TI TPS61087

TPS61087
Actual Size
3 mm x 3 mm
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650 kHz/1.2 MHz, 18.5 V STEP-UP DC-DC CONVERTER
FEATURES
1
•
•
•
•
•
•
•
APPLICATIONS
2.5 V to 6.0 V Input Voltage Range
18.5 V Boost Converter With 3.2 A Switch
Current
650 kHz/1.2 MHz Selectable Switching
Frequency
Adjustable Soft-Start
Thermal Shutdown
Undervoltage Lockout
10-Pin QFN Package
•
•
•
•
•
•
•
Handheld Devices
GPS Receiver
Digital Still Camera
Portable Applications
DSL Modem
PCMCIA Card
TFT LCD Bias Supply
DESCRIPTION
The TPS61087 is a high frequency, high efficiency DC to DC converter with an integrated 3.2 A, 0.13 Ω power
switch capable of providing an output voltage up to 18.5 V. The selectable frequency of 650 kHz and 1.2 MHz
allows the use of small external inductors and capacitors and provides fast transient response. The external
compensation allows optimizing the application for specific conditions. A capacitor connected to the soft-start pin
minimizes inrush current at startup.
L
3.3 mH
VIN
2.5 V to 6 V
Cin
2* 10 mF
16 V
8
Cby
1 mF
16 V
3
9
4
5
IN
SW
EN
SW
FREQ
FB
AGND
COMP
PGND
SS
TPS61087
D
SL22
6
VS
15 V/500 mA
R1
200 kW
7
Cout
4* 10 mF
25 V
2
R2
18 kW
1
Rcomp
100 kW
10
Css
100 nF
Ccomp
820 pF
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 © 2008, Texas Instruments Incorporated
TPS61087
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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 (1) (2)
(1)
(2)
TA
ORDERING
PACKAGE
PACKAGE MARKING
–40 to 85°C
TPS61087DRC
QFN-10 (DRC)
PMOQ
The DRC package is available taped and reeled.
For the most current package and ordering information, see the Package Option Addendum at the end
of this document, or see the TI website at www.ti.com.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1)
VALUE
UNIT
–0.3 to 7.0
V
–0.3 to 7.0
V
20
V
ESD rating HBM
2
kV
ESD rating MM
200
V
ESD rating CDM
500
V
Input voltage range IN
(2)
Voltage range on pins EN, FB, SS, FREQ, COMP
Voltage on pin SW
Continuous power dissipation
See Dissipation Rating Table
Operating junction temperature range
–40 to 150
°C
Storage temperature range
–65 to 150
°C
260
°C
Lead temperature (soldering, 10 sec)
(1)
(2)
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.
DISSIPATION RATINGS (1) (2)
(1)
(2)
PACKAGE
RθJA
TA ≤ 25°C
POWER RATING
TA = 70°C
POWER RATING
TA = 85°C
POWER RATING
QFN
30°C/W
3.3 W
1.8 W
1.3 W
PD = (TJ – TA)/RθJA.
The exposed thermal die is soldered to the PCB using thermal vias. For more information, please refer
to the Texas Instruments Application report SLMA002 regarding thermal characteristics of the
PowerPAD package.
RECOMMENDED OPERATING CONDITIONS
MIN
VIN
Input voltage range
VS
Boost output voltage range
TA
Operating free-air temperature
TJ
Operating junction temperature
2
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TYP
MAX
UNIT
2.5
6.0
V
VIN +
0.5
18.5
V
–40
85
°C
–40
125
°C
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ELECTRICAL CHARACTERISTICS
VIN = 5 V, EN = IN, Vs = 15 V, TA = –40°C to 85°C, typical values are at TA = 25°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY
VIN
Input voltage range
2.5
IQ
Operating quiescent current into IN
Device not switching, VFB = 1.3 V
ISDVIN
Shutdown current into IN
EN = GND
VUVLO
Under-voltage lockout threshold
VIN falling
TSD
Thermal shutdown
TSDHYS
Thermal shutdown hysteresis
75
VIN rising
6.0
V
100
µA
1
µA
2.4
V
2.5
Temperature rising
V
150
°C
14
°C
LOGIC SIGNALS EN, FREQ
VIH
High level input voltage
VIN = 2.5 V to 6.0 V
VIL
Low level input voltage
VIN = 2.5 V to 6.0 V
2
0.5
V
V
IINLEAK
Input leakage current
EN = FREQ = GND
0.1
µA
18.5
V
BOOST CONVERTER
VS
Boost output voltage
VIN +
0.5
VFB
Feedback regulation voltage
1.230
gm
Transconductance error amplifier
IFB
Feedback input bias current
VFB = 1.238 V
0.1
µA
RDS(ON)
N-channel MOSFET on-resistance
VIN = VGS = 5 V, ISW = current limit
0.13
0.18
Ω
VIN = VGS = 3V, ISW = current limit
0.16
0.23
ISWLEAK
SW leakage current
10
µA
ILIM
N-Channel MOSFET current limit
4.0
4.8
A
ISS
Soft-start current
VSS = 1.238 V
7
10
13
µA
fosc
Oscillator frequency
FREQ = high
0.9
1.2
1.5
MHz
FREQ = low
480
650
820
kHz
1.238
1.246
EN = GND, VSW = 6.0V
3.2
Line regulation
VIN = 2.5 V to 6.0 V, IOUT = 10 mA
Load regulation
VIN = 5.0 V, IOUT = 1 mA to 1 A
0.0002
%/V
0.11
%/A
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V
µA/V
107
3
TPS61087
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PIN ASSIGNMENT
DRC PACKAGE
(TOP VIEW)
COMP
SS
FB
EN
FREQ
Thermal
Pad
IN
AGND
SW
PGND
SW
10-PIN 3mm x 3mm x 1mm QFN
TERMINAL FUNCTIONS
TERMINAL
NAME
NO.
I/O
DESCRIPTION
COMP
1
I/O
FB
2
I
Feedback pin
EN
3
I
Shutdown control input. Connect this pin to logic high level to enable the device
AGND
4
Analog ground
PGND
5
Power ground
SW
6, 7
IN
8
FREQ
9
SS
10
Compensation pin
Switch pin
Input supply pin
I
Frequency select pin. The power switch operates at 650 kHz if FREQ is connected to GND and at 1.2 MHz if
FREQ is connected to IN
Soft-start control pin. Connect a capacitor to this pin if soft-start needed. Open = no soft-start
TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
FIGURE
η
Efficiency
vs Load current, VS = 15 V, VIN = 5 V
Figure 1
η
Efficiency
vs Load current, VS = 9 V, VIN = 3.3 V
Figure 2
PWM switching - discontinuous conduction
Figure 3
PWM switching - continuous conduction
Figure 4
Load transient response
at High frequency
Figure 5
Load transient response
at Low frequency
Figure 6
Soft-start
4
Figure 7
Supply current
vs Supply voltage
Figure 8
Frequency
vs Load current
Figure 9
Frequency
vs Supply voltage
Figure 10
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EFFICIENCY
vs
LOAD CURRENT
100
100
90
90
70
f = 650 kHz
L = 6.8 mH
60
50
40
70
f = 1.2 Mhz
L = 3.3 mH
60
50
40
30
30
20
VIN = 5 V
VS = 15 V
10
0
0.0 0.1
f = 650 kHz
L = 6.8 mH
80
f = 1.2 Mhz
L = 3.3 mH
Efficiency - %
80
Efficiency - %
EFFICIENCY
vs
LOAD CURRENT
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
IO - Load current - A
20
VIN = 3.3 V
VS = 9 V
10
0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
IO - Load current - A
Figure 1.
Figure 2.
PWM SWITCHING
DISCONTINUOUS CONDUCTION MODE
PWM SWITCHING
CONTINUOUS CONDUCTION MODE
VSW
10 V/div
VSW
10 V/div
VS_AC
50 mV/div
VS_AC
50 mV/div
VIN = 5 V
VS = 15 V/2 mA
Il
1 A/div
VIN = 5 V
VS = 15 V/500 mA
IL
500 mA/div
200 ns/div
200 ns/div
Figure 3.
Figure 4.
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LOAD TRANSIENT RESPONSE
HIGH FREQUENCY (1.2 MHz)
LOAD TRANSIENT RESPONSE
LOW FREQUENCY (650 kHz)
VIN = 5 V
VS = 15 V
VIN = 5 V
VS = 15 V
COUT = 40 mF
L = 6.8 mH
Rcomp = 110 kW
Ccomp = 1 nF
VS_AC
100 mV/div
COUT = 40 mF
L = 3.3 mH
Rcomp = 150 kW
Ccomp = 820 pF
IOUT = 100 mA - 500 mA
VS_AC
100 mV/div
IOUT = 100 mA - 500 mA
IOUT
200 mA/div
IOUT
200 mA/div
200 ms/div
200 ms/div
Figure 5.
Figure 6.
SOFT-START
SUPPLY CURRENT
vs
SUPPLY VOLTAGE
2.0
SWITCHING
f = 1.2 Mhz
L = 3.3 mH
1.8
EN
5 V/div
VIN = 5 V
VS = 15 V/500 mA
VS
5 V/div
CSS = 100 nF
IL
1 A/div
ICC - Supply Current - mA
1.6
1.4
SWITCHING
f = 650 kHz
L = 6.8 mH
1.2
1.0
0.8
0.6
0.4
0.2
2 ms/div
0
2.5
Figure 7.
6
NOT SWITCHING
3.0
3.5
4.0
4.5
5.0
VCC - Supply Voltage - V
5.5
6.0
Figure 8.
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FREQUENCY
vs
LOAD CURRENT
FREQUENCY
vs
SUPPLY VOLTAGE
1600
1400
VS = 15 V / 200 mA
1400
FREQ = VIN
1200
FREQ = VIN
L = 3.3 mH
1000
800
FREQ = GND
L = 6.8 mH
600
400
VIN = 5 V
VS = 15 V
200
0
0.0 0.1
L = 3.3 mH
1000
f - Frequency - kHz
f - Frequency - kHz
1200
0.2
0.3
0.4 0.5 0.6
0.7 0.8 0.9
800
600
FREQ = GND
L = 6.8 mH
400
200
1.0
0
2.5
IO - Load current - mA
Figure 9.
3
3.5
4
4.5
5
VCC - Supply Voltage - V
5.5
6
Figure 10.
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DETAILED DESCRIPTION
VIN
VS
EN
SS
IN
SW
FREQ
SW
Current limit
and
Soft Start
Toff Generator
AGND
Bias Vref = 1.24 V
UVLO
Thermal Shutdown
Ton
PWM
Generator
Gate Driver of
Power
Transistor
COMP
GM Amplifier
FB
Vref
PGND
Figure 11. Block Diagram
The boost converter is designed for output voltages up to 18.5 V with a switch peak current limit of 3.2 A
minimum. The device, which operates in a current mode scheme with quasi-constant frequency, is externally
compensated for maximum flexibility and stability. The switching frequency is selectable between 650 kHz and
1.2 MHz and the minimum input voltage is 2.5 V. To control the inrush current at start-up a soft-start pin is
available.
During the on-time, the voltage across the inductor causes the current in it to rise. When the current reaches a
threshold value set by the internal GM amplifier, the power transistor is turned off, the energy stored into the
inductor is then released and the current flows through the Schottky diode towards the output of the boost
converter. The off-time is fixed for a certain VIN and VS, and therefore maintains the same frequency when
varying these parameters.
However, for different output loads, the frequency may slightly change due to the voltage drop across the Rdson
of the power transistor which will have an effect on the voltage across the inductor and thus on tON (tOFF remains
fixed). Some slight frequency changes might also appear with a fixed output load due to the fact that the output
voltage VS is not sensed directly but via the SW Pin, which affects accuracy.
Because of the quasi-constant frequency behavior of the device, the TPS61087 eliminates the need for an
internal oscillator and slope compensation, which provides better stability for the system over a wide of input and
output voltages range, and more stable and accurate current limiting operation compared to boost converters
operating with a conventional PWM scheme. The TPS61087 topology has also the benefits of providing very
good load and line regulations, and excellent load transient response.
8
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Design Procedure
The first step in the design procedure is to verify that the maximum possible output current of the boost converter
supports the specific application requirements. A simple approach is to estimate the converter efficiency, by
taking the efficiency numbers from the provided efficiency curves or to use a worst case assumption for the
expected efficiency, e.g. 90%.
D = 1-
1. Duty Cycle:
VIN ´h
VS
DI ö
æ
Iout = ç I swpeak - L ÷ ´ (1 - D )
2 ø
è
2. Maximum output current:
3. Peak switch current:
DI L =
with
I swpeak =
I
DI L
+ out
2 1- D
VIN ´ D
fs ´ L
and
Iswpeak = converter switch current (minimum switch current limit = 3.2 A)
fs = Converter switching frequency (typically 1.2 MHz)
L = Selected inductor value
η = Estimated converter efficiency (please use the number from the efficiency plots or 90% as an estimation)
ΔIL = Inductor peak-to-peak ripple current
The peak switch current is the steady state peak switch current that the integrated switch, inductor and external
Schottky diode has to be able to handle. The calculation must be done for the minimum input voltage where the
peak switch current is the highest.
Soft-start
The boost converter has an adjustable soft-start to prevent high inrush current during start-up. To minimize the
inrush current during start-up an external capacitor connected to the soft-start pin SS is used to slowly ramp up
the internal current limit of the boost converter when charged with a constant current. When the EN pin is pulled
high, the soft-start capacitor CSS) is immediately charged to 0.3 V. The capacitor is then charged at a constant
current of 10 µA typically until the output of the boost converter VS has reached its Power Good threshold (90%
of VS nominal value). During this time, the SS voltage directly controls the peak inductor current, starting with 0 A
at VSS = 0.3 V up to the full current limit at VSS ≈ 800 mV. The maximum load current is available after the
soft-start is completed. The larger the capacitor the slower the ramp of the current limit and the longer the
soft-start time. A 100 nF capacitor is usually sufficient for most of the applications. When the EN pin is pulled
low, the soft-start capacitor is discharged to ground.
Inductor Selection
The TPS61087 is designed to work with a wide range of inductors. The main parameter for the inductor selection
is the saturation current of the inductor which should be higher than the peak switch current as calculated in the
Design Procedure section with additional margin to cover for heavy load transients. An alternative, more
conservative, is to choose an inductor with a saturation current at least as high as the maximum switch current
limit of 4.8 A. The other important parameter is the inductor DC resistance. Usually the lower the DC resistance
the higher the efficiency. It is important to note that the inductor DC resistance is not the only parameter
determining the efficiency. Especially for a boost converter where the inductor is the energy storage element, the
type and core material of the inductor influences the efficiency as well. At high switching frequencies of 1.2 MHz
inductor core losses, proximity effects and skin effects become more important. Usually an inductor with a larger
form factor gives higher efficiency. The efficiency difference between different inductors can vary between 2% to
10%. For the TPS61087, inductor values between 3 µH and 6 µH are a good choice with a switching frequency
of 1.2 MHz, typically 3.3 µH. At 650 kHz we recommend inductors between 6 µH and 13 µH, typically 6.8 µH.
Possible inductors are shown in Table 1.
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Typically, it is recommended that the inductor current ripple is below 20% of the average inductor current. The
following equation can therefore be used to calculate the inductor value:
2
æ VS-VIN ö æ h ö
æ VIN ö
L= ç
×ç
÷×ç
÷
÷
è VS ø
è Iout_max×f ø è 0.35 ø
(1)
Table 1. Inductor Selection
L
(µH)
SUPPLIER
COMPONENT
CODE
SIZE
(L×W×H mm)
DCR TYP
(mΩ)
Isat (A)
4.2
Sumida
CDRH5D28
4.7
5.7 × 5.7 × 3
23
2.2
Würth Elektronik
7447785004
5.9 × 6.2 × 3.3
60
2.5
5
Coilcraft
MSS7341
7.3 × 7.3 × 4.1
24
2.9
1.2 MHz
5
Sumida
CDRH6D28
7×7×3
23
2.4
4.6
Sumida
CDR7D28
7.6 × 7.6 × 3
38
3.15
4.7
Würth Elektronik
7447789004
7.3 × 7.3 × 3.2
33
3.9
3.3
Würth Elektronik
7447789003
7.3 × 7.3 × 3.2
30
4.2
744778910
7.3 × 7.3 × 3.2
51
2.2
650 kHz
10
Würth Elektronik
10
Sumida
CDRH8D28
8.3 × 8.3 × 3
36
2.7
6.8
Sumida
CDRH6D26HPNP
7 × 7 × 2.8
52
2.9
6.2
Sumida
CDRH8D58
8.3 × 8.3 × 6
25
3.3
10
Coilcraft
DS3316P
12.95 × 9.40 ×
5.08
80
3.5
10
Sumida
CDRH8D43
8.3 × 8.3 × 4.5
29
4
6.8
Würth Elektronik
74454068
12.7 × 10 × 4.9
55
4.1
Rectifier Diode Selection
To achieve high efficiency a Schottky type should be used for the rectifier diode. The reverse voltage rating
should be higher than the maximum output voltage of the converter. The averaged rectified forward current Iavg,
the Schottky diode needs to be rated for, is equal to the output current Iout:
I avg = I out
Usually a Schottky diode with 2 A maximum average rectified forward current rating is sufficient for most
applications. The Schottky rectifier can be selected with lower forward current capability depending on the output
current Iout but has to be able to dissipate the power. The dissipated power is the average rectified forward
current times the diode forward voltage.
PD = Iavg × Vforward
Typically the diode should be able to dissipate around 500mW depending on the load current and forward
voltage.
Table 2. Rectifier Diode Selection
10
CURRENT
RATING Iavg
Vr
Vforward / Iavg
2A
20 V
0.44 V / 2 A
Vishay Semiconductor
SL22
2A
20 V
0.5 V / 2 A
Fairchild Semiconductor
SS22
SUPPLIER
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COMPONENT CODE
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Setting the Output Voltage
The output voltage is set by an external resistor divider. Typically, a minimum current of 50 µA flowing through
the feedback divider gives good accuracy and noise covering. A standard low side resistor of 18 kΩ is typically
selected. The resistors are then calculated as:
R2 =
Vref
» 18k W
70 m A
æ VS
ö
- 1÷
R1 = R 2 ´ ç
Vref
è
ø
(2)
Compensation (COMP)
The regulator loop can be compensated by adjusting the external components connected to the COMP pin. The
COMP pin is the output of the internal transconductance error amplifier. Standard values of RCOMP = 16 kΩ and
CCOMP = 2.7 nF will work for the majority of the applications.
Please refer to Table 3 for dedicated compensation networks giving an improved load transient response. The
following equations can be used to calculate RCOMP and CCOMP:
110 × V IN × V S × Cout
L × Iout_max
R COMP =
C COMP =
V S × Cout
7.5 × Iout_max × R COMP
(3)
Table 3. Recommended Compensation Network Values at High/Low Frequency
FREQUENCY
L
VS
15 V
High (1.2 MHz)
3.3 H
12 V
9V
15 V
Low (650 kHz)
6.8 H
12 V
9V
VIN ± 20%
RCOMP
CCOMP
5V
100 kΩ
820 pF
3.3 V
91 kΩ
1.2 nF
820 pF
5V
68 kΩ
3.3 V
68 kΩ
1.2 nF
5V
39 kΩ
820 pF
3.3 V
39 kΩ
1.2 nF
5V
51 kΩ
1.5 nF
3.3 V
47 kΩ
2.7 nF
5V
33 kΩ
1.5 nF
3.3 V
33 kΩ
2.7 nF
5V
18 kΩ
1.5 nF
3.3 V
18 kΩ
2.7 nF
Table 3 gives conservatives Rcomp and Comp values for certain inductors, input and output voltages providing a
very stable system. For a faster response time, a higher Rcomp value can be used to enlarge the bandwidth, as
well as a slightly lower value of Ccomp to keep enough phase margin. These adjustments should be performed
in parallel with the load transient response monitoring of TPS61087.
Input Capacitor Selection
For good input voltage filtering low ESR ceramic capacitors are recommended. TPS61087 has an analog input
IN. Therefore, a 1 µF bypass is highly recommended as close as possible to the IC from IN to GND.
Two 10 µF (or one 22 F) ceramic input capacitors are sufficient for most of the applications. For better input
voltage filtering this value can be increased. Refer to Table 4 and typical applications for input capacitor
recommendations.
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Output Capacitor Selection
For best output voltage filtering a low ESR output capacitor like ceramic capcaitor is recommended. Four 10 µF
ceramic output capacitors (or two 22 µF) work for most of the applications. Higher capacitor values can be used
to improve the load transient response. Refer to Table 4 for the selection of the output capacitor.
Table 4. Rectifier Input and Output Capacitor Selection
CAPACITOR
VOLTAGE RATING
SUPPLIER
COMPONENT CODE
CIN
22 µF/1206
16 V
Taiyo Yuden
EMK316 BJ 226ML
IN bypass
1 µF/0603
16 V
Taiyo Yuden
EMK107 BJ 105KA
COUT
10 µF/1206
25 V
Taiyo Yuden
TMK316 BJ 106KL
Frequency Select Pin (FREQ)
The frequency select pin FREQ allows to set the switching frequency of the device to 650 kHz (FREQ = low) or
1.2 MHz (FREQ = high). Higher switching frequency improves load transient response but reduces slightly the
efficiency. The other benefits of higher switching frequency are a lower output ripple voltage. Usually, it is
recommended to use 1.2 MHz switching frequency unless light load efficiency is a major concern.
Undervoltage Lockout (UVLO)
To avoid mis-operation of the device at low input voltages an undervoltage lockout is included that disables the
device, if the input voltage falls below 2.4 V.
Thermal Shutdown
A thermal shutdown is implemented to prevent damages due to excessive heat and power dissipation. Typically
the thermal shutdown threshold is 150°C. When the thermal shutdown is triggered the device stops switching
until the temperature falls below typically 136°C. Then the device starts switching again.
12
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TPS61087
www.ti.com ............................................................................................................................................................... SLVS821A – MAY 2008 – REVISED JUNE 2008
APPLICATION INFORMATION
L
3.3 mH
VIN
5 V ± 20%
Cin
2* 10 mF
16 V
8
Cby
1 mF
16 V
3
9
4
5
IN
SW
EN
SW
FREQ
FB
AGND
COMP
PGND
SS
VS
15 V/900 mA max
D
SL22
6
R1
200 kW
7
Cout
4* 10 mF
25 V
2
R2
18 kW
1
Rcomp
100 kW
10
Css
100 nF
TPS61087
Ccomp
820 pF
Figure 12. Typical Application, 5 V to 15 V (fsw = 1.2 MHz)
L
6.8 mH
VIN
5 V ± 20%
Cin
2* 10 mF
16 V
8
Cby
1 mF
16 V
3
9
4
5
IN
SW
EN
SW
FREQ
FB
AGND
COMP
PGND
SS
TPS61087
VS
15 V/900 mA max
D
SL22
6
R1
200 kW
7
Cout
4* 10 mF
25 V
2
R2
18 kW
1
Rcomp
51 kW
10
Css
100 nF
Ccomp
1.6 pF
Figure 13. Typical Application, 5 V to 15 V (fsw = 650 kHz)
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Product Folder Link(s): TPS61087
13
TPS61087
SLVS821A – MAY 2008 – REVISED JUNE 2008 ............................................................................................................................................................... www.ti.com
L
3.3 mH
VIN
3.3 V ± 20%
Cin
2* 10 mF
16 V
8
Cby
1 mF
16 V
3
9
4
5
IN
SW
EN
SW
FREQ
FB
AGND
COMP
PGND
SS
D
SL22
6
VS
9 V/950 mA max
R1
110 kW
7
Cout
4* 10 mF
25 V
2
R2
18 kW
1
Rcomp
38 kW
10
Css
100 nF
TPS61087
Ccomp
1.2 nF
Figure 14. Typical Application, 3.3 V to 9 V (fsw = 1.2 MHz)
L
6.8 mH
VIN
3.3 V ± 20%
Cin
2* 10 mF
16 V
8
Cby
1 mF
16 V
3
9
4
5
IN
SW
EN
SW
FREQ
FB
AGND
COMP
PGND
SS
TPS61087
VS
9 V/950 mA max
D
SL22
6
R1
110 kW
7
Cout
4* 10 mF
25 V
2
R2
18 kW
1
Rcomp
18 kW
10
Css
100 nF
Ccomp
2.5 nF
Figure 15. Typical Application, 3.3 V to 9 V (fsw = 650 kHz)
14
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Product Folder Link(s): TPS61087
TPS61087
www.ti.com ............................................................................................................................................................... SLVS821A – MAY 2008 – REVISED JUNE 2008
Riso
10 kW
L
6.8 mH
VIN
5 V ± 20%
Cin
2* 10 mF/
16 V
Cby
1 mF/16 V
8
3
9
4
SW
IN
SW
EN
FREQ
FB
AGND
COMP
PGND
SS
5
TPS61087
VS
15 V/300 mA
BC857C
D
SL22
6
Ciso
1 mF/ 25 V
7
R1
200 kW
2
Cout
4*10 mF/
25 V
R2
18 kW
1
Rcomp
51 kW
10
Css
100 nF
Ccomp
1.8 nF
Figure 16. Typical Application with External Load Disconnect Switch
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Product Folder Link(s): TPS61087
15
TPS61087
SLVS821A – MAY 2008 – REVISED JUNE 2008 ............................................................................................................................................................... www.ti.com
TFT LCD APPLICATION
T2
BC850B
3. Vs
Vgl
-7 V/20 mA
T1
BC857B
-Vs
R8
7 kW
C14
470 nF/
25 V
C16
100 nF/
50 V
D2
BAV99
C15
100 nF/
50 V
D3
BAV99
D4
BAV99
C18
470 nF/
50 V
D5
BAV99
C17
100 nF/
50 V
D6
BAV99
D8
BZX84C7V5
Vgh
27 V/20 mA
R10
13 kW
2. Vs
C20
1 mF/
35 V
C19
470 nF/
50 V
D9
BZX84C27V
D7
BAV99
L
3.3 mH
VIN
5 V ± 20%
Cin
2*10 mF/
16 V
Cby
1 mF/
16 V 8
D
SL22
IN
SW
EN
SW
3
7
9
R1
200 kW
Cout
4*10µF/
25V
2
FREQ
FB
4
5
VS
15 V/500 mA
6
R2
18 kW
1
AGND
COMP
PGND
SS
TPS61087
Rcomp
100 kW
10
Css
100 nF
Ccomp
820 pF
Figure 17. Typical Application 5 V to 15 V (fsw = 1.2 MHz) for TFT LCD with External Charge Pumps (VGH,
VGL)
16
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Product Folder Link(s): TPS61087
TPS61087
www.ti.com ............................................................................................................................................................... SLVS821A – MAY 2008 – REVISED JUNE 2008
WHITE LED APPLICATIONS
L
6.8 mH
VIN
5 V ± 20%
Cin
2* 10 mF/
16 V
Cby
1 mF/ 16 V
6
8
3
9
4
5
IN
SW
EN
SW
D
SL22
Dz
BZX84C 18 V
VS
500 mA
3S3P wLED
LW E67C
7
Cout
4* 10 mF/
25 V
2
FREQ
FB
AGND
COMP
PGND
SS
1
Rcomp
51 kW
10
TPS61087
Css
100 nF
Rsense
14 W
Ccomp
1.8 nF
Figure 18. Simple Application (5 V input voltage) (fsw = 650 kHz) for wLED Supply (3S3P) (with optional
clamping Zener diode)
L
6.8 mH
VIN
5 V ± 20%
Cin
2* 10 mF/
16 V
Cby
1 mF/ 16 V
3
9
4
PWM
100 Hz to 500 Hz
6
8
5
IN
SW
EN
SW
D
SL22
Dz
BZX84C 18 V
VS
500 mA
3S3P wLED
LW E67C
7
Cout
4* 10 mF/
25 V
2
FREQ
FB
AGND
COMP
PGND
SS
TPS61087
1
Rcomp
51 kW
10
Css
100 nF
Rsense
14 W
Ccomp
1.8 nF
Figure 19. Simple Application (5 V input voltage) (fsw = 650 kHz) for wLED Supply (3S3P) with Adjustable
Brightness Control using a PWM Signal on the Enable Pin (with optional clamping Zener diode)
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TPS61087
SLVS821A – MAY 2008 – REVISED JUNE 2008 ............................................................................................................................................................... www.ti.com
L
6.8 mH
VIN
5 V ± 20%
Cin
2* 10 mF/
16 V
Cby
1 mF/ 16 V
6
8
3
9
IN
SW
EN
SW
D
SL22
Dz
BZX84C 18 V
VS
500 mA
3S3P wLED
LW E67C
7
2
FREQ
FB
AGND
COMP
PGND
SS
Cout
4* 10 mF/
25 V
R1
180 kW
4
5
TPS61087
1
R2
Rcomp
127 kW
51 kW
10
Css
100 nF
Ccomp
1.8 nF
Rsense
33 W
Analog Brightness Control
3.3 V ~ wLED off
0 V ~ lled = 30 mA (each string)
PWM Signal
Can be used Swinging from 0 V to 3.3 V
Figure 20. Simple Application (5 V input voltage) (fsw = 650 kHz) for wLED Supply (3S3P) with Adjustable
Brightness Control using an Analog Signal on the Feedback Pin (with optional clamping Zener diode)
18
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PACKAGE OPTION ADDENDUM
www.ti.com
4-Jun-2008
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPS61087DRCR
ACTIVE
SON
DRC
10
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS61087DRCT
ACTIVE
SON
DRC
10
250
CU NIPDAU
Level-2-260C-1 YEAR
Green (RoHS &
no Sb/Br)
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-Jun-2008
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
Diameter Width
(mm) W1 (mm)
A0 (mm)
B0 (mm)
K0 (mm)
P1
(mm)
W
Pin1
(mm) Quadrant
TPS61087DRCR
SON
DRC
10
3000
330.0
12.4
3.3
3.3
1.1
8.0
12.0
Q2
TPS61087DRCT
SON
DRC
10
250
180.0
12.4
3.3
3.3
1.1
8.0
12.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
4-Jun-2008
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
TPS61087DRCR
SON
DRC
10
3000
346.0
346.0
29.0
TPS61087DRCT
SON
DRC
10
250
346.0
346.0
29.0
Pack Materials-Page 2
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