TK712xx is a low dropout, linear regulator. Since a PNP
power transistor is used, dropout voltage is very low,
making it possible to maintain stable output voltage even
as the battery decreases. This allows longer battery life.
The TK712xx has a noise bypass pin available for noise
reduction.
The TK712xx is available in a miniature SOT-25 surface
mount package.
APPLICATIONS
■ Battery Powered Systems
■ Portable Consumer Equipment
■ Cordless Telephones
■ Personal Communications Equipment
■ Radio Control Systems
■ Toys
■ Low Voltage Systems
TK712xx
NOISE
BYPASS
GND
GND
V
V
IN
OUT
ORDERING INFORMATION
TK712 M
VoltageCode
VOLTAGE CODE
20 = 2.0 V35 = 3.5 V
25 = 2.5 V40 = 4.0 V
28 = 2.8 V45 = 4.5 V
30 = 3.0 V50 = 5.0 V
33 = 3.3 V
January 1999 TOKO, Inc.Page 1
Tape/Reel Code
TAPE/REEL CODE
TL: Tape Left
NOISE
BYPASS
V
IN
BLOCK DIAGRAM
THERMAL
PROTECTION
BANDGAP
REFERENCE
GND
V
GND
OUT
Page 2
TK712xx
ABSOLUTE MAXIMUM RATINGS
Input Voltage ............................................................ 15 V
Power Dissipation (Note 1) ................................ 350 mW
Operating Voltage Range............................... 1.4 to 14 V
Junction Temperature ........................................... 150 °C
TK71220 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 3 V, TA = 25 °C, unless otherwise specified.
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
Storage Temperature Range ................... -55 to +150 °C
Operating Temperature Range ...................-30 to +80 °C
Lead Soldering Temperature (10 s) ...................... 235 °C
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
fer
/∆T
∆V
TUO
Note 1: Power dissipation is 350 mW when mounted as recommended. Derate at 2.8 mW/°C for operation above 25 °C.
egatloV
erutarepmeTtneiciffeoC51.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V0.3=
TUO
I,V8.1=
TUO
I,V0.3=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=9.10.21.2V
Am03=001002Vm
I,V0.3=
TUO
Am03=5.15.3Am
V0.31ot0.3=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TUO
Am01=36Bd
72.1V
Page 2January 1999 TOKO, Inc.
Page 3
TK71225 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 3.5 V, TA = 25 °C, unless otherwise specified.
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
TK712xx
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC51.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V5.3=
TUO
I,V0.2=
TUO
I,V5.3=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=4.25.26.2V
Am03=001002Vm
I,V5.3=
TUO
Am03=5.15.3Am
V5.31ot5.3=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TK71228 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 3.8 V, TA = 25 °C, unless otherwise specified.
TUO
Am01=36Bd
72.1V
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC81.0C°/Vm
lanimretssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V8.3=
TUO
I,V5.2=
TUO
I,V8.3=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=7.28.29.2V
Am03=001002Vm
I,V8.3=
TUO
Am03=5.15.3Am
V8.31ot8.3=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TUO
Am01=36Bd
72.1V
January 1999 TOKO, Inc.Page 3
Page 4
TK712xx
TK71230 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 4.0 V, TA = 25 °C, unless otherwise specified.
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC81.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V0.4=
TUO
I,V5.2=
TUO
I,V0.4=
TUO
Am03=001002Vm
I,V0.4=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=9.20.31.3V
Am03=5.15.3Am
V0.41ot0.4=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TK71233 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 3.9 V, TA = 25 °C, unless otherwise specified.
TUO
Am01=36Bd
72.1V
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC81.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V9.3=
TUO
I,V8.2=
TUO
I,V9.3=
TUO
Am03=001002Vm
I,V9.3=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=2.33.34.3V
Am03=5.15.3Am
V0.41ot9.3=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TUO
Am01=36Bd
72.1V
Page 4January 1999 TOKO, Inc.
Page 5
TK71235 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 4.1 V, TA = 25 °C, unless otherwise specified.
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
TK712xx
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC2.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V1.4=
TUO
I,V0.3=
TUO
I,V1.4=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=93.305.316.3V
Am03=001002Vm
I,V1.4=
TUO
Am03=5.15.3Am
V0.41ot1.4=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TK71240 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 4.6 V, TA = 25 °C, unless otherwise specified.
TUO
Am01=36Bd
72.1V
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC2.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V6.4=
TUO
I,V5.3=
TUO
I,V6.4=
TUO
Am03=001002Vm
I,V6.4=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=88.300.421.4V
Am03=5.15.3Am
V0.41ot6.4=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TUO
Am01=36Bd
72.1V
January 1999 TOKO, Inc.Page 5
Page 6
TK712xx
TK71245 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 5.1 V, TA = 25 °C, unless otherwise specified.
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC52.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V1.5=
TUO
I,V0.4=
TUO
I,V1.5=
TUO
Am03=001002Vm
I,V1.5=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=63.405.446.4V
Am03=5.15.3Am
V0.41ot1.5=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TK71250 ELECTRICAL CHARACTERISTICS
Test Conditions: VIN = 5.6 V, TA = 25 °C, unless otherwise specified.
TUO
Am01=36Bd
72.1V
LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU
V
I
Q
V
TUO
V
PORD
I
TUO
I
DNG
tnerruCtnecseiuQ
egatloVtuoporDI
tnerruCtuptuO001061Am
tnerruCdnuorGV
geReniLnoitalugeReniLV
geRdaoLnoitalugeRdaoLI
RRnoitcejeRelppiRC
V
∆V
fer
/∆T
TUO
egatloV
erutarepmeTtneiciffeoC52.0C°/Vm
lanimreTssapyBesioN
NI
V
NI
egatloVtuptuOdetalugeRV
NI
TUO
NI
NI
TUO
L
I,V6.5=
TUO
I,V0.4=
TUO
I,V6.5=
TUO
Am0=031003Aµ
Am0=4.10.3Am
Am01=58.400.551.5V
Am03=001002Vm
I,V6.5=
TUO
Am03=5.15.3Am
V0.41ot6.5=0103Vm
Am06ot1=0204Vm
I,zH004=f,Fµ3.3=
TUO
Am01=36Bd
72.1V
Page 6January 1999 TOKO, Inc.
Page 7
TK712xx
I
(
A)
NOISE
(dB)
NOISE
(
V)
TEST CIRCUIT
I
IN
V
IN
V
OUT
(mV)
OUT
-10
V
-30
50
30
10
TYPICAL PERFORMANCE CHARACTERISTICS
OUTPUT VOLTAGE
INPUT VOLTAGE
VS.
+
V
IN
NOISE
BYPASS
C
N
GND
+
C
L
I
OUT
V
OUT
TA = 25 ° C, unless otherwise specified.
m
GND
GROUND CURRENT
AMBIENT TEMPERATURE
5
4
3
2
1
I
OUT
I
OUT
VS.
= 60 mA
= 30 mA
500
400
300
(mV)
200
DROP
V
100
DROPOUT VOLTAGE
VS.
AMBIENT TEMPERATURE
I
= 60 mA
OUT
I
= 30 mA
OUT
-50
0 10 20
VIN (V)
NOISE VOLTAGE
BYPASS CAPACITOR
300
CL = 1.0 µF
CL = 3.3 µF
200
µ
150
CL = 10 µF
CL = 10 µF
100
V
= 2 V
10 pF
OUT
100 pF
1000 pF
C
N
50
0
1 pF
I
OUT
VS.
V
= 30 mA
OUT
0.01 µF
= 5 V
.1 µF
0
-50 0 50 100
TA (°C)
NOISE SPECTRUM
-50
I
= 30 mA
OUT
CN = 0.01 µF
CL = 1 µF
-100
INSTRUMENT NOISE FLOOR
-150
0 500 1000
FREQUENCY (kHz)
0
-50 0 50 100
TA (°C)
RIPPLE REJECTION VS.
FREQUENCY
0
CL = 1 µF
-50
RR (dB)
CL = 10 µF
-100
100 1 k 10 k 100 k
FREQUENCY (Hz)
January 1999 TOKO, Inc.Page 7
Page 8
TK712xx
I
(
A)
V
(
0
V
/
DIV)
)
LINE TRANSIENT RESPONSE
IN
V
V
OUT(TYP)
OUT
V
(20 mV / DIV)
OUT
V
TIME (50 µs / DIV
OUTPUT VOLTAGE VS.
INPUT VOLTAGE
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
LOAD TRANSIENT RESPONSE
V
OUT(TYP)
+ 1 V
+ 2 V
OUT
I
OUT
V
(400 mV / DIV)
OUT
V
CL = 1.0 µF
I
OUT
0 mA
CL = 3.3 µF
TIME (50 µs / DIV)
= 30 mA
10
8
6
m
4
GND
2
0
0 50 100
GROUND CURRENT VS.
OUTPUT CURRENT
I
(mA)
OUT
m
5
OUT
I
OUT
V
OUT(TYP)
= 0 mA
+ 1 V
60 mA
V
VIN (100 mV / DIV)
30 mA
= V
IN
OUT
Page 8January 1999 TOKO, Inc.
Page 9
TK71220
2.05
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
OUTPUT VOLTAGE
OUTPUT CURRENT
VS.
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
VS.
150
= 0 mA
TK712xx
OUTPUT CURRENT
AMBIENT TEMPERATURE
VS.
(V)
2.00
OUT
V
1.95
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71225
OUTPUT VOLTAGE
OUTPUT CURRENT
2.55
VS.
VS.
1
(mA)
Q
I
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
VS.
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
2.05
(V)
2.00
OUT
V
1.95
150
AMBIENT TEMPERATURE
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
VS.
VS.
I
= 0 mA
OUT
(V)
2.50
OUT
V
2.45
0 50 100
I
(mA)
OUT
(mA)
1
Q
I
0
0 5 10
VIN (V)
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
January 1999 TOKO, Inc.Page 9
Page 10
TK712xx
TK71225 (CONT.)
DROPOUT VOLTAGE
OUTPUT CURRENT
500
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
VS.
SHORT CIRCUIT PROTECTION
5
2.55
OUTPUT VOLTAGE
AMBIENT TEMPERATURE
VS.
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71228
OUTPUT VOLTAGE
OUTPUT CURRENT
2.85
(V)
2.80
OUT
V
VS.
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
1
(mA)
Q
I
VS.
= 0 mA
(V)
2.50
OUT
V
2.45
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
150
(mA)
100
OUT
I
VS.
2.75
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
VS.
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
2.85
(V)
2.80
OUT
V
2.75
AMBIENT TEMPERATURE
-50 0 50 100
TA (°C)
VS.
Page 10January 1999 TOKO, Inc.
Page 11
TK71230
3.05
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
OUTPUT VOLTAGE
OUTPUT CURRENT
VS.
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
VS.
150
= 0 mA
TK712xx
OUTPUT CURRENT
AMBIENT TEMPERATURE
VS.
(V)
3.00
OUT
V
2.95
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71233
OUTPUT VOLTAGE
OUTPUT CURRENT
3.35
VS.
VS.
1
(mA)
Q
I
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
VS.
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
3.05
(V)
3.00
OUT
V
2.95
150
AMBIENT TEMPERATURE
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
VS.
VS.
I
= 0 mA
OUT
(V)
3.30
OUT
V
3.25
0 50 100
I
(mA)
OUT
1
(mA)
Q
I
0
0 5 10
VIN (V)
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
January 1999 TOKO, Inc.Page 11
Page 12
TK712xx
TK71233 (CONT.)
DROPOUT VOLTAGE
OUTPUT CURRENT
500
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
VS.
SHORT CIRCUIT PROTECTION
5
3.35
OUTPUT VOLTAGE
AMBIENT TEMPERATURE
VS.
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71235
OUTPUT VOLTAGE
OUTPUT CURRENT
3.55
(V)
3.50
OUT
V
VS.
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
1
(mA)
Q
I
VS.
= 0 mA
(V)
3.30
OUT
V
3.25
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
150
(mA)
100
OUT
I
VS.
3.45
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
VS.
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
3.55
(V)
3.50
OUT
V
3.45
AMBIENT TEMPERATURE
-50 0 50 100
TA (°C)
VS.
Page 12January 1999 TOKO, Inc.
Page 13
TK71240
4.05
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
OUTPUT VOLTAGE
OUTPUT CURRENT
VS.
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
VS.
150
= 0 mA
TK712xx
OUTPUT CURRENT
AMBIENT TEMPERATURE
VS.
(V)
4.00
OUT
V
3.95
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71245
OUTPUT VOLTAGE
OUTPUT CURRENT
4.55
VS.
VS.
1
(mA)
Q
I
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
VS.
= 0 mA
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
AMBIENT TEMPERATURE
4.05
(V)
4.00
OUT
V
3.95
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
150
VS.
VS.
(V)
4.50
OUT
V
4.45
0 50 100
I
(mA)
OUT
1
(mA)
Q
I
0
0 5 10
VIN (V)
(mA)
100
OUT
I
50
-50 0 50 100
TA (°C)
January 1999 TOKO, Inc.Page 13
Page 14
TK712xx
TK71245 (CONT.)
DROPOUT VOLTAGE
OUTPUT CURRENT
500
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
TA = 25 ° C, unless otherwise specified.
VS.
SHORT CIRCUIT PROTECTION
5
4.55
OUTPUT VOLTAGE
AMBIENT TEMPERATURE
VS.
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
TK71250
OUTPUT VOLTAGE
OUTPUT CURRENT
5.05
(V)
5.00
OUT
V
VS.
4
3
(V)
OUT
2
V
1
0
0 100 200
I
(mA)
OUT
QUIESCENT CURRENT
INPUT VOLTAGE
2
I
OUT
1
(mA)
Q
I
VS.
= 0 mA
(V)
4.50
OUT
V
4.45
-50 0 50 100
TA (°C)
OUTPUT CURRENT
AMBIENT TEMPERATURE
150
(mA)
100
OUT
I
VS.
4.95
0 50 100
I
(mA)
OUT
DROPOUT VOLTAGE
OUTPUT CURRENT
500
400
300
(mV)
200
DROP
V
100
0
0 50 100
I
(mA)
OUT
VS.
0
0 5 10
VIN (V)
SHORT CIRCUIT PROTECTION
5
4
(V)
3
OUT
V
2
1
0
0 100 200
I
(mA)
OUT
50
-50 0 50 100
TA (°C)
OUTPUT VOLTAGE
5.05
(V)
5.00
OUT
V
4.95
AMBIENT TEMPERATURE
-50 0 50 100
TA (°C)
VS.
Page 14January 1999 TOKO, Inc.
Page 15
DEFINITION AND EXPLANATION OF TECHNICAL TERMS
TK712xx
LINE REGULATION (LINE REG)
Line regulation is the ability of the regulator to maintain a
constant output voltage as the input voltage changes.
LOAD REGULATION (LOAD REG)
Load regulation is the ability of the regulator to maintain a
constant output voltage as the load current changes. It is
a pulsed measurement to minimize temperature effects.
The load regulation is specified an output current step
condition of 1 mA to 60 mA.
QUIESCENT CURRENT (IQ)
The quiescent current is the current which flows through
the ground terminal under no load conditions (I
GROUND CURRENT (I
GND
)
OUT
= 0 mA).
Ground current is the current which flows through the
ground pin(s). It is defined as IIN - I
DROPOUT VOLTAGE (V
DROP
)
, excluding I
OUT
CONT
This is a measure of how well the regulator performs as the
input voltage decreases. The smaller the number, the
further the input voltage can decrease before regulation
problems occur. Nominal output voltage is first measured
when VIN = V
+ 1 at a chosen load current. When the
OUT
output voltage has dropped 100 mV from the nominal, V
- VO is the dropout voltage. This voltage is affected by load
current and junction temperature.
OUTPUT NOISE VOLTAGE
PACKAGE POWER DISSIPATION (PD)
This is the power dissipation level at which the thermal
sensor is activated. The IC contains an internal thermal
sensor which monitors the junction temperature. When the
junction temperature exceeds the monitor threshold of
150 °C, the IC is shut down. The junction temperature
rises as the difference between the input power (VIN x IIN)
and the output power (V
OUT
x I
) increases. The rate of
OUT
temperature rise is greatly affected by the mounting pad
configuration on the PCB, the board material, and the
ambient temperature. When the IC mounting has good
thermal conductivity, the junction temperature will be low
even if the power dissipation is great. When mounted on
the mounting pad, the power dissipation of the SOT-25 is
increased to 350 mW. For operation at ambient
temperatures over 25 °C, the power dissipation of the
SOT-25 device should be derated at 2.8 mW/°C. To
determine the power dissipation for shutdown when
mounted, attach the device on the actual PCB and
deliberately increase the output current (or raise the input
.
voltage) until the thermal protection circuit is activated.
Calculate the power dissipation of the device by subtracting
the output power from the input power. These
measurements should allow for the ambient temperature
of the PCB. The value obtained from PD /(150 °C - TA) is the
derating factor. The PCB mounting pad should provide
maximum thermal conductivity in order to maintain low
device temperatures. As a general rule, the lower the
temperature, the better the reliability of the device. The
thermal resistance when mounted is expressed as follows:
IN
Tj = 0jA x PD + T
A
This is the effective AC voltage that occurs on the output
voltage under the condition where the input noise is low
For Toko ICs, the internal limit for junction temperature is
150 °C. If the ambient temperature (TA) is 25 °C, then:
and with a given load, filter capacitor, and frequency
range.
150 °C = 0jA x PD + 25 °C
THERMAL PROTECTION
0jA = 125 °C / P
D
This is an internal feature which turns the regulator off
when the junction temperature rises above 150 °C. After
the regulator turns off, the temperature drops and the
regulator output turns back on. Under certain conditions,
the output waveform may appear to be an oscillation as the
output turns off and on and back again in succession.
PD is the value when the thermal sensor is activated. A
simple way to determine PD is to calculate VIN x IIN when
the output side is shorted. Input current gradually falls as
temperature rises. You should use the value when thermal
equilibrium is reached.
January 1999 TOKO, Inc.Page 15
Page 16
TK712xx
DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.)
The range of usable currents can also be found from the
graph below.
(mW)
P
D
3
D
PD
6
4
5
255075150
TA (°C)
Procedure:
1) Find P
D
2) PD1 is taken to be PD x (~ 0.8 - 0.9)
3) Plot PD1 against 25 °C
4) Connect P
to the point corresponding to the 150 °C
D1
with a straight line.
5) In design, take a vertical line from the maximum
operating temperature (e.g., 75 °C) to the derating
curve.
6) Read off the value of PD against the point at which the
vertical line intersects the derating curve. This is taken
as the maximum power dissipation, DPD.
The maximum operating current is:
I
= (D
OUT
1000
800
600
(mW)
D
400
P
200
0
050100
PD
/ (V
IN(MAX) - VOUT
MOUNTED
FREE AIR
TA (°C)
)
150
SOT-25 POWER DISSIPATION CURVE
Page 16January 1999 TOKO, Inc.
Page 17
APPLICATION INFORMATION
TK712xx
INPUT/OUTPUT DECOUPLING CAPACITOR
CONSIDERATIONS
Voltage regulators require input and output decoupling
capacitors. The required value of these capacitors vary
with application. Capacitors made by different
manufacturers can have different characteristics,
particularly with regard to high frequencies and Equivalent
Series Resistance (ESR) over temperature. The type of
capacitor is also important. For example, a 4.7 µF aluminum
electrolytic may be required for a certain application. If a
tantalum capacitor is used, a lower value of 2.2 µF would
be adequate. It is important to consider the temperature
characteristics of the decoupling capacitors. While Toko
regulators are designed to operate as low as -40 °C, many
capacitors will not operate properly at this temperature.
The capacitance of aluminum electrolytic capacitors may
decrease to 0 at low temperatures. This may cause
oscillation on the output of the regulator since some
capacitance is required to guarantee stability. Thus, it is
important to consider the characteristics of the capacitor
over temperature when selecting decoupling capacitors.
The ESR is another important parameter. The ESR will
increase with temperature but low ESR capacitors are
often larger and more costly. In general, tantalum capacitors
offer lower ESR than aluminum electrolytic, but new low
ESR aluminum electrolytic capacitors are now available
from several manufacturers. Usually a bench test is
sufficient to determine the minimum capacitance required
for a particular application. After taking thermal
characteristics and tolerance into account, the minimum
capacitance value should be approximately two times this
value. The recommended minimum capacitance for the
TK712xx is 2.2 µF for a tantalum capacitor or 3.3 µF for an
aluminum electrolytic. Please note that linear regulators
with a low dropout voltage have high internal loop gains
which require care in guarding against oscillation caused
by insufficient decoupling capacitance. The use of high
quality decoupling capacitors suited for your application
will guarantee proper operation of the circuit. Pay attention
to temperature characteristics of the capacitor, especially
the increase of ESR and decrease of capacitance in low
temperatures. Oscillation, reduction of ripple rejection and
increased noise may occur in some cases if the proper
capacitor is not used. An output capacitor more than 1.0 µF
is required to maintain stability. The standard test condition
is 3.3 µF (TA = 25 °C).
OPTIMUM PERFORMANCE
Optimum performance can only be achieved when the IC
is mounted on a PC board according to the diagram below.
This is because of the extremely small package and limited
power dissipation. Shape the metal portion of the PCB as
shown in the following drawing.
V
GND
IN
++
+
C
N
V
OUT
GND
SOT-25 BOARD LAYOUT
Use a large bypass capacitor and connect it in a place near
GND of the IC. Pay attention to temperature characteristics
of the capacitor, especially the increase of ESR and
decrease of capacitance in low temperatures. Oscillation,
reduction of ripple rejection and increased noise may
occur in some cases if the proper capacitor is not used. An
output capacitor more than 1.0 µF is required to maintain
stability. The standard test condition is 3.3 µF (TA = 25 °C).
Semiconductor Technical Support
Toko Design Center
4755 Forge Road
Colorado Springs, CO 80907
Tel: (719) 528-2200
Fax: (719) 528-2375
Visit our Internet site at http://www.tokoam.com
The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its
products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of
third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc.