GC3-I017 Page 1
APPLICATION MANUAL
LDO REGULATOR WITH ON/OFF SWITCH
TK121xxCS
CONTENTS
1 . DESCRIPTION 2
2 . FEATURES 2
3 . APPLICATIONS 2
4 . PIN CONFIGURATION 2
5 . BLOCK DIAGRAM 2
6 . ORDERING INFORMATION 3
7 . ABSOLUTE MAXIMUM RATINGS 3
8 . ELECTRICAL CHARACTERISTICS 4
9 . TEST CIRCUIT 8
10 . APPLICATION EXAMPLE 8
11 . TYPICAL CHARACTERISTICS 9
12 . PIN DESCRIPTION 20
13 . APPLICATIONS INFORMATION 21
14 . NOTES 27
15 . OFFICES 27
MEETING YOUR NEEDS
TK121xxCS
GC3-I017 Page 2
LDO REGULATOR WITH ON/OFF SWITCH
TK121xxCS
1. DESCRIPTION
The TK121xxCS is a low dropout linear regulator with
ON/OFF control, which can supply 200mA load current.
The output voltage, trimmed with high accuracy, is
available from 1.5 to 5.0V in 0.1V steps. This allows the
optimum voltage to be selected for the equipment.
The TK121xxCS is an integrated circuit with a silicon
monolithic bipolar structure. This regulator IC is the low
saturation voltage output type with very Low quiescent
current.
The PNP pass transistor is built-in. The I/O voltage
difference is 0.12V (typical) when a current of 100mA is
supplied to the system. Because of the low voltage drop,
the voltage source can be effectively used; this makes it
very suitable for battery powered equipment.
The on/off function is built into the IC. The current
during standby mode becomes very small (pA level).
The over current sensor circuit and the reverse-bias
protection circuit are built-in.
It is a very rugged design because the ESD protection is
high. Therefore, the TK121xxCS can be used with
confidence.
When mounted on the PCB, the power dissipation rating
becomes about 500mW, even though the package is very
small.
The TK121xxCS features very high stability in both DC
and AC.
The capacitor on the output side provides stable operation
with 0.1µF with 2.5V ≤ Vout. A capacitor of any type can
be used; however, the larger this capacitor is, the better
the overall characteristics are.
2. FEATURES
n On/Off Control available (High ON).
n Very Good Stability: Ceramic capacitor can be used.
: CL≥0.1µF at Vout≥2.5V
n High Precision Output Voltage (±1.5% or ±50mV)
n Excellent Ripple Rejection Ratio: -80dB at 1kHz
n Output Current: 200mA (peak 320mA)
n Very Low Dropout Voltage: 120mV at Iout=100mA
n Wide Operating Voltage Range: 2.1V∼12V
n Very Low Noise with Noise Bypass pin
n Short Circuit Protection (Over Current Protection)
n Internal Thermal Shutdown (Over Heat Protection)
n Internal Reverse Bias Protection
3. APPLICATIONS
n Any Electronic Equipment
n Battery Powered Systems
n Mobile Communication
4. PIN CONFIGURATION
Top View
1
3
2
5
4
Vin
VoutNp
GND
Vcont
5. BLOCK DIAGRAM
Bandgap
Reference
Over Heat &
Over Current
Protection
Vin
GND
Vout
NpVcont
320kΩ
Control
Circuit
TK121xxCS
GC3-I017 Page 3
6. ORDERING INFORMATION
LC ST K 1 2 1
Voltage Code
ex. 3.3V : 33
Package Code
S : SOT23-5
Tape / Reel Code
Rank Code
C : C Rank
I : I Rank
Standard Voltage (net multiplication bold-faced type)
TK12115CS TK12118CS TK12125CS TK12128CS TK12133CS
*Please contact your authorized TOKO representatives for voltage availability.
If you need the voltage except the above table, please contact TOKO.
7. ABSOLUTE MAXIMUM RATINGS
Ta=25°C
Parameter Symbol Rating UnitsConditions
Absolute Maximum Ratings
Supply Voltage VccMAX -0.4 ~ 16 V
-0.4 ~ 6 VVout ≤ 2.0V
Reverse Bias VrevMAX -0.4 ~ 12 V2.1V ≤ Vout
Np pin Voltage VnpMAX -0.4 ~ 5 V
Control pin Voltage VcontMAX -0.4 ~ 16 V
Storage Temperature Range Tstg -55 ~ 150 °C
Power Dissipation PD500 when mounted on PCB mW Internal Limited Tj=150°C *
Operating Condition
Operating Temperature Range TOP -40 ~ 85 °C
Operating Voltage Range VOP 2.1 ~ 12 V
Short Circuit Current Ishort 360 mA
* PD must be decreased at rate of 4.0mW/°C for operation above 25°C.
The maximum ratings are the absolute limitation values with the possibility of the IC breakage.
When the operation exceeds this standard quality cannot be guaranteed.
TK121xxCS
GC3-I017 Page 4
8. ELECTRICAL CHARACTERISTICS
8-1. C Rank (TK121xxCSC)
The parameters with min. or max. values will be guaranteed at Ta=25°C with test when manufacturing or
SQC(Statistical Quality Control) methods. The operation between -40 ~ 85°C is guaranteed when design.
Vin=VoutTYP+1V,Vcont=0.9V,Ta=25°C
Value
Parameter Symbol MIN TYP MAX UnitsConditions
Output Voltage Vout Refer to TABLE 8-1-1 ~ 3 VIout = 5mA
Line Regulation LinReg 0.0 5.0 mV ∆Vin = 5V
Load Regulation LoaReg Refer to TABLE 8-1-1 ~ 3 mV Iout = 5mA ~ 100mA
Refer to TABLE 8-1-1 ~ 3 mV Iout = 5mA ~ 200mA
Dropout Voltage *1 Vdrop 80 140 mV Iout = 50mA
120 210 mV Iout = 100mA
230 350 mV Iout = 180mA (2.1V ≤ Vout ≤ 2.3V)
200 350 mV Iout = 200mA (2.4V ≤ Vout)
Maximum Output Current *2 IoutMAX 240 320 mA When Vout down 0.3V
Supply Current Icc Refer to TABLE 8-1-1 ~ 3 µAIout = 0mA
Standby Current Istandby 0.0 0.1 µAVcont = 0V
Quiescent Current Iq 1.0 1.8 mA Iout = 50mA
Control Terminal *3
Control Current Icont 0.7 2.0 µAVcont = 0.9V
Control Voltage Vcont 0.9 VVout ON state
0.2 VVout OFF state
Reference Value (TK12125CS)
Np Terminal Voltage Vnp 1.28 V
Output Voltage / Temp. Vo/Ta 35 ppm
/°C
Output Noise Voltage Vno 34 µVrms CL=1.0µF, Cnp=0.01µF
Iout=30mA
Ripple Rejection R.R 80 dB CL=1.0µF, Cnp=0.001µF
Iout=10mA, 1kHz
Rise Time tr 36 µsCL=1.0µF, Cnp=0.001µF
Vcont: Pulse Wave (100Hz)
Vcont ON → Vout×95% point
*1: For Vout ≤ 2.0V, not guaranteed.
*2: The maximum output current is limited by package power dissipation.
*3: The input current decreases to pA level when control terminal is connected to GND (Off state).
General Note: Parameter with only typical value is for reference only.
General Note: Output noise voltage can be reduced by connecting a capacitor to a noise bypass terminal (Np). The
noise level depends on the capacitance and capacitor characteristics.
TK121xxCS
GC3-I017 Page 5
TABLE 8-1-1.Preferred Products Load Regulation
Output Voltage Iout = 100mA Iout = 200mA Supply Current
MIN TYP MAX TYP MAX TYP MAX TYP MAX
Part Number
VVVmV mV mV mV
µ
A
µ
A
TK12128CSC 2.750 2.800 2.850 11 26 25 60 92 146
TK12133CSC 3.250 3.300 3.350 12 28 27 64 97 155
TABLE 8-1-2.Limited Availability Products Load Regulation
Output Voltage Iout = 100mA Iout = 200mA Supply Current
MIN TYP MAX TYP MAX TYP MAX TYP MAX
Part Number
VVVmV mV mV mV
µ
A
µ
A
TK12115CSC 1.450 1.500 1.550 10 23 21 49 78 125
TK12118CSC 1.750 1.800 1.850 10 24 22 51 81 130
TK12125CSC 2.450 2.500 2.550 11 25 24 57 89 142
Notice.
Please contact your authorized TOKO representative for voltage availability.
If you need the voltage except the above table, please contact TOKO.
TK121xxCS
GC3-I017 Page 6
8-2. I Rank (TK121xxCSI)
The parameters with min. or max. values will be guaranteed at Ta=-40~85°C with SQC(Statistical Quality Control)
methods. Vin=VoutTYP+1V,Vcont=0.9V,Ta=-40 ~ 85°C
Value
Parameter Symbol MIN TYP MAX UnitsConditions
Output Voltage Vout Refer to TABLE 8-2-1 ~ 3 VIout = 5mA
Line Regulation LinReg 0.0 8.0 mV ∆Vin = 5V
Load Regulation LoaReg Refer to TABLE 8-2-1 ~ 3 mV Iout = 5mA ~ 100mA
Refer to TABLE 8-2-1 ~ 3 mV Iout = 5mA ~ 200mA
Dropout Voltage *1 Vdrop 80 180 mV Iout = 50mA
120 270 mV Iout = 100mA
230 390 mV Iout = 180mA (2.2V ≤ Vout ≤ 2.3V)
200 390 mV Iout = 200mA (2.4V ≤ Vout)
Maximum Output Current *2 IoutMAX 220 320 mA When Vout down 0.3V
Supply Current Icc Refer to TABLE 8-2-1 ~ 3 µAIout = 0mA
Standby Current Istandby 0.0 0.5 µAVcont = 0V
Quiescent Current Iq 1.0 2.2 mA Iout = 50mA
Control Terminal *3
Control Current Icont 0.7 2.5 µAVcont = 0.9V
0.9 VVout ON stateControl Voltage Vcont
0.2 VVout OFF state
Reference Value (TK12125CS)
Np Terminal Voltage Vnp 1.28 V
Output Voltage / Temp. Vo/Ta 35 ppm
/°C
Output Noise Voltage Vno 34 µVrms CL=1.0µF, Cnp=0.01µF
Iout=30mA
Ripple Rejection R.R 80 dB CL=1.0µF, Cnp=0.001µF
Iout=10mA, 1kHz
Rise Time tr 36 µsCL=1.0µF, Cnp=0.001µF
Vcont: Pulse Wave (100Hz)
Vcont ON → Vout×95% point
*1: For Vout ≤ 2.1V, not guaranteed.
*2: The maximum output current is limited by package power dissipation.
*3: The input current decreases to pA level when control terminal is connected to GND (Off state).
General Note: Parameter with only typical value is for reference only.
General Note: Output noise voltage can be reduced by connecting a capacitor to a noise bypass terminal (Np). The
noise level depends on the capacitance and capacitor characteristics.
TK121xxCS
GC3-I017 Page 7
TABLE 8-2-1.Preferred Products Load Regulation
Output Voltage Iout = 100mA Iout = 200mA Supply Current
MIN TYP MAX TYP MAX TYP MAX TYP MAX
Part Number
VVVmV mV mV mV
µ
A
µ
A
TK12128CSI 2.720 2.800 2.880 11 32 25 80 92 163
TK12133CSI 3.217 3.300 3.383 12 33 27 88 97 172
TABLE 8-2-2.Limited Availability Products Load Regulation
Output Voltage Iout = 100mA Iout = 200mA Supply Current
MIN TYP MAX TYP MAX TYP MAX TYP MAX
Part Number
VVVmV mV mV mV
µ
A
µ
A
TK12115CSI 1.420 1.500 1.580 10 27 21 63 78 139
TK12118CSI 1.720 1.800 1.880 10 28 22 63 81 145
TK12125CSI 2.420 2.500 2.580 11 30 24 75 89 158
Notice.
Please contact your authorized TOKO representative for voltage availability.
If you need the voltage except the above table, please contact TOKO.
TK121xxCS
GC3-I017 Page 8
9. TEST CIRCUIT
Vin
Icont
Vcont
Iin
Cin Iout Vout
1.0µF1.0µF
0.001µF
A
V
A
1 32
5 4
Vin Vout
NpGNDVcont
CL
Cnp
+ +
10. APPLICATION EXAMPLE
Vin Cin
To load
1.0µF1.0µF
0.001µF
CL
Cnp
1 32
5 4
Vin Vout
NpGNDVcont
Vcont
TK121xxCS
GC3-I017 Page 9
11. TYPICAL CHARACTERISTICS
11-1. DC CHARACTERISTICS
n Line Regulation Test conditions
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
0 2 4 6 8 10 12 14 16
Vin (V)
Vout (mV)
Vout=
1.5, 1.8, 2.5, 2.8, 3.3V
VoutTYP
121xxC
Cnp
0.001µF
CL
1µF
Iout=5mA
Cin
1µF
Vcont
0.9V
Vin
=VoutTYP+1V
1 3
5 4
n Vin vs Vout Regulation Point n Load Regulation
-160
-140
-120
-100
-80
-60
-40
-20
0
20
40
-100 0100 200 300 400
∆Vin (mV) = Vin - VoutTYP
Vout (mV)
Iout=0,50,100,150,200mA
VoutTYP
-35
-30
-25
-20
-15
-10
-5
0
5
0100 200
Iout (mA)
Vout (mA)
Vout=1.5V
1.8V
2.5V
2.8V
3.3V
VoutTYP
n Dropout Voltage n Short Circuit Current
-200
-100
0
0100 200
Iout (mA)
Vdrop (mV)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0100 200 300 400 500
Iout (mA)
Vout (V)
3.3V
2.8V
2.5V
1.8V
1.5V
Vout=
TK121xxCS
GC3-I017 Page 10
Test conditions: Vin=VoutTYP+1V, Iout=5mA, Vcont=0.9V, Cin=1µF, CL=1µF, Cnp=0.001µF
n Vin vs Iin (Iout=0mA) n Vin vs Iin (Iout=0mA)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 2 4 6 8 10 12 14 16
Vin (V)
Iin (mA)
Vout=
1.5, 1.8, 2.5, 2.8, 3.3V
60
80
100
120
140
160
180
200
220
240
0 2 4 6 8 10 12 14 16
Vin (V)
Iin ( A)
Vout=1.5, 1.8, 2.5, 2.8, 3.3V
n Standby Current (Vcont=0V) n Quiescent Current
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
0 2 4 6 8 10 12 14 16
Vin (V)
Iin (A)
0
1
2
3
4
5
6
7
8
9
10
0100 200
Iout (mA)
IQ (mA)
n Vcont vs Icont , Vout n Reverse Bias Current
0
1
2
3
4
5
6
0.0 1.0 2.0
Vcont (V)
Icont ( A)
IcontVout
0
50
100
150
200
250
0 1 2 3 4 5 6
Vout (V)
Irev ( A)
Vout=1.5V
1.8V
2.5V
2.8V
3.3V
TK121xxCS
GC3-I017 Page 11
Temperature Characteristics
n Vout
TK12125CS Test conditions
-30.0
-25.0
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
-40 -20 020 40 60 80 100
Ta(°C)
Vout(mV)
121xxC
Cnp
0.001µF
CL
1µF
Iout=5mA
Cin
1µF
Vcont
0.9V
Vin
=VoutTYP+1V
1 3
5 4
n Line Regulation n Load Regulation
TK12125CS
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
-40 -20 020 40 60 80 100
Ta(℃)
LinReg(mV)
-80
-70
-60
-50
-40
-30
-20
-10
0
-40 -20 020 40 60 80 100
Ta(℃)
LoaReg(mV)
Iout=50mA
Iout=100mA
Iout=200mA
n Dropout Voltage n Iout MAX
0
50
100
150
200
250
300
350
-40 -20 020 40 60 80 100
Ta(°C)
Vdrop(mV)
Iout=200mA
Iout=100mA
Iout=50mA
220
240
260
280
300
320
340
360
-40 -20 0 20 40 60 80 100
Ta(℃)
IoutMAX(mA)
TK121xxCS
GC3-I017 Page 12
Test conditions: Vin=VoutTYP+1V, Iout=5mA, Vcont=0.9V, Cin=1µF, CL=1µF, Cnp=0.001µF
n Supply Current
TK12125CS (Vin=3.5V)
n Quiescent Current
50
60
70
80
90
100
110
120
130
-40 -20 020 40 60 80 100
Ta
（℃）
Icc( A)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
-40 -20 020 40 60 80 100
Ta(°C)
Iq(mA)
Iout=200mA
Iout=100mA
Iout=50mA
n Control Current n Control Voltage
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
-40 -20 020 40 60 80 100
Ta(℃)
Icont( A)
Vcont=4V
Vcont=3V
Vcont=2V
Vcont=0.9V
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-40 -20 020 40 60 80 100
Ta
（℃）
Vcont(V)
Vout_ON
Vout_OFF
TK121xxCS
GC3-I017 Page 13
11-2. AC CHARACTERISTICS
Ripple Rejection
n CL = 1µF: MLCC (C), Tantalum (T)
TK12125CS Test conditions
121xxC
Cnp
0.001µF
CL
1µF
Iout=10mA
Vcont
0.9V
1 3
5 4
Vin(DC)=VoutTYP+1.5V
f=100Hz ∼ 1MHz
200mVp-p
Vripple
n CL = 0.22µF: MLCC (C), Tantalum (T)
TK12125CS
n CL = 0.22µF, 10µF: Tantalum (T)
TK12125CS
n Cap = 0.001µF, 0.1µF: CL = 1.0µF Tantalum (T)
TK12125CS The ripple rejection characteristic depends on the
characteristic and the capacitance value of the capacitor
connected to the output side. The RR characteristic of
50kHz or more varies greatly with the capacitor on the
output side and PCB pattern. If necessary, please confirm
stability while operating.
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
CL=1
F (T)
CL=1
F (C)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
CL=0.22
µ
F (T)
CL=0.22
µ
F (C)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
CL=0.22
F (T)
CL=10
F (T)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
Cnp=0.001
F
Cnp=0.1
F
TK121xxCS
GC3-I017 Page 14
Test conditions: Vin=VoutTYP+1.5V, Iout=10mA, Vcont=0.9V, CL=1µF (Tantalum), Cnp=0.001µF
n TK12115CS n TK12118CS
n TK12125CS n TK12128CS
n TK12133CS
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
0dB
-50dB
-100dB
100 1k 10k 100k 1M
Frequency (Hz)
TK121xxCS
GC3-I017 Page 15
ON/OFF Transient Test conditions
Rise Time
Vout×95%
Vcont
Vout
Time
Voltage
121xxC
Cnp
0.001µF
CL
1µF
Iout=30mA
Cin
1µF
Vin
=VoutTYP+1V
1 3
5 4
Vcont=0V⇔1V
(f=100Hz)
n CL=0.22µF, 1.0µF, 2.2µFn CL=0.22µF, 1.0µF, 2.2µF
n Cnp=0.001µF, 0.01µFn Cnp=0.001µF, 0.01µF, 0.1µF
The rise time of the regulator depends on CL and Cnp; the
fall time depends on CL.
1.0V/div
10
µ
s/div
Vout
Vcont OFF ON
CL=
0.22
µ
F
2.2
µ
F
1.0
µ
F
1.0V/div
100
µ
s/div
Vout
Vcont OFF
ON
1.0
µ
F
2.2
µ
F
CL=
0.22
µ
F
1.0V/div
100
µ
s/div
Vout
Vcont OFF ON
Cnp=
0.001
µ
F
0.01
µ
F
OFF ON
1.0V/div
1.0ms/div
Vout
Vcont
Cnp=
0.001
µ
F
0.01
µ
F0.1
µ
F
TK121xxCS
GC3-I017 Page 16
Test conditions: Vin=VoutTYP+1V, Iout=30mA, Vcont=0V⇔1V (100Hz), Cin=1µF, CL=1µF, Cnp=0.001µF
n Vout=1.5V, 1.8V, 2.5V, 2.8V, 3.3V
n Vout=1.5V, 1.8V, 2.5V, 2.8V, 3.3V
Vcont: one pulse (after discharge Cnp, CL)
1.0V/div
10
µ
s/div
Vout
Vcont OFF ON
Vout=
3.3V
2.8V
2.5V
1.8V
1.5V
1.0V/div
10
µ
s/div
Vout
Vcont OFF ON
Vout=
3.3V
2.8V
2.5V
1.8V
1.5V
TK121xxCS
GC3-I017 Page 17
LOAD Transient
n CL=0.22µF, 1.0µF, 2.2µF: Iout=5⇔35mA Test conditions
121xxC
Cnp
CL
1µF
Cin
1µF
Vcont
0.9V
Vin
=VoutTYP+1V
1 3
5 4 Iout
ON⇔OFF
0.001µF
n Iout=0⇔30mA, 5⇔35mA n Iout=0⇒30mA, 5⇒35mA
The no load voltage change can be greatly improved by
delivering a little load current to ground (see the above
curve).
Increase the load side capacitor when the load change is fast
or when there is a large current change. In addition, at no
load, delivering a little load current to ground can reduce
the voltage change.
Vout
Iout 5mA 35mA
5mA
35mA
100mV/div
10
µ
s/div
1.0
µ
F
2.2
µ
F
CL=
0.22
µ
F
2.2
µ
F
1.0
µ
F
0.22
µ
F
Vout
Iout
200mV/div
1.0ms/div
Iout=0
⇔
30mA
Iout=5
⇔
35mA
30mA or 35mA
0mA or 5mA
30mA or 35mA
Vout
Vout
Iout
200mV/div
10
µ
s/div
Iout=0
⇒
30mA
Iout=5
⇒
35mA
30mA or 35mA
0mA or 5mA
Vout
TK121xxCS
GC3-I017 Page 18
LINE Transient
n CL=0.22µF, 1.0µF, 2.2µFTest conditions
121xxC
Cnp
0.001µF
CL
1µF
Iout=30mA
Vcont
0.9V
1 3
5 4
Vin
=VoutTYP+1V⇔+2V
n Cnp=0.001µF, 0.01µF, 0.1µF
Vout
Vin VoutTYP + 2V
10mV/div
100
µ
s/div
CL=0.22
µ
F
CL=1.0
µ
F
CL=2.2
µ
F
VoutTYP + 1V
Vout
Vin VoutTYP + 2V
10mV/div
100
µ
s/div
Cnp=0.001
µ
F
Cnp=0.01
µ
F
Cnp=0.1
µ
F
VoutTYP + 1V
TK121xxCS
GC3-I017 Page 19
Output Noise Characteristics
n Vout vs Noise Test conditions
15
20
25
30
35
40
45
50
55
60
65
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
Vout(V)
Noise(uVrms)
121xxC
Cnp
0.01µF
CL
1µF
Iout=30mA
Cin
1µF
Vcont
0.9V
Vin
=VoutTYP+1V
1 3
5 4
BPF=400Hz ∼ 80kHz
n Cnp vs Noise (CL: Tantalum)
TK12125CS
n Cnp vs Noise (CL: MLCC)
TK12125CS
0
50
100
150
200
250
300
1p 10p 100p 1000p 0.01u 0.1u
Cnp(F)
Noise(uVrms)
CL=0.22uF
CL=0.47uF
CL=1.0uF
CL=2.2uF
CL=10uF
0
50
100
150
200
250
300
1p 10p 100p 1000p 0.01u 0.1u
Cnp(F)
Noise(uVrms)
CL=0.22uF
CL=0.47uF
CL=1.0uF
CL=2.2uF
CL=10uF
n Iout vs Noise (CL: Tantalum)
TK12125CS
n Iout vs Noise (CL: MLCC)
TK12125CS
20
25
30
35
40
45
50
55
050 100 150 200
Iout(mA)
Noise(uVrms)
CL=0.22uF
CL=0.47uF
CL=1.0uF
CL=2.2uF
CL=10uF
20
25
30
35
40
45
50
55
050 100 150 200
Iout(mA)
Noise(uVrms)
CL=0.22uF
CL=0.47uF
CL=1.0uF
CL=2.2uF
CL=10uF
Increase Cnp to decrease the noise. The recommended Cnp
capacitance is 0.0068µF ∼ 0.01µF.
The amount of noise increases with the higher output
voltages.
TK121xxCS
GC3-I017 Page 20
12. PIN DESCRIPTION
Pin No. Pin Description Internal Equivalent Circuit Description
1Vcont
1Vcont 320kΩ
On/Off Control Terminal
The pull down resistance is not built in.
2GND GND Terminal
3Np Np
3
Noise Bypass Terminal
Connect a bypass capacitor between GND.
4 Vout Vout
Vin
Vref
4
Output Terminal
5 Vin Input Terminal
TK121xxCS
GC3-I017 Page 21
13. APPLICATIONS INFORMATION
13-1. Stability
Linear regulators require input and output capacitors in
order to maintain the regulator's loop stability. If a 0.1µF
capacitor is connected to the output side, the IC provides
stable operation at any voltage in the practical current
region. However, increase the CL capacitance when
using the IC in the low current region and low voltage.
Otherwise, the IC oscillates.
The equivalent series resistance (ESR) of the output
capacitor must be in the stable operation area. However,
it is recommended to use as large a value of capacitance
as is practical. The output noise and the ripple noise
decrease as the capacitance value increases. ESR values
vary widely between ceramic and tantalum capacitors.
However, tantalum capacitors are assumed to provide
more ESR damping resistance, which provides greater
circuit stability. This implies that a higher level of circuit
stability can be obtained by using tantalum capacitors
when compared to ceramic capacitors with similar values.
A recommended value of the application is as follows.
Cin=CL ≥ 0.22µF at Iout ≥ 0.5mA
TK121xxCS
Cin≥0.22µF
Vin Vout
CL≥0.22µF
Cnp
≥0.001µF
GND
However, above recommended value is not satisfied some
condition.
Refer to “Output Voltage, Output Current vs. Stable
Operation Area“ at the next page.
Select the CL capacitance according to the condition of
used.
If the fast road transient response is necessary, increase
the CL capacitance as much as possible.
The input capacitor is necessary when the battery is
discharged, the power supply impedance increases, or the
line distance to the power supply is long.
This capacitor might be necessary on each individual IC
even if two or more regulator ICs are used. It is not
possible to determine this indiscriminately. Please
confirm the stability while mounted
TK121xxCS
GC3-I017 Page 22
Output Voltage, Output Current vs. Stable Operation Area
Vout=1.5V Vout=1.8V Vout=2.5V Vout=2.8V Vout=3.3V
The above graphs show stable operation with a ceramic
capacitor of 0.1µF (excluding the low current region). If
the capacitance is not increased in the low voltage, low
current area, stable operation may not be achieved. Please
select the best output capacitor according to the voltage
and current used. The stability of the regulator improves if
a big output side capacitor is used (the stable operation
area extends.) Please use as large a capacitance as is
practical. Although operation above 150mA has not been
described, stability is equal to or better than operation at
150mA.
For evaluation
Kyocera: CM05B104K10AB, CM05B224K10AB,
CM105B104K16A, CM105B224K16A,
CM21B225K10A
Murata: GRM36B104K10, GRM42B104K10,
GRM39B104K25, GRM39B224K10,
GRM39B105K6.3
ex. Ceramic Capacitance vs Voltage, Temperature
Generally, a ceramic capacitor has both a temperature
characteristic and a voltage characteristic. Please consider
both characteristics when selecting the part. The B curves
are the recommend characteristics.
%
Capacitance vs. Voltage
0Bias Voltage (V)
CAP
24 6 810
50
60
70
80
90
100
B Curve
F Curve
Capacitance vs. Temperature
%
60
50
80
90
100
70
CAP
-50 -25 0 25 50 75 100
Ta (
°
C)
B Curve
F Curve
0.01
0.1
1
10
100
0 50 100 150
Iout [mA]
ESR [Ω]
Stable area
CL=0.1
µ
F
Unstable area
0.01
0.1
1
10
100
0 50 100 150
Iout [mA]
ESR [Ω]
Stable area
CL=0.1
µ
F
Unstable area
0.01
0.1
1
10
100
0 50 100 150
Iout [mA]
ESR [Ω]
Stable area
CL=0.1
µ
F
Unstable area
0.01
0.1
1
10
100
050 100 150
Iout [mA]
ESR [Ω]
Stable area
CL=0.1
µ
F
0.01
0.1
1
10
100
0 50 100 150
Iout [mA]
ESR [Ω]
Stable area
CL=0.1
µ
F
3.0 2.0 0.5 0.5 0.5
TK121xxCS
GC3-I017 Page 23
13-2. Definition of Technical Terms
♦
Output Voltage (Vout)
The output voltage is specified with Vin=(VoutTYP+1V)
and Iout=5mA.
♦
Maximum Output Current (Iout MAX)
The rated output current is specified under the condition
where the output voltage drops 0.3V the value specified
with Iout=5mA. The input voltage is set to VoutTYP+1V
and the current is pulsed to minimize temperature effect.
♦
Dropout Voltage (Vdrop)
The dropout voltage is the difference between the input
voltage and the output voltage at which point the regulator
starts to fall out of regulation. Below this value, the output
voltage will fall as the input voltage is reduced. It is
dependent upon the load current and the junction
temperature.
♦
Line Regulation (LinReg)
Line regulation is the ability of the regulator to maintain a
constant output voltage as the input voltage changes. The
line regulation is specified as the input voltage is changed
from Vin=VoutTYP+1V to Vin=VoutTYP+6V. It is a pulse
measurement to minimize temperature effect.
♦
Load Regulation (LoaReg)
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 with
the input voltage set to Vin=VoutTYP+1V. The load
regulation is specified output current step conditions of
5mA to 100mA.
♦
Ripple Rejection (R.R)
Ripple rejection is the ability of the regulator to attenuate
the ripple content of the input voltage at the output. It is
specified with 200mVrms, 1kHz super-imposed on the input
voltage, where Vin=Vout+1.5V. Ripple rejection is the
ratio of the ripple content of the output vs. input and is
expressed in dB.
♦
Standby Current (Istandby)
Standby current is the current, which flows into the
regulator when the output is turned off by the control
function (Vcont=0V).
♦
Over Current Sensor
The over current sensor protects the device when there is
excessive output current. It also protects the device if the
output is accidentally connected to ground.
♦
Thermal Sensor
The thermal sensor protects the device in case the junction
temperature exceeds the safe value (TJ=150°C). This
temperature rise can be caused by external heat, excessive
power dissipation caused by large input to output voltage
drops, or excessive output current. The regulator will shut
off when the temperature exceeds the safe value. As the
junction temperatures decrease, the regulator will begin to
operate again. Under sustained fault conditions, the
regulator output will oscillate as the device turns off then
resets. Damage may occur to the device under extreme
fault.
Please reduce the loss of the regulator when this protection
operate, by reducing the input voltage or make better heat
efficiency.
*In the case that the power, Vin × Ishort(Short Circuit Current),
becomes more than twice of the maximum rating of its power
dissipation in a moment, there is a possibility that the IC is
destroyed before internal thermal protection works.
♦
Reverse Voltage Protection
Reverse voltage protection prevents damage due to the
output voltage being higher than the input voltage. This
fault condition can occur when the output capacitor
remains charged and the input is reduced to zero, or when
an external voltage higher than the input voltage is applied
to the output side
♦
ESD
MM: 200pF 0Ω 200V or more
HBM: 100pF 1.5kΩ 2000V or more
VoutVin
GND
TK121xxCS
GC3-I017 Page 24
13-3. Board Layout
PCB Material: Glass epoxy (t=0.8mm)
Please do derating with 4.0mW/°C at Pd=500mW and
25°C or more. Thermal resistance (θja) is=250°C/W.
25 50 100
Pd(mW)
150°C
500
00(85°C)
-4.0mW/°C
The package loss is limited at the temperature that the
internal temperature sensor works (about 150°C).
Therefore, the package loss is assumed to be an internal
limitation. There is no heat radiation characteristic of the
package unit assumed because of the small size. The
device being mounted on the PCB carries heat away. This
value changes by the material and the copper pattern etc.
of the PCB. The losses are approximately 500mW.
Enduring these losses becomes possible in a lot of
applications operating at 25°C.
The overheating protection circuit operates when there are
a lot of losses with the regulator (When outside
temperature is high or heat radiation is bad). The output
current cannot be pulled enough and the output voltage
will drop when the protection circuit operates. When the
junction temperature reaches 150°C, the IC is shut down.
However, operation begins at once when the IC stops
operation and the temperature of the chip decreases.
How to determine the thermal resistance when
mounted on PCB
The thermal resistance when mounted is expressed as
follows:
Tj=θja×Pd+Ta
Tj of IC is set around 150°C. Pd is the value when the
thermal sensor is activated.
If the ambient temperature is 25°C, then:
150=θja×Pd+25
θja=125/Pd (°C /mW)
The simple method to calculate Pd
Mount the IC on the print circuit board. Short between the
output pin and ground. after that, raise input voltage from
0V to evaluated voltage (see*1) gradually.
At shorted the output pin, the power dissipation PD can be
expressed as Pd=Vin × Iin.
The input current decreases gradually as the temperature
of the chip becomes high. After a while, it reaches the
thermal equilibrium. Use this currrent value at the thermal
equilibrium. In almost all the cases, it shows 500mW or
more.
*1 In the case that the power, Vin × Ishort(Short Circuit Current),
becomes more than twice of the maximum rating of its power
dissipation in a moment, there is a possibility that the IC is
destroyed before internal thermal protection works.
0 25 50 75 100 150
Pd(mW)
Pd
DPd
2
3
5
4
Ta(℃)
Procedure (When mounted on PCB.)
1. Find Pd (Vin×Iin when the output side is short-circuited).
2. Plot Pd against 25°C.
3. Connect Pd to the point corresponding to the 150°C with a
straight line.
4. In design, take a vertical line from the maximum operating
temperature (e.g., 75°C) to the derating curve.
5. 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.
6. DPd ÷ (Vinmax−Vout)=Iout (at 75°C)
The maximum output current at the highest operating
temperature will be Iout
≅
DPd
÷
(VinMax
−
Vout).
Please use the device at low temperature with better
radiation. The lower temperature provides better quality.
on/off
Vin Vout
Np
TK121xxCS
GC3-I017 Page 25
13-4. On/Off Control
It is recommended to turn the regulator off when the
circuit following the regulator is non-operating. A design
with little electric power loss can be implemented. We
recommend the use of the on/off control of the regulator
without using a high side switch to provide an output from
the regulator. A highly accurate output voltage with low
voltage drop is obtained.
REG
Vsat
On/Off Cont.
Because the control current is small, it is possible to
control it directly by CMOS logic.
Parallel-Connected ON/OFF Control
2.0V
5V
3.3V
On/Off Cont.
Vin
TK12150CS
RTK12133CS
TK12120CS
Vout
The above figure is multiple regulators being controlled by
a single On/Off control signal. There is fear of overheating,
because the power loss of the low voltage side IC
(TK12120CS) is large. The series resistor (R) is put in the
input line of the low output voltage regulator in order to
prevent over-dissipation. The voltage dropped across the
resistor reduces the large input-to-output voltage across
the regulator, reducing the power dissipation in the device.
When the thermal sensor works, a decrease of the output
voltage, oscillation, etc. may be observed.
13-5. Noise Bypass
The noise and the ripple rejection characteristics depend
on the capacitance on the Np terminal.
The ripple rejection characteristic of the low frequency
region improves by increasing the capacitance of Cnp.
A standard value is Cnp=0.001µF. Increase Cnp in a
design with important output noise and ripple rejection
requirements. The IC will not be damaged if the capacitor
value is increased.
The on/off switching speed changes depending on the Np
terminal capacitance. The switching speed slows when the
capacitance is large.
TK121xxCS
GC3-I017 Page 26
13-6. Outline; PCB; Stamps
2.9
1.6
1.1
0.15
0.4
2.8
2.4
Reference Mount Pad
1.0
0.7
(0.3)
0 ~0.1 ±0.1
1.3max
0.1
±0.2
Mark
±0.2
±0.2
54
13
+0.10
−0.05
+0.10
−
0.05
0.95 0.95
0.95 0.95
M
0.1
Unit: mm
Package Structure
Package Material: Epoxy Resin
Terminal Material: Copper Alloy
Mass (Reference): 0.016g
V OUT V CODE V OUT V CODE V OUT V CODE
1.5V 15 2.5V 25 3.3V 33
1.8V 18 2.8V 28
The output voltage table indicates the standard value when manufactured.
Please contact your authorized Toko representative for voltage availability.
x x R
TK121xxCS
GC3-I017 Page 27
14. NOTES
n Please be sure that you carefully discuss your planned
purchase with our office if you intend to use the products in
this application manual under conditions where particularly
extreme standards of reliability are required, or if you intend
to use products for applications other than those listed in this
application manual.
l Power drive products for automobile, ship or aircraft
transport systems; steering and navigation systems,
emergency signal communications systems, and any
system other than those mentioned above which include
electronic sensors, measuring, or display devices, and
which could cause major damage to life, limb or property
if misused or failure to function.
l Medical devices for measuring blood pressure, pulse,
etc., treatment units such as coronary pacemakers and heat
treatment units, and devices such as artificial organs and
artificial limb systems which augment physiological
functions.
l Electrical instruments, equipment or systems used in
disaster or crime prevention.
n Semiconductors, by nature, may fail or malfunction in
spite of our devotion to improve product quality and
reliability. We urge you to take every possible precaution
against physical injuries, fire or other damages which may
cause failure of our semiconductor products by taking
appropriate measures, including a reasonable safety margin,
malfunction preventive practices and fire-proofing when
designing your products.
n This application manual is effective from Oct 2002. Note
that the contents are subject to change or discontinuation
without notice. When placing orders, please confirm
specifications and delivery condition in writing.
n TOKO is not responsible for any problems nor for any
infringement of third party patents or any other intellectual
property rights that may arise from the use or method of use
of the products listed in this application manual. Moreover,
this application manual does not signify that TOKO agrees
implicitly or explicitly to license any patent rights or other
intellectual property rights which it holds.
n None of the ozone depleting substances(ODS) under the
Montreal Protocol are used in our manufacturing process.
15. OFFICES
If you need more information on this product and other
TOKO products, please contact us.
n TOKO Inc. Headquarters
1-17, Higashi-yukigaya 2-chome, Ohta-ku, Tokyo,
145-8585, Japan
TEL: +81.3.3727.1161
FAX: +81.3.3727.1176 or +81.3.3727.1169
Web site: http://www.toko.co.jp/
n TOKO America
Web site: http://www.toko.com/
n TOKO Europe
Web site: http://www.tokoeurope.com/
n TOKO Hong Kong
Web site: http://www.toko.com.hk/
n TOKO Taiwan
Web site: http://www.tokohc.com.tw/
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Web site: http://www.toko.com.sg/
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Web site: http://www.toko.co.kr/
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Web site: http://www.toko.com.ph/
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Web site: http://www.toko.com.br/
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