TI TPS65055RSMR

TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
2.25 MHz Dual Step-Down Converter With 4 Low Input Voltage LDOs
FEATURES
1
• Up to 95% Efficiency
• Output Current for DCDC Converters 2 × 0.6A
• Two Selectable Fixed Output Voltages 1.0
V/1.2 V for DCDC2
• VIN Range for DCDC Converters From 2.5 V to
6V
• 2.25 MHz Fixed Frequency Operation
• Power Save Mode at Light Load Current
• 180° Out of Phase Operation
• Output Voltage Accuracy in PWM Mode ±1%
• Low Ripple PFM Mode
• Total Typ. 32 µA Quiescent Current for Both
DCDC Converters
• 100% Duty Cycle for Lowest Dropout
• 2 General Purpose 400 mA- High PSRR LDOs
• 2 General Purpose 200 mA- High PSRR LDOs
• VIN Range for LDOs from 1.5 V to 6.5 V
• Digital Voltage Selection for the LDOs
• I2C Compatible Interface
• Available in a 4 mm × 4 mm 32-Pin QFN
Package
2
APPLICATIONS
•
•
•
•
•
•
•
Cell Phones, Smart-phones
WLAN
PDAs, Pocket PCs
OMAP™ and Low Power DSP Supply
XScale
Portable Media Players
Digital Cameras
DESCRIPTION
The TPS65055 is an integrated Power Management
IC for applications powered by one Li-Ion or
Li-Polymer cell, which require multiple power rails.
The TPS65055 provides two highly efficient,
2.25 MHz step-down converters targeted at providing
the core voltage and I/O voltage in a processor-based
system. Both step-down converters enter a low power
mode at light load for maximum efficiency across the
widest possible range of load currents.
For low noise applications the device can be forced
into fixed frequency PWM mode using the I2C
compatible interface. In shutdown mode, current
consumption is reduced to less than 1 µA.
The device allows the use of small inductors and
capacitors to achieve a small solution size.
The TPS65055 provides an output current of up to
0.6 A on each dcdc converter.
The TPS65055 also integrates two 400 mA LDO and
two 200 mA LDO voltage regulators, which can be
turned on/off using separate enable pins on each
LDO. Each LDO operates with an input voltage range
between 1.5 V and 6.5 V allowing them to be
supplied from one of the step-down converters or
directly from the main battery. Two digital input pins
are used to set the output voltage of the LDOs from a
set of 9 different combinations for LDO1 to LDO4.
Additionally, the converters can be controlled by an
I2C compatible interface.
The TPS65055 is available in a small 32-pin leadless
package (4 mm × 4 mm QFN) with a 0,4 mm pitch.
1
2
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.
OMAP, PowerPAD are trademarks of Texas Instruments.
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
TPS65055
SLVS844 – SEPTEMBER 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 (1)
TA
PART NUMBER
–40°C to 85°C
(1)
(2)
(2)
OUTPUT CURRENT FOR DCDC
CONVERTERS
QFN (2) PACKAGE
PACKAGE
MARKING
2 × 600 mA
RSM
65055
TPS65055
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 RSM package is available in tape and reel. Add R suffix (TPS65055RSMR) to order quantities of 3000 parts per reel. Add T suffix
(TPS65055RSMT) to order quantities of 250 parts per reel.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
(1)
VALUE
UNIT
–0.3 to 7
V
–0.3 to VCC+0.5
V
Input voltage range on all pins except A/PGND, EN_LDO1 pins with respect to AGND
Input voltage range on EN_LDO1 pins with respect to AGND
Output voltage range on LDO1, LDO2, LDO3, LDO4 pins with respect to AGND
–0.3 to 4.0
V
Current at VINDCDC1/2, L1, PGND1, L2, PGND2
1800
mA
Current at all other pins
1000
mA
Continuous total power dissipation
See Dissipation Rating Table
TA
Operating free-air temperature
–40 to 85
°C
TJ
Maximum junction temperature
125
°C
Tst
Storage temperature
–65 to 150
°C
260
°C
Lead temperature 1,6 mm (1/16-inch) from case for 10 seconds
(1)
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. This device
contains circuits to protect its inputs and outputs against damage due to high static voltages or electrostatic fields. These circuits have
been qualified to protect this device against electrostatic discharges; HBM according to EIA/JESD22-A114-B: 1.5kV; and CDM
according EIA/JESD22C101C: 500V, however, it is advised that precautions should be taken to avoid application of any voltage higher
than maximum-rated voltages to these high-impedance circuits. During storage or handling, the device leads should be shorted together
or the device should be placed in conductive foam. In a circuit, unused inputs should always be connected to an appropriated logic
voltage level, preferably either VCC or ground. Specific guidelines for handling devices of this type are contained in the publication
Guidelines for Handling Electrostatic-Discharge-Sensitive (ESDS) Devices and Assemblies available from Texas Instruments.
DISSIPATION RATINGS
(1)
PACKAGE
RθJA
TA ≤ 25°C
POWER RATING
DERATING FACTOR
ABOVE TA = 25°C
TA = 70°C
POWER RATING
TA = 85°C
POWER RATING
RSM (1)
58 K/W
1.7 W
17 mW/K
0.95 W
0.68 W
The thermal resistance junction-to-case of the RSM package is 4 K/W measured on a high K board.
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
MAX
VINDCDC1/2
Input voltage range for step-down converters
2.5
4
6.0
V
VDCDC1
Output voltage range for VDCDC1 step-down converter
0.6
VINDCDC1
V
VDCDC2
Output voltage range for VDCDC2 step-down converter
0.6
VINDCDC2
V
VINLDO1, VINLDO2,
VINLDO3/4
Input voltage range for LDOs
1.5
6.5
V
VLDO1-3
Output voltage range for LDO1 and LDO3
0.8
2.8
V
VLDO2-4
Output voltage range for LDO2 and LDO4
1.0
3.0
V
2
Submit Documentation Feedback
UNIT
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
RECOMMENDED OPERATING CONDITIONS (continued)
over operating free-air temperature range (unless otherwise noted)
MIN
IOUTDCDC1
Output current at L1
L1
Inductor at L1 (1)
1.5
(1)
NOM
MAX
UNIT
600
mA
µH
2.2
µF
CINDCDC1/2
Input capacitor at VINDCDC1/2
COUTDCDC1
Output capacitor at VDCDC1 (1)
22
IOUTDCDC2
Output current at L2
L2
Inductor at L2 (1)
1.5
2.2
µH
COUTDCDC2
Output capacitor at VDCDC2 (1)
10
22
µF
CVCC
Input capacitor at VCC
10
µF
22
600
mA
1
µF
Cin1-2
Input capacitor at VINLDO1/2
(1)
2.2
µF
Cin3-4
Input capacitor at VINLDO3/4 (1)
2.2
µF
COUT1-2
Output capacitor at VLDO1-4 (1)
2.2
ILDO1,2
Output current at VLDO1,2
ILDO3,4
Output current at VLDO3,4
TA
Operating ambient temperature
–40
TJ
Operating junction temperature
–40
RCC
(1)
(2)
(1)
Resistor from battery voltage to Vcc used for filtering
(2)
µF
1
400
mA
200
mA
85
°C
125
°C
10
Ω
See application section for more details.
Up to 2 mA can flow into Vcc when both converters are running in PWM, this resistor causes the UVLO threshold to be shifted
accordingly.
ELECTRICAL CHARACTERISTICS
VIN = 3.6 V, EN = VIN, MODE = GND, L = 2.2 µH, COUT = 22 µF, 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
Vcc
Input voltage range
2.5
6.0
V
30
40
µA
40
55
µA
One converter, IOUT = 0 mA, PFM mode enabled; device not
switching, EN_DCDC1 = VIN or EN_DCDC2 = VIN;
EN_LDO1 = EN_LDO2 = EN_LDO3 = EN_LDO4 = VIN
190
260
µA
One converter, IOUT = 0 mA,
Switching with no load, PWM operation EN_DCDC1 = VIN or
EN_DCDC2 = VIN;
EN_LDO1 = EN_LDO2 = EN_LDO3/4 = GND
0.85
mA
Two converters, IOUT = 0 mA,
Switching with no load, PWM operation EN_DCDC1 = VIN AND
EN_DCDC2 = VIN;
EN_LDO1 = EN_LDO2 = EN_LDO3/4 = GND
1.25
mA
One converter, IOUT = 0 mA. PFM mode enabled; device not
switching, EN_DCDC1 = VIN or EN_DCDC2 = VIN;
EN_LDO1 = EN_LDO2 = EN_LDO3/4 = GND
IQ
IQ
Operating quiescent current
Two converters, IOUT = 0 mA, PFM mode device not switching,
Total current into VCC, VINDCDC1/2, VINLDO1, EN_DCDC1 = VIN and EN_DCDC2 = VIN;
VINLDO2, VINLDO3/4
EN_LDO1 = EN_LDO2 = EN_LDO3/4 = GND
Operating quiescent current into VCC
I(SD)
Shutdown current
EN_DCDC1 = EN_DCDC2 = GND
EN_LDO1 = EN_LDO2 = EN_LDO3 = EN_LDO4 = GND
18
22
µA
V(UVLO)
Undervoltage lockout threshold for DCDC
converters and LDOs
Voltage at VCC
1.8
2
V
1.2
VCC
V
0
0.4
V
EN_DCDC1, EN_DCDC2, DEFDCDC2, DEFLDO1, DEFLDO2, EN_LDO1, EN_LDO2, EN_LDO3, EN_LDO4
VIH
High-level input voltage, SDAT, SCLK,
EN_DCDC1, EN_DCDC2, DEFDCDC2,
EN_LDO1, EN_LDO2, EN_LDO3, EN_LDO4
VIL
Low-level input voltage SDAT, SCLK,
EN_DCDC1, EN_DCDC2, EN_LDO1,
EN_LDO2, EN_LDO3, EN_LDO4, DEFDCDC2
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
3
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
VIN = 3.6 V, EN = VIN, MODE = GND, L = 2.2 µH, COUT = 22 µF, TA = –40°C to 85°C, Typical values are at TA = 25°C (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
0.01
1.0
UNIT
IIN
Input bias current SDAT, SCLK,
EN_DCDC1, EN_DCDC2, DEFDCDC2,
DEFLDO1, DEFLDO2, EN_LDO1, EN_LDO2,
EN_LDO3, EN_LDO4
VIH
DEFLDO1, DEFLDO2
VCC = 2.5 V
VIL
DEFLDO1, DEFLDO2
VCC = 6.5 V
RPD
Pull-down resistor at DEFLDO1, DEFLDO2 for
LOW signal
Pulled to GND
1
kΩ
RPU
Pull-up resistor at DEFLDO1, DEFLDO2 for
HIGH signal
Pulled to VCC
1
kΩ
1.0
µA
V
0.38
V
RGNDop Resistance at DEFLDO1, DEFLDO2 to GND to
en
detect open state
10
MΩ
RVCCop
en
20
MΩ
Resistance at DEFLDO1, DEFLDO2 to Vcc to
detect open state
POWER SWITCH
DCDC1,
DCDC2
VINDCDC1/2 = 3.6 V
280
VINDCDC1/2 = 2.5 V
400
630
rDS(on)
P-channel MOSFET on
resistance
ILD_PMOS
P-channel leakage current
VDS = 6 V
rDS(on)
N-channel MOSFET on
resistance
VINDCDC1/2 = 3.6 V
220
VINDCDC1/2 = 2.5 V
320
ILK_NMOS
N-channel leakage current
I(LIMF)
Forward current limit PMOS
(high-side) and NMOS (low
side)
TSD
Thermal shutdown
Increasing junction temperature
150
°C
Thermal shutdown hysteresis
Decreasing junction temperature
20
°C
DCDC1,
DCDC2
1
VDS = 6 V
DCDC1
DCDC2
2.5 V ≤ VIN ≤ 6 V
450
7
10
0.85
1.0
1.15
0.85
1.0
1.15
mΩ
µA
mΩ
µA
A
OSCILLATOR
fSW
4
Oscillator frequency
2.025
Submit Documentation Feedback
2.25
2.475
MHz
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
ELECTRICAL CHARACTERISTICS (continued)
VIN = 3.6 V, EN = VIN, MODE = GND, L = 2.2 µH, COUT = 22 µF, TA = –40°C to 85°C, Typical values are at TA = 25°C (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
OUTPUT
VOUT
VOUT
Output voltage range
DC output voltage accuracy
0.8
DCDC1,
DCDC2 (1)
(2)
VIN = 2.5 V to 6 V, Mode = GND,
PFM operation, 0 mA < IOUT < IOUTMAX
–1.5
VIN = 2.5 V to 6 V, Mode = VIN,
PWM operation, 0 mA < IOUT < IOUTMAX
–1.5
VIN
V
0
3.5
%
0
1.5
%
ΔVOUT
Power save mode ripple voltage
25
mVPP
tStart
Start-up time
Time from active EN to start switching
170
µs
tRamp
VOUT Ramp up time
Time to ramp from 5% to 95% of VOUT
750
µs
RDIS
Internal discharge resistor at L1, L2
VOL
RST, DPD, discharge output low voltage
IOUT = 1 mA, PFM = GND, Bandwidth = 20 MHz
IOL = 1 mA, Vthreshold < 0.8 V
0.3
RST, DPD sink current
IOL
discharge sink current
Vth
Ω
350
RST, DPD, discharge output leakage current
Vthreshold > 0.8 V, RST and DPD outputs turned off (internal
NMOS in high impedance state)
Vthreshold voltage
Voltage rising
Hysteresis on threshold
Voltage decreasing
V
1
mA
10
mA
0.78
0.01
1.0
0.8
0.82
80
µA
V
mV
VLDO1, VLDO2, VLDO3 and VLDO4 LOW DROPOUT REGULATORS
VINLDO
Input voltage range for LDO1, LDO2, LDO3,
LDO4
1.5
6.5
V
VLDO1
LDO1 output voltage range
0.8
2.8
V
VLDO2
LDO2 output voltage range
1.2
3.0
V
VLDO3
LDO3 output voltage
0.8
2.8
V
VLDO4
LDO4 output voltage range
1.2
3.0
V
Maximum output current for LDO1,LDO2
400
Maximum output current for LDO3, LDO4
200
IO
I(SC)
mA
LDO1 and LDO2 short-circuit current limit
VLDO1 = GND, VLDO2 = GND
800
mA
LDO3 and LDO4 short-circuit current limit
VLDO3 = GND, VLDO4 = GND
400
mA
Dropout voltage at LDO1
IO = 250 mA, VINLDO = 1.8 V
600
mV
Dropout voltage at LDO2
IO = 400 mA, VINLDO = 3.3 V
450
mV
Dropout voltage at LDO3, LDO4
IO = 200 mA, VINLDO = 1.8 V
280
mV
Output voltage accuracy for LDO1, LDO2,
LDO3
IO = 10 mA
Leakage current from VINLDOx to VLDOx
LDO enabled, VINLDOx = 6.5 V; VO = 1.0 V, T = 140°C
Output voltage accuracy for LDO1, LDO2,
LDO3, LDO4
IO = 10 mA
–2%
1%
Line regulation for LDO1, LDO2, LDO3, LDO4
VINLDO1,2 = VLDO1,2 + 0.5 V (min. 2.5 V) to 6.5 V,
VINLDO3,4 = VLDO3,4 + 0.5 V (min. 2.5 V) to 6.5 V,
IO = 10 mA
–1%
1%
Load regulation for LDO1, LDO2, LDO3, LDO4
IO = 0mA to 400 mA for LDO1, LDO2
IO = 0mA to 200 mA for LDO3, LDO4
–1%
1%
–2%
1%
µA
3
Regulation time for LDO1, LDO2, LDO3, LDO4
Load change from 10% to 90%
10
µs
PSRR
Power supply rejection ratio
f = 10 kHz; IO = 50 mA; VI = VO + 1 V
70
dB
RDIS
Internal discharge resistor at VLDO1, VLDO2,
VLDO3, VLDO4
350
Ω
TSD
Thermal shutdown
Increasing junction temperature
140
°C
Thermal shutdown hysteresis
Decreasing junction temperature
20
°C
(1)
(2)
Output voltage specification does not include tolerance of external voltage programming resistors
In power save mode, PWM operation is typically entered at IPSM = VIN/32Ώ
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
5
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
DEVICE INFORMATION
VDCDC1
PGND1
L1
VINDCDC1/2
L2
PGND2
VDCDC2
DEFDCDC2
PIN ASSIGNMENT (TOP VIEW)
24 23 22 21 20 19 18 17
EN_DCDC1
EN_DCDC2
EN_LDO1
EN_LDO2
VINLDO1
VLDO1
SDAT
SCLK
25
26
27
28
29
30
31
32
16
15
14
13
12
11
10
9
TPS65055
2 3
4
5
6
7
8
BP
AGND
Vcc
VINLDO2
VLDO2
DEFLDO2
threshold
RST
1
EN_LDO4
EN_LDO3
discharge
DPD
VLDO4
VINLDO3/4
VLDO3
DEFLDO1
TERMINAL FUNCTIONS
TERMINAL
NAME
NO.
I/O
DESCRIPTION
Vcc
3
I
Power supply for digital and analog circuitry of DCDC1, DCDC2 and LDOs. This pin must be connected
to the same voltage supply as VINDCDC1/2.
VDCDC1
24
I
Feedback voltage sense input, connect directly to Vout1
VINDCDC1/2
21
VDCDC2
18
DEF_DCDC2
L1
Input voltage for VDCDC1 and VDCDC2 step-down converter. This must be connected to the same
voltage supply as VCC.
I
Feedback voltage sense input, connect directly to Vout2
17
I
Select pin of converter 2 output voltage. High = 1.0 V, low = 1.2 V
22
O
Switch pin of converter1. Connected to inductor
PGND1
23
I
GND for converter 1
PGND2
19
I
GND for converter 2
AGND
2
I
Analog GND, connect to PGND and PowerPAD
L2
20
O
Switch pin of converter 2. Connected to inductor.
EN_DCDC1
25
I
Enable input for converter1, active high
EN_DCDC2
26
I
Enable input for converter2, active high
VINLDO1
29
I
Input voltage for LDO1
VINLDO2
4
I
Input voltage for LDO2
VINLDO3/4
11
I
Input voltage for LDO3 and LDO4
VLDO1
30
O
Output voltage of LDO1
VLDO2
5
O
Output voltage of LDO2
VLDO3
10
O
Output voltage of LDO3
VLDO4
12
O
Output voltage of LDO4
DEFLDO1
9
I
Digital input, used to set the default output voltage of LDO1 to LDO4; LSB
Digital input, used to set the default output voltage of LDO1 to LDO4; MSB
DEFLDO2
6
I
SDAT
31
I/O
SCLK
32
I
6
Data line for the I2C compatible interface.
Clock input for the I2C compatible interface.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
TERMINAL FUNCTIONS (continued)
TERMINAL
NAME
NO.
I/O
DESCRIPTION
EN_LDO1
27
I
Enable input for LDO1. Logic high enables the LDO, logic low disables the LDO.
EN_LDO2
28
I
Enable input for LDO2. Logic high enables the LDO, logic low disables the LDO.
EN_LDO3
15
I
Enable input for LDO3. Logic high enables the LDO, logic low disables the LDO.
EN_LDO4
16
I
Enable input for LDO4. Logic high enables the LDO, logic low disables the LDO.
threshold
7
I
Input to comparator driving the discharge output. If the input voltage at threshold is < 0.8 V, the discharge
output is actively pulled low.
discharge
14
O
Open drain output driven by the signal at the threshold input
RST
8
O
Open drain active low output; low after UVLO event
DPD
13
O
Open drain active low output; low after UVLO event
BP
1
I
Input for bypass capacitor for internal reference
PowerPAD™
–
Connect to GND
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
7
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
FUNCTIONAL BLOCK DIAGRAM
TPS65055
VINDCDC1/2
1R
Vbat
VCC
10 mF
1 mF
2.2 mH
DCDC1 (I/O)
ENABLE
SCLK
SDAT
DEFLDO1
DEFLDO2
EN_DCDC1
STEP-DOWN
CONVERTER
600 mA
1 V / 1.2 V
VIN
ENABLE
VIN
ENABLE
VIN
ENABLE
ENABLE
VDCDC1
10 mF
PGND1
Interface
L2
DCDC2 (core)
ENABLE
L1
STEP-DOWN
CONVERTER
600 mA
EN_DCDC2
DEFDCDC2
VDCDC2
2.2 mH
10 mF
PGND2
VLDO1
VIN_LDO1
VLDO1
EN_LDO1
4.7 mF
400 mA LDO
VIN_LDO2
VLDO2
EN_LDO2
VLDO2
4.7 mF
400 mA LDO
VIN_LDO3/4
VLDO3
EN_LDO3
200 mA LDO
EN_LDO4
VLDO4
VLDO3
2.2 mF
BP
0.1 mF
VLDO4
2.2 mF
200 mA LDO
RST
I/O voltage
R19
I/O voltage
DPD
R20
discharge
THRESHOLD
comparator
AGND
8
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
PARAMETER MEASUREMENT INFORMATION
The measurements for the graphs were taken using the EVM in the configuration shown in the functional block
diagram. The inductors used were Coilcraft LPS3010.
TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
FIGURE
η
Efficiency DCDC1 (VO = 2.1 V)
vs Load current / PWM mode
1
η
Efficiency DCDC1 (VO = 2.1 V)
vs Load current / PFM mode
2
η
Efficiency DCDC2 (VO = 1.575 V)
vs Load current / PWM mode
3
η
Efficiency DCDC2 (VO = 1.575 V)
vs Load current / PFM mode
4
η
Efficiency DCDC2 (VO = 1.2 V)
vs Load current / PWM mode
5
η
Efficiency DCDC2 (VO = 1.2 V)
vs Load current / PFM mode
6
Output voltage ripple in PFM mode
Scope plot
7
Output voltage ripple in PWM mode
Scope plot
8
Startup timing DCDC1, DCDC2, LDO1
Scope plot
9
Startup timing LDO1, LDO2, LDO3, LDO4
Scope plot
10
Load transient response DCDC1; PWM
Scope plot
11
Load transient response DCDC1; PFM
Scope plot
12
Load transient response DCDC2; PWM
Scope plot
13
Load transient response DCDC2;PFM
Scope plot
14
Line transient response DCDC1 (VO = 2.1 V)
Scope plot
15
Line transient response DCDC2 (VO = 1.2 V)
Scope plot
16
Load transient response LDO1
Scope plot
17
Load transient response LDO4
Scope plot
18
Line transient response LDO1
Scope plot
19
EFFICIENCY DCDC1 (VO = 2.1 V)
vs
LOAD CURRENT / PWM MODE
EFFICIENCY DCDC1 (VO = 2.1 V)
vs
LOAD CURRENT / PFM MODE
100
100
90
80
TA = 25°C,
PWM Mode,
VO = 2.1 V
90
3V
80
3V
Efficiency - %
Efficiency - %
60
3.6 V
50
4.2 V
40
5V
4.2 V
50
5V
40
20
TA = 25°C,
PWM/PFM Mode,
VO = 2.1 V
10
10
0
0.0001
60
30
30
20
3.6 V
70
70
0.001
0.01
0.1
IO - Output Current - A
1
0
0.0001
Figure 1.
0.001
0.01
0.1
IO - Output Current - A
1
Figure 2.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
9
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
EFFICIENCY DCDC2 (VO = 1.575 V)
vs
LOAD CURRENT / PWM MODE
EFFICIENCY DCDC2 (VO = 1.575 V)
vs
LOAD CURRENT / PFM MODE
100
100
TA = 25°C,
90
PWM Mode,
80 VO = 1.575 V
3V
90 2.5 V
80
5V
4.2 V
70
Efficiency - %
Efficiency - %
70
60
4.2 V
50
3.6 V
40
3.3 V
30
TA = 25°C,
PWM/PFM Mode,
VO = 1.575 V
10
0
0.0001
0.001
0.01
0.1
IO - Output Current - A
0
0.0001
1
0.001
0.01
0.1
IO - Output Current - A
Figure 3.
Figure 4.
EFFICIENCY DCDC2 (VO = 1.2 V)
vs
LOAD CURRENT / PWM MODE
EFFICIENCY DCDC2 (VO = 1.2 V)
vs
LOAD CURRENT / PFM MODE
1
100
100
80
40
20
6V
10
90
50
30
5V
3V
20
60
3.6 V
3.3 V
TA = 25°C,
PWM Mode,
VO = 1.2 V
90
80
3V
70
Efficiency - %
Efficiency - %
70
60
5V
50
4.2 V
40
30
20
40
20
3V
10
0.001
0.01
0.1
IO - Output Current - A
1
0
0.0001
Figure 5.
10
4.2 V
50
5V
30
3.6 V
10
0
0.0001
3.6 V
60
TA = 25°C,
PWM/PFM Mode,
VO = 1.2 V
0.001
0.01
0.1
IO - Output Current - A
1
Figure 6.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
VDCD1 = 2.1 V
VDCD2 = 1.2 V
Load DCDC1 = 80 mA
Load DCDC2 = 80 mA
ENDCDC1 = High
ENDCDC2 = High
ENLDO1 = Low
ENLDO2 = Low
ENLDO3 = Low
ENLDO4 = Low
CH1: VDCD1 (Black)
CH2: VDCD2 (Green)
CH3: Inductor Current DCDC2 (Red)
CH4: Inductor Current DCDC1 (Blue)
Figure 7. Output Voltage Ripple in PFM Mode
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
VDCD1 = 2.1 V
VDCD2 = 1.2 V
Load DCDC1 = 600 mA
Load DCDC2 = 600 mA
ENDCDC1 = High
ENDCDC2 = High
ENLDO1 = Low
ENLDO2 = Low
ENLDO3 = Low
ENLDO4 = Low
CH1: VDCD1 (Black)
CH2: VDCD2 (Green)
CH3: Inductor Current DCDC2 (Red)
CH4: Inductor Current DCDC1 (Blue)
Figure 8. Output Voltage Ripple in PWM Mode
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
11
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
VDCD1 = 2.1 V
VDCD2 = 1.2 V
Load DCDC1 = 600 mA
Load DCDC2 = 600 mA
ENDCDC1 = 0 V to 3.6 V
ENDCDC2 = 0 V to 3.6 V
ENLDO1 = 0 V to 3.6 V
ENLDO2 = Low
ENLDO3 = Low
ENLDO4 = Low
CH4: EN_DCDC1/2, ENLDO1 (Blue)
CH3: VLDO1 (Red)
CH2: VDCDC2 (Green)
CH1: VDCDC1 (Black)
Figure 9. Startup Timing DCDC1, DCDC2, and LDO1
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
VLDO1 = 3.3 V
VLDO2 = 2.85 V
VLDO3 = 1.1 V
VLDO3 = 1.3 V
Load Current = 100 mA each
ENLDO1 = 0 V to 3.6 V
ENLDO2 = 0 V to 3.6 V
ENLDO3 = 0 V to 3.6 V
ENLDO4 = 0 V to 3.6 V
R1: Enable (Blue)
CH1: VDCD1 (Black)
CH2: VDCD2 (Green)
CH3: VLDO3 (Red)
CH4: VLDO4 (Turquoise)
Figure 10. Startup Timing LDO1, LDO2, LDO3, and LDO4
12
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 60 mA to 540 mA
VDCDC1 = 2.1 V
CH1: VDCD1 (Green)
CH2: Load Current (Blue)
Figure 11. Load Transient Response DCDC1; PWM
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 60 mA to 540 mA
VDCDC1 = 2.1 V
CH1: VDCD1 (Green)
CH2: Load Current (Blue)
Figure 12. Load Transient Response DCDC1; PFM
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
13
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 60 mA to 540 mA
VDCDC1 = 2.1 V
CH1: VDCD1 (Green)
CH2: Load Current (Blue)
Figure 13. Load Transient Response DCDC2; PWM
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 60 mA to 540 mA
VDCDC1 = 2.1 V
CH1: VDCD1 (Green)
CH2: Load Current (Blue)
Figure 14. Load Transient Response DCDC2; PFM
14
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 600 mA
VDCDC2 = 2.1 V
CH1: Input Voltage (Black)
CH2: Output Voltage (Green)
Figure 15. Line Transient Response DCDC1 (VO = 2.1 V)
TEST CONDITIONS
VIN = 3.3 V to 4.2 V to 3.3 V
TA = 25°C
Load Current = 600 mA
VDCDC2 = 2.1 V
CH1: Input Voltage (Black)
CH2: Output Voltage (Green)
Figure 16. Line Transient Response DCDC2 (VO = 1.2 V)
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
15
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 40 mA to 360 mA
VLDO1 = 1.2 V
CH1: VLDO1 (Green)
CH2: Load Current (Blue)
Figure 17. Load Transient Response LDO1
TEST CONDITIONS
VIN = 3.6 V
TA = 25°C
Load Current = 20 mA to 180 mA
VLDO4 = 2.8 V
CH1: VLDO4 (Green)
CH2: Load Current (Blue)
Figure 18. Load Transient Response LDO4
16
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
TEST CONDITIONS
VIN = 3.6 V to 4.2 V to 3.6 V
TA = 25°C
Load Current = 100 mA
VLDO1 = 1.2 V
CH1: VINLDO1 (Black)
CH2: VLDO1 (Green)
Figure 19. Line Transient Response LDO1
DETAILED DESCRIPTION
OPERATION
The TPS65055 includes two synchronous step-down converters. The converters operate with typically 2.25 MHz
fixed frequency pulse width modulation (PWM) at moderate to heavy load currents. At light load currents the
converters automatically enter power save mode and operate with PFM (pulse frequency modulation).
During PWM operation the converters 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 P-channel MOSFET switch is
turned on and the inductor current ramps up until the comparator trips and the control logic turns off the switch.
The current limit comparator also turns off the switch in case the current limit of the P-channel switch is
exceeded. After the adaptive dead time preventing shoot through current, the N-channel MOSFET rectifier is
turned on and the inductor current ramps down. The next cycle is initiated by the clock signal again turning off
the N-channel rectifier and turning on the P-channel switch.
The two dc-dc converters operate synchronized to each other, with converter 1 as the master. A 180° phase shift
between converter 1 and converter 2 decreases the input RMS current. Therefore smaller input capacitors can
be used.
DCDC1 Converter
The converter 1 output voltage is set by the status of the DEFLDO1 and DEFLDO2 pins. The pins can be pulled
low, pulled high or left floating to allow 9 different logic states. See the description for the LDOs for further
details. With the TPS65055 it is also possible to change the output voltage of converter DCDC1 via the I2C
compatible interface. The VDCDC1 pin must be directly connected to VOUT1 and no external resistor network may
be connected.
DCDC2 Converter
The VDCDC2 pin must be directly connected to the DCDC2 converter output voltage. The DCDC2 converter
output voltage can be selected via the DEFDCDC2 pin or the I2C compatible interface.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
17
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
The DEFDCDC2 pin can either be connected to GND, or to VCC. The converter 2 defaults to 1.0 V or 1.2 V
depending on the logic level of the DEFDCDC2 pin. If DEFDCDC2 is tied to ground, the default is 1.2 V; if it is
tied to VCC, the default is 1.0 V.
With the TPS65055, the voltage can also be changed using the I2C registers – see the application section for
details.
POWER SAVE MODE
Power safe mode is enabled per default and can be disabled using the I2C compatible interface. If the load
current decreases, the converters enter power save mode operation automatically. During power save mode the
converters operate with reduced switching frequency in PFM mode and with a minimum quiescent current to
maintain high efficiency. The converter positions the output voltage typically 1% above the nominal output
voltage. This voltage positioning feature minimizes voltage drops caused by a sudden load step.
In order to optimize converter efficiency at light load the average current is monitored, and if in PWM mode the
inductor current remains below a certain threshold, then power save mode is entered. The typical threshold can
be calculated according to:
Equation 1: Average output current threshold to enter PFM mode
VINDCDC
IPFM_enter =
32 W
Equation 2: Average output current threshold to leave PFM mode
VINDCDC
IPSMDCDCleave =
24 W
During power save mode, the output voltage is monitored with a comparator. As the output voltage falls below
the skip comparator threshold (skip comp) of VOUTnominal +1%, the P-channel switch turns on and the converter
effectively delivers a constant current as defined above. If the load is below the delivered current, then the output
voltage rises until the same threshold is crossed again, whereupon all switching activity ceases, hence reducing
the quiescent current to a minimum until the output voltage has dropped below the threshold again. If the load
current is greater than the delivered current, then the output voltage falls until it crosses the skip comparator low
(skip comp low) threshold set to 1% below nominal Vout, whereupon power save mode is exited and the
converter returns to PWM mode.
These control methods reduce the quiescent current typically to 12 µA per converter and the switching frequency
to a minimum achieving the highest converter efficiency. PFM mode operates with very low output voltage ripple.
The ripple depends on the comparator delay and the size of the output capacitor; increasing capacitor values
makes the output ripple tend to zero.
Dynamic Voltage Positioning
This feature reduces the voltage under/overshoots at load steps from light to heavy load and vice versa. It is
activated in power save mode operation when the converter runs in PFM mode. It provides more headroom for
both, the voltage drop at a load step and the voltage increase at a load throw-off. This improves load transient
behavior.
At light loads, in which the converter operates in PFM mode, the output voltage is regulated typically 1% higher
than the nominal value. In case of a load transient from light load to heavy load, the output voltage drops until it
reaches the skip comparator low threshold set to –1% below the nominal value and enters PWM mode. During a
load throw off from heavy load to light load, the voltage overshoot is also minimized due to active regulation
turning on the N-channel switch.
18
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
Smooth
increased load
+1%
Fast Load Transient
PFM Mode
light load
PFM Mode
light load
VOUT_NOM
PWM Mode
Medium/Heavy Load
PWM Mode
Medium/Heavy Load
COMP_LOW threshold
Soft Start
The two converters have an internal soft start circuit that limits the inrush current during start-up. During soft
start, the output voltage ramp up is controlled as shown in Figure 20.
EN
95%
5%
VOUT
tStart
tRAMP
Figure 20. Soft Start
100% Duty Cycle Low Dropout Operation
The converters offer a low input to output voltage difference while still maintaining operation with the use of the
100% duty cycle mode. In this mode the P-channel switch is constantly turned on. This is particularly useful in
battery-powered applications to achieve the longest operation time by taking full advantage of the whole battery
voltage range, for example. The minimum input voltage to maintain regulation depends on the load current and
output voltage and can be calculated as:
Vinmin = Voutmax + Ioutmax ´ (RDSonmax + RL )
With:
Ioutmax = maximum output current plus inductor ripple current
RDSonmax = maximum P-channel switch RDSon.
RL = DC resistance of the inductor
Voutmax = nominal output voltage plus maximum output voltage tolerance
With decreasing load current, the device automatically switches into pulse skipping operation in which the power
stage operates intermittently based on load demand. By running cycles periodically the switching losses are
minimized and the device runs with a minimum quiescent current maintaining high efficiency.
In power save mode the converter only operates when the output voltage trips below its nominal output voltage.
It ramps up the output voltage with several pulses and goes again into power save mode once the output voltage
exceeds the nominal output voltage.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
19
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
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 converters and LDOs. The under-voltage lockout threshold is
typically 1.8 V.
ENABLE
The DCDC converters and the LDOs are enabled using external enable pins or enable bits with the I2C
compatible interface. The signal of the enable pin and the enable bit are logically XORed to generate the enable
signal to the converter or LDO. There is one enable pin and one enable bit for each of the LDOs or DCDC
converters, which allows start up of each converter independently. If EN_DCDC1, EN_DCDC2, EN_LDO1,
EN_LDO2, ENLDO3, or EN_LDO4 are set to high, the corresponding converter starts up with soft start as
previously described. The converters and LDOs can also be enabled by setting the enable bits for each of the
LDOs or DCDC converters in register REG_CTRL. See the register description for more details.
Disabling the DCDC converter or LDO forces the device into shutdown with a shutdown quiescent current as
defined in the electrical characteristics. In this mode, the P and N-Channel MOSFETs are turned-off, and the
entire internal control circuitry is switched-off. For proper operation the enable pins must be terminated and must
not be left floating.
discharge
The TPS65055 contains a comparator that supervises a voltage applied to the threshold pin and drives a open
drain NMOS according to the input level applied at threshold. If the input voltage at the threshold pin is lower
than 1V, the open drain NMOS at the discharge output is turned on, pulling the pin to GND. This circuitry is
functional as soon as the supply voltage at Vcc exceeds the undervoltage lockout threshold. Therefore the
TPS65055 has a shutdown current (all DCDC converters and LDOs are off) of 9µA in order to supply bandgap
and comparator.
Vbat
threshold
+
discharge
Vref = 1V
Vbat
threshold
discharge
RST and DPD
The TPS65055 contains two open drain outputs that are controlled by the I2C compatible interface. The RST and
DPD outputs are low (internal NMOS active) per default, once the undervoltage lockout threshold has been
exceeded. The status of these outputs can be changed using the REG_CTRL register. See the register
description for more details.
SHORT-CIRCUIT PROTECTION
All outputs are short-circuit protected with a maximum output current as defined in the electrical specifications.
20
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
THERMAL SHUTDOWN
As soon as the junction temperature, TJ, exceeds typically 150°C for the dcdc converters, the device goes into
thermal shutdown. In this mode, the P- and N-Channel MOSFETs are turned-off. The device continues its
operation when the junction temperature falls below the thermal shutdown hysteresis again. A thermal shutdown
for one of the dcdc converters disables both converters simultaneously.
The thermal shutdown temperature for the LDOs are set to typically 140°C. Therefore, a LDO which may be
used to power an external voltage never heats up the device that high to turn off the dcdc converters. If one LDO
exceeds the thermal shutdown temperature, all LDOs turn off simultaneously.
LDO1 to LDO4
The low dropout voltage regulators are designed to operate well with low value ceramic input and output
capacitors. They operate with input voltages down to 1.5 V. The LDOs offer a maximum dropout voltage of 280
mV at rated output current. Each LDO supports a current limit feature. The LDOs are enabled by the EN_LDO1,
ENLDO2, EN_LDO3, and EN_LDO4 pin EXOR with a bit in register REG_CTRL (Reg#02h).
Default Voltage Setting for LDOs and DCDC1
In the TPS65055, the output voltage of the LDOs and of DCDC1 is set using two pins, DEFLDO1 and DEFLDO2.
These pins can either be connected to a logic low level, a logic high level, or left floating to define a set of output
voltages for LDO1 to LDO4 and DCDC1 according to the following table. The status of the DEFLDO pins is
latched after an undervoltage lockout event (UVLO) and sets the registers LDO_CTRL1, LDO_CTRL2, and
DEFDCDC1 accordingly. The output voltage of each LDO and DCDC1 can be changed later by reprogramming
these registers. See the register description for more details.
The TPS65055 default voltage options are adjustable with DEFLDO2 and DEFLDO1 according to the following
table:
DEFLDO2
DEFLDO1
VLDO1
VLDO2
VLDO3
VLDO4
DCDC1
0
0
400mA LDO
400mA LDO
200mA LDO
200mA LDO
600mA
1.2 V
1.8 V
2.8 V
1.3 V
0
2.1 V
float
1.2 V
1.8 V
2.8 V
2.8 V
1.8 V
0
1
1.2 V
1.8 V
2.8 V
1.3 V
1.8 V
float
0
1.2 V
1.8 V
2.8 V
2.8 V
2.1 V
float
float
1.2 V
1.8 V
2.8 V
1.8 V
2.1 V
float
1
1.2 V
1.8 V
2.8 V
2.8 V
1.2 V
1
0
1.2 V
1.8 V
2.8 V
1.0 V
1.9 V
1
float
1.2 V
1.8 V
2.8 V
3.0 V
2.1 V
1
1
1.0 V
1.2 V
1.0 V
1.0 V
1.2 V
INTERFACE SPECIFICATION
Serial Interface
The serial interface is compatible with the standard and fast mode I2C specifications, allowing transfers at up to
400 kHz. The interface adds flexibility to the power supply solution, enabling most functions to be programmed to
new values depending on the instantaneous application requirements and charger status to be monitored.
Register contents remain intact as long as VCC remains above the UVLO threshold. The TPS65055 has a 7bit
address: ‘1001000’, other addresses are available upon contact with the factory. Attempting to read data from
register addresses not listed in this section result in 00h being read out.
For normal data transfer, DATA is allowed to change only when CLK is low. Changes when CLK is high are
reserved for indicating the start and stop conditions. During data transfer, the data line must remain stable
whenever the clock line is high. There is one clock pulse per bit of data. Each data transfer is initiated with a start
condition and terminated with a stop condition. When addressed, the TPS65055 device generates an
acknowledge bit after the reception of each byte. The master device (microprocessor) must generate an extra
clock pulse that is associated with the acknowledge bit. The TPS65055 device must pull down the DATA line
during the acknowledge clock pulse so that the DATA line is a stable low during the high period of the
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
21
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
acknowledge clock pulse. The DATA line is a stable low during the high period of the acknowledge – related
clock pulse. Setup and hold times must be taken into account. During read operations, a master must signal the
end of data to the slave by not generating an acknowledge bit on the last byte that was clocked out of the slave.
In this case, the slave TPS65055 device must leave the data line high to enable the master to generate the stop
condition.
DATA
CLK
Change
of data
allowed
Data line
stable;
data valid
Figure 21. Bit Transfer on the Serial Interface
DATA
CLK
S
P
START Condition
STOP Condition
Figure 22. Start and Stop Conditions
SCLK
SDAT
...
A6
A5 A4 ...
...
A0 R/W
0
Start
Slave Address
AC
K
R7
R6
R5
...
...
R0
0
AC
K
D7
AC
D6 D5 ... D0
K
0
0
Register Address
Data
Stop
NOTE: SLAVE = TPS65055
Figure 23. Serial I/F Write to the TPS65055 Device
22
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
SCLK
...
SDAT
A6
..
...
R/W ACK
A0
0
R7
..
...
ACK
R0
0
...
..
A6
A0
1
0
Start
Register
Address
Slave Address
.. D0
R/W ACK D7
0
Stop
Master
Drives
ACK and Stop
Slave
Drives
the Data
Slave Address
Repeated
Start
NOTE: SLAVE = TPS65055
ACK
Figure 24. Serial I/FRead From TPS65055: Protocol A
SCLK
...
SDAT
A6 ..
...
A0
R/W ACK
0
Start
R7
..
..
...
R0 ACK
0
0
A6
A0
R/W ACK
1
Stop Start
Register
Address
Slave Address
..
D7
..
D0
0
Slave Address
NOTE: SLAVE = TPS65055
Slave
Drives
the Data
ACK
Stop
Master
Drives
ACK and Stop
Figure 25. Serial I/F Read From TPS65055: Protocol B
DATA
t(BUF)
th(STA)
t(LOW)
tr
tf
CLK
t(HIGH)
th(STA)
th(DATA)
STO
STA
tsu(STA)
th(DATA)
t su(STO)
STA
STO
Figure 26. Serial I/F Timing Diagram
MIN
MAX
UNIT
400
kHz
fMAX
Clock frequency
twH(HIGH)
Clock high time
600
twL(LOW)
Clock low time
1300
tR
DATA and CLK rise time
300
ns
tF
DATA and CLK fall time
300
ns
th(STA)
Hold time (repeated) start condition (after this period the first clock pulse is generated)
600
ns
th(DATA)
Setup time for repeated start condition
600
ns
th(DATA)
Data input hold time
100
ns
tsu(DATA)
Data input setup time
100
ns
tsu(STO)
Stop condition setup time
600
ns
ns
ns
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
23
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
MIN
t(BUF)
Bus free time
MAX
UNIT
1300
ns
PGOODZ. Register Address: 01h (read only)
PGOODZ
B7
B6
B5
B4
B3
B2
B1
BO
discharge
DVM
PGOODZ
VDCDC1
PGOODZ
VDCDC2
PGOODZ
LDO1
PGOODZ
LDO2
PGOODZ
LDO3
PGOODZ
LDO4
Set by signal
PGOODZ
VDCDC1
PGOODZ
VDCDC2
PGOODZ
LDO1
PGOODZ
LDO2
PGOODZ
LDO3
PGOODZ
LDO4
Default value loaded
by:
PGOOD
VDCDC1
PGOOD
VDCDC2
PGOOD
LDO1
PGOOD
LDO2
PGOOD
LDO3
PGOOD
LDO4
R
R
R
R
R
R
Bit name and function
Read/write
R
R
Bit 7
discharge:
0 = Indicates that the comparator input voltage is below the 1 V threshold.
1 = Indicates that the comparator input voltage is above the 1 V threshold.
Bit 6
DVM:
0 = Indicates that the voltage of DCDC2 is not changing
1 = Indicates that a voltage change of DCDC2 is ongoing
Bit 5
PGOODZ VDCDC1:
0 = Indicates that the VDCDC1 converter output voltage is within its nominal range.
1 = Indicates that the VDCDC1 converter output voltage is below its target regulation voltage or is
disabled.
Bit 4
PGOODZ VDCDC2:
0 = Indicates that the VDCDC2 converter output voltage is within its nominal range.
1 = Indicates that the VDCDC2 converter output voltage is below its target regulation voltage or is
disabled.
Bit 3
PGOODZ LDO1:
0 = Indicates that the LDO1 output voltage is within its nominal range.
1 = Indicates that the LDO1 output voltage is below its target regulation voltage or is disabled.
Bit 2
PGOODZ LDO2:
0 = Indicates that the LDO2 output voltage is within its nominal range.
1 = Indicates that LDO2 output voltage is below its target regulation voltage or is disabled.
Bit 1
PGOODZ LDO3:
0 = Indicates that the LDO3 output voltage is within its nominal range.
1 = Indicates that the LDO3 output voltage is below its target regulation voltage or is disabled.
Bit 0
PGOODZ LDO4:
0 = Indicates that the LDO4 output voltage is within its nominal range.
1 = Indicates that the LDO4 output voltage is below its target regulation voltage or is disabled.
REG_CTRL. Register Address: 02h (read/write)
REG_CTRL
Bit name and function
Default
Default Value: 00h
B7
B6
B5
B4
B3
B2
B1
BO
RST
DPD
DCDC1
ENABLE
DCDC2
ENABLE
LDO1
ENABLE
LDO2
ENABLE
LDO3
ENABLE
LDO4
ENABLE
0
0
0
0
0
0
0
0
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Set by signal
Default value loaded by:
Read/write
24
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
The REG_CTRL register can be used to disable and enable all power supplies via the serial interface. The
following tables indicate how the enable pins and the REG_CTRL register are combined.
EN_DCDC1 Pin
REG_CTRL<5>
DCDC1 Converter
EN_LDO2 Pin
REG_CTRL<2>
LDO2
0
0
Disabled
0
0
Disabled
0
1
Enabled
0
1
Enabled
1
0
Enabled
1
0
Enabled
1
1
Disabled
1
1
Disabled
EN_DCDC2 pin
REG_CTRL<4>
DCDC2
EN_LDO3 pin
REG_CTRL<1>
LDO3
0
0
Disabled
0
0
Disabled
0
1
Enabled
0
1
Enabled
1
0
Enabled
1
0
Enabled
1
1
Disabled
1
1
Disabled
EN_LDO1 pin
REG_CTRL<3>
LDO1
EN_LDO4 pin
REG_CTRL<0>
LDO4
0
0
Disabled
0
0
Disabled
0
1
Enabled
0
1
Enabled
1
0
Enabled
1
0
Enabled
1
1
Disabled
1
1
Disabled
Bit 7
RST:
0 = The internal NMOS is turned on and drives the output to GND
1 = The internal NMOS is turned off, an external pull-up resistor at RST drives the output high
Bit 6
DPD:
0 = The internal NMOS is turned on and drives the output to GND
1 = The internal NMOS is turned off, an external pull-up resistor at DPD drives the output high
CON_CTRL. Register Address: 03h (read/write)
CON_CTRL
B7
B6
Default Value: 00h
B5
B4
Bit name and function
Default
0
0
0
0
Default value loaded by:
Read/write
R
R
R
R
B3
B2
B1
BO
LOW RIPPLE
DCDC1
LOW RIPPLE
DCDC2
FPWM
DCDC1
FPWM
DCDC2
0
0
0
1
UVLO
UVLO
UVLO
UVLO
R/W
R/W
R/W
R/W
The CON_CTRL register is used to force any or all of the converters into forced PWM operation, when low
output voltage ripple is vital.
Bit 3
LOW RIPPLE DCDC1:
0 = PFM mode operation optimized for high efficiency for DCDC1
1 = PFM mode operation optimized for low output voltage ripple for DCDC1
Bit 2
LOW RIPPLE DCDC2:
0 = PFM mode operation optimized for high efficiency for DCDC2
1 = PFM mode operation optimized for low output voltage ripple for DCDC2
Bit 1
FPWM DCDC1:
0 = DCDC1 converter operates in PWM / PFM mode
1 = DCDC1 converter is forced into fixed frequency PWM mode
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
25
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
Bit 0
FPWM DCDC2:
0 = DCDC2 converter operates in PWM / PFM mode
1 = DCDC2 converter is forced into fixed frequency PWM mode
CON_CTRL2. Register Address: 04h (read/write)
CON_CTRL2
B7
Bit name and function
GO
Default
B6
0
Default value loaded by:
Read/write
Default Value: 0Fh
0
UVLO +
DONE*
R
R
B5
B4
B3
B2
B1
BO
DCDC1
discharge
DCDC2
discharge
LDO1
discharge
LDO2
discharge
LDO3
discharge
LDO4
discharge
0
0
1
1
1
1
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
R/W
R/W
R/W
R/W
R/W
R/W
The CON_CTRL2 register can be used to take control of the inductive converters.
Bit 7
GO:
0 = No change in the output voltage for the DCDC2 converter
1 = A voltage change for the DCDC2 converter is ongoing. The voltage is changed to the value written
into the DEFDCDC2_HIGH or DEFDCDC2_LOW register with the slew rate defined in DEFSLEW.
This bit is automatically set and cleared internally. The transition is considered complete in this case
when the desired output voltage code has been reached, not when the VDCDC2 output voltage is
actually in regulation at the desired voltage. The GO bit is also high when a voltage change is ongoing
caused by changing the logic level of the DEFDCDC2 pin.
Bit 5–0 0 = The output capacitor of the associated converter or LDO is not actively discharged when the
converter or LDO is disabled
1 = The output capacitor of the associated converter or LDO is actively discharged when the converter
or LDO is disabled. This decreases the fall time of the output voltage at light load
DEFDCDC2_LOW. Register Address: 05h (read/write)
DEFDCDC2_LOW
B7
B6
0
0
Bit name and function
Default
Default Value: 10h
B5
B4
B3
B2
B1
BO
DCDC2[5]
DCDC2[4]
DCDC2[3]
DCDC2[2]
DCDC2[1]
DCDC2[0]
0
1
0
0
0
0
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
R/W
R/W
R/W
R/W
R/W
R/W
Default value loaded by:
Read/write
R
R
DEFDCDC2_HIGH. Register Address: 06h (read/write)
DEFDCDC2_HIGH
B7
B6
Bit name and function
Default
0
0
R
R
Default value loaded by:
Read/write
Default Value: 08h
B5
B4
B3
B2
B1
BO
DCDC2[5]
DCDC2[4]
DCDC2[3]
DCDC2[2]
DCDC2[1]
DCDC2[0]
0
0
1
0
0
0
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
R/W
R/W
R/W
R/W
R/W
R/W
The output voltage for DCDC2 is switched between the value defined in DEFDCDC2_LOW and
DEFDCDC2_HIGH depending on the status of the DEFDCDC2 pin. IF DEFDCDC2 is low, the value in
DEFDCDC2_LOW is selected, if DEFDCDC2 = high, the value in DEFDCDC2_HIGH is selected.
Table 1. VOLTAGE TABLE FOR DCDC2
26
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
0
0.800
0
0
0
0
0
0
1
0.825
0
0
0
0
0
1
2
0.850
0
0
0
0
1
0
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
Table 1. VOLTAGE TABLE FOR DCDC2 (continued)
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
3
0.875
0
0
0
0
1
1
4
0.900
0
0
0
1
0
0
5
0.925
0
0
0
1
0
1
6
0.950
0
0
0
1
1
0
7
0.975
0
0
0
1
1
1
8
1.000
0
0
1
0
0
0
9
1.025
0
0
1
0
0
1
10
1.050
0
0
1
0
1
0
11
1.075
0
0
1
0
1
1
12
1.100
0
0
1
1
0
0
13
1.125
0
0
1
1
0
1
14
1.150
0
0
1
1
1
0
15
1.175
0
0
1
1
1
1
16
1.200
0
1
0
0
0
0
17
1.225
0
1
0
0
0
1
18
1.250
0
1
0
0
1
0
19
1.275
0
1
0
0
1
1
20
1.300
0
1
0
1
0
0
21
1.325
0
1
0
1
0
1
22
1.350
0
1
0
1
1
0
23
1.375
0
1
0
1
1
1
24
1.400
0
1
1
0
0
0
25
1.425
0
1
1
0
0
1
26
1.450
0
1
1
0
1
0
27
1.475
0
1
1
0
1
1
28
1.500
0
1
1
1
0
0
29
1.525
0
1
1
1
0
1
30
1.550
0
1
1
1
1
0
31
1.575
0
1
1
1
1
1
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
27
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
VOLTAGE TABLE FOR DCDC2
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
0
1.600
1
0
0
0
0
0
1
1.650
1
0
0
0
0
1
2
1.700
1
0
0
0
1
0
3
1.750
1
0
0
0
1
1
4
1.800
1
0
0
1
0
0
5
1.850
1
0
0
1
0
1
6
1.900
1
0
0
1
1
0
7
1.950
1
0
0
1
1
1
8
2.000
1
0
1
0
0
0
9
2.050
1
0
1
0
0
1
10
2.100
1
0
1
0
1
0
11
2.150
1
0
1
0
1
1
12
2.200
1
0
1
1
0
0
13
2.250
1
0
1
1
0
1
14
2.300
1
0
1
1
1
0
15
2.350
1
0
1
1
1
1
16
2.400
1
1
0
0
0
0
17
2.450
1
1
0
0
0
1
18
2.500
1
1
0
0
1
0
19
2.550
1
1
0
0
1
1
20
2.600
1
1
0
1
0
0
21
2.650
1
1
0
1
0
1
22
2.700
1
1
0
1
1
0
23
2.750
1
1
0
1
1
1
24
2.800
1
1
1
0
0
0
25
2.850
1
1
1
0
0
1
26
2.900
1
1
1
0
1
0
27
2.950
1
1
1
0
1
1
28
3.000
1
1
1
1
0
0
29
3.100
1
1
1
1
0
1
30
3.200
1
1
1
1
1
0
31
3.300
1
1
1
1
1
1
DEFSLEW. Register Address: 07h (read/write)
DEFSLEW
B7
Default Value: 06h
B6
B5
B4
B3
Bit name and function
Default
0
0
0
0
0
Default value loaded by:
Read/write
28
R
R
R
R
Submit Documentation Feedback
R
B2
B1
BO
SLEW2
SLEW1
SLEW0
1
1
0
UVLO
UVLO
UVLO
R/W
R/W
R/W
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
SLEW2
SLEW1
SLEW0
VDCDC3 SLEW RATE
0
0
0
0.11 mV/µs
0
0
1
0.22 mV/µs
0
1
0
0.45 mV/µs
0
1
1
0.9 mV/µs
1
0
0
1.8 mV/µs
1
0
1
3.6 mV/µs
1
1
0
7.2 mV/µs
1
1
1
Immediate
LDO_CTRL1. Register Address: 08h (r/w)
LDO_CTRL
Default Value: set with DEFLDO1, DEFLDO2
B7
B6
LDO2[2]
LDO2[1]
LDO2[0]
0
DEFLDO
pins
DEFLDO
pins
DEFLDO
pins
UVLO
UVLO
UVLO
R/W
R/W
R/W
Bit name and function
Default
Default value loaded by:
Read/write
R
B5
B4
B3
B2
LDO1[2]
LDO1[1]
LDO1[0]
0
DEFLDO
pins
DEFLDO
pins
DEFLDO
pins
UVLO
UVLO
UVLO
R/W
R/W
R/W
R
B1
BO
The LDO_CTRLx registers can be used to set the output voltages of LDO1 to LDO4. The default value is loaded
at power-up depending on the status of the DEFLDO pins. See section Default Voltage Setting for LDOs and
DCDC1 for details. The status of the DEFLDO pins is latched after the undervoltage lockout threshold is
exceeded, so the voltage can be changed by reprogramming the register content.
LDO2[2]
LDO2[1]
LDO2[0]
LDO2
OUTPUT
VOLTAGE
LDO1[2]
LDO1[1]
LDO1[0]
0
0
0
1.2 V
0
0
0
0.8V
0
0
1
1.3 V
0
0
1
1.0 V
0
1
0
1.8 V
0
1
0
1.2 V
0
1
1
2.6 V
0
1
1
1.5 V
1
0
0
2.7 V
1
0
0
1.8 V
1
0
1
2.8 V
1
0
1
2.1 V
1
1
0
2.9 V
1
1
0
2.5 V
1
1
1
3.0 V
1
1
1
2.8 V
LDO_CTRL2. Register Address: 09h (r/w)
LDO_CTRL
B7
Bit name and function
Default
0
Default value loaded
by:
Read/write
R
LDO1
OUTPUT
VOLTAGE
Default Value: set with DEFLDO1, DEFLDO2
B6
B5
B4
LDO4[2]
LDO4[1]
LDO4[0]
DEFLDO
pins
DEFLD
O pins
DEFLDO
pins
UVLO
UVLO
UVLO
R/W
R/W
R/W
B3
B2
B1
BO
LDO3[2 LDO3[1 LDO3[0]
]
]
0
R
DEFLD
O pins
DEFLD
O pins
DEFLD
O pins
UVLO
UVLO
UVLO
R/W
R/W
R/W
The default value is loaded at power-up depending on the status of the DEFLDO pins. See section Default
Voltage Setting for LDOs and DCDC1 for details. The status of the DEFLDO pins is latched after the
undervoltage lockout threshold is exceeded, so the voltage can be changed by reprogramming the register
content.
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
29
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
LDO4[2]
LDO4[1]
LDO4[0]
LDO4
OUTPUT
VOLTAGE
LDO3[2]
LDO3[1]
LDO3[0]
LDO3
OUTPUT
VOLTAGE
0
0
0
1.0 V
0
0
0
0.8V
0
0
1
1.2 V
0
0
1
1.0 V
0
1
0
1.3 V
0
1
0
1.2 V
0
1
1
1.8 V
0
1
1
1.5 V
1
0
0
2.6 V
1
0
0
1.8 V
1
0
1
2.7 V
1
0
1
2.1 V
1
1
0
2.8 V
1
1
0
2.5 V
1
1
1
3.0 V
1
1
1
2.8 V
DEFDCDC1. Register Address: 0Ah (r/w)
DEFDCDC1
B7
Default Value: set with DEFLDO1, DEFLDO2
B6
B5
B4
B3
B2
B1
BO
DCDC1[5]
DCDC1[4]
DCDC1[3]
DCDC1[2]
DCDC1[1]
DCDC1[0]
0
DEFLDO pins
DEFLDO
pins
DEFLDO
pins
DEFLDO
pins
DEFLDO
pins
DEFLDO
pins
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
UVLO
R
R/W
R/W
R/W
R/W
R/W
R/W
Bit name and function
Default
0
Default value loaded by:
Read/write
R
Per default the DCDC1 converter is internally adjustable and the default output voltage for DCDC1 (bits B0 to
B5) depends on the status of the DEFLDO pins – see section Default Voltage Setting for LDOs and DCDC1. The
status of the DEFLDO pins is latched after the undervoltage lockout threshold is exceeded, so the voltage can be
changed by reprogramming the register content.
DCDC1 voltage is listed in the following table.
30
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
0
0.800
0
0
0
0
0
0
1
0.825
0
0
0
0
0
1
2
0.850
0
0
0
0
1
0
3
0.875
0
0
0
0
1
1
4
0.900
0
0
0
1
0
0
5
0.925
0
0
0
1
0
1
6
0.950
0
0
0
1
1
0
7
0.975
0
0
0
1
1
1
8
1.000
0
0
1
0
0
0
9
1.025
0
0
1
0
0
1
10
1.050
0
0
1
0
1
0
11
1.075
0
0
1
0
1
1
12
1.100
0
0
1
1
0
0
13
1.125
0
0
1
1
0
1
14
1.150
0
0
1
1
1
0
15
1.175
0
0
1
1
1
1
16
1.200
0
1
0
0
0
0
17
1.225
0
1
0
0
0
1
18
1.250
0
1
0
0
1
0
19
1.275
0
1
0
0
1
1
20
1.300
0
1
0
1
0
0
21
1.325
0
1
0
1
0
1
22
1.350
0
1
0
1
1
0
23
1.375
0
1
0
1
1
1
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
24
1.400
0
1
1
0
0
0
25
1.425
0
1
1
0
0
1
26
1.450
0
1
1
0
1
0
27
1.475
0
1
1
0
1
1
28
1.500
0
1
1
1
0
0
29
1.525
0
1
1
1
0
1
30
1.550
0
1
1
1
1
0
31
1.575
0
1
1
1
1
1
OUTPUT VOLTAGE
[V]
B5
B4
B3
B2
B1
B0
0
1.600
1
0
0
0
0
0
1
1.650
1
0
0
0
0
1
2
1.700
1
0
0
0
1
0
3
1.750
1
0
0
0
1
1
4
1.800
1
0
0
1
0
0
5
1.850
1
0
0
1
0
1
6
1.900
1
0
0
1
1
0
7
1.950
1
0
0
1
1
1
8
2.000
1
0
1
0
0
0
9
2.050
1
0
1
0
0
1
10
2.100
1
0
1
0
1
0
11
2.150
1
0
1
0
1
1
12
2.200
1
0
1
1
0
0
13
2.250
1
0
1
1
0
1
14
2.300
1
0
1
1
1
0
15
2.350
1
0
1
1
1
1
16
2.400
1
1
0
0
0
0
17
2.450
1
1
0
0
0
1
18
2.500
1
1
0
0
1
0
19
2.550
1
1
0
0
1
1
20
2.600
1
1
0
1
0
0
21
2.650
1
1
0
1
0
1
22
2.700
1
1
0
1
1
0
23
2.750
1
1
0
1
1
1
24
2.800
1
1
1
0
0
0
25
2.850
1
1
1
0
0
1
26
2.900
1
1
1
0
1
0
27
2.950
1
1
1
0
1
1
28
3.000
1
1
1
1
0
0
29
3.100
1
1
1
1
0
1
30
3.200
1
1
1
1
1
0
31
3.300
1
1
1
1
1
1
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
31
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
VERSION. Register Address: 0Bh (r)
LDO_CTRL
B7
B6
B5
B4
B3
B2
B1
Default
0
0
0
0
0
0
0
0
Read/write
R
R
R
R
R
R
R
R
32
Submit Documentation Feedback
BO
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
TPS65055
www.ti.com.......................................................................................................................................................................................... SLVS844 – SEPTEMBER 2008
APPLICATION INFORMATION
OUTPUT VOLTAGE SETTING
Converter 1 (DCDC1)
The output voltage of converter 1 is set by the status of the DEFLDO pins and the I2C compatible interface.
Converter 2 (DCDC2)
The output voltage of converter 2 is selected with the DEFDCDC2 pin.
Table 2. Default Fixed Output Voltages
CONVERTER 2
DEFDCDC2 = LOW
DEFDCDC2 = HIGH
TPS65055
1.2 V
1.0 V
OUTPUT FILTER DESIGN (INDUCTOR AND OUTPUT CAPACITOR)
Inductor Selection
The two converters operate typically with 2.2 µH output inductors . Larger or smaller inductor values can be used
to optimize the performance of the device for specific operation conditions. The selected inductor has to be rated
for its dc resistance and saturation current. The dc resistance of the inductance influences directly the efficiency
of the converter. Therefore an inductor with the lowest dc resistance should be selected for highest efficiency.
Due to the internal control scheme used, the inductor should have a minimum value of 3.3 µH for an output
voltage of 3.0 V or higher.
Formula 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 Formula 1. This is
recommended because during heavy load transient the inductor current rises above the calculated value.
Vout
1DI
Vin
Formula 1: DIL = Vout ´
(3) ILmax = Ioutmax + L
L ´ f
2
With:
f = Switching frequency (2.25 MHz typical)
L = Inductor value
ΔIL = Peak-to-peak inductor ripple current
ILmax = Maximum inductor current
The highest inductor current occurs at maximum Vin.
Open core inductors have a soft saturation characteristic and they can usually handle higher inductor currents
versus a comparable shielded inductor.
A more conservative approach is to select the inductor current rating just for the maximum switch current of the
corresponding converter. It must be considered, that the core material from inductor to inductor differs and has
an impact on the efficiency especially at high switching frequencies.
Refer to Table 3 and the typical applications for possible inductors.
Table 3. Tested Inductors
INDUCTOR TYPE
INDUCTOR VALUE
SUPPLIER
LPS3010
2.2 µH
Coilcraft
VLF3010
2.2 µH
TDK
LPS4012
2.2 µH
Coilcraft
VLF4012
2.2 µH
TDK
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
33
TPS65055
SLVS844 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
Output Capacitor Selection
The advanced fast response voltage mode control scheme of the two converters allows the use of small ceramic
capacitors with a typical value of 22 µF, without having large output voltage under and overshoots during heavy
load transients. Ceramic capacitors having low ESR values result in the lowest output voltage ripple and are
therefore recommended. Refer to Table 4 for recommended components.
If ceramic output capacitors are used, the capacitor RMS ripple current rating always meets the application
requirements. For completeness, the RMS ripple current is calculated as:
Vout
11
Vin ´
IRMSCout = Vout ´
L ´ f
2 ´ 3
At nominal load current the inductive converters operate 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:
Vout
1ö
1
Vin × æ
+ ESR ÷
DVout = Vout ´
ç
L ´ f
è 8 ´ Cout ´ f
ø
Where the highest output voltage ripple occurs at the highest input voltage, Vin.
At light load currents the converters operate in power save mode, and the output voltage ripple is dependent on
the output capacitor value. The output voltage ripple is set by the internal comparator delay and the external
capacitor. The typical output voltage ripple is less than 1% of the nominal output voltage.
Input Capacitor Selection
Because of the nature of the buck converter having a pulsating input current, a low ESR input capacitor is
required for best input voltage filtering and minimizing interference with other circuits caused by high input
voltage spikes. The converters require a ceramic input capacitor of 10 µF. The input capacitor can be increased
without limit for better input voltage filtering.
Table 4. Possible Capacitors
34
22 µF
0805
TDK C2012X5R0J226MT
Ceramic
22 µF
0805
Taiyo Yuden JMK212BJ226MG
Ceramic
10 µF
0805
Taiyo Yuden JMK212BJ106M
Ceramic
10 µF
0805
TDK C2012X5R0J106M
Ceramic
10 µF
0603
Taiyo Yuden JMK107BJ106MA
Ceramic
Submit Documentation Feedback
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS65055
PACKAGE OPTION ADDENDUM
www.ti.com
2-Oct-2008
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPS65055RSMR
ACTIVE
QFN
RSM
32
3000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
TPS65055RSMT
ACTIVE
QFN
RSM
32
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
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Amplifiers
Data Converters
DSP
Clocks and Timers
Interface
Logic
Power Mgmt
Microcontrollers
RFID
RF/IF and ZigBee® Solutions
amplifier.ti.com
dataconverter.ti.com
dsp.ti.com
www.ti.com/clocks
interface.ti.com
logic.ti.com
power.ti.com
microcontroller.ti.com
www.ti-rfid.com
www.ti.com/lprf
Applications
Audio
Automotive
Broadband
Digital Control
Medical
Military
Optical Networking
Security
Telephony
Video & Imaging
Wireless
www.ti.com/audio
www.ti.com/automotive
www.ti.com/broadband
www.ti.com/digitalcontrol
www.ti.com/medical
www.ti.com/military
www.ti.com/opticalnetwork
www.ti.com/security
www.ti.com/telephony
www.ti.com/video
www.ti.com/wireless
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2008, Texas Instruments Incorporated