TPS61166
www.ti.com.......................................................................................................................................................................................... SLVS991 – SEPTEMBER 2009
WHITE LED DRIVER WITH INTEGRATED POWER DIODE AND FAST BURST MODE
DIMMING
FEATURES
1
•
•
•
•
•
•
•
•
•
•
DESCRIPTION
IC Supply Range: 2.5-V to 6-V
Power Stage Input Range: 4.5-V to 10-V
Integrated 1.1-A / 20-V Internal Switch FET and
Power Diode
Drive up to 5 LEDs in Series
Fast on/off LED Current Within 1-µs in
Brightness Dimming
Burst PWM Dimming Method With Frequency
Range From 60-Hz to 40-kHz
Built-in Soft Start-up
Over Load Protection
Over Voltage Protection
2.5 × 2.5 × 0.8 mm SON Package
The TPS61166 is a boost converter with a 20-V rated
integrated switch FET and power diode that drives up
to 5 LEDs in series. This device integrates a high
side switch FET that can turn on/off the LED current
within 1-µs of the applied external PWM signal. The
high side switch also provides input-to-output
isolation during IC shutdown.
The default white LED current is set with the external
sensor resistor R1, and the feedback voltage is
regulated to 200-mV, as shown in the typical
application circuit. The LED current can be adjusted
using a pulse width modulation (PWM) signal through
the PWM pin. The LED current is synchronized to the
PWM signal. The device does not discharge the
output ceramic capacitor during dimming, thus
reducing audible noise when dimming.
APPLICATIONS
•
•
•
•
•
Separating the IC input (VIN pin) and power stage
input (VBAT pin) makes the device flexible enough to
support single- or two-cell Li-ion battery applications.
Other protection features include 1.1-A peak-to-peak
over current protection (OCP), over voltage protection
(OVP), over load protection (OLP), and thermal
shutdown. The TPS61166 is available in a 2.5 mm ×
2.5 mm SON package with thermal pad.
Small Form Factor LCD Backlight
Mobile Phone
Digital Camera
Personal Camcorder
Single Lens Reflex
Vin 2.5 V to 6 V
L1
4.7 mH
C1
4.7 mF
TPS61166
VBAT
15 kHz / 50% duty cycle
SW
VIN
VO
NC
OUT
EN
PWM
C2
4.7 mF
FB
GND
R1
8
Figure 1. Single Cell Li-Ion Battery Typical Application
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 © 2009, Texas Instruments Incorporated
TPS61166
SLVS991 – SEPTEMBER 2009.......................................................................................................................................................................................... www.ti.com
L1
Vin 4.5 V to 10 V
4.7 mH
C1
4.7 mF
TPS61166
VBAT
C3
15 kHz / 50% duty cycle
VIN
VO
NC
OUT
EN
C2
4.7 mF
SW
FB
PWM
GND
R1
8
Figure 2. Two Cell Li-Ion Battery Typical Application
ORDERING INFORMATION (1)
(1)
(2)
PART NUMBER
OVER VOLTAGE PROTECTION
PACKAGE MARKING
TPS61166DSK (2)
18V (TYP)
OAO
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com
The DSK package is available in tape and reel. Add R suffix (TPS61166DSKR) to order quantities of 3000 parts per reel, or add T suffix
(TPS61166DSKT) to order 250 parts per reel.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
(1)
VALUE / UNITS
Supply voltage on pin VBAT (2)
Voltage on pins VIN, EN, and PWM
–0.3 V to 10 V
(2)
–0.3 V to 7 V
Voltage on pins SW, VO, and OUT (2)
–0.3 V to 20 V
Voltage on pin FB (2)
–0.3 V to 3 V
HBM ESD rating
(3)
2 kV
Operating temperature range, TA
–40°C to 85°C
Maximum operating junction temperature, TJ
150°C
Storage temperature, Tst
(1)
(2)
(3)
–55°C to 150°C
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 (HBM) is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin. The testing is done according
JEDECs EIA/JESD22-A114
DISSIPATION RATINGS
(1)
2
PACKAGE
THERMAL
RESISTANCE
θJA (1)
THERMAL
RESISTANCE
θJP
THERMAL
RESISTANCE
θJC
POWER RATING
TA ≤ 25°C (1)
DERATING FACTOR ABOVE
TA = 25°C (1)
DSK
60.6°C/W
6.3°C/W
40°C/W
1650 mW
17 mW/°C
Thermal ratings are determined assuming a high K PCB design according to JEDEC standard JESD51-7.
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RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
MAX
UNIT
VBAT
Battery input voltage range
4.5
10
V
Vin
IC Input voltage range
2.5
6
V
Vo
Output voltage at VO pin
L
Inductor (1)
fdim
PWM signal frequency
Cin
Input capacitor
Co
Output capacitor at VO pin (1)
C3
Pre-regulator capacitor at VIN pin (2)
0.1
TJ
Operating junction temperature
–40
125
°C
TA
Operating free-air temperature
–40
85
°C
(1)
(2)
2.2
4.7
0.06
17
V
10
µH
40
kHz
µF
4.7
1
4.7
10
µF
µF
These values are recommended values that have been successfully tested in several applications. Other values may be acceptable in
other applications but should be fully tested by the user.
For a two cell Li-ion battery application or input supply above 6 V as shown in Figure 2, C3 is needed for the internal pre-regulator.
Otherwise, C3 is not needed as shown in Figure 1.
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TPS61166
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ELECTRICAL CHARACTERISTICS
VIN=3.6V, EN=VIN, TA = –40°C to 85°C, typical values are at TA = 25°C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY CURRENT
VIN
IC input voltage range, VIN
2.5
VBAT
Battery input voltage range, VBAT
IQ
Operating quiescent current into VIN
Device PWM switching no load
ISD
Shutdown current
EN = GND, VIN = 6 V
UVLO
Undervoltage lockout threshold
VIN falling
Vhys
Undervoltage lockout hysterisis
6
4.5
0.9
1.5
V
10
V
1.5
mA
1
µA
1.55
50
V
mV
ENABLE AND PWM CONTROL
VENH
EN and PWM logic high voltage
VIN = 2.5 V to 6 V
VENL
En and PWM logic low voltage
VIN = 2.5 V to 6 V
REN
EN and PWM pull down resistor
Toff
EN pulse width to shutdown
1.2
V
0.3
400
800
EN high to low
V
1600
kΩ
1
ms
206
mV
200
nA
1.4
MHz
VOLTAGE CONTROL
VREF
Voltage feedback regulation voltage
IFB
Voltage feedback input bias current
fS
Oscillator frequency
Dmax
Maximum duty cycle
Tmin_on
Minimum on pulse width
194
VFB = 0.1 V, TA = 85°C
200
1.0
1.2
90%
93%
65
ns
POWER SWITCH, ISOLATION FET
RDS(ON)N
N-channel MOSFET on-resistance
VIN = 3 V
0.25
0.4
Ω
RDS(ON)iso
Isolation FET on-resistance
VO = 5 V
2.5
4
Ω
VO = 3.5 V
4.5
ILN_N
N-channel leakage current
VDS = 20 V, TA = 25°C
1
µA
ILN_iso
Isolation FET leakage current
VDS = 20 V, TA = 25°C
1
µA
VF
Power diode forward voltage
Current = 500 mA
0.8
V
OC, ILIM, OVP SC AND SS
ILIM
N-Channel MOSFET current limit
Vovp
Over voltage protection threshold
Vovp_hys
Over voltage protection hysteresis
IOL
Over load protection
Measured on the VO pin
0.9
1.1
18
19
1.5
A
0.6
V
200
300
mA
V
THERMAL SHUTDOWN
Tshutdown
Thermal shutdown threshold
150
°C
Thysteresis
Thermal shutdown hysteresis
15
°C
4
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DEVICE INFORMATION
PIN ASSIGNMENTS
TOP VIEW
VO
GND
VIN
VBAT
SW
Thermal
Pad
OUT
NC
FB
EN
PWM
10-PIN 2.5mm x 2.5mm QFN
PIN FUNCTIONS
PIN
NAME
NO.
I/O
DESCRIPTION
VIN
2
I
IC Supply voltage input.
VO
10
O
Output of the boost converter. When the output voltage exceeds the over voltage protection (OVP) threshold,
the power switch turns off until VO drops below the over voltage protection hysteresis.
OUT
8
O
Isolation switch is between this pin and the VO pin. Connect the anode of the LED to this pin.
GND
1
–
Ground of the IC.
VBAT
3
I
Battery supply voltage input. It can be tied with VIN pin when using a signal Li-ion battery.
EN
5
I
Enable pin (HIGH = enable). When the pin is pulled low for 1 ms, the IC turns off and consumes less than 1-µA
current. For a 2-cell battery application, a logic high signal turns on the internal pre-regulator and enables the
IC. Therefore, do not connect the EN pin to the VIN pin in the Figure 2 application.
PWM
6
I
Control LED on/off. A PWM signal from 60 Hz to 40 kHz connects to the pin for LED brightness control.
FB
7
I
Cathode of the LED connects to this pin. Its voltage is regulated at 0.2 V. An external resistor connected to this
pin programs the LED current.
SW
9
I
Switching node of the IC where the PWM switching operates.
NC
4
–
No connect pin. Connect to ground is recommended, or can float.
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TPS61166
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FUNCTIONAL BLOCK DIAGRAM
FB
EN
VBAT
SW
NC
OUT
VO
Soft
Startup
Ref
.
EN
Preregulator
VIN
OVP
OLP
EA
Gate
Driver
Gate
Driver
PWM Control
EN
Precharge
On/off control
Oscillator
Ramp
Generator
+
Current Sensor
GND
VIN
PWM
TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
(Figure 1), L = TOKO #A915_Y-4R7M, VIN = 3.6 V, LOAD = 4 LEDS unless otherwise noted
FIGURE
η
LED Efficiency
vs Led current; Five LEDs (14.5 V)
3
η
LED Efficiency
vs Led current; Four LEDs (11.5 V)
4
η
LED Efficiency
vs Led current; Three LEDs (8.5 V)
5
VFB
FB voltage
vs Input voltage
6
VFB
FB voltage
vs VBAT voltage
7
VFB
FB voltage
vs Free-air temperature
8
Switch current limit
vs Free-air temperature
9
PWM dimming operation
1 kHz with 30% duty cycle
10
PWM dimming operation
15 kHz with 10% duty cycle
11
PWM switch operation
15 kHz with 10% duty cycle
12
PWM dimming linearity
100 Hz, 1 kHz, 40 kHz;
13
PWM dimming linearity (zoom in)
100 Hz, 1 kHz, 40 kHz;
14
6
Over voltage protection
15
Soft start up in PWM dimming
16
Soft start up with EN and PWM tied together
17
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LED EFFICIENCY
vs
LED CURRENT
LED EFFICIENCY
vs
LED CURRENT
100
100
5 LEDs = 14.5 V
4 LEDs = 11.5 V
VI = 8 V
80
80
VI = 5 V
VI = 2.7 V
70
70
VI = 3.6 V
60
Efficiency - %
Efficiency - %
VI = 5 V
90
90
50
40
VI = 2.7 V
60
VI = 3.6 V
50
40
30
30
20
20
10
10
0
0
1
10
100
1
1000
10
100
1000
Load - mA
Figure 4.
Load - mA
Figure 3.
LED EFFICIENCY
vs
LED CURRENT
FB VOLTAGE
vs
INPUT VOLTAGE
200.5
100
3 LEDs = 8.5 V
90
VI = 5 V
80
200
VI = 2.7 V
60
VI = 3.6 V
VFB - mV
Efficiency - %
70
50
40
199.5
30
199
20
10
198.5
0
1
10
100
1000
2.5
Load - mA
Figure 5.
3
3.5
4
4.5
5
VI - Input Voltage - V
5.5
6
Figure 6.
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TPS61166
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FB VOLTAGE
vs
FREE-AIR TEMPERATURE
200.5
0.202
200
0.201
VFB - V
VFB - mV
FB VOLTAGE
vs
VBAT VOLTAGE
199.5
199
198.5
4.5
0.2
0.199
5
5.5
6
6.5
7 7.5 8
VBAT - V
8.5
9
9.5 10
0.198
-40
-20
0
20
40
60
80
100
TA - Free-Air Temperature - ºC
Figure 7.
Figure 8.
SWITCH CURRENT LIMIT
vs
FREE-AIR TEMPERATURE
1-kHz PWM DIMMING WITH DUTY=30%
1.3
120
VO
100 mV; AC
1.2
LED Current
50 mA/div
ILIM - A
1.1
1
Inductor Current
500 mA/div
0.9
0.8
-40
-20
0
20
40
60
80
100
120
t - Time = 400 ms/div
TA - Free-Air Temperature - ºC
Figure 9.
8
Figure 10.
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15-kHz PWM DIMMING WITH DUTY=10%
15-kHz PWM DIMMING WITH DUTY=10%
VO
100 mV; AC
VO
100 mV; AC
LED Current
50 mA/div
LED Current
50 mA/div
Inductor Current
500 mA/div
Inductor Current
500 mA/div
t - Time = 20 ms/div
t - Time = 2 ms/div
Figure 11.
Figure 12.
PWM DIMMING LINEARITY
PWM DIMMING LINEARITY
8
80
70
1 kHz
6
60
LED Current - mA
LED Current - mA
1 kHz
50
40
100 Hz
40 kHz
30
100 Hz
40 kHz
4
2
20
10
0
0
0
10
20
30
40 50 60 70
Duty Cycle - %
Figure 13.
80
90
100
1
2
3
4
5
6
7
Duty Cycle - %
8
9
10
Figure 14.
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TPS61166
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OVER VOLTAGE PROTECTION
SOFT START UP IN PWM DIMMING
VO
1 V/div, 18 V offset
VO
5V/div
LED Current
50 mA/div
Inductor Current
100 mA/div
Inductor Current
200 mA/div
t - Time = 2 ms/div
t - Time = 4 ms/div
Figure 15.
Figure 16.
SOFT START UP
VO
5 V/div
LED Current
50 mA/div
Inductor Current
200 mA/div
t - Time = 400 ms/div
Figure 17.
DETAILED DESCRIPTION
OPERATION
The TPS61166 adopts peak current-mode control with a constant pulse-width-modulation (PWM) frequency of
1.2-MHz. PWM operation turns on the PWM switch at the beginning of each switching cycle. The input voltage is
applied across the inductor and the inductor current ramps up. In this mode, the output capacitor is discharged
by the load current. When the inductor current hits the threshold set by the error amplifier output, the PWM
switch is turned off, and the power diode is forward-biased. The inductor transfers its stored energy to replenish
the output capacitor. This operation repeats in the next switching cycle. The error amplifier compares the FB pin
voltage with an internal reference, and its output determines the duty cycle of the PWM switching. This
closed-loop system requires frequency compensation for stable operation. The device has a built-in
compensation circuit that can accommodate a wide range of input and output voltages. To avoid the
sub-harmonic oscillation intrinsic to current-mode control, the IC also integrates the slope compensation, which
adds an artificial slope to the current ramp.
10
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The device integrates a high side switch FET between the VO pin and the OUT pin to turn LEDs on/off quickly.
The LED current is synchronous with the external PWM signal that is applied to the PWM pin. The delay
between the PWM signal and the rising/falling edge of the LED current is less than 1-µs. The IC’s isolation switch
prevents the output capacitor from discharging during dimming, thus reducing the ceramic output capacitor’s
audible noise to neglible levels.
STARTUP AND SHUTDOWN
The TPS61166 starts to turn on the isolation FET and PWM switch when the EN pin is pulled high. In the boost
power stage, the IC ramps up the over-current limit of the PWM switch to 1.1-A in 8 steps, and each step takes
213-µs. This ensures that the VO pin voltage rises slowly to reduce input inrush current. The Vgs of the isolation
switch is self-clamped by the VO pin voltage, so that the high on-resistance of the switch during startup limits the
output current.
When the EN pin is pulled low for 1-ms, the IC stops the PWM switch and turns off the isolation switch, providing
isolation between input and output. In the shutdown mode, less than 1-µA input current is consumed by the IC.
UNDER VOLTAGE LOCKOUT (UVLO), OVER LOAD PROTECTION (OLP), AND OVER VOLTAGE
PROTECTION (OVP)
An under voltage lockout circuit prevents improper operation of the device for input voltages below 1.55-V. When
the input voltage is below the undervoltage threshold, both the PWM switch and isolation switch remain off.
If the current passing through the isolation switch is above the over load limit of 300-mA (IOL,typ) for 1.5-µs, the
TPS61166 is switched off until the fault clears and the EN pin toggles. Over load protection is disabled until the
over current limit ramp is completed during startup.
To prevent the PWM switch and the output capacitor from exceeding maximum voltage ratings, an over votlage
protection circuit turns off the boost switch as soon as the output voltage at the VO pin exceeds the OVP
threshold. Simultaneously, the isolation switch opens. The regulator resumes PWM switching after the VO pin
voltage falls 0.6 V below the threshold. This function provides protection for open LED protection as well.
THERMAL SHUTDOWN
An internal thermal shutdown turns off the isolation and PWM switches when the typical junction temperature of
150°C is exceeded. The thermal shutdown has a hysteresis of 15°C, typical.
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APPLICATION INFORMATION
SWITCH DUTY CYCLE
The maximum switch duty cycle (D) of the TPS61166 is 90% (MIN). The duty cycle of a boost converter in
continuous conduction mode (CCM) is given by:
Vout + 0.8 V - Vin
D=
Vout + 0.8 V
(1)
where Vout = ∑VFWD(LED)+200mV. The duty cycle must be lower than the specification in the application;
otherwise the output voltage cannot be regulated.
LED CURRENT PROGRAMMING
The FB voltage is regulated to a low 0.2-V reference voltage. LED current is programmed externally using a
current sense resistor R1 in series with the LED string. The value of R1 is calculated using Equation 2:
200 mV
ILED =
R1
(2)
The output current tolerance depends on FB accuracy and current sensor resistor accuracy. Maximum LED
current can be calculated using Equation 3.
DIL
Iout_MAX = (ILIM ) ´ (1 - D)
2
1
DIL =
é
æ
1
1 öù
+
êL ´ fSW ´ ç
÷ú
è VO + 0.8 V - VIN VIN ø û
ë
(3)
Where
ΔIL = Inductor peak to peak current;
L = Selected inductor value;
fSW = Converter switching frequency (typically 1.2-MHz);
For instance, the TPS61166 can support 4 LEDs (equivalent output voltage of 14-V) with 160-mA output current
at 3.3-V input supply at typical conditions.
LED BRIGHTNESS DIMMING
A PWM signal applied to the PWM pin can adjust the LED brightness. The signal controls whether the isolation
switch is on or off; therefore LED current is directly proportion to the duty cycle of the PWM signal. During the on
periods, LED current is defined by the value as described in Equation 2.
The recommended PWM signal frequency range is 60-Hz to 40-kHz. The IC needs several µ-seconds to settle
the LED current after the isolation switch turns on. This settling time affects the LED current linearity at low duty
cycle. A 1% duty cycle is the minimum recommended duty cycle for a PWM dimming signal with 1-kHz
frequency, and 0.1% is recommended for a 100-Hz frequency.
The isolation switch ON time determines the maximum PWM frequency. The ON time must be at least twice as
long as one switch cycle of 2/fs(max) = 2/1.4MHz = 1.2-µs. A PWM dimming frequency above 40 kHz may be
acceptable, but needs to be fully tested by the user.
INDUCTOR SELECTION
Because the selection of the inductor affects steady state operation, transient behavior, and loop stability, the
inductor is the most important component in power regulator design. There are three important inductor
specifications: inductor value, saturation current, and dc resistance. Considering inductor value alone is not
enough.
The saturation current of the inductor should be higher than the peak switch current as calculated in the following
equations:
12
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IL_peak = IL_DC +
IL_DC =
DIL
2
Vout ´ Iout
Vin ´ h
(4)
Where
IL_DC = Inductor average current
η = Estimated converter efficiency
The inductor value should not be outside the 2.2 µH to 10 µH range listed in the recommended operating
conditions table, otherwise internal slope compensation and loop compensation are ineffective.Table 1 lists the
recommended inductors for the TPS61166.
Table 1. Recommended Inductors for the TPS61166
PART NUMBER
L
(µH)
DCR MAX
(mΩ)
SATURATION
CURRENT (A)
SIZE (L×W×H mm)
VENDOR
#A915_Y-4R7M
4.7
#A915_Y-100M
10
45
1.5
5.2x5.2x3.0
Toko
90
1.09
5.2x5.2x3.0
VLS4012-4R7M
4.7
Toko
132
1.1
4.0x4.0x1.2
TDK
VLS4012-100M
10
240
0.82
4.0x4.0x1.2
TDK
CDRH3D23/HP
4.7
95.5
1.6
4.0x4.0x2.5
Sumida
LPS4012-472ML
4.7
175
1.6
4.0x4.0x1.2
Coilcraft
INPUT AND OUTPUT CAPACITOR SELECTION
The output capacitor is mainly selected to meet the requirements for output ripple and loop stability. This ripple
voltage is related to the capacitor’s capacitance and its equivalent series resistance (ESR). Assuming a ceramic
capacitor with zero ESR, the minimum capacitance needed for a given ripple can be calculated by Equation 5:
D ´ Iout
Cout =
Fs ´ Vripple
(5)
where, Vripple = peak to peak output ripple. The ESR impact on the output ripple must be considered if tantalum
or electrolytic capacitors are used.
Care must be taken when evaluating a ceramic capacitor’s derating under dc bias, aging, and ac signal. For
example, larger form factor capacitors (in 1206 size) have their self resonant frequencies in the range of the
switching frequency. So the effective capacitance is significantly lower. The dc bias can also significantly reduce
capacitance. A ceramic capacitor can loose as much as 50% of its capacitance at its rated voltage. Therefore,
always leave margin on the voltage rating to ensure adequate capacitance at the required output voltage.
At least a 4.7-µF input capacitor is recommended. The output requires a capacitor in the range of 1 µF to 10 µF.
The output capacitor affects the loop stability of the boost regulator. If the output capacitor is below the range,
the boost regulator can potentially become unstable.
The popular vendors for high value ceramic capacitors are:
• TDK (http://www.component.tdk.com/components.php)
• Murata (http://www.murata.com/cap/index.html)
LAYOUT CONSIDERATIONS
As for all switching power supplies, especially those running at high switching frequency and high currents,
layout is an important design step. If layout is not carefully performed, the regulator could suffer from instability
as well as noise problems. To maximize efficiency, switch rise and fall times are very fast. To prevent radiation of
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Product Folder Link(s): TPS61166
13
TPS61166
SLVS991 – SEPTEMBER 2009.......................................................................................................................................................................................... www.ti.com
high frequency noise (e.g., EMI), proper layout of the high frequency switching path is essential. Minimize the
length and area of all traces connected to the SW pin and always use a ground plane under the switching
regulator to minimize interplane coupling. The high current path including the switch and output capacitor
contains nanosecond rise and fall times and should be kept as short as possible. The input capacitor needs not
only to be close to the VIN pin, but also to the GND pin in order to reduce input supply ripple.
L1
C2
C1
Vin
VO
GND
Th
VIN
SW
er
LED +
m
VBAT
OUT
al
LED -
Pa
NC
Minimize the
area of SW
trace
FB
d
EN
PWM
PWM
EN
R1
Place enough
VIAs around
thermal pad to
enhace thermal
performance
GND
THERMAL CONSIDERATIONS
The maximum IC junction temperature should be restricted to 125°C under normal operating conditions. This
restriction limits the power dissipation of the TPS61166. Calculate the maximum allowable dissipation, PD(MAX)
and keep the actual dissipation less than or equal to PD(MAX). The maximum-power-dissipation limit is determined
using Equation 6:
125 °C - TA
PD(MAX) =
RqJA
(6)
where
TA = Maximum ambient temperature for the application.
RθJA = Thermal resistance junction-to-ambient listed in the dissipation ratings table.
The TPS61166 is available in a thermally enhanced QFN package. This package includes a thermal pad that
improves the thermal capabilities of the package. The RθJA of the QFN package greatly depends on the PCB
layout and thermal pad connection. The thermal pad must be soldered to the analog ground on the PCB. Using
thermal vias underneath the thermal pad as illustrated in the layout example. Also, see the QFN/SON PCB
Attachment application report (SLUA271).
14
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Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): TPS61166
TPS61166
www.ti.com.......................................................................................................................................................................................... SLVS991 – SEPTEMBER 2009
ADDITIONAL APPLICATION
Multiple LED Strings Bar Application
Vin 5 V
L1
4.7 mH
C1
4.7 mF
C2
4.7 mF
TPS61166
VBAT
Total LED current = 300 mA
SW
VIN
VO
NC
OUT
EN
FB
PWM
GND
R1
LED Efficiency Measurement Application
Vin 4.5 V to 10 V
L1
A
V
4.7 mH
C1
4.7 mF
C3
C2
4.7 mF
TPS61166
VBAT
VIN
VO
NC
OUT
EN
PWM
V
SW
FB
GND
A
R1
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Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s): TPS61166
15
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
TPS61166DSKR
ACTIVE
SON
DSK
10
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
OAO
TPS61166DSKT
ACTIVE
SON
DSK
10
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
OAO
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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