1
FEATURES
APPLICATIONS
DESCRIPTION
L
C1
10µF
L1
4.7 µH
VIN
VOUT
FB
C2
10µ F
EN
GND
TPS61220
VOUT
1.8Vto5.5V
R1
R2
0.7VtoVOUT
VIN
0.01 0.1 110 100
2.8
2.3
1.8
1.3
0.8
OUT
I-OutputCurrent-mA
IN
V-InputVoltage-V
≥90%
≥80%
≥70%
OUT
(V =3.3V)
EfficiencyvsOutputCurrentandInputVoltage
TPS61220
TPS61221
TPS61222
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............................................................................................................................................................................................... SLVS776 – JANUARY 2009
LOW INPUT VOLTAGE STEP-UP CONVERTER IN 6 PIN SC-70 PACKAGE
•Adjustable Output Voltage from 1.8 V to 5.5 V•Up to 95% Efficiency at Typical Operating •Fixed Output Voltage VersionsConditions
•Small 6-pin SC-70 Package•5.5 µA Quiescent Current•Startup Into Load at 0.7 V Input Voltage
•Battery Powered Applications•Operating Input Voltage from 0.7 V to 5.5 V
– 1 to 3 Cell Alkaline, NiCd or NiMH•Pass-Through Function during Shutdown
– 1 cell Li-Ion or Li-Primary•Minimum Switching Current 200 mA
•Solar or Fuel Cell Powered Applications•Protections:
•Consumer and Portable Medical Products– Output Overvoltage
•Personal Care Products– Overtemperature
•White or Status LEDs– Input Undervoltage Lockout
•Smartphones
The TPS6122x family devices provide a power-supply solution for products powered by either a single-cell,two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Possible output currentsdepend on the input-to-output voltage ratio. The boost converter is based on a hysteretic controller topologyusing synchronous rectification to obtain maximum efficiency at minimal quiescent currents. The output voltage ofthe adjustable version can be programmed by an external resistor divider, or is set internally to a fixed outputvoltage. The converter can be switched off by a featured enable pin. While being switched off, battery drain isminimized. The device is offered in a 6-pin SC-70 package (DCK) measuring 2 mm x 2 mm to enable smallcircuit layout size.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Copyright © 2009, Texas Instruments IncorporatedProducts conform to specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.
ABSOLUTE MAXIMUM RATINGS
DISSIPATION RATINGS TABLE
RECOMMENDED OPERATING CONDITIONS
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
AVAILABLE DEVICE OPTIONS
(1)
PACKAGEOUTPUT VOLTAGET
A
PACKAGE
(2)
PART NUMBER
(3)DC/DC
MARKING
Adjustable CKR TPS61220DCK– 40 ° C to 85 ° C 3.3 V CKS 6-Pin SC-70 TPS61221DCK5.0 V CKT TPS61222DCK
(1) Contact the factory to check availability of other fixed output voltage versions.(2) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TIwebsite at www.ti.com .(3) The DCK package is available taped and reeled. Add R suffix to device type (e.g., TPS61220DCKR) to order quantities of 3000 devicesper reel. It is also available in minireels. Add a T suffix to the device type (i.e. TPS61220DCKT) to order quantities of 250 devices perreel.
over operating free-air temperature range (unless otherwise noted)
(1)
TPS6122x UNIT
V
IN
Input voltage range on VIN, L, VOUT, EN, FB – 0.3 to 7.5 VT
J
Operating junction temperature range – 40 to 150 ° CT
stg
Storage temperature range – 65 to 150 ° CHuman Body Model (HBM)
(2)
2 kVESD Machine Model (MM)
(2)
200 VCharged Device Model (CDM)
(2)
1.5 kV
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratingsonly, and functional operation of the device at these or any other conditions beyond those indicated under Recommended OperatingConditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.(2) ESD testing is performed according to the respective JESD22 JEDEC standard.
THERMAL THERMAL THERMAL DERATING FACTORPOWER RATINGPACKAGE RESISTANCE RESISTANCE RESISTANCE ABOVET
A
≤25 ° CΘ
JA
(1)
Θ
JB
Θ
JC
T
A
= 25 ° C
DCK 225 ° C/W 70 ° C/W 110 ° C/W 444 mW 4.44 mW/ ° C
(1) Thermal ratings are determined assuming a high K PCB design according to JEDEC standard JESD51-7.
MIN NOM MAX UNIT
V
IN
Supply voltage at VIN 0.7 5.5 VT
A
Operating free air temperature range – 40 85 ° CT
J
Operating virtual junction temperature range – 40 125 ° C
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ELECTRICAL CHARACTERISTICS
TPS61220
TPS61221
TPS61222
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............................................................................................................................................................................................... SLVS776 – JANUARY 2009
over recommended free-air temperature range and over recommended input voltage range (typical at an ambient temperaturerange of 25 ° C) (unless otherwise noted)
DC/DC STAGE
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
IN
Input voltage range 0.7 5.5 VV
IN
Minimum input voltage at startup R
Load
≥150 Ω0.7 VV
OUT
TPS61220 output voltage range V
IN
< V
OUT
1.8 5.5 VV
FB
TPS61220 feedback voltage 483 500 513 mVV
OUT
TPS61221 output voltage (3.3V) V
IN
< V
OUT
3.20 3.30 3.41 VV
OUT
TPS61222 output voltage (5V) V
IN
< V
OUT
4.82 5.00 5.13 VI
LH
Inductor current ripple 200 mAV
OUT
= 3.3 V, V
IN
= 1.2 V, T
A
= 25 ° C 240 400 mAI
SW
switch current limit
V
OUT
= 3.3 V 200 400 mAV
OUT
= 3.3 V 1000 m ΩR
DSon_HSD
Rectifying switch on resistance
V
OUT
= 5.0 V 700 m Ω
V
OUT
= 3.3 V 600 m ΩR
DSon_LSD
Main switch on resistance
V
OUT
= 5.0 V 550 m Ω
Line regulation V
IN
< V
OUT
0.5 %Load regulation V
IN
< V
OUT
0.5 %V
IN
0.5 0.9 µAQuiescentI
Q
I
O
= 0 mA, V
EN
= V
IN
= 1.2 V, V
OUT
= 3.3 Vcurrent
V
OUT
5 7.5 µAShutdownI
SD
V
IN
V
EN
= 0 V, V
IN
= 1.2 V, V
OUT
≥V
IN
0.2 0.5 µAcurrentI
LKG_VOUT
Leakage current into VOUT V
EN
= 0 V, V
IN
= 1.2 V, V
OUT
= 3.3 V 1 µAI
LKG_L
Leakage current into L V
EN
= 0 V, V
IN
= 1.2 V, V
L
= 1.2 V, V
OUT
≥V
IN
0.01 0.2 µATPS61220 Feedback inputI
FB
V
FB
= 0.5 V 0.01 µAcurrentI
EN
EN input current Clamped on GND or V
IN
(V
IN
< 1.5 V) 0.005 0.1 µA
CONTROL STAGE
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
IL
EN input low voltage V
IN
≤1.5 V 0.2 × V
IN
VV
IH
EN input high voltage V
IN
≤1.5 V 0.8 × V
IN
VV
IL
EN input low voltage 5 V > V
IN
> 1.5 V 0.4 VV
IH
EN input high voltage 5 V > V
IN
> 1.5 V 1.2 VV
UVLO
Undervoltage lockout threshold for turn off V
IN
decreasing 0.5 0.7 VOvervoltage protection threshold 5.5 7.5 VOvertemperature protection 140 ° COvertemperature hysteresis 20 ° C
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
PIN ASSIGNMENTS
GND
L
VIN EN
VOUT
FB
DCKPACKAGE
(TOP VIEW)
Current
Sensor
Gate
Driver
Device
Control
GND
EN FB
VOUT
L
VREF
VIN
Device
Control
StartUp
VIN
VOUT
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
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Terminal Functions
TERMINAL
I/O DESCRIPTIONNAME NO.
EN 6 I Enable input (1: enabled, 0: disabled). Must be actively tied high or low.FB 2 I Voltage feedback of adjustable version. Must be connected to V
OUT
at fixed output voltage versions.GND 3 Control / logic and power groundL 5 I Connection for InductorVIN 1 I Boost converter input voltageVOUT 4 O Boost converter output voltage
FUNCTIONAL BLOCK DIAGRAM (ADJUSTABLE VERSION)
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Current
Sensor
Gate
Driver
Device
Control
GND
EN
FB
VOUT
L
VREF
VIN
Device
Control
StartUp
VIN
VOUT
PARAMETER MEASUREMENT INFORMATION
L
L1
VIN
VOUT
FB C2
EN
GND
TPS6122x
VOUT
R1
R2
V
IN
C1
TPS61220
TPS61221
TPS61222
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............................................................................................................................................................................................... SLVS776 – JANUARY 2009
FUNCTIONAL BLOCK DIAGRAM (FIXED OUTPUT VOLTAGE VERSION)
List of Components:
COMPONENT
PART NUMBER MANUFACTURER VALUEREFERENCE
C
1
GRM188R60J106ME84D Murata 10 µF, 6.3V. X5R CeramicC
2
GRM188R60J106ME84D Murata 10 µF, 6.3V. X5R CeramicL
1
EPL3015-472MLB Coilcraft 4.7 µHadjustable version: Values depending on theprogrammed output voltageR
1
, R
2
fixed version: R
1
= 0 Ω, R
2
not used
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
TYPICAL CHARACTERISTICS
Table of Graphs
0.01 0.1 1 10 100
I -OutputCurrent-mA
O
0
10
20
30
40
50
60
70
80
90
100
h-Efficiency-%
V =0.7V
I
V =1.2V
I
V =1.5V
I
V =1.8V
O
0
50
100
150
200
250
300
0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7
V -InputVoltage-V
I
TPS61221V =3.3V
O
TPS61220V =1.8V
O
TPS61222V =5V
O
MaximumoutputCurrent-mA
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
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FIGURE
Maximum Output Current vs Input Voltage (TPS61220, TPS61221, TPS61222) 1vs Output Current, V
OUT
= 1.8 V, V
IN
= [0.7 V; 1.2 V; 1.5 V] (TPS61220) 2vs Output Current, V
IN
= [0.7 V; 1.2 V; 2.4 V; 3 V] (TPS61221) 3vs Output Current, V
IN
= [0.7 V; 1.2 V; 2.4V; 3.6 V; 4.2 V] (TPS61222) 4Efficiency
vs Input Voltage, V
OUT
= 1.8 V, I
OUT
= [100 uA; 1 mA; 10 mA; 50 mA]
5(TPS61220)
vs Input Voltage, I
OUT
= [100 uA; 1 mA; 10 mA; 50 mA] (TPS61221) 6vs Input Voltage, I
OUT
= [100 uA; 1 mA; 10 mA; 50 mA] (TPS61222) 7Input Current at No Output Load, Device Enabled (TPS61220, TPS61221, TPS61222) 8vs Output Current, V
OUT
= 1.8 V, V
IN
= [0.7 V; 1.2 V] (TPS61220 ) 9vs Output Current, V
IN
= [0.7 V; 1.2 V; 2.4 V] (TPS61221) 10Output Voltage
vs Output Current, V
IN
= [0.7 V; 1.2 V; 2.4 V; 3.6 V] (TPS61222) 11vs Input Voltage, Device Disabled, R
LOAD
= [1 k Ω; 10 k Ω] (TPS6122x) 12Output Voltage Ripple, V
IN
= 0.8 V, V
OUT
= 1.8 V, I
OUT
= 20 mA (TPS61220) 13Output Voltage Ripple V
IN
= 1.8 V, I
OUT
= 50mA (TPS61221) 14Load Transient Response, V
IN
= 1.2 V, I
OUT
= 6 mA to 50 mA (TPS61221) 15Load Transient Response, V
IN
= 2.4 V, I
OUT
= 14 mA to 126 mA (TPS61222) 16Line Transient Response, V
IN
= 1.8 V to 2.4 V, R
LOAD
= 100 Ω(TPS61221) 17Line Transient Response, V
IN
= 2.8 V to 3.6 V, R
LOAD
= 100 Ω(TPS61222) 18Waveforms
Startup after Enable, V
IN
= 0.7 V, V
OUT
= 1.8 V, R
LOAD
= 150 Ω(TPS61220) 19Startup after Enable, V
IN
= 0.7 V, R
LOAD
= 150 Ω, (TPS61222) 20Continuous Current Operation, V
IN
= 1.2 V, V
OUT
= 1.8 V, I
OUT
= 50mA
21(TPS61220 )Discontinuous Current Operation, V
IN
= 1.2 V, V
OUT
= 1.8 V, I
OUT
= 10mA
22(TPS61220)
MAXIMUM OUTPUT CURRENT vs EFFICIENCY vsINPUT VOLTAGE (TPS61220, TPS61221, TPS61222) OUTPUT CURRENT AND INPUT VOLTAGE (TPS61220)
Figure 1. Figure 2.
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0
10
20
30
40
50
60
70
80
90
100
h-Efficiency-%
0.01 0.1 1 10 100
I -OutputCurrent-mA
O
V =0.7V
I
V =1.2V
I
V =2.4V
I
V =3.3V
O
V =3V
I
0.7 1.2 1.7 2.2 2.7 3.2
0
10
20
30
40
50
60
70
80
90
100
h-Efficiency-%
V -InputVoltage-V
I
I =50mA
O
I =100 A
Om
I =10mA
O
I =1mA
O
V =3.3V
O
0.7 0.9 1.1 1.3 1.5 1.7
V -InputVoltage-V
I
0
10
20
30
40
50
60
70
80
90
100
h-Efficiency-%
I =50mA
O
I =100 A
Om
I =10mA
O
I =1mA
O
V =1.8V
O
0
20
40
60
80
100
0.7 1.7 2.7 3.7 4.7
V -InputVoltage-V
I
h-Efficiency-%
I =50mA
O
I =100 A
Om
I =10mA
O
I =1mA
O
V =5V
O
0
10
20
30
40
50
60
70
80
0.7 1.7 2.7 3.7 4.7
V -InputVoltage-V
I
I -InputCurrent- A
Im
TPS61222,V =5V
O
TPS61220,V =1.8V
O
TPS61221,V =3.3V
O
DeviceEnabled
TPS61220
TPS61221
TPS61222
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............................................................................................................................................................................................... SLVS776 – JANUARY 2009
EFFICIENCY vs EFFICIENCY vsOUTPUT CURRENT AND INPUT VOLTAGE (TPS61221) OUTPUT CURRENT AND INPUT VOLTAGE (TPS61222)
Figure 3. Figure 4.
EFFICIENCY vs EFFICIENCY vsINPUT VOLTAGE AND OUTPUT CURRENT (TPS61220) INPUT VOLTAGE AND OUTPUT CURRENT (TPS61221)
Figure 5. Figure 6.
NO LOAD INPUT CURRENT vsEFFICIENCY vs INPUT VOLTAGE, DEVICE ENABLED (TPS61220 V
OUT
=1.8,INPUT VOLTAGE AND OUTPUT CURRENT (TPS61222) TPS61221, TPS61222)
Figure 7. Figure 8.
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1.7
1.75
1.8
1.85
1.9
0.01 0.1 1 10 100
I -OutputCurrent-mA
O
V -OutputVoltage-V
O
V =0.7V
I
V =1.2V
I
V =1.8V
O
3.1
3.2
3.3
3.4
3.5
0.01 0.1 1 10 100
I -OutputCurrent-mA
O
V =0.7V
I
V =1.2V
I
V =2.4V
I
V =3.3V
O
V -OutputVoltage-V
O
4.8
4.9
5
5.1
5.2
0.01 0.1 1 10 100
I -OutputCurrent-mA
O
V =0.7V
I
V =1.2V
I
V =2.4V
I
V =5V
O
V -OutputVoltage-V
O
V =3.6V
I
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2
V -InputVoltage-V
I
V -OutputVoltage-V
O
V =0V
EN
R =10k
LOAD W
R =1k
LOAD W
Icoil
50mA/div
VO
10mA/div
1 s/divm
Offset:1.8V
Offset:0V
V =0.8V,V =1.8V,I =20mA
I O O
Icoil
50mA/div
V
10mV/div
O
Offset:0 A
Offset:3.31V
1 s/divm
V =1.8V,V =3.3V,I =50mA
I O O
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
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OUTPUT VOLTAGE vs OUTPUT VOLTAGE vsOUTPUT CURRENT AND INPUT VOLTAGE (TPS61220) OUTPUT CURRENT AND INPUT VOLTAGE (TPS61221)
Figure 9. Figure 10.
OUTPUT VOLTAGE vs OUTPUT VOLTAGE vsOUTPUT CURRENT AND INPUT VOLTAGE (TPS61222) INPUT VOLTAGE, DEVICE DISABLED (TPS61220)
Figure 11. Figure 12.
OUTPUT VOLTAGE RIPPLE (TPS61220) OUTPUT VOLTAGE RIPPLE (TPS61221)
Figure 13. Figure 14.
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
VO
50mV/div
200mA/div
IL
200 s/divm
50mA/div
IO
Offset:0 A
Offset:0 A
Offset:5V
V =2.4V,I =14mA to126mA
I O
VO
50mV/div
200mA/div
IL
200 s/divm
20mA/div
IO
Offset:3.31V
Offset:0 A
Offset:0 A
V =1.2V,I =6mA to50mA
I O
VI
200mV/div
VO
20mV/div
Offset:2.8V
Offset:5V
200 s/divm
V 2.8to3.6V,R =100 ,t =t =20ms
I LOAD rise fall
W
VI
200mV/div
V
20mV/div
O
Offset:1.8V
Offset:3.3V
V 1.8to2.4V,R =100 ,t =t =20ms
I LOAD rise fall
W
200 s/divm
VEN
500mV/div
Icoil
100mA/div
VL
1V/div
V
1V/div
O
Offset:0 A
Offset:0V
Offset:0V
Offset:0V
500 s/divm
V =0.7V,V =1.8V,R =150
I O LOAD W
V =0.7V,V =3.3V,R =50
I O LOAD W
Icoil
100mA/div
V
2V/div
L
V
500mV/div
EN
V
2V/div
O
Offset:0V
Offset:0 A
Offset:0V
Offset:0V
500 s/divm
TPS61220
TPS61221
TPS61222
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............................................................................................................................................................................................... SLVS776 – JANUARY 2009
LOAD TRANSIENT RESPONSE (TPS61221) LOAD TRANSIENT RESPONSE (TPS61222)
Figure 15. Figure 16.
LINE TRANSIENT RESPONSE (TPS61221) LINE TRANSIENT RESPONSE (TPS61222)
Figure 17. Figure 18.
STARTUP AFTER ENABLE (TPS61120) STARTUP AFTER ENABLE (TPS61221)
Figure 19. Figure 20.
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V =1.2V,V =1.8V,I =50mA
I O O
Icoil
V
10mV/div
O
Offset:0 A
Offset:1.8V
100mA/div
V
2V/div
L
Offset:0V
1 s/divm
V =1.2V,V =1.8V,I =10mA
I O O
Icoil
V
10mV/div
O
Offset:0 A
Offset:1.8V
100mA/div
V
2V/div
L
Offset:0V
1 s/divm
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
www.ti.com
CONTINUOUS CURRENT OPERATION (TPS61220) DISCONTINUOUS CURRENT OPERATION (TPS61220)
Figure 21. Figure 22.
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
DETAILED DESCRIPTION
OPERATION
CONTROLLER CIRCUIT
IL
t
200mA
(typ.)
ContinuousCurrentOperation DiscontinuousCurrentOperation
200mA
(typ.)
Device Enable and Shutdown Mode
Startup
Operation at Output Overload
TPS61220
TPS61221
TPS61222
www.ti.com
............................................................................................................................................................................................... SLVS776 – JANUARY 2009
The TPS6122x is a high performance, high efficient family of switching boost converters. To achieve highefficiency the power stage is realized as a synchronous boost topology. For the power switching two activelycontrolled low R
DSon
power MOSFETs are implemented.
The device is controlled by a hysteretic current mode controller. This controller regulates the output voltage bykeeping the inductor ripple current constant in the range of 200 mA and adjusting the offset of this inductorcurrent depending on the output load. In case the required average input current is lower than the averageinductor current defined by this constant ripple the inductor current gets discontinuous to keep the efficiency highat low load conditions.
Figure 23. Hysteretic Current Operation
The output voltage V
OUT
is monitored via the feedback network which is connected to the voltage error amplifier.To regulate the output voltage, the voltage error amplifier compares this feedback voltage to the internal voltagereference and adjusts the required offset of the inductor current accordingly. At fixed output voltage versions aninternal feedback network is used to program the output voltage, at adjustable versions an external resistordivider needs to be connected.
The self oscillating hysteretic current mode architecture is inherently stable and allows fast response to loadvariations. It also allows using inductors and capacitors over a wide value range.
The device is enabled when EN is set high and shut down when EN is low. During shutdown, the converter stopsswitching and all internal control circuitry is turned off. In this case the input voltage is connected to the outputthrough the back-gate diode of the rectifying MOSFET. This means that there always will be voltage at the outputwhich can be as high as the input voltage or lower depending on the load.
After the EN pin is tied high, the device starts to operate. In case the input voltage is not high enough to supplythe control circuit properly a startup oscillator starts to operate the switches. During this phase the switchingfrequency is controlled by the oscillator and the maximum switch current is limited. As soon as the device hasbuilt up the output voltage to about 1.8V, high enough for supplying the control circuit, the device switches to itsnormal hysteretic current mode operation. The startup time depends on input voltage and load current.
If in normal boost operation the inductor current reaches the internal switch current limit threshold the mainswitch is turned off to stop further increase of the input current.
In this case the output voltage will decrease since the device can not provide sufficient power to maintain the setoutput voltage.
If the output voltage drops below the input voltage the backgate diode of the rectifying switch gets forward biasedand current starts flow through it. This diode cannot be turned off, so the current finally is only limited by theremaining DC resistances. As soon as the overload condition is removed, the converter resumes providing theset output voltage.
Copyright © 2009, Texas Instruments Incorporated Submit Documentation Feedback 11
Product Folder Link(s): TPS61220 TPS61221 TPS61222
Undervoltage Lockout
Overvoltage Protection
Overtemperature Protection
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
www.ti.com
An implemented undervoltage lockout function stops the operation of the converter if the input voltage dropsbelow the typical undervoltage lockout threshold. This function is implemented in order to prevent malfunctioningof the converter.
If, for any reason, the output voltage is not fed back properly to the input of the voltage amplifier, control of theoutput voltage will not work anymore. Therefore an overvoltage protection is implemented to avoid the outputvoltage exceeding critical values for the device and possibly for the system it is supplying. For this protection theTPS6122x output voltage is also monitored internally. In case it reaches the internally programmed threshold of6.5 V typically the voltage amplifier regulates the output voltage to this value.
If the TPS6122x is used to drive LEDs, this feature protects the circuit if the LED fails.
The device has a built-in temperature sensor which monitors the internal IC junction temperature. If thetemperature exceeds the programmed threshold (see electrical characteristics table), the device stops operating.As soon as the IC temperature has decreased below the programmed threshold, it starts operating again. Toprevent unstable operation close to the region of overtemperature threshold, a built-in hysteresis is implemented.
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
APPLICATION INFORMATION
DESIGN PROCEDURE
Programming the Output Voltage
L
L1
VIN
VOUT
FB C2
EN
GND
TPS6122x
fixedoutputvoltage
VOUT
V
IN
C1
æ ö
ç ÷
è ø
OUT
FB
V
R = R x - 1
1 2 V
(1)
L
L1
VIN
VOUT
FB C2
EN
GND
TPS6122x
VOUT
R1
R2
V
IN
C1
TPS61220
TPS61221
TPS61222
www.ti.com
............................................................................................................................................................................................... SLVS776 – JANUARY 2009
The TPS6122x DC/DC converters are intended for systems powered by a single cell battery to up to threeAlkaline, NiCd or NiMH cells with a typical terminal voltage between 0.7 V and 5.5 V. They can also be used insystems powered by one-cell Li-Ion or Li-Polymer batteries with a typical voltage between 2.5 V and 4.2 V.Additionally, any other voltage source with a typical output voltage between 0.7 V and 5.5 V can be used with theTPS6122x family.
Fixed output voltage versions
At fixed voltage versions, the output voltage is set by a resistor divider internally. The FB pin is used to sense theoutput voltage. To configure the fixed output devices properly, the FB pin needs to be connected directly toVOUT as shown in Figure 24 .
Figure 24. Typical Application Circuit for Fixed Output Voltage Option
Adjustable output voltage version
In the adjustable output versions, an external resistor divider is used to adjust the output voltage. The resistordivider needs to be connected between VOUT, FB and GND as shown in Figure 25 . When the output voltage isregulated properly, the typical voltage value at the FB pin is 500 mV for the adjustable devices. The maximumrecommended value for the output voltage is 5.5 V. The current through the resistive divider should be about 100times greater than the current into the FB pin. The typical current into the FB pin is 0.01 µA, and the voltageacross the resistor between FB and GND, R
2
, is typically 500 mV. Based on those two values, the recommendedvalue for R
2
should be lower than 500 k Ω, in order to set the divider current to 1 µA or higher. The value of theresistor connected between VOUT and FB, R
1
, depending on the needed output voltage (V
OUT
), can becalculated using Equation 1 :
As an example, if an output voltage of 3.3 V is needed, a 1-M Ωresistor is calculated for R
1
when for R
2
a 180-k Ωhas been selected.
Figure 25. Typical Application Circuit for Adjustable Output Voltage Option
Copyright © 2009, Texas Instruments Incorporated Submit Documentation Feedback 13
Product Folder Link(s): TPS61220 TPS61221 TPS61222
Inductor Selection
´
´
´
IN OUT IN
OUT
V (V - V )
1
L = f 200 mA V
(2)
´
ì
ï´
í
ï
î
OUT OUT
IN
L,MAX
V I + 100 mA; continous current operation
0.8 V
I =
200 mA; discontinuous current operation
(3)
´
> ´
OUT OUT
IN
V I 0.8 100 mA
V
(4)
Capacitor Selection
Input Capacitor
Output Capacitor
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
www.ti.com
To make sure that the TPS6122x devices can operate, a suitable inductor must be connected between pin VINand pin L. Inductor values of 4.7 µH show good performance over the whole input and output voltage range .
Choosing other inductance values affects the switching frequency fproportional to 1/L as shown in Equation 2 .
Choosing inductor values higher than 4.7 µH can improve efficiency due to reduced switching frequency andtherefore with reduced switching losses. Using inductor values below 2.2 µH is not recommended.
Having selected an inductance value, the peak current for the inductor in steady state operation can becalculated. Equation 3 gives the peak current estimate.
For selecting the inductor this would be the suitable value for the current rating. It also needs to be taken intoaccount that load transients and error conditions may cause higher inductor currents.
Equation 4 provides an easy way to estimate whether the device will work in continuous or discontinuousoperation depending on the operating points. As long as the inequation is true, continuous operation is typicallyestablished. If the inequation becomes false, discontinous operation is typically established.
The following inductor series from different suppliers have been used with TPS6122x converters:
Table 1. List of Inductors
VENDOR INDUCTOR SERIES
EPL3015Coilcraft
EPL2010Murata LQH3NPTajo Yuden NR3015Wurth Elektronik WE-TPC Typ S
At least a 10- µF input capacitor is recommended to improve transient behavior of the regulator and EMI behaviorof the total power supply circuit. A ceramic capacitor placed as close as possible to the VIN and GND pins of theIC is recommended.
For the output capacitor C
2
, it is recommended to use small ceramic capacitors placed as close as possible tothe VOUT and GND pins of the IC. If, for any reason, the application requires the use of large capacitors whichcan not be placed close to the IC, the use of a small ceramic capacitor with an capacitance value of around2.2 µF in parallel to the large one is recommended. This small capacitor should be placed as close as possible tothe VOUT and GND pins of the IC.
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
³ ´
2
L
C
2
(5)
Layout Considerations
VIN
VOUT
GND
L1
C1 C2
R1
R2
GND
Enable
VIN
VOUT
TPS61220
TPS61221
TPS61222
www.ti.com
............................................................................................................................................................................................... SLVS776 – JANUARY 2009
A minimum capacitance value of 4.7 µF should be used, 10 µF are recommended. If the inductor value exceeds4.7 µH, the value of the output capacitance value needs to be half the inductance value or higher for stabilityreasons, see Equation 5 .
The TPS6122x is not sensitive to the ESR in terms of stability. Using low ESR capacitors, such as ceramiccapacitors, is recommended anyway to minimize output voltage ripple. If heavy load changes are expected, theoutput capacitor value should be increased to avoid output voltage drops during fast load transients.
As for all switching power supplies, the layout is an important step in the design, especially at high peak currentsand high switching frequencies. If the layout is not carefully done, the regulator could show stability problems aswell as EMI problems. Therefore, use wide and short traces for the main current path and for the power groundpaths. The input and output capacitor, as well as the inductor should be placed as close as possible to the IC.
The feedback divider should be placed as close as possible to the control ground pin of the IC. To lay out theground, it is recommended to use short traces as well, separated from the power ground traces. This avoidsground shift problems, which can occur due to superimposition of power ground current and control groundcurrent. Assure that the ground traces are connected close to the device GND pin.
Figure 26. PCB Layout Suggestion for Adjustable Output Voltage Options
Copyright © 2009, Texas Instruments Incorporated Submit Documentation Feedback 15
Product Folder Link(s): TPS61220 TPS61221 TPS61222
THERMAL INFORMATION
TPS61220
TPS61221
TPS61222
SLVS776 – JANUARY 2009 ...............................................................................................................................................................................................
www.ti.com
Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requiresspecial attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, addedheat sinks and convection surfaces, and the presence of other heat-generating components affect thepower-dissipation limits of a given component.
Three basic approaches for enhancing thermal performance are listed below.•Improving the power-dissipation capability of the PCB design•Improving the thermal coupling of the component to the PCB•Introducing airflow in the system
For more details on how to use the thermal parameters in the dissipation ratings table please check the ThermalCharacteristics Application Note (SZZA017) and the IC Package Thermal Metrics Application Note (SPRA953) .
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Product Folder Link(s): TPS61220 TPS61221 TPS61222
PACKAGING INFORMATION
Orderable Device Status (1) Package
Type Package
Drawing Pins Package
Qty Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
TPS61220DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS61220DCKT ACTIVE SC70 DCK 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS61221DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS61221DCKT ACTIVE SC70 DCK 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS61222DCKR ACTIVE SC70 DCK 6 3000 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
TPS61222DCKT ACTIVE SC70 DCK 6 250 Green (RoHS &
no Sb/Br) CU NIPDAU Level-1-260C-UNLIM
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
PACKAGE OPTION ADDENDUM
www.ti.com 23-Apr-2009
Addendum-Page 1
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
TPS61220DCKR SC70 DCK 6 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
TPS61220DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
TPS61221DCKR SC70 DCK 6 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
TPS61221DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
TPS61222DCKR SC70 DCK 6 3000 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
TPS61222DCKT SC70 DCK 6 250 179.0 8.4 2.2 2.5 1.2 4.0 8.0 Q3
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Sep-2011
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
TPS61220DCKR SC70 DCK 6 3000 203.0 203.0 35.0
TPS61220DCKT SC70 DCK 6 250 203.0 203.0 35.0
TPS61221DCKR SC70 DCK 6 3000 203.0 203.0 35.0
TPS61221DCKT SC70 DCK 6 250 203.0 203.0 35.0
TPS61222DCKR SC70 DCK 6 3000 203.0 203.0 35.0
TPS61222DCKT SC70 DCK 6 250 203.0 203.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Sep-2011
Pack Materials-Page 2
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