.306
V
100
uA
329
350
371
mA
282
300
318
mA
244
260
275
mA
225
240
254
mA
197
210
222
mA
164
175
185
mA
112
120
127
mA
94
100
106
mA
56
60
63
mA
18.5
20
21.5
mA
0.02
1
uA
VLED= 3.3V, VDD=0V, TA=+25°C
TM Technology Inc. reserves the right
P. 3
to change products or specifications without notice.
6
Unit
30
ms
2.0
V
0.8
160
V
°C
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
Functional Description
The T6327A provides constant current bias
supply for white LED designs. The T6327A Build
in Morse Code S.O.S Signal and Single Flash
Loop Flicker Function. The T6327A offers
several advantages over using ballast resistors,
such as improved LED dimming, lower bias
variation with supply voltage changes,
significantly lower dropout voltage, and in some
applications, significantly improved efficiency.
Off–> ILED(max.)-> ILED(max.)(33%)–> off / loop
If tSH pulse width over 2sec of Any
states(tSH>2sec), LED Flicker mode jump to
Morse Code S.O.S Signal or Single Flash Loop
Flicker Function.
3 0 m s < tS H < 2 s e c
IL E D
( m a x .)
O FF
3 0 m s < tS H < 2 se c
3 0 m s < tS H < 2 s e c
IL E D
(m a x .)
(3 3 % )
Setting the Output Current
RSET controls the LED bias current. Current
flowing into LED1 and LED2 500 or 1000 times,
greater than the current flowing into RSET. Set
the output current as follows:
SOP-8 package each channel:
ILED = 500 (0.306V / RSET )
TO-252 package:
ILED = 1000 (0.306V / RSET )
SET Function
The SET is high active LED ON / OFF,
dimming and flicker mode.
Dimming step :
If SET pin high pulse width(tSH) over 30ms and
under 2sec(30ms< tSH < 2sec), dimming control
jump to next step.
Mode1(1 dimming step) dimming and flicker step :
Off–> ILED(max.) –> off / loop
If tSH pulse width over 2sec of Any
states(tSH>2sec), LED Flicker mode jump to
Morse Code S.O.S Signal or Single Flash Loop
Flicker Function.
3 0 m s < tS H < 2 s e c
IL E D
( m a x .)
O FF
tS H > 2 s e c
tS H > 2 s e c
3 0 m s < tS H < 2 se c
tS H > 2 s e c
S .O .S
or
fla s h
Mode3 (3 dimming step) dimming and flicker
step :
Off –> ILED(max.) -> ILED(max.)(50%) –>
ILED(max.)(25%) -> off / loop
If tSH pulse width over 2sec of Any
states(tSH>2sec), LED Flicker mode jump to
Morse Code S.O.S Signal or Single Flash Loop
Flicker Function.
3 0 m s< tS H < 2 se c
IL E D
( m a x .)
O FF
3 0 m s < tS H < 2 s e c
3 0 m s < tS H < 2 s e c
IL E D
(m a x .)
(2 5 % )
3 0 m s < tS H < 2 s e c
IL E D
(m a x .)
(5 0 % )
tS H > 2 s e c
3 0 m s < tS H < 2 s e c
tS H > 2 s e c
tS H > 2 se c
3 0 m s< tS H < 2 se c
S .O .S
or
fla s h
tS H > 2 s e c
tS H > 2 s e c
TEST Function
3 0 m s < tS H < 2 se c
S .O .S
or
fla s h
tS H > 2 s e c
The test pin is high active, if test pin turns high,
the internal circuit can start the self-test function,
if the function test pass, then LED turns on.
Mode2(2 dimming step) dimming and flicker step :
TM Technology Inc. reserves the right
P. 4
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
Applications Information
Very Low-Cost, High-Efficiency Solution . A battery (single Li+ or three NiMH cells) powers the LEDs
directly. This is the least expensive and most efficient architecture. Due to the high forward voltage of white
LEDs, the LED dimming may dim slightly at the end of battery life. The T6327A current regulating
architecture and low dropout greatly minimize this effect compared to using simple ballast resistors.
TYPICAL APPLICATION CIRCUITS
V IN 2.7V ~6V
LED
T6327A
VD D
SW
RSET
SET GN D
Rs
0.1uF
Very low-cost, high-efficiency solution for TO-252 package
V IN 2.7V~6V
SW
LED1 LED2
T6327A
VDD
SET RSET
GND TEST
0.1uF
RS
Very low-cost, high-efficiency solution for SOP-8 package
TM Technology Inc. reserves the right
P. 5
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
PACKAGE DIMENSIONS
5-LEAD TO-252
E
A
A1
6
L2
2
3
4
D1
SEATING PLANE
D
1
E1
c1
b2
5
H
L
L1
c
e
b
e1
Symbol
A
A1
b
b2
c
c1
D
D1
E
E1
e
e1
H
L
L1
L2
Dimension in inch
Min.
Max.
0.087
0.094
0.040
0.050
0.016
0.24
0.205
0.213
0.017
0.023
0.017
0.023
0.213
0.224
0.150 (REF.)
0.250
0.262
0.150 (REF.)
0.050 (TYP.)
0.200 (TYP.)
0.313
0.338
0.055
0.070
0.043
0.047
0.050
0.060
Dimension in mm
Min.
Max.
2.20
2.40
1.00
1.27
0.40
0.60
5.20
5.40
0.43
0.58
0.43
0.58
5.40
5.70
3.80 (REF.)
6.35
6.65
3.80 (REF.)
1.27 (TYP.)
5.08 (TYP.)
7.94
8.6
1.40
1.78
1.09
1.19
1.30
1.50
TM Technology Inc. reserves the right
P. 6
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A
tm
TE
CH
T6327A
PACKAGE DIMENSIONS
8-LEAD SOP
B
B1
K
T h e rm a l P a d *
J
A1
C1
A
C
C2
F
D
Symbol
A
A1
B
B1
C
C1
C2
D
E
F
J
K
H
Min.
5.70
3.75
1.35
0.10
0.31
0.30
0.10
Dimension in mm
Typ.
6.00
3.95
1.27
1.55
0.41
0.50
0.15
2.23 REF
2.97 REF
0~8
E
H
Max.
6.30
4.10
5.13
1.80
1.75
0.25
0.51
0.70
0.25
Min.
0.224
0.148
0.052
0.001
0.012
0.012
0.004
Dimension in inch
Typ.
0.236
0.156
0.050
0.061
0.016
0.020
0.006
0.088 REF
0.117 REF
0~8
Max.
0.248
0.164
0.202
0.071
0.069
0.004
0.020
0.028
0.010
*Note :
The thermal pad on the IC’s bottom has to be mounted on the copper foil.
To eliminate the noise influence, the thermal pad is suggested to be connected to GND on PCB.
In addition, desired thermal conductivity will be improved, if a heat-conducting copper foil on
PCB is soldered with thermal pad. The thermal pad enhances the power dissipation. As a result, a
large amount of current can be sunk safely in one package.
TM Technology Inc. reserves the right
P. 7
to change products or specifications without notice.
Publication Date: MAR. 2008
Revision: A