TI TPS62273DRVTG4

TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
2.25 MHz 400-mA Step Down Converter With Selectable VOUT
FEATURES
1
•
•
•
•
•
•
•
•
•
High Efficiency Step Down Converter
Output Current up to 400 mA
VIN Range From 2V to 6V for Li-Ion Batteries
With Extended Voltage Range
2.25 MHz Fixed Frequency Operation
Pin-Selectable Fixed Output Voltage
Power Save Mode for Highest Efficiency
Automatic transition between PFM and PWM
Mode
Voltage Positioning in PFM Mode
Typical 15-µA Quiescent Current
100% Duty Cycle for Lowest Dropout
Available in 2×2×0,8 mm SON Package
Allows <1 mm Solution Height
APPLICATIONS
•
•
•
•
•
•
VIN = 2 V to 6 V
VIN
CIN
4.7 mF
With an input voltage range of 2.0 V to 6 V the device
supports Li-Ion batteries with extended voltage range,
and is ideal to power portable applications like mobile
phones and other portable equipment.
The TPS62270 operates at 2.25 MHz fixed switching
frequency and enters Power Save Mode operation at
light load currents to maintain high efficiency over the
entire load current range. The Power Save Mode is
optimized for low output voltage ripple.
With the VSEL pin, two different fixed output voltages
can be selected. This function features a dynamic
voltage scaling for low power processor cores.
The TPS62270 is available in a 2 mm × 2 mm, 6-pin
SON package.
L
2.2 mH
VOUT
0.9 V / 1.15 V
up to 400 mA
SW
EN
GND
The TPS62270 device is a high efficiency
synchronous step down DC-DC converter optimized
for battery powered portable applications. It provides
up to 400 mA output current from a single Li-Ion cell.
In the shutdown mode, the current consumption is
reduced to less than 1µA. TPS62270 allows the use
of small inductors and capacitors to achieve a small
solution size.
Low Power Processor Supply
Cell Phones, Smart-phones
Navigation Systems
Low Power DSP Supply
Portable Media Players
Digital Cameras
TPS62270DRV
DESCRIPTION
FB
COUT
10 mF
COUT
VIN CIN
U1
VOUT
3.3mm
•
•
•
L1
1.15 V
0.9 V
VSEL
GND
6.5 mm
Total area
21.5 mm²
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007–2008, Texas Instruments Incorporated
TPS62270
TPS62273
SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008................................................................................................................................................... www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
–40°C to 85°C
(1)
(2)
VSEL = 1
VSEL = 0
PACKAGE
DESIGNATOR
ORDERING(1)
TPS62270
1.15 V
0.9 V
DRV
TPS62270DRV
CCX
TPS62273
3.3V
2.5V
DRV
TPS62273DRV
CGW
PART NUMBER (1)
TA
OUTPUT VOLTAGE (2)
PACKAGE
MARKING
The DRV (SON2x2) package is available in tape on reel. Add R suffix to order quantities of 3000 parts per reel, add T suffix to order
quantities of 250 parts per reel.
contact TI for other fixed output voltage options.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
(1)
Input voltage range (2)
Voltage range at EN, VSEL
Voltage on SW
Peak output current
ESD rating (3)
VALUE
UNIT
–0.3 to 7
V
–0.3 to VIN +0.3, ≤7
V
–0.3 to 7
V
Internally limited
A
HBM Human body model
2
CDM Charge device model
1
Machine model
kV
200
V
TJ
Maximum operating junction temperature
–40 to 125
°C
Tstg
Storage temperature range
–65 to 150
°C
(1)
(2)
(3)
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability.
All voltage values are with respect to network ground terminal.
The human body model is a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200 pF
capacitor discharged directly into each pin.
DISSIPATION RATINGS
PACKAGE
RθJA
POWER RATING
FOR TA ≤ 25＝C
DERATING FACTOR
ABOVE TA = 25°C
DRV
76°C/W
1300 mW
13 mW/°C
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
MAX
UNIT
VIN
Supply Voltage
2.0
6
V
TA
Operating ambient temperature
–40
85
°C
TJ
Operating junction temperature
–40
125
°C
2
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Product Folder Link(s): TPS62270 TPS62273
TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
ELECTRICAL CHARACTERISTICS
Over full operating ambient temperature range, typical values are at TA = 25°C. Unless otherwise noted, specifications apply
for condition VIN = EN = 3.6V. External components CIN = 4,7µF 0603, COUT = 10µF 0603, L = 2.0µH, refer to parameter
measurement information.
PARAMETER
TEST CONDITIONS
MIN
TYP MAX
UNIT
SUPPLY
VIN
Input voltage range
2
6
2.5 V ≤ VIN ≤ 6 V
400
2.0 V ≤ VIN ≤ 2.5 V
150
IOUT
Output current
IOUT = 0 mA, device not switching
15
IQ
Operating quiescent current
IOUT = 0 mA, device switching with no load,
VOUT = 1.15V
18
ISD
Shutdown current
EN = GND
UVLO
Undervoltage lockout threshold
0.1
Falling
1.85
Rising
1.95
V
mA
µA
1
µA
V
ENABLE, VSEL
VIH
High level input voltage, EN, VSEL
2 V ≤ VIN ≤ 6 V
1
VIN
VIL
Low Level Input Voltage, EN, VSEL
2 V ≤ VIN ≤ 6 V
0
0.4
V
IIN
Input bias Current, EN, VSEL
EN, VSEL = GND or VIN
0.01
1.0
µA
High side MOSFET on-resistance
VIN = VGS = 3.6V, TA = 25°C
240
480
mΩ
Low side MOSFET on-resistance
VIN = VGS = 3.6V, TA = 25°C
180
380
mΩ
Forward current limit MOSFET high-side and
low side
VIN = VGS = 3.6 V
0.7
0.84
A
Thermal shutdown
Increasing junction temperature
140
Thermal shutdown hysteresis
Decreasing junction temperature
20
V
POWER SWITCH
RDS(on)
ILIMF
TSD
0.56
°C
OSCILLATOR
fSW
2 V ≤ VIN ≤ 6 V
Oscillator frequency
2
2.25
2.5
VSEL = 1
1.13
1.15
1.16
7
VSEL = 0
0.88
6
0.9
0.91
4
VSEL = 1
3.23
3.3
3.37
VSEL = 0
2.45
2.5
2.55
MHz
OUTPUT
TPS62270
VOUT
Output voltage PWM
TPS62273
VOUT
Output voltage in PFM mode, voltage
positioning
PWM operation, 2 V ≤ VIN ≤ 6 V,
FB pin connected to VOUT (1)
PWM operation,
FB pin connected to VOUT (1)
Device in PFM mode
VSEL = 1
1.16
VSEL = 0
0.91
VSEL = 1
3.34
VSEL = 0
2.53
tStart
Start-up time
Time from active EN to reach 95% of VOUT
500
tRamp
VOUT ramp up time
Time to ramp from 5% to 95% of VOUT
250
Ilkg
Leakage Current into SW pin
VIN = 3.6 V, VIN = VOUT = VSW, EN = GND (2)
0.1
(1)
(2)
V
V
µs
µs
1
µA
For VIN = VOUT + 0.6 V
In fixed output voltage versions, the internal resistor divider network is disconnected from FB pin.
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62273
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TPS62270
TPS62273
SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008................................................................................................................................................... www.ti.com
PIN ASSIGNMENTS
1
VSEL
2
FB
3
GND
6
Po
Pa we
d r
SW
5
VIN
4
EN
Top view DRV package
TERMINAL FUNCTIONS
TERMINAL
NAME
I/O
DESCRIPTION
NO.
(SON)
VIN
5
PWR
VIN power supply pin.
GND
6
PWR
GND supply pin
EN
4
I
SW
1
OUT
FB
3
I
Feedback Pin for the internal regulation loop. Connect the external resistor divider to this pin. In case of fixed
output voltage option, connect this pin directly to the output capacitor
VSEL
2
I
Voltage Select input. Please refer to table ordering information for available output voltage selections.
This is the enable pin of the device. Pulling this pin to low forces the device into shutdown mode. Pulling this
pin to high enables the device. This pin must be terminated.
This is the switch pin and is connected to the internal MOSFET switches. Connect the inductor to this
terminal
FUNCTIONAL BLOCK DIAGRAM
VIN
Current
Limit Comparator
Thermal
Shutdown
VIN
Undervoltage
Lockout 1.8V
Limit
High Side
EN
PFM Comparator
Reference
0.6V VREF
FB
VREF +1%
VSEL
Softstart
VOUT RAMP
CONTROL
Gate Driver
Anti
Shoot-Through
Control
Stage
Error Amp.
SW1
VREF
Integrator
FB
RI 1
FB
PWM
Comp.
Limit
Low Side
RI3
RI..N
Zero-Pole
AMP.
Internal Voltage
Setting Network
Sawtooth
Generator
GND
Current
Limit Comparator
2.25 MHz
Oscillator
GND
4
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TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
PARAMETER MEASUREMENT INFORMATION
TPS6227XDRV
VIN
VIN
CIN
L
2.2 mH
SW
COUT
EN
4.7 mF
VOUT
up to 400 mA
10 mF
FB
GND
High
VSEL
Low
L:
MIPSA2520D2R2 2.0 mH
CIN: GRM188R60J106M 4.7 mF
COUT: GRM188R60J106M 10 mF
TYPICAL CHARACTERISTICS
Table of Graphs
Figure
Efficiency
vs Output Current
Figure 1
Efficiency
vs Output Current
Figure 2
Output voltage
vs Output Current
Figure 3
Output Voltage
vs Output Current
Figure 4
Output Voltage
vs Output Current
Figure 5
Output Voltage
vs Output Current
Figure 6
Output Voltage
vs Output Current
Figure 7
Output Voltage
vs Output Current
Figure 8
PWM Mode Operation
Figure 9
PFM Mode Operation
Figure 10
Load Transient Response
PFM Mode
Figure 11
Load Transient Response
PFM/PWM Mode
Figure 12
Load Transient Response
PFM/PWM Mode
Figure 13
VSEL Output Voltage Response
Figure 14
Startup in 10 Ω Load
at 1.15 V Output Voltage
Figure 15
Startup in 100 Ω Load
at 0.9 V Output Voltage
Figure 16
Quiescent Current
vs Input Voltage
Figure 17
Shutdown Current
vs Input Voltage
Figure 18
Static Drain Source On-state Resistance
vs Input Voltage
Figure 19
Static Drain Source On-state Resistance
vs Input Voltage
Figure 20
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62273
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TPS62270
TPS62273
SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008................................................................................................................................................... www.ti.com
EFFICIENCY
vs
OUTPUT CURRENT
100
100
VO = 1.15 V
VI = 2.7 V
90
80
EFFICIENCY
vs
OUTPUT CURRENT
80
VI = 2.3 V
70
VI = 5 V
Efficiency - %
Efficiency - %
70
60
VI = 4.2 V
50
VI = 3.6 V
40
VI = 3.3 V
30
VI = 3.3 V
VI = 2.7 V
VI = 2.3 V
60
VI = 5 V
50
VI = 4.2 V
40
VI = 3.6 V
30
20
VO = 1.15 V,
VSEL = VI,
20
VO = 0.9 V,
VSEL = VI,
10
L = 2 mH MIPSA2520D2R2,
CO = 10 mF
10
L = 2 mH MIPSA2520D2R2,
CO = 10 mF
0
0.00001
0.0001
0.01
0.1
0.001
IO - Output Current - A
0
0.00001
1
0.001
0.01
0.1
IO - Output Current - A
Figure 2.
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
VI = 4.2 V
VI = 2.3 V VI = 2.7 V
VI = 5 V
VO - Output Voltage (DC) - V
VI = 3.6 V
PFM MODE, Voltage Positioning
VI = 3.3 V
1.15
VI = 3.6 V VI = 4.2 V
VI = 5 V
VI = 2.3 V VI = 2.7 V
VI = 3.3 V
VO = 1.15 V,
TA = -40°C
VO = 1.15 V,
TA = 25°C
1.1
0.00001
0.0001
0.01
0.1
0.001
IO - Output Current - A
1
1.1
0.00001
0.0001
Figure 3.
6
1
1.2
PFM MODE, Voltage Positioning
1.15
0.0001
Figure 1.
1.2
VO - Output Voltage (DC) - V
VO = 0.9 V
90
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0.001
0.01
IO - Output Current - A
0.1
1
Figure 4.
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62273
TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
1.2
0.930
PFM MODE, Voltage Positioning
VI = 3.6 V VI = 4.2 V
VI = 2.3 V V = 2.7 V
I
VI = 3.3 V
1.15
0.0001
0.001
0.01
IO - Output Current - A
0.1
VI = 5 V
0.910
VI = 2.3 V V = 2.7 V
I
VI = 3.3 V
0.900
0.890
VO = 0.9 V,
TA = 25°C
0.870
0.00001
1
0.0001
0.001
0.01
IO - Output Current - A
Figure 5.
Figure 6.
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
OUTPUT VOLTAGE
vs
OUTPUT CURRENT
0.1
1
0.930
0.930
PFM MODE, Voltage Positioning
PFM MODE, Voltage Positioning
VI = 3.6 V
0.920
VI = 3.6 V
VI = 4.2 V
0.910
VI = 2.3 V
VI = 2.7 V
VI = 3.3 V
0.900
0.890
0.880
0.870
0.00001
0.1
0.910
VI = 2.3 V
VI = 2.7 V
VI = 5 V
VI = 3.3 V
0.900
0.890
0.880
VO = 0.9 V,
TA = -40°C
0.0001
0.001
0.01
IO - Output Current - A
VI = 4.2 V
0.920
VI = 5 V
VO - Output Voltage (DC) - V
VO - Output Voltage (DC) - V
VI = 4.2 V
0.880
VO = 1.15 V,
TA = 85°C
1.1
0.00001
VI = 3.6 V
0.920
VI = 5 V
VO - Output Voltage (DC) - V
VO - Output Voltage (DC) - V
PFM MODE, Voltage Positioning
1
0.870
0.00001
VO = 0.9 V,
TA = 85°C
0.0001
Figure 7.
0.001
0.01
IO - Output Current - A
0.1
1
Figure 8.
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TPS62273
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PWM MODE OPERATION
VIN = 3.6 V,
VOUT = 1.15 V,
IOUT = 150 mA
VOUT 50 mV/Div
PFM MODE OPERATION
VIN = 3.6 V,
VOUT = 1.15 V,
IOUT = 10 mA
VOUT 50 mV/Div
SW 2 V/Div
SW 2 V/Div
IL 200 mA/Div
IL 200 mA/Div
Time base - 5 ms/Div
Time base - 1 ms/Div
Figure 9.
Figure 10.
LOAD TRANSIENT RESPONSE PFM MODE
LOAD TRANSIENT RESPONSE PFM/PWM MODE
VIN = 3.6 V,
VOUT = 0.9 V,
IOUT = 5 mA to 50 mA
VOUT 50 mV/Div
IOUT 50 mA/Div
50 mA
VIN = 3.6 V,
VOUT = 0.9 V,
IOUT = 150 mA to 200 mA
VOUT 50 mV/Div
Voltage Positioning
IOUT 200 mA/Div
200 mA
50 mA
5 mA
IL 200 mA/Div
IL 200 mA/Div
Time base - 50 ms/Div
Time base - 20 ms/Div
Figure 11.
8
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Figure 12.
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62273
TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
LOAD TRANSIENT RESPONSE PFM/PWM MODE
VOUT 50 mV/Div
VSEL OUTPUT VOLTAGE RESPONSE
VIN = 3.6 V,
VOUT = 1.15 V,
IOUT = 50 mA to 200 mA
Voltage Positioning
1.15 V/86 mA
VIN = 3.6 V,
VOUT = 0.9 V/1.15 V,
RLOAD = 13.3 W
VOUT 100 mV/Div
1.15 V
IOUT 200 mA/Div
0.9 V/68 mA
200 mA
VSEL 500 mV/Div
50 mA
IL 200 mA/Div
IL 500 mA/Div
Time base - 20 ms/Div
Time base - 20 ms/Div
Figure 13.
Figure 14.
STARTUP IN 10 Ω LOAD
AT 1.15 V OUTPUT VOLTAGE
STARTUP IN 100 Ω LOAD
AT 0.9 V OUTPUT VOLTAGE
EN 2 V/Div
EN 2 V/Div
SW 2 V/Div
SW 2 V/Div
VOUT 1 V/Div
VIN = 3.6 V,
VOUT = 0.9 V,
VOUT 1 V/Div
VIN = 3.6 V,
VOUT = 1.15 V,
IIN 20 mA/Div
RLOAD = 100 W,
VSEL = GND
IIN 20 mA/Div
RLOAD = 10 W,
VSEL = VIN
Time base - 100 ms/Div
Time base - 100 ms/Div
Figure 15.
Figure 16.
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TPS62270
TPS62273
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QUIESCENT CURRENT
vs
INPUT VOLTAGE
SHUTDOWN CURRENT
vs
INPUT VOLTAGE
20
0.8
EN = VIN,
Devise Not Switching
EN = GND
IQ - Quiescent Current - mA
18
ISD - Shutdown Current into VIN - mA
TA = 85ºC
16
TA = 25ºC
14
TA = -40ºC
12
10
8
2
2.5
3
3.5
4
4.5
5
VIN - Input Voltage - V
5.5
0.7
0.6
TA = 85ºC
0.5
0.4
0.3
0.2
TA = 25ºC
0
2
6
2.5
3
3.5
4
4.5
5
VIN - Input Voltage - V
STATIC DRAIN SOURCE ON-STATE RESISTANCE
vs
INPUT VOLTAGE
0.8
0.7
TA = 85ºC
TA = 25ºC
0.4
0.3
0.2
TA = -40ºC
0.1
0
2
2.5
3
3.5
4
VIN - Input Voltage - V
4.5
5
0.4
Low Side Switch
0.35
0.3
TA = 85ºC
0.25
TA = 25ºC
0.2
0.15
0.1
TA = -40ºC
0.05
0
2
2.5
Figure 19.
10
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STATIC DRAIN SOURCE ON-STATE RESISTANCE
vs
INPUT VOLTAGE
High Side Switch
0.5
5.5
Figure 18.
RDS(on) - Static Drain-Source On-State Resistance - W
RDS(on) - Static Drain-Source On-State Resistance - W
Figure 17.
0.6
TA = -40ºC
0.1
3
3.5
4
VIN - Input Voltage - V
4.5
5
Figure 20.
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62270 TPS62273
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TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
DETAILED DESCRIPTION
OPERATION
The TPS62270 step down converter operates with typically 2.25 MHz fixed frequency pulse width modulation
(PWM) at moderate to heavy load currents. At light load currents the converter automatically enters Power Save
Mode and operates then in PFM mode.
During PWM operation the converter use a unique fast response voltage mode controller scheme with input
voltage feed-forward to achieve good line and load regulation allowing the use of small ceramic input and output
capacitors. At the beginning of each clock cycle initiated by the clock signal, the High Side MOSFET switch is
turned on. The current flows now from the input capacitor via the High Side MOSFET switch through the inductor
to the output capacitor and load. During this phase, the current ramps up until the PWM comparator trips and the
control logic will turn off the switch. The current limit comparator will also turn off the switch in case the current
limit of the High Side MOSFET switch is exceeded. After a dead time preventing shoot through current, the Low
Side MOSFET rectifier is turned on and the inductor current will ramp down. The current flows now from the
inductor to the output capacitor and to the load. It returns back to the inductor through the Low Side MOSFET
rectifier.
The next cycle will be initiated by the clock signal again turning off the Low Side MOSFET rectifier and turning on
the on the High Side MOSFET switch.
Power Save Mode
If the load current decreases, the converter will enter Power Save Mode operation automatically. During Power
Save Mode the converter skips switching and operates with reduced frequency in PFM mode with a minimum
quiescent current to maintain high efficiency.
The transition from PWM mode to PFM mode occurs once the inductor current in the Low Side MOSFET switch
becomes zero, which indicates discontinuous conduction mode.
During the Power Save Mode the output voltage is monitored with a PFM comparator. As the output voltage falls
below the PFM comparator threshold of VOUT +1%, the device starts a PFM current pulse. For this the High
Side MOSFET switch will turn on and the inductor current ramps up. After the On-time expires the switch will be
turned off and the Low Side MOSFET switch will be turned on until the inductor current becomes zero.
The converter effectively delivers a current to the output capacitor and the load. If the load is below the delivered
current the output voltage will rise. If the output voltage is equal or higher than the PFM comparator threshold,
the device stops switching and enters a sleep mode with typical 15µA current consumption.
In case the output voltage is still below the PFM comparator threshold, further PFM current pulses will be
generated until the PFM comparator threshold is reached. The converter starts switching again once the output
voltage drops below the PFM comparator threshold.
With a fast single threshold comparator, the output voltage ripple during PFM mode operation can be kept very
small. The PFM Pulse is timing controlled, which allows to modify the charge transferred to the output capacitor
by the value of the inductor. The resulting PFM output voltage ripple depends in first order on the size of the
output capacitor and the inductor value. Increasing output capacitor values and/or inductor values will minimize
the output ripple.
The PFM mode is left and PWM mode entered in case the output current can not longer be supported in PFM
mode.
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Output voltage
Voltage Positioning
Vout +1%
PFM Comparator
threshold
Light load
PFM Mode
Vout (PWM)
moderate to heavy load
PWM Mode
Figure 21. Power Save Mode
100% Duty Cycle Low Dropout Operation
The device starts to enter 100% duty cycle Mode once the input voltage comes close the nominal output voltage.
In order to maintain the output voltage, the High Side MOSFET switch is turned on 100% for one or more cycles.
With further decreasing VIN the High Side MOSFET switch is turned on completely. In this case the converter
offers a low input-to-output voltage difference. This is particularly useful in battery-powered applications to
achieve longest operation time by taking full advantage of the whole battery voltage range.
The minimum input voltage to maintain regulation depends on the load current and output voltage, and can be
calculated as:
Vinmin = Voutmax + loutmax × (RDS(on)max + RL)
With
Ioutmax = maximum output current plus inductor ripple current
RDS(on)max = maximum P-channel switch RDS(on).
RL = DC resistance of the inductor
Voutmax = nominal output voltage plus maximum output voltage tolerance
Under-Voltage Lockout
The under voltage lockout circuit prevents the device from malfunctioning at low input voltages and from
excessive discharge of the battery and disables the output stage of the converter. The under-voltage lockout
threshold is typically 1.85V with falling VIN.
Output Voltage Selection VSEL
The VSEL pin features output voltage selection. The output voltages are set with an internal high precision
feedback divider network. No further external components for output voltage setting or compensation are
required. This features smallest solution size.
Connecting the VSEL pin to an external logic control signal allows simple dynamic voltage scaling for low power
processors cores. During operation of the device, the output voltage can be changed with VSEL pin.
This allows setting the core voltage of an processor according to its operating mode and helps to optimize power
consumption. Table 1 shows an overview of the selectable output voltages.
12
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TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
Table 1. VSEL Output Voltage Selection
DEVICE
OUTPUT VOLTAGE VOUT
VSEL = low
VSEL = high
TPS62270
0.9 V
1.15 V
TPS62273
2.5V
3.3V
Enable
The device is enabled setting EN pin to high. During the start up time tStart up the internal circuits are settled.
Afterwards the device activates the soft start circuit. The EN input can be used to control power sequencing in a
system with various DC/DC converters. The EN pin can be connected to the output of another converter, to drive
the EN pin high and getting a sequencing of supply rails.
Soft Start
The TPS62270 has an internal soft start circuit that controls the ramp up of the output voltage. The output
voltage ramps up from 5% to 95% of its nominal value within typ. 250µs. This limits the inrush current in the
converter during start up and prevents possible input voltage drops when a battery or high impedance power
source is used. The Soft start circuit is enabled after the start up time tStart up has expired.
Short-Circuit Protection
The High Side and Low Side MOSFET switches are short-circuit protected with maximum output current = ILIMF.
Once the High Side MOSFET switch reaches its current limit, it is turned off and the Low Side MOSFET switch is
turned on. The High Side MOSFET switch can only turn on again, once the current in the Low Side MOSFET
switch decreases below its current limit.
Thermal Shutdown
As soon as the junction temperature, TJ, exceeds 150°C (typical) the device goes into thermal shutdown. In this
mode, the High Side and Low Side MOSFETs are turned-off. The device continues its operation when the
junction temperature falls below the thermal shutdown hysteresis.
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Product Folder Link(s): TPS62270 TPS62273
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TPS62270
TPS62273
SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008................................................................................................................................................... www.ti.com
APPLICATION INFORMATION
TPS62270DRV
VIN = 2 V to 6 V
VIN
CIN
VOUT
0.9 V / 1.15 V
up to 400 mA
SW
COUT
EN
10 mF
4.7 mF
GND
L
2.2 mH
FB
1.15 V
0.9 V
VSEL
Figure 22. TPS62270DRV Application Circuit
OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR)
The TPS62270 is designed to operate with inductors in the range of 1.5µH to 4.7µH and with output capacitors in
the range of 4.7µF to 22µF. The part is optimized for operation with a 2.2µH inductor and 10µF output capacitor.
Larger or smaller inductor values can be used to optimize the performance of the device for specific operation
conditions. For stable operation, the L and C values of the output filter may not fall below 1µH effective
inductance and 3.5µF effective capacitance.
Inductor Selection
The inductor value has a direct effect on the ripple current. The selected inductor has to be rated for its dc
resistance and saturation current. The inductor ripple current (ΔIL) decreases with higher inductance and
increases with higher VI or VO.
The inductor selection has also impact on the output voltage ripple in PFM mode. Higher inductor values will lead
to lower output voltage ripple and higher PFM frequency, lower inductor values will lead to a higher output
voltage ripple but lower PFM frequency.
Equation 1 calculates the maximum inductor current under static load conditions. The saturation current of the
inductor should be rated higher than the maximum inductor current as calculated with Equation 2. This is
recommended because during heavy load transient the inductor current will rise above the calculated value.
DI L + Vout
1 * Vout
Vin
L
I Lmax + I outmax )
ƒ
(1)
DI L
2
(2)
With:
f = Switching Frequency (2.25 MHz typical)
L = Inductor Value
ΔIL = Peak to Peak inductor ripple current
ILmax = Maximum Inductor current
A more conservative approach is to select the inductor current rating just for the maximum switch current of the
corresponding converter.
Accepting larger values of ripple current allows the use of low inductance values, but results in higher output
voltage ripple, greater core losses, and lower output current capability.
The total losses of the coil have a strong impact on the efficiency of the DC/DC conversion and consist of both
the losses in the dc resistance (R(DC)) and the following frequency-dependent components:
• The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies)
• Additional losses in the conductor from the skin effect (current displacement at high frequencies)
• Magnetic field losses of the neighboring windings (proximity effect)
• Radiation losses
14
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TPS62270
TPS62273
www.ti.com................................................................................................................................................... SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008
Table 2. List of Inductors
DIMENSIONS
[mm3]
INDUCTOR TYPE
SUPPLIER
2.5 × 2.0 × 1.0
MIPS2520
FDK
2.5 × 2.0 × 1.2
MIPSA2520
FDK
2.5 × 2.0 × 1.0
KSLI-252010AG2R2
Hitachi Metals
2.5 × 2.0 × 1.2
LQM2HPN2R2MJ0L
Murata
Output Capacitor Selection
The advanced fast-response voltage mode control scheme of the TPS62270 allows the use of tiny ceramic
capacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple and are
recommended. The output capacitor requires either an X7R or X5R dielectric. Y5V and Z5U dielectric capacitors,
aside from their wide variation in capacitance over temperature, become resistive at high frequencies.
At nominal load current, the device operates in PWM mode and the RMS ripple current is calculated as:
1 * Vout
1
Vin
I RMSCout + Vout
ƒ
L
2
Ǹ3
(3)
At nominal load current, the device operates in PWM mode and the overall output voltage ripple is the sum of the
voltage spike caused by the output capacitor ESR plus the voltage ripple caused by charging and discharging the
output capacitor:
DVout + Vout
1 * Vout
Vin
L
ƒ
ǒ8
1
Cout
ƒ
Ǔ
) ESR
(4)
At light load currents the converter operates in Power Save Mode and the output voltage ripple is dependent on
the output capacitor and inductor value. Larger output capacitor and inductor values minimize the voltage ripple
in PFM mode and tighten DC output accuracy in PFM mode.
Input Capacitor Selection
An input capacitor is required for best input voltage filtering, and minimizing the interference with other circuits
caused by high input voltage spikes. For most applications, a 4.7µF to 10µF ceramic capacitor is recommended.
Because ceramic capacitor loses up to 80% of its initial capacitance at 5 V, it is recommended that 10µF input
capacitors be used for input voltages >4.5V. The input capacitor can be increased without any limit for better
input voltage filtering. Take care when using only small ceramic input capacitors. When a ceramic capacitor is
used at the input and the power is being supplied through long wires, such as from a wall adapter, a load step at
the output or VIN step on the input can induce ringing at the VIN pin. This ringing can couple to the output and
be mistaken as loop instability or could even damage the part by exceeding the maximum ratings.
Table 3. List of Capacitors
CAPACITANCE
TYPE
SIZE mm3
SUPPLIER
4.7 µF
GRM188R60J475K
0603: 1.6 × 0.8 × 0.8 mm3
Murata
10 µF
GRM188R60J106M69D
0603: 1.6 × 0.8 × 0.8 mm3
Murata
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Product Folder Link(s): TPS62270 TPS62273
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TPS62270
TPS62273
SLVS799B – NOVEMBER 2007 – REVISED JUNE 2008................................................................................................................................................... www.ti.com
LAYOUT CONSIDERATIONS
As for all switching power supplies, the layout is an important step in the design. Proper function of the device
demands careful attention to PCB layout. Care must be taken in board layout to get the specified performance. If
the layout is not carefully done, the regulator could show poor line and/or load regulation, stability issues as well
as EMI problems. It is critical to provide a low inductance, impedance ground path. Therefore, use wide and
short traces for the main current paths. The input capacitor should be placed as close as possible to the IC pins
as well as the inductor and output capacitor.
Connect the GND Pin of the device to the Power Pad of the PCB and use this Pad as a star point. Use a
common Power GND node and a different node for the Signal GND to minimize the effects of ground noise.
Connect these ground nodes together to the Power Pad (star point) underneath the IC. Keep the common path
to the GND PIN, which returns the small signal components and the high current of the output capacitors as
short as possible to avoid ground noise. The FB line should be connected right to the output capacitor and routed
away from noisy components and traces (e.g., SW line).
COUT
VOUT
U1
GND
3.3mm
VIN CIN
L1
Total area
21.5 mm²
6.5 mm
Figure 23. Suggested Board Layout
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PACKAGE OPTION ADDENDUM
www.ti.com
11-Jul-2008
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPS62270DRVR
ACTIVE
SON
DRV
6
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62270DRVRG4
ACTIVE
SON
DRV
6
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62270DRVT
ACTIVE
SON
DRV
6
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62270DRVTG4
ACTIVE
SON
DRV
6
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62273DRVR
ACTIVE
SON
DRV
6
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62273DRVRG4
ACTIVE
SON
DRV
6
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62273DRVT
ACTIVE
SON
DRV
6
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TPS62273DRVTG4
ACTIVE
SON
DRV
6
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
Lead/Ball Finish
MSL Peak Temp (3)
(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.
Addendum-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
4-Jul-2008
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
TPS62270DRVR
SON
DRV
6
SPQ
Reel
Reel
Diameter Width
(mm) W1 (mm)
A0 (mm)
B0 (mm)
K0 (mm)
P1
(mm)
W
Pin1
(mm) Quadrant
3000
179.0
8.4
2.2
2.2
1.2
4.0
8.0
Q2
TPS62270DRVT
SON
DRV
6
250
179.0
8.4
2.2
2.2
1.2
4.0
8.0
Q2
TPS62273DRVR
SON
DRV
6
3000
179.0
8.4
2.2
2.2
1.2
4.0
8.0
Q2
TPS62273DRVT
SON
DRV
6
250
179.0
8.4
2.2
2.2
1.2
4.0
8.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
4-Jul-2008
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
TPS62270DRVR
SON
DRV
6
3000
195.0
200.0
45.0
TPS62270DRVT
SON
DRV
6
250
195.0
200.0
45.0
TPS62273DRVR
SON
DRV
6
3000
195.0
200.0
45.0
TPS62273DRVT
SON
DRV
6
250
195.0
200.0
45.0
Pack Materials-Page 2
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