TPS51123A
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SLUSAA6C – APRIL 2011 – REVISED SEPTEMBER 2012
Dual-Synchronous, Step-Down Controller with Out-of-Audio™ Operation and 100-mA
LDOs for Notebook System Power
Check for Samples: TPS51123A
FEATURES
APPLICATIONS
•
•
•
•
•
•
•
•
1
2
•
•
•
•
•
•
•
•
Wide-Input Voltage Range: 5.5 V to 28 V
Output Voltage Range: 2 V to 5.5 V
Built-in 100-mA 5-V/3.3-V LDO with Switches
Built-in 1% 2-V Reference Output
With/Without Out-of-Audio™ Mode Selectable
Light-Load and PWM-Only Operation
Internal 1.6-ms Voltage Servo Soft-Start
Adaptive On-Time Control Architecture with
Four Selectable Frequency Setting
4500 ppm/°C RDS(on) Current Sensing
Built-In Output Discharge
Power Good Output
Built-in OVP/UVP/OCP
Thermal Shutdown (Non-latch)
24-Pin QFN (RGE) Package
Notebook Computers
I/O Supplies
System Power Supplies
DESCRIPTION
The TPS51123A is a cost effective, dual-synchronous
buck controller targeted for notebook system power
supply solutions. It provides 5-V and 3.3-V LDOs and
requires few external components. The TPS51123A
supports high-efficiency, fast transient responses and
provides a combined power-good signal. Out-ofAudio™ mode light-load operation enables low
acoustic noise at much higher efficiency than
conventional forced PWM operation. Adaptive ontime D-CAP™ control provides convenient and
efficient operation. The part operates with supply
input voltages ranging from 5.5 V to 28 V and
supports output voltages from 2 V to 5.5 V. The
TPS51123A is available in a 24-pin QFN package
and is specified from -40°C to 85°C ambient
temperature range.
Table 1. Differences Between the TPS51123 and TPS51123A
LDO Output Capacitance Requirement
TPS51123
TPS51123A
VREG5: at least 33 µF
VREG5: 10 µF or larger (X5R or X7R)
VREG3: at most 10 µF
(1 µF acceptable at no load)
VREG3: 10 µF or larger (X5R or X7R)
(1 µF acceptable at no load)
VREF: 0.22 µF to 1 µF
VREF: 0.22 µF to 1 µF (X5R or X7R)
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.
Out-of-Audio, D-CAP 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 © 2011–2012, Texas Instruments Incorporated
TPS51123A
SLUSAA6C – APRIL 2011 – REVISED SEPTEMBER 2012
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This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
13 kW
20 kW
20 kW
VIN
30 kW
VIN
220 nF
130 kW
VIN
2
1
VFB2
TONSEL
VREF
VFB1
TRIP1
7
VO2
8
VREG3
9
VBST2
10 DRVH2
TPS51123ARGE
(QFN-24)
VREG5
0.1 mF
VBST1 22
5.1 W
3.3 mF
VO1
DRVH1 21
PowerPAD
LL1 20
13
14
15
16
17
18
330 mF
5V
ENC
DRVL1 19
12 DRVL2
EN0
100 kW
PGOOD 23
VREG5
11 LL2
5.5 V
to
28 V
VO1 24
VIN
330 mF
5.1 W
3
GND
3.3 mF
VO2
4
SKIPSEL
0.1 mF
5
EN0
10 mF
6
TRIP2
10 mF x 2
10 mF x 2
3.3 V
130 kW
ENC
VREG5
10 mF
VIN
2
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ORDERING INFORMATION (1)
(1)
ORDERABLE
DEVICE
TA
PACKAGE
-40°C to 85°C
Plastic Quad Flat Pack
(QFN)
TPS51123ARGER
TPS51123ARGET
OUTPUT
SUPPLY
MINIMUM
QUANTITY
Tape/Reel
3000
Small Tape/Reel
250
PINS
24
ECO PLAN
Green (RoHS and
no Sb/Br)
For the most current spcifications and package information, see the Package Option Addendum located at the end of this data sheet or
refer to our web site at http://www.ti.com.
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
VALUE
PARAMETER
Input voltage range
(1)
MIN
MAX
VBST1, VBST2
–0.3
36
VIN
–0.3
30
LL1, LL2
–2.0
30
–5.0
30
LL1, LL2, pulse width < 20 ns
VBST1, VBST2
Output voltage range
(1)
(2)
–0.3
6
EN0, ENC, TRIP1, TRIP2, VFB1, VFB2, VO1, VO2, TONSEL,
SKIPSEL
–0.3
6
DRVH1, DRVH2
–1.0
36
–0.3
6
–0.3
6
DRVH1, DRVH2
(2)
PGOOD, VREG3, VREG5, VREF, DRVL1, DRVL2
Electrostatic discharge
Human body model QSS 009-105 (JESD22-A114A)
Charged device model QSS 009-147 (JESD22-C101B.01)
UNIT
V
V
2
kV
1.5
kV
Junction temperature range, TJ
–40
125
°C
Storage temperature, Tstg
–55
150
°C
(1)
(2)
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Voltage values are with respect to the corresponding LLx terminal.
DISSIPATION RATINGS
2-oz. trace and copper pad with solder.
(1)
PACKAGE
TA < 25°C POWER RATING
DERATING FACTOR ABOVE TA
= 25°C
TA = 85°C POWER RATING
24-pin RGE (1)
1.85 W
18.5 mW/°C
0.74 W
Enhanced thermal conductance by 3 x 3 thermal vias beneath thermal pad.
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RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
PARAMETER
Supply voltage
Input voltage range
Output voltage range
TA
4
VIN
MIN
5.5
TYP
MAX
28
VBST1, VBST2
-0.1
34
VBST1, VBST2 (wrt LLx)
-0.1
5.5
EN0, ENC, TRIP1, TRIP2, VFB1, VFB2, VO1, VO2,
TONSEL, SKIPSEL
-0.1
5.5
DRVH1, DRVH2
-0.8
34
DRVH1, DRVH2 (wrt LLx)
-0.1
5.5
LL1, LL2
-1.8
28
VREF, VREG3, VREG5
-0.1
5.5
PGOOD, DRVL1, DRVL2
-0.1
5.5
Operating free-air temperature
-40
85
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UNIT
V
°C
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ELECTRICAL CHARACTERISTICS
over operating free-air temperature range, VIN = 12 V (unless otherwise noted)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLY CURRENT
IVIN1
VIN supply current1
VIN current, T A = 25°C, no load, VO1 = 0 V,
VO2 = 0 V, EN0=open, ENC = 5 V,
TRIP1 = TRIP2 = 2 V, VFB1 = VFB2 = 2.05 V
0.55
1.00
mA
IVIN2
VIN supply current2
VIN current, TA = 25°C, no load, VO1 = 5 V,
VO2 = 3.3 V, EN0=open, ENC = 5 V,
TRIP1 = TRIP2 = 2 V, VFB1 = VFB2 = 2.05 V
4.0
6.5
μA
IVO1
VO1 current
VO1 current, TA = 25°C, no load, VO1 = 5 V,
VO2 = 3.3 V, EN0=open, ENC = 5 V,
TRIP1 = TRIP2 = 2 V, VFB1 = VFB2 = 2.05 V
0.8
1.5
mA
IVO2
VO2 current
VO2 current, TA = 25°C, no load, VO1 = 5 V,
VO2 = 3.3 V, EN0=open, ENC = 5 V,
TRIP1 = TRIP2 = 2 V, VFB1 = VFB2 = 2.05 V
12
100
IVINSTBY
VIN standby current
VIN current, TA = 25°C, no load,
EN0 = 1.2 V, ENC = 0 V
95
150
IVINSDN
VIN shutdown current
VIN current, TA = 25°C, no load,
EN0 = ENC = 0 V
10
25
μA
VREF OUTPUT
VVREF
VREF output voltage
IVREF = 0 A
1.98
2.00
2.02
–5 μA < IVREF < 100 μA
1.97
2.00
2.03
4.8
5
5.2
VO1 = 0 V, IVREG5 < 100 mA,
6.5 V < VIN < 28 V
4.75
5
5.25
VO1 = 0 V, IVREG5 < 50 mA, 5.5 V < VIN < 28 V
V
VREG5 OUTPUT
VO1 = 0 V, IVREG5 < 100 mA, TA = 25°C
VVREG5
VREG5 output voltage
IVREG5
VREG5 output current
VTH5VSW
Switch over threshold
R5VSW
5 V SW RON
4. 75
5
5.25
VO1 = 0 V, VREG5 = 4.5 V
100
175
250
Turns on
4.55
4.7
4.85
Hysteresis
0.15
0.25
0.3
1
3
VO1 = 5 V, IVREG5 = 100 mA
V
mA
V
Ω
VREG3 OUTPUT
VO2 = 0 V, IVREG3 < 100 mA, TA= 25°C
VVREG3
VREG3 output voltage
IVREG3
VREG3 output current
VTH3VSW
Switch over threshold
R3VSW
3 V SW RON
3.2
3.33
3.46
VO2 = 0 V, IVREG3 < 100 mA, 6.5 V < VIN < 28 V
3.13
3.33
3.5
VO2 = 0 V, IVREG3 < 50 mA, 5.5 V < VIN < 28 V
3.13
3.33
3.5
VO2 = 0 V, VREG3 = 3 V
100
175
250
Turns on
3.05
3.15
3.25
0.1
0.2
0.25
1.5
4
1.98
2.01
1.98
2.01
2.04
2.00
2.035
2.07
V
20
nA
Hysteresis
VO2 = 3.3 V, IVREG3 = 100 mA
V
mA
V
Ω
INTERNAL REFERENCE VOLTAGE
VIREF
Internal reference voltage
IVREF = 0 A, beginning of ON state
1.95
FB voltage, IVREF = 0 A, skip mode
VVFB
VFB regulation voltage
FB voltage, IVREF = 0 A, OOA mode
(1)
FB voltage, IVREF = 0 A, continuous conduction
mode (1)
IVFB
VFB input current
2.00
VFBx = 2.0 V, TA= 25°C
-20
ENC = 0 V, VOx = 0.5 V
10
OUTPUT VOLTAGE, VOUT DISCHARGE
IDischg
(1)
VOUT discharge current
60
mA
Ensured by design. Not production tested.
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ELECTRICAL CHARACTERISTICS (continued)
over operating free-air temperature range, VIN = 12 V (unless otherwise noted)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
OUTPUT DRIVERS
RDRVH
DRVH resistance
RDRVL
DRVL resistance
tDEAD
Dead time
Source, VBSTx - DRVHx = 100 mV
4
8
1.5
4
4
8
Sink, VDRVLx = 100 mV
1.5
4
DRVHx-off to DRVLx-on
10
DRVLx-off to DRVHx-on
30
Sink, VDRVHx - LLx = 100 mV
Source, VVREG5 - DRVLx = 100 mV
Ω
ns
INTERNAL BST DIODE
VFBST
Forward voltage
VVREG5-VBSTx, IF = 10 mA, TA = 25 °C
0.8
0.9
V
IVBSTLK
VBST leakage current
VBSTx = 34 V, LLx = 28 V, TA = 25 °C
0.7
0.1
1
μA
DUTY AND FREQUENCY CONTROL
tON11
CH1 on time 1
VIN = 12 V, VO1 = 5 V, 200 kHz setting
2080
tON12
CH1 on time 2
VIN = 12 V, VO1 = 5 V, 245 kHz setting
1700
tON13
CH1 on time 3
VIN = 12 V, VO1 = 5 V, 300 kHz setting
1390
tON14
CH1 on time 4
VIN = 12 V, VO1 = 5 V, 365 kHz setting
1140
tON21
CH2 on time 1
VIN = 12 V, VO2 = 3.3 V, 250 kHz setting
1100
tON22
CH2 on time 2
VIN = 12 V, VO2 = 3.3 V, 305 kHz setting
900
tON23
CH2 on time 3
VIN = 12 V, VO2 = 3.3 V, 375 kHz setting
730
tON24
CH2 on time 4
VIN = 12 V, VO2 = 3.3 V, 460 kHz setting
600
tON(min)
Minimum on time
TA = 25 °C
80
tOFF(min)
Minimum off time
TA = 25 °C
300
ns
SOFT-START
tSS
Internal SS time
Internal soft start
1.1
1.6
2.1
ms
POWERGOOD
VTHPG
PG threshold
PG in from lower
92.50%
95%
97.50%
PG in from higher
102.50%
105%
107.50%
2.50%
5%
7.50%
PG hysteresis
IPGMAX
PG sink current
PGOOD = 0.5 V
tPGDEL
PG delay
Delay for PG in
5
12
350
510
mA
670
μs
LOGIC THRESHOLD AND SETTING CONDITIONS
VEN0
EN0 setting voltage
IEN0
EN0 current
VENC
ENC threshold voltage
VEN(trip)
TRIP1, TRIP2 threshold
Shutdown
Enable
0.4
2.4
VEN0 = 0.2 V
2
Enable
TONSEL setting voltage
2
Shutdown
350
400
450
Hysteresis
10
30
60
6
SKIPSEL setting voltage
1.9
2.1
300 kHz/375 kHz
2.7
3.6
365 kHz/460 kHz
4.7
V
mV
V
1.5
PWM only
1.9
OOA auto skip
2.7
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μA
1.5
245 kHz/305 kHz
Auto skip
VSKIPSEL
5
0.6
200 kHz/250 kHz
VTONSEL
3.5
Shutdown
V
2.1
V
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ELECTRICAL CHARACTERISTICS (continued)
over operating free-air temperature range, VIN = 12 V (unless otherwise noted)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
PROTECTION: CURRENT SENSE
ITRIP
TRIPx source current
TCITRIP
TRIPx current temperature
coefficient
On the basis of 25°C
VOCLoff
OCP comparator offset
((VTRIPx-GND/9)-24 mV -VGND-LLx) voltage, VTRIPxGND = 920 mV
VOCL(max)
Maximum OCL setting
VTRIPx = 5 V
VZC
Zero cross detection
comparator offset
VGND-LLx voltage
VTRIP
Current limit threshold
VTRIPx = 920 mV, TA= 25°C
VTRIPx-GND voltage
9.4
(2)
(2)
10
4500
ppm/°C
-8
0
8
185
205
225
-5
0
5
0.515
μA
10.6
2
mV
V
PROTECTION: UNDERVOLTAGE AND OVERVOLTAGE PROTECTION
VOVP
OVP trip threshold
tOVPDEL
OVP prop delay
OVP detect
110%
115%
120%
μs
2
UVP detect
55%
60%
65%
VUVP
Output UVP trip threshold
tUVPDEL
Output UVP prop delay
20
32
40
μs
tUVPEN
Output UVP enable delay
1.4
2
2.6
ms
Hysteresis
10%
UNDERVOLTAGE LOCKOUT (UVLO)
VUVVREG5 VREG5 UVLO threshold
VUVVREG3 VREG3 UVLO threshold
Wake up
Hysteresis
Shutdown
(2)
4.1
4.2
4.3
0.38
0.43
0.48
V
VO2-1
THERMAL SHUTDOWN
TSDN
(2)
Thermal shutdown threshold
Shutdown temperature
Hysteresis
(2)
(2)
150
10
°C
Ensured by design. Not production tested.
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DEVICE INFORMATION
Table 2.
TERMINAL
NAME
NO.
DRVH1
21
DRVH2
10
DRVL1
19
DRVL2
12
EN0
I/O
DESCRIPTION
O
High-side N-channel MOSFET driver outputs. LL referenced drivers.
O
Low-side N-channel MOSFET driver outputs. GND referenced drivers.
13
I/O
Master enable input.
Open : LDOs on, and ready to turn both switcher channels.
GND : disable all circuit
ENC
18
I
Channel 1 and Channel 2 enable input. Pull up to the voltage ranging 3.3-V to 5-V to turn on both
switcher channels. Short to ground to shutdown them.
GND
15
–
Ground.
LL1
20
LL2
11
I
Switch node connections for high-side drivers, current limit and control circuitry.
PGOOD
23
O
Powergood window comparator output for channel 1 and 2. (Logical AND)
SKIPSEL
14
I
Selection pin for operation mode:
OOA auto skip : Connect to VREG3 or VREG5
PWM only: Connect to VREF
Auto skip: Connect to GND
TRIP1
1
TRIP2
6
TONSEL
4
VBST1
22
VBST2
9
VFB1
2
VFB2
5
VIN
16
VO1
24
VO2
7
VREF
I/O
Channel 1 and Channel 2 enable and OCL trip setting pins. Connect resistor from this pin to GND to
set threshold for synchronous RDS(on) sense. Short to ground to shut down a switcher channel.
I
On-time adjustment pin.
365 kHz/460 kHz setting: connect
300 kHz/375 kHz setting: connect
245 kHz/305 kHz setting: connect
200 kHz/250 kHz setting: connect
I
Supply input for high-side N-channel MOSFET driver (boost terminal).
I
SMPS feedback inputs. Connect with feedback resistor divider.
I
High voltage power supply input for 5-V/3.3-V LDO.
to VREG5
to VREG3
to VREF
to GND
I/O
Output connection to SMPS. These terminals work as fixed voltage inputs and output discharge
inputs. VO1 and VO2 also work as 5-V and 3.3-V switch over return power input respectively.
3
O
2-V reference voltage output. Connect a high-quality X5R or X7R ceramic capacitor with a value
between 220-nF and 1-µF to signal GND near the device.
VREG3
8
O
3.3-V power supply output. Connect a high-quality X5R or X7R ceramic capacitor with a value of 10µF or larger to power GND near the device. A 1-μF ceramic capacitor is acceptable when not loaded.
VREG5
17
O
5-V power supply output. Connect a high-quality X5R or X7R ceramic capacitor with a value of 10-µF
or larger to power GND near the device.
8
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VO1
PGOOD
VBST1
DRVH1
LL1
DRVL1
QFN PACKAGE (TOP VIEW)
24
23
22
21
20
19
TRIP1
1
18 ENC
VFB1
2
17 VREG5
VREF
3
TONSEL
4
15 GND
VFB2
5
14 SKIPSEL
TRIP2
6
16 VIN
TPS51123ARGE
(QFN-24)
VBST2
12
DRVL2
VREG3
11
LL2
8
10
DRVH2
7
VO2
13 EN0
9
Functional Block Diagram
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Switcher Controller Block
10
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TYPICAL CHARACTERISTICS
VIN SUPPLY CURRENT1
vs
JUNCTION TEMPERATURE
VIN SUPPLY CURRENT1
vs
INPUT VOLTAGE
800
800
IVIN1 - VIN Supply Current1 - mA
IVIN1 - VIN Supply Current1 - mA
700
700
600
500
400
300
200
100
600
500
400
300
200
100
0
-50
0
50
100
0
150
5
TJ - Junction Temperature - °C
10
15
20
25
V IN - Input Voltage - V
Figure 1.
Figure 2.
VIN SUPPLY CURRENT2
vs
INPUT VOLTAGE
9
9
8
8
IVIN2 - VIN Supply Current2 - mA
IVIN2 - VIN Supply Current2 - mA
VIN SUPPLY CURRENT2
vs
JUNCTION TEMPERATURE
7
6
5
4
3
2
7
6
5
4
3
2
1
1
0
0
-50
0
50
100
150
5
10
15
20
25
V IN - Input Voltage - V
T J - Junction Temperature - °C
Figure 3.
Figure 4.
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TYPICAL CHARACTERISTICS (continued)
.
VIN STANDBY CURRENT
vs
INPUT VOLTAGE
250
250
200
200
IVINSTBY –VIN Standby Current – µA
IVINSTBY - VIN Standby Current - mA
VIN STANDBY CURRENT
vs
JUNCTION TEMPERATURE
150
100
50
0
50
0
50
100
150
100
50
0
150
5
10
TJ - Junction Temperature - °C
Figure 5.
25
VIN SHUTDOWN CURRENT
vs
INPUT VOLTAGE
25
IVINSDN - VIN Shutdown Current - mA
25
IVINSDN - VIN Shutdown Current - mA
20
Figure 6.
VIN SHUTDOWN CURRENT
vs
JUNCTION TEMPERATURE
20
15
10
5
20
15
10
5
0
0
-50
0
50
100
150
5
10
15
20
25
V IN - Input Voltage - V
T J - Junction Temperature - °C
Figure 7.
12
15
VIN – Input Voltage – V
Figure 8.
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TYPICAL CHARACTERISTICS (continued)
SWITCHING FREQUENCY
vs
INPUT VOLTAGE
CURRENT SENSE CURRENT
vs
JUNCTION TEMPERATURE
500
TONSEL = GND
13
fSW - Swithching Frequency - kHz
ITRIP - Current Sense Current - mA
14
12
11
10
9
8
400
300
CH2
200
CH1
100
7
6
0
50
0
50
100
6
150
8
10
12
14
18
20
22
24
26
V IN - Input Voltage - V
TJ - Junction Temperature - °C
Figure 9.
Figure 10.
SWITCHING FREQUENCY
vs
INPUT VOLTAGE
SWITCHING FREQUENCY
vs
INPUT VOLTAGE
500
500
TONSEL = 3.3V
f SW - Swithching Frequency - kHz
TONSEL = 2V
f SW - Swithching Frequency - kHz
16
400
CH2
300
CH1
200
100
CH2
400
300
CH1
200
100
0
0
6
8
10
12
14
16
18
20
22
24
26
6
8
10
12
14
16
18
20
22
24
26
V IN - Input Voltage - V
V IN - Input Voltage - V
Figure 11.
Figure 12.
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TYPICAL CHARACTERISTICS (continued)
SWITCHING FREQUENCY
vs
OUTPUT CURRENT
SWITCHING FREQUENCY
vs
INPUT VOLTAGE
500
500
TONSEL = 5V
400
f SW - Swithching Frequency - kHz
f SW - Swithching Frequency - kHz
TONSEL = GND
CH2
CH1
300
200
100
400
300
CH2 PWM Only
200
CH1 PWM Only
100
CH2 Auto-skip
CH2 OOA
CH1 OOA
CH1 Auto-skip
0
0.001
0
6
8
10
12
14
16
18
20
22
24
26
0.01
Figure 13.
500
TONSEL = 3.3V
f SW - Swithching Frequency - kHz
TONSEL = 2V
f SW - Swithching Frequency - kHz
10
SWITCHING FREQUENCY
vs
OUTPUT CURRENT
500
400
CH2 PWM Only
300
CH1 PWM Only
CH2 Auto-skip
100
CH2 OOA
400
CH2 PWM Only
300
CH1 PWM Only
200
CH2 Auto-skip
100
CH2 OOA
CH1 OOA
CH1 OOA
CH1 Auto-skip
CH1 Auto-skip
0
0.001
0.01
0.1
1
10
0
0.001
0.01
0.1
1
10
IOUT - Output Current - A
IOUT - Output Current - A
Figure 15.
14
1
Figure 14.
SWITCHING FREQUENCY
vs
OUTPUT CURRENT
200
0.1
IOUT - Output Current - A
V IN - Input Voltage - V
Figure 16.
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TYPICAL CHARACTERISTICS (continued)
SWITCHING FREQUENCY
vs
OUTPUT CURRENT
OVP/UVP THRESHOLD VOLTAGE
vs
JUNCTION TEMPERATURE
500
150
TONSEL = 5V
400
V OVP/VUVP - OVP/UVP Threshold - %
f SW - Swithching Frequency - kHz
140
CH2 PWM Only
CH1 PWM Only
300
200
CH2 Auto-skip
CH2 OOA
100
CH1 OOA
CH1 Auto-skip
0
0.001
130
120
110
100
90
80
70
60
50
40
0.01
0.1
1
10
-50
IOUT - Output Current - A
0
TJ
50
100
- Junction Temperature - °C
Figure 17.
Figure 18.
VREG3 OUTPUT VOLTAGE
vs
OUTPUT CURRENT
VREG5 OUTPUT VOLTAGE
vs
OUTPUT CURRENT
3.35
V VREG3 - VREG3 Output Voltage - V
5.05
V VREG5 - VREG5 Output Voltage - V
150
5.00
4.95
3.3
3.25
3.2
4.90
0
20
40
60
80
100
0
20
40
60
80
100
IVREG3 - VREG3 Output Current - m A
IVREG5 - VREG5 Output Current - m A
Figure 19.
Figure 20.
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TYPICAL CHARACTERISTICS (continued)
VREF OUTPUT VOLTAGE
vs
OUTPUT CURRENT
5-V OUTPUT VOLTAGE
vs
OUTPUT CURRENT
5.075
2.020
OOA
V OUT1 - 5-V Output Voltage - V
V VREF - VREF Output Voltage - V
2.015
2.010
2.005
2.000
1.995
1.990
5.050
5.025
5.000
Auto-skip
PWM Only
4.975
1.985
4.950
0.001
1.980
0
20
40
60
80
0.01
100
0.1
1
10
IOUT1 - 5-V Output Current - A
IVREF - VREF Output Current - mA
Figure 21.
Figure 22.
3.3-V OUTPUT VOLTAGE
vs
OUTPUT CURRENT
5-V OUTPUT VOLTAGE
vs
INPUT VOLTAGE
3.360
5.075
V OUT1 - 5-V Output Voltage - V
V OUT2 - 3.3-V Output Voltage - V
OOA
3.330
Auto-skip
3.300
PWM Only
3.270
3.240
0.001
5.050
IO = 0A
5.025
5.000
IO = 6A
4.975
4.950
0.01
0.1
1
10
6
8
12
14
16
18
20
22
24
26
V IN - Input Voltage - V
IOUT2 - 3.3-V Output Current - A
Figure 23.
16
10
Figure 24.
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TYPICAL CHARACTERISTICS (continued)
5-V EFFICIENCY
vs
OUTPUT CURRENT
3.3-V OUTPUT VOLTAGE
vs
INPUT VOLTAGE
100
Auto-Skip
80
3.330
h – Efficiency – %
V OUT2 - 3.3-V Output Voltage - V
3.360
IO = 0A
3.300
IO = 6A
VIN = 20 V
60
VIN = 12 V
40
3.270
VIN = 8 V
20
OOA
PWM Only
3.240
6
8
10
12
14
16
18
20
22
24
0
0.001
26
V IN - Input Voltage - V
0.01
0.1
1
10
IOUT1 – 5-V Output Current – A
Figure 25.
Figure 26.
3.3-V EFFICIENCY
vs
OUTPUT CURRENT
100
Auto-skip
h - Efficiency - %
80
VIN=8V
60
VIN=12V
40
20
VIN=20V
OOA
PWM Only
0
0.001
0.01
5-V Switcher ON
0.1
1
10
IOUT2 - 3.3-V Output Current - A
Figure 27.
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TYPICAL CHARACTERISTICS (continued)
5-V Load Transient Response
3.3-V Load Transient Response
VOUT2 (100mV/div)
VOUT1 (100mV/div)
IIND (5A/div)
IIND (5A/div)
IOUT2 (5A/div)
IOUT1 (5A/div)
Figure 28.
Figure 29.
5-V Startup Waveforms
3.3-V Startup Waveforms
ENC (5 V/div)
ENC (5 V/div)
VOUT1 (2 V/div)
VOUT2 (2 V/div)
PGOOD (5 V/div)
PGOOD (5 V/div)
Figure 30.
18
Figure 31.
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TYPICAL CHARACTERISTICS (continued)
5-V Switchover Waveforms
3.3-V Switchover Waveforms
VREG5 (200mV/div)
VREG3 (200mV/div)
VOUT2 (200mV/div)
VOUT1 (200mV/div)
Figure 32.
Figure 33.
5-V Soft-stop Waveforms
3.3-V Soft-stop Waveforms
ENC (10 V/div)
ENC (10 V/div)
VOUT1 (2 V/div)
VOUT2 (2 V/div)
PGOOD (5 V/div)
PGOOD (5 V/div)
DRVL1 (5 V/div)
DRVL2 (5 V/div)
Figure 34.
Figure 35.
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APPLICATION INFORMATION
PWM Operations
The main control loop of the switch mode power supply (SMPS) is designed as an adaptive on-time pulse width
modulation (PWM) controller. It supports a proprietary D-CAP™ mode. D-CAP™ mode does not require external
compensation circuit and is suitable for low external component count configuration when used with appropriate
amount of ESR at the output capacitor(s).
At the beginning of each cycle, the synchronous top MOSFET is turned on, or becomes ‘ON’ state. This
MOSFET is turned off, or becomes OFF state, after internal one shot timer expires. This one shot is determined
by VIN and VOUT to keep frequency fairly constant over input voltage range, hence it is called adaptive on-time
control. The MOSFET is turned on again when the feedback point voltage, VVFBx, decreased to match with
internal 2-V reference. The inductor current information is also monitored and should be below the over current
threshold to initiate this new cycle. Repeating operation in this manner, the controller regulates the output
voltage. The synchronous bottom or the rectifying MOSFET is turned on at the beginning of each OFF state to
keep the conduction loss minimum.The rectifying MOSFET is turned off before the top MOSFET turns on at next
switching cycle or when inductor current information detects zero level. In the auto-skip mode or the OOA skip
mode, this enables seamless transition to the reduced frequency operation at light load condition so that highefficiency is kept over broad range of load current.
Adaptive On-Time Control and PWM Frequency
TPS51123A does not have a dedicated oscillator on board. However, the part runs with pseudo-constant
frequency by feed-forwarding the input and output voltage into the on-time, one-shot timer. The on-time is
controlled inverse proportional to the input voltage and proportional to the output voltage so that the duty ratio is
kept as VOUT/VIN technically with the same cycle time. The frequencies are set by the TONSEL pin as shown in
Table 3.
Table 3. TONSEL Connection and Switching Frequency
TONSEL CONNECTION
20
SWITCHING FREQUENCY (kHz)
CH1
CH2
GND
200
250
VREF
245
305
VREG3
300
375
VREG5
365
460
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Loop Compensation
From small-signal loop analysis, a buck converter using D-CAPTM mode can be simplified as below.
VIN
R1
DRVH
PWM
VFB
+
+
R2
Control
logic
&
Driver
Lx
Ic
IL
DRVL
Io
2V
ESR
Vc
Voltage Divider
RL
Switching Modulator
Co
Output Capacitor
Figure 36. Simplifying the Modulator
The output voltage is compared with internal reference voltage after divider resistors, R1 and R2. The PWM
comparator determines the timing to turn on high-side MOSFET. The gain and speed of the comparator is high
enough to keep the voltage at the beginning of each on cycle substantially constant. For the loop stability, the
0dB frequency, f0, defined below need to be lower than 1/4 of the switching frequency.
f0 =
f
1
£ SW
2p ´ ESR ´ CO
4
(1)
TM
As f0 is determined solely by the output capacitor's characteristics, loop stability of D-CAP mode is determined
by the capacitor's chemistry. For example, specialty polymer capacitors (SP-CAP) have Co in the order of
several 100 μF and ESR in range of 10 mΩ. These make f0 on the order of 100 kHz or less and the loop will be
stable. However, ceramic capacitors have f0 at more than 700 kHz, which is not suitable for this operational
mode.
Ramp Signal
The TPS51123A adds a ramp signal to the 2-V reference in order to improve its jitter performance. As described
in the previous section, the feedback voltage is compared with the reference information to keep the output
voltage in regulation. By adding a small ramp signal to the reference, the dignal-to-noise ratio at the onset of a
new switching cycle is improved. Therefore the operation becomes less jitter and stable. The ramp signal is
controlled to start with -20 mV at the beginning of ON-cycle and to become 0 mV at the end of OFF-cycle in
steady state. By using this scheme, the TPS51123A improve jitter performance without sacrificing the reference
accuracy.
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Light Load Condition in Auto-Skip Operation
The TPS51123A automatically reduces switching frequency at light load conditions to maintain high-efficiency.
This reduction of frequency is achieved smoothly and without increase of VOUT ripple. Detail operation is
described as follows. As the output current decreases from heavy load condition, the inductor current is also
reduced and eventually comes to the point that its valley touches zero current, which is the boundary between
continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when this zero
inductor current is detected. As the load current further decreased, the converter runs in discontinuous
conduction mode and it takes longer and longer to discharge the output capacitor to the level that requires next
ON cycle. The ON time is kept the same as that in the heavy load condition. In reverse, when the output current
increase from light load to heavy load, switching frequency increases to the preset value as the inductor current
reaches to the continuous conduction. The transition load point to the light load operation IOUT(LL) (i.e. the
threshold between continuous and discontinuous conduction mode) can be calculated as follows;
IOUT(LL) =
1
2´L´f
´
(VIN - VOUT )´ VOUT
VIN
(2)
where f is the PWM switching frequency.
Switching frequency versus output current in the light load condition is a function of L, VIN and VOUT, but it
decreases almost proportional to the output current from the IOUT(LL) shown in Equation 2. For example, it ise 60
kHz at IOUT(LL)/5 if the frequency setting is 300 kHz.
Out-of-Audio™ Light-Load Operation
Out-of-Audio™ (OOA) light-load mode is a unique control feature that keeps the switching frequency above
acoustic audible frequencies toward virtually no load condition while maintaining best of the art high conversion
efficiency. When the Out-of-Audio™ operation is selected, OOA control circuit monitors the states of both
MOSFET and force to change into the ON state if both of MOSFETs are off for more than 32 μs. This means that
the top MOSFET is turned on even if the output voltage is higher than the target value so that the output
capacitor is tends to be overcharged.
The OOA control circuit detects the over-voltage condition and begins to modulate the on time to keep the output
voltage regulated. As a result, the output voltage becomes 0.5% higher than normal light-load operation.
22
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Enable and Soft Start
EN0 is the control pin of VREG5, VREG3 and VREF regulators. Bring this node down to GND disables those
three regulators and minimize the shutdown supply current to 10 μA. Pulling this node up to 3.3 V or 5 V will turn
the three regulators on to standby mode. The two switch mode power supplies (channel-1, channel-2) become
ready to enable at this standby mode. The TPS51123A has an internal, 1.6 ms, voltage servo soft-start for each
channel.
Both channel 1 and channel 2 can be enabled simultaneously with the ENC pin when only the OCL trip setting
resistance is connected to TRIPx pin. Channel 1 and channel 2 can be disabled independently by shorting the
TRIPx pin to ground when the ENC pin voltage is higher than its enable threshold, which is typically 1.26 V. After
enabling channel 1 and/or channel 2, an internal DAC begins ramping up the reference voltage of the PWM
comparator. Smooth control of the output voltage is maintained during start up. As TPS51123A shares one DAC
with both channels, if TRIPx pin becomes higher than the enable threshold voltage while another channel is
starting up, soft-start is postponed until another channel soft-start has completed. If both of TRIP1 and TRIP2
become higher than the enable threshold voltage at the same time (within 60 µs), both channels start up
simultaneously.
Table 4. Enabling State
(1)
EN0
ENC
TRIP1
TRIP2
VREF
VREG5
VREG3
CH1
CH2
GND
No effect (1)
No effect (1)
No effect (1)
Off
Off
Off
Off
Off
(1)
(1)
Open
Low
On
On
On
Off
Off
Open
High
No effect
Low
No effect
Low
On
On
On
Off
Off
Open
High
High
Low
On
On
On
On
Off
Open
High
Low
High
On
On
On
Off
On
Open
High
High
High
On
On
On
On
On
Either high or low, does no affect the enable state.
VREG5/VREG3 Linear Regulators
There are two sets of 100-mA standby linear regulators which outputs 5 V and 3.3 V, respectively. The VREG5
serves as the main power supply for the analog circuitry of the device and provides the current for gate drivers.
The VREG3 is intended mainly for auxiliary 3.3-V supply for the notebook system during standby mode.
Add a high-quality X5R or X7R ceramic capacitor with a value of 10-µF or larger placed close to the VREG5 and
VREG3 pins to stabilize LDOs. For VREG3, a 1-µF ceramic capacitor is acceptable when not loaded.
VREG5 Switch Over
When the VO1 voltage becomes higher than 4.7 V AND channel-1 internal powergood flag is generated, internal
5-V LDO regulator is shut off and the VREG5 output is connected to VO1 by internal switch over MOSFET. The
510-μs powergood delay helps a switch over without glitch.
VREG3 Switch Over
When the VO2 voltage becomes higher than 3.15 V AND channel-2 internal powergood flag is generated,
internal 3.3-V LDO regulator is shut off and the VREG3 output is connected to VO2 by internal switch over
MOSFET. The 510-μs powergood delay helps a switch over without glitch.
Powergood
The TPS51123A has one powergood output that indicates a high state when both switcher outputs are within the
targets (AND gated). The powergood function is activated with 2-ms internal delay after ENC goes high. If the
output voltage becomes within ±5% of the target value, internal comparators detect power good state and the
powergood signal becomes high after 510-μs internal delay. Therefore PGOOD goes high around 2.5 ms after
ENC goes high. If the output voltage goes outside of ±10% of the target value, the powergood signal becomes
low after 2-μs internal delay. The powergood output is an open drain output and is needed to be pulled up
outside.
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Also note that, in the case of Auto-skip or Out-of-Audio™ mode, if the output voltage goes +10% above the
target value and the power-good signal flags low, then the loop attempts to correct the output by turning on the
low-side driver (forced PWM mode). After the feedback voltage returns to be within +5% of the target value and
the power-good signal goes high, the controller returns back to auto-skip mode or Out-of-Audio™ mode.
Output Discharge Control
When ENC is low, the TPS51123A discharges outputs using internal MOSFET which is connected to VOx and
GND. The current capability of these MOSFETs is limited to discharge slowly.
Low-Side Driver
The low-side driver is designed to drive high current low RDS(on) N-channel MOSFET(s). The drive capability is
represented by its internal resistance, which are 4 Ω for VREG5 to DRVLx and 1.5 Ω for DRVLx to GND. A dead
time to prevent shoot through is internally generated between top MOSFET off to bottom MOSFET on, and
bottom MOSFET off to top MOSFET on. 5-V bias voltage is delivered from VREG5 supply. The instantaneous
drive current is supplied by an input capacitor connected between VREG5 and GND. The average drive current
is equal to the gate charge at Vgs = 5 V times switching frequency. This gate drive current as well as the highside gate drive current times 5 V makes the driving power which need to be dissipated from TPS51123A
package.
High-Side Driver
The high-side driver is designed to drive high current, low RDS(on) N-channel MOSFET(s). When configured as a
floating driver, 5-V bias voltage is delivered from VREG5 supply. The average drive current is also calculated by
the gate charge at Vgs = 5 V times switching frequency. The instantaneous drive current is supplied by the flying
capacitor between VBSTx and LLx pins. The drive capability is represented by its internal resistance, which are 4
Ω for VBSTx to DRVHx and 1.5Ω for DRVHx to LLx.
Current Protection
TPS51123A has cycle-by-cycle over current limiting control. The inductor current is monitored during the ‘OFF’
state and the controller keeps the ‘OFF’ state during the inductor current is larger than the over current trip level.
In order to provide both good accuracy and cost effective solution, TPS51123A supports temperature
compensated MOSFET RDS(on) sensing. The TRIPx pin should be connected to GND through the trip voltage
setting resistor, RTRIP. TRIPx terminal sources ITRIP current, which is 10 μA typically at room temperature, and the
trip level is set to the OCL trip voltage VTRIP as below. Note that the VTRIP is limited up to about 205 mV
internally.
VTRIP (mV ) =
RTRIP (kW )´ ITRIP (mA )
9
- 24 (mV )
(3)
Note that when TRIPx voltage is under a certain thershould (typically 0.4V), the switcher channel concerned is
shut down. The inductor current is monitored by the voltage between GND pin and LLx pin so that LLx pin should
be connected to the drain terminal of the bottom MOSFET properly. Itrip has 4500 ppm/°C temperature slope to
compensate the temperature dependency of the RDS(on). GND is used as the positive current sensing node so
that GND should be connected to the proper current sensing device, i.e. the source terminal of the bottom
MOSFET.
As the comparison is done during the OFF state, VTRIP sets valley level of the inductor current. Thus, the load
current at over current threshold, IOCP, can be calculated in Equation 4.
IOCP =
(VIN - VOUT )´ VOUT
VTRIP
I
V
1
+ RIPPLE = TRIP +
´
RDS(on )
2
RDS(on ) 2 ´ L ´ f
VIN
(4)
In an overcurrent condition, the current to the load exceeds the current to the output capacitor thus the output
voltage tends to fall down. Eventually, it ends up with crossing the under voltage protection threshold and
shutdown both channels.
24
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Overvoltage and Undervoltage Protection
TPS51123A monitors a resistor divided feedback voltage to detect over and under voltage. When the feedback
voltage becomes higher than 115% of the target voltage, the OVP comparator output goes high and the circuit
latches as the top MOSFET driver OFF and the bottom MOSFET driver ON.
Also, TPS51123A monitors VOx voltage directly and if it becomes greater than 5.75 V the TPS51123A turns off
the top MOSFET driver.
When the feedback voltage becomes lower than 60% of the target voltage, the UVP comparator output goes
high and an internal UVP delay counter begins counting. After 32 μs, TPS51123A latches OFF both top and
bottom MOSFETs drivers, and shut off both drivers of another channel. This function is enabled after 2 ms
following ENC has become high.
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UVLO Protection
TPS51123A has VREG5 under voltage lock out protection (UVLO). When the VREG5 voltage is lower than
UVLO threshold voltage both switch mode power supplies are shut off. This is non-latch protection. When the
VREG3 voltage is lower than (VOUT2 - 1 V), both switch mode power supplies are also shut off
Thermal Shutdown
TPS51123A monitors the temperature of itself. If the temperature exceeds the threshold value (typically 150°C),
TPS51123A is shut off including LDOs. This is non-latch protection.
External Parts Selection
The external components selection is much simple in D-CAP™ Mode.
1. Determine output voltage
The output voltage is programmed by the voltage-divider resistor, R1 and R2, as shown in Figure 36. R1 is
connected between VFBx pin and the output, and R2 is connected betwen the VFBx pin and GND.
Recommended R2 value is from 10 kΩ to 20 kΩ. Determine R1 using equation as below.
R1 =
(VOUT - 2.0 ) ´ R2
2.0
(5)
2. Choose the Inductor
The inductance value should be determined to give the ripple current of approximately 1/4 to 1/2 of maximum
output current. Larger ripple current increases output ripple voltage and improves S/N ratio and helps stable
operation.
L=
1
IIND(ripple ) ´ f
´
(V
IN(max ) - VOUT
)´ V
OUT
VIN(max )
=
3
IOUT(max ) ´ f
´
(V
IN(max ) - VOUT
VIN(max )
)´ V
OUT
(6)
The inductor also needs to have low DCR to achieve good efficiency, as well as enough room above peak
inductor current before saturation. The peak inductor current can be estimated as follows.
IIND(peak ) =
VTRIP
RDS (on )
+
1
L´f
´
(V
IN(max )
- VOUT
)´ V
OUT
VIN(max )
(7)
3. Choose the Output Capacitor(s)
Organic semiconductor capacitor(s) or specialty polymer capacitor(s) are recommended. Determine ESR to meet
required ripple voltage. A quick approximation is as shown in Equation 8. This equation is based on that required
output ripple slope is approximately 20 mV per TSW (switching period) in terms of VFB terminal voltage.
ESR =
V OUT ´20 (mV )´ (1 - D )
2 (V )´ IRIPPLE
-
20 (mV )´ L ´ f
2 (V )
where
•
•
D is the duty cycle
the required output ripple slope is approximately 20 mV per tSW (switching period) in terms of VFB terminal
voltage
(8)
4. Choose the Low-Side MOSFET
It is highly recommended that the low-side MOSFET should have an integrated Schottky barrier diode, or an
external Schottky barrier diode in parallel to achieve stable operation.
26
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Layout Considerations
Certain points must be considered before starting a layout work using the TPS51123A.
• TPS51123A has only one GND pin and special care of GND trace design makes operation stable, especially
when both channels operate. Group GND terminals of output voltage divider of both channels and the VREF
capacitor as close as possible, and connect them to an inner GND plane with PowerPad and the overcurrent
setting resistor, as shown in the thin GND line of Figure 37. This trace is named Signal Ground (SGND).
Group ground terminals of VIN capacitor(s), VOUT capacitor(s) and source of low-side MOSFETs as close as
possible, and connect them to another inner GND plane with GND pin of the device and the GND terminal of
VREG3 and VREG5 capacitors, as shown in the bold GND line of Figure 37. This trace is named Power
Ground (PGND). SGND should be connected to PGND at the middle point between ground terminal of VOUT
capacitors.
• Inductor, VOUT capacitor(s), VIN capacitor(s) and MOSFETs are the power components and should be placed
on one side of the PCB (solder side). Power components of each channel should be at the same distance
from the TPS51123A. Other small signal parts should be placed on another side (component side). Inner
GND planes should shield and isolate the small signal traces from noisy power lines.
• PCB trace defined as LLx node, which connects to source of high-side MOSFET, drain of low-side MOSFET
and high-voltage side of the inductor, should be as short and wide as possible.
• A high-quality X5R or X7R ceramic bypass capacitor should be placed close to the device and traces should
be no longer than 10 mm. Use the following capacitance values.
– VREG5: 10 µF or larger
– VREG3: 10 µF or larger (1 µF is acceptable when not loaded)
– VREF: between 220 nF and 1 µF
• Connect the overcurrent setting resistors from TRIPx to SGND and close to the device, right next to the
device if possible.
• The discharge path (VOx) should have a dedicated trace to the output capacitor; separate from the output
voltage sensing trace. When LDO5 is switched over Vo1 trace should be 1.5 mm with no loops. When LDO3
is switched over and loaded VO2 trace should also be 1.5 mm with no loops. There is no restriction for just
monitoring Vox. Make the feedback current setting resistor (the resistor between VFBx to SGND) close to the
device. Place on the component side and avoid vias between this resistor and the device.
• Connections from the drivers to the respective gate of the high-side or the low-side MOSFET should be as
short as possible to reduce stray inductance. Use 0.65-mm (25 mils) or wider trace and via(s) of at least 0.5
mm (20 mils) diameter along this trace.
• All sensitive analog traces and components such as VOx, VFBx, VREF, GND, EN0, TRIPx, PGOOD,
TONSEL and SKIPSEL should be placed away from high-voltage switching nodes such as LLx, DRVLx, and
DRVHx nodes to avoid coupling.
• Traces for VFB1 and VFB2 should be short and laid apart each other to avoid channel to channel
interference.
• In order to effectively remove heat from the package, prepare thermal land and solder to the package’s
thermal pad. Three by three or more vias with a 0.33-mm (13 mils) diameter connected from the thermal land
to the internal ground plane should be used to help dissipation. This thermal land underneath the package
should be connected to SGND, and should NOT be connected to PGND.
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TPS51123A
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www.ti.com
SGND
VIN
VIN
220 nF
VOUT2
5
3
2
VFB2
VREF
VFB1
DRVL2
VOUT1
DRVL1
5
19
TPS51123A
VREG5
PowerPAD
GND VREG3
PGND
PGND
17
15
10 mF
8
10 mF
SGND
UDG-10087
Figure 37. Ground System
28
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Figure 38. PCB Layout
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TPS51123A
SLUSAA6C – APRIL 2011 – REVISED SEPTEMBER 2012
www.ti.com
Application Circuit
SGND
R1
13kW
R2
20kW
C6
0.22mF
R5
130kW
3.3V/100mA
R4
30kW
R3
20kW
R6
130kW
SGND
SGND
3
2
1
VF
B1
TR
IP1
7 VO2
PGND
VIN
VIN
5.5 ~ 28V
8 VREG3
VO1
24
PGOOD
23
VBST1
22
VREG5
PGND
PGND
L1
3.3mH
Q1
IRF7821
C4
0.1mF
9 VBST2
R7
5.1W
R9
5.1W
TPS51123ARGE
(QFN24)
10 DRVH2
VO2
3.3V/8A
11 LL2
DRVH1
21
LL1
20
PowerPAD
C7
0.1mF
Q3
IRF7821
GN
D
VIN
VR
EG
5
EN
C
PGND
DRVL1
SK
IP
VO2_GND
SE
L
12 DRVL2
13
14
15
16
17
18
L2
3.3mH
VO1
5V/8A
Q2
FDS6690AS
EN
0
C5
POSCAP
330 mF
C9
10mF
C8
10 mF
R8
100kW
C3
10 mF
PGND
4
VR
EF
C2
10mF
5
VF
B2
C1
10mF
TR
IP2
6
TO
NS
EL
VIN
C10
POSCAP
330mF
Q4
FDS6690AS
19
VO1_GND
PGND
PGND
SGND
VREG5
EN0
5V/100mA
C11
10 mF
ENC
SGND PGND
PGND
UDG-10085
Figure 39. 5-V/8-A, 3.3-V/8-A Application Circuit (245-kHz/305-kHz Setting)
Table 5. List of Materials for 5-V/8-A, 3.3-V/8-A Application Circuit
REFERENCE
DESIGNATOR
SPECIFICATION
MANUFACTURER
PART NUMBER
C1, C2, C8, C9
10 μF/25 V
Taiyo Yuden
TMK325BJ106MM
C3, C11
10 μF/6.3 V
TDK
C2012X5R0J106K
C5, C10
330 μF/6.3 V/25 mΩ
Sanyo
6TPE330ML
L1, L2
3.3 μH, 15.6 A, 5.92 mΩ
TOKO
FDA1055-3R3M
30 V, 9.5 mΩ
IR
IRF7821
30 V, 12 mΩ
Fairchild
FDS6690AS
Q1, Q3
Q2, Q4
(1)
30
(1)
Use a MOSFET with an integrated Schottky barrier diode (SBD) for the low-side, or add an SBD in parallel with a normal MOSFET.
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SLUSAA6C – APRIL 2011 – REVISED SEPTEMBER 2012
REVISION HISTORY
Changes from Revision A (May 2011 ) to Revision B
•
Page
Added LL1, LL2, pulse width < 20 ns parameters with a value of -5.0 V to 30 V. ............................................................... 3
Changes from Revision B (MARCH 2012) to Revision C
•
Page
ESD ratings in ABSOLUTE MAXIMUM RATINGS table ...................................................................................................... 3
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31
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)
TPS51123ARGER
ACTIVE
VQFN
RGE
24
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
51123A
TPS51123ARGET
ACTIVE
VQFN
RGE
24
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
51123A
(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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