Texas Instruments TPS549B22EVM-847 User manual

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
User's Guide
SLUUBN2–March 2017
TPS549B22EVM-847, 25-A Single Synchronous Step-Down
Converter With Full Differential Sense and PMBus™
This user's guide describes the characteristics, operation, and use of the TPS549B22 Evaluation Module
(EVM). The user's guide includes test information, descriptions, and results. A complete schematic
diagram, printed-circuit board layouts, and bill of materials are also included in this document. Throughout
this user's guide, the abbreviations EVM, TPS549B22EVM, and the term evaluation module are
synonymous with the TPS549B22EVM-847, unless otherwise noted.
Contents
1 Introduction ................................................................................................................... 3
1.1 Before You Begin................................................................................................... 3
2 Description.................................................................................................................... 4
2.1 Typical End-User Applications .................................................................................... 4
2.2 EVM Features....................................................................................................... 4
3 EVM Electrical Performance Specifications.............................................................................. 5
4 Schematic..................................................................................................................... 6
5 Test Setup .................................................................................................................... 7
5.1 Test and Configuration Software ................................................................................. 7
6 Test Equipment .............................................................................................................. 8
7 PWR-847EVM................................................................................................................ 9
8 List of Test Points, Jumpers, and Switch ............................................................................... 11
9 EVM Configuration Using the Fusion GUI .............................................................................. 12
10 Test Procedure ............................................................................................................. 13
10.1 Line and Load Regulation Measurement Procedure ......................................................... 13
10.2 Efficiency ........................................................................................................... 13
10.3 Equipment Shutdown............................................................................................. 13
11 Performance Data and Typical Characteristic Curves................................................................. 14
11.1 Efficiency ........................................................................................................... 14
11.2 Load Regulation................................................................................................... 14
11.3 Line Regulation.................................................................................................... 15
11.4 Transient Response............................................................................................... 18
11.5 Output Ripple ...................................................................................................... 18
11.6 Control On.......................................................................................................... 19
11.7 Control Off.......................................................................................................... 20
11.8 Thermal Image..................................................................................................... 21
12 Fusion GUI ................................................................................................................. 22
13 EVM Assembly Drawing and PCB Layout .............................................................................. 33
14 List of Materials............................................................................................................. 38
List of Figures
1 PWR-847EVM Schematic .................................................................................................. 6
2 PWR-847EVM Overview.................................................................................................... 9
3 Tip and Barrel Measurement............................................................................................... 9
4 EVM and USB Interface Adapter......................................................................................... 10
5 Efficiency vs Output Current SKIP Mode ............................................................................... 14
6 Power Loss vs Output Current SKIP Mode............................................................................. 14

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
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7 Line Regulation of 1-V Output............................................................................................ 15
8 PMBus VOUT Step-Up = 0.6 V to 1.2 V at 0 A........................................................................... 15
9 PMBus VOUT Step-Down = 1.2 V to 0.6 V at 0 A ....................................................................... 16
10 PMBus VOUT Step-Up = 0.6 V to 1.2 V at 25 A ......................................................................... 16
11 PMBus VOUT Step-Down = 1.2 V to 0.6 V at 25 A...................................................................... 17
12 PMBUS Multiple Commands ............................................................................................. 17
13 Transient Response of 1-V Output at 12 VIN, Transient is 0.5 A to 15.5 A, the Step is 15 A at 40 A/µs ....... 18
14 Output Ripple and SW Node of 1-V Output at 12 VIN, 25-A Output ................................................. 18
15 Output Ripple and SW Node of 1-V Output at 12 VIN, 0-A Output .................................................. 19
16 Start up from Control, 1-V Output at 12 VIN, 0-A Output .............................................................. 19
17 0.5-V Pre-bias start up from Control, 1-V Output at 12 VIN, 10-A Output........................................... 20
18 Start-Up and Shutdown, 1-V Output at 12 VIN, 0.5-A Output......................................................... 20
19 Thermal Image at 1-V Output at 12 VIN, 25-A Output, 650 kHz at 25°C Ambient ................................. 21
20 First Window at Fusion Launch .......................................................................................... 22
21 Scan Finds Device Successfully ......................................................................................... 22
22 Software Launch Continued .............................................................................................. 22
23 Software Launch Continued .............................................................................................. 22
24 First Screen After Successful Launch Configure: Limits and On/Off................................................ 23
25 Configure: Frequency- FS Configuration Pop-up ...................................................................... 24
26 Configure: Frequency- FS Config Pop-Up with Change .............................................................. 25
27 Configure: Store Config to NVM.......................................................................................... 26
28 Change View Screen to Monitor Screen................................................................................ 27
29 System Dashboard......................................................................................................... 28
30 Status Screen............................................................................................................... 29
31 Store Configuration To Memory.......................................................................................... 30
32 PMBus Logging............................................................................................................. 31
33 PMBus Log Details......................................................................................................... 32
34 PWR-847EVM Top Layer Assembly Drawing (Top View)............................................................ 33
35 PWR-847EVM Top Solder Mask (Top View)........................................................................... 33
36 PWR-847EVM Top Layer (Top View) ................................................................................... 34
37 PWR-847EVM Inner Layer 1 (Top View) ............................................................................... 34
38 PWR-847EVM Inner Layer 2 (Top View) ............................................................................... 35
39 PWR-847EVM Inner Layer 3 (Top View) ............................................................................... 35
40 PWR-847EVM Inner Layer 4 (Top View) ............................................................................... 36
41 PWR-847EVM Bottom Layer (Top View) ............................................................................... 36
42 PWR-847EVM Bottom Solder Mask (Top View)....................................................................... 37
43 PWR-847EVM Bottom Overlay Layer (Top View) ..................................................................... 37
List of Tables
1 PWR-847EVM Electrical Performance Specifications .................................................................. 5
2 Test Point Functions....................................................................................................... 11
3 Key Factory Configuration Parameters.................................................................................. 12
4 List of Test Points for Line and Load Measurements ................................................................. 13
5 List of Test Points for Efficiency Measurements ....................................................................... 13
6 PWR847 List of Materials ................................................................................................. 38

!
www.ti.com Introduction
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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
1 Introduction
The PWR847EVM evaluation module uses the TPS549B22 device. The TPS549B22 is a highly integrated
synchronous buck converter that is designed for up to 25-A current output.
1.1 Before You Begin
The following warnings and cautions are noted for the safety of anyone using or working close to the
TPS549B22EVM-847. Observe all safety precautions.
Warning The TPS549B22EVM-847 circuit module may become hot
during operation due to dissipation of heat. Avoid contact with
the board. Follow all applicable safety procedures applicable
to your laboratory.
Caution Do not leave the EVM powered when unattended.
WARNING
The circuit module has signal traces, components, and component
leads on the bottom of the board. This may result in exposed
voltages, hot surfaces or sharp edges. Do not reach under the
board during operation.
CAUTION
The circuit module may be damaged by over temperature. To avoid damage,
monitor the temperature during evaluation and provide cooling, as needed, for
your system environment.
CAUTION
Some power supplies can be damaged by application of external voltages. If
using more than 1 power supply, check your equipment requirements and use
blocking diodes or other isolation techniques, as needed, to prevent damage to
your equipment.
CAUTION
The communication interface is not isolated on the EVM. Be sure no ground
potential exists between the computer and the EVM. Also be aware that the
computer is referenced to the Battery- potential of the EVM.

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2 Description
The PWR-847EVM is designed as a single output DC-DC converter that demonstrates the TPS549B22 in
a typical low-voltage application while providing a number of test points to evaluate the performance. It
uses a nominal 12-V input bus to produce a regulated 1-V output at up to 25-A load current.
2.1 Typical End-User Applications
• Enterprise Storage, SSD, NAS
• Wireless and Wired Communication Infrastructure
• Industrial PCs, Automation, ATE, PLC, Video Surveillance
• Enterprise Server, Switches, Routers
• ASIC, SoC, FPGA, DSP Core and I/O Rails
2.2 EVM Features
• Regulated 1-V output up to 25-A, steady-state output current
• Convenient test points for probing critical waveforms
• PMBus™ connector for easy connection with the TI USB adapter

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
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3 EVM Electrical Performance Specifications
Table 1 lists the PWR-847EVM electrical performance specifications.
Table 1. PWR-847EVM Electrical Performance Specifications
Parameter Test Conditions Min Typ Max Units
Input Characteristics
Voltage range VIN tied to VDD 5 12 14 V
Maximum input current VIN = 12 V, IO= 25 A 12 A
No load input current VIN = 12 V, IO= 0 A 60 mA
Output Characteristics
VOUT Output voltage Output current = 10 A 1 V
IOUT Output load current IOUT(min) to IOUT(max) 0 25 A
Output voltage regulation Line regulation: input voltage = 5 V to 14 V 0.5%
Load regulation: output current = 0 A to IOUT(max) 0.5%
VOUT Output voltage ripple VIN = 12 V, IOUT = 25 A 10 mVPP
VOUT Output overcurrent 32 A
Systems Characteristics
Switching frequency FSW 650 kHz
VOUT Peak efficiency VIN = 12 V, IO= 12 A, FSW = 650 kHz 90%
Operating temperature Toper 0 85 ºC

PGND
22uF
C16
DNP
22uF
C15
DNP
22uF
C14
DNP
22µF
C13
330uF
C12
DNP
330uF
C1
DNP
2200pF
C10
22µF
C2
22µF
C9
22µF
C8
22µF
C7
22µF
C6
22µF
C5
22µF
C4
22µF
C3
DRGND
1uF
C34
DNP 1µF
C35
100µF
C33
100µF
C40
100µF
C41
DNP
100µF
C42
100µF
C29
0.1µF
C22
330nH
L1
TP3
CHB
100µF
C27
DNP
100µF
C28
DNP
100µF
C39
6800pF
C32
DNP
TP7
CHA
470pF
C21
DNP
0.1uF
C31
DNP
100µF
C26
100µF
C25
0
R14
DNP1000pF
C36
DNP
3.01
R9
DNP
1uF
C44DNP
4.7µF
C45
TP12
ILIM
0
R4
AGND
DRGND
DRGND
470uF
C37
DNP
470µF
C24
470µF
C38
470µF
C23
DNP
0
R16
1000pF
C46DNP
AGND
0
R2
DNP 0
R3
DNP
TP8
PGOOD
100k
R13
PGND
TP13
AGND PGND DRGND
CNTL
CLK
DATA
ALERT
MODE
FSEL
VSEL
PGND
PGND
PGND
100µF
C11
TP2
TP10
1 2
3 4
5 6
7 8
9 10
J6
DATA CLK ALERT
PMBus
AGND
----- GND NET TIES -----
Remote Sense pos/neg should run as balanced pair
VIN = 6V - 16V
I_OUT = 25A MAX
22uF
C17
DNP
22uF
C18
DNP
22uF
C19
DNP
22µF
C20
DNP
TP6
TP11
0
R17
DNP 0
R18
DNP
1.00
R1
0
R10
1.10k
R8
1.50k
R5
DNP
NT1
Net-Tie
NT2
Net-Tie
TP5
SW
TP4
MODE FSELVSEL
25.5k
R25
AGND
CNTL/EN_UVLO
LOW
10.0k
R15
TP9
BP
TP14
100k
R20
100k
R21
100k
R22
BP
100uF
C43
DNP
100uF
C30
DNP
J1
200k
R6
100k
R12
J4
TP1
VDD
TP17
FSEL
TP16
MODE
TP15
VSEL
0
R11
VDD
TP18
PGND
TP19
TP20
CLK
TP21
DATA
TP22
ALERT
61.9k
R19
37.4k
R23
42.2k
R24
0
R7
J2
J3
J5
VOUT = 1V
NetC31_1
NetC31_1
DRGND
BP
SMB_ALRT#
1
PMB_DATA
2
PMB_CLK
3
EN_UVLO
4
BOOT 5
NC 6
NC 7
SW 8
SW 9
SW 10
SW 11
SW 12
PGND 13
PGND 14
PGND 15
PGND 16
PGND 17
PGND 18
PGND 19
PGND 20
PVIN
21
PVIN
22
PVIN
23
PVIN
24
PVIN
25
NC 26
NC 27
VDD
28
DRGND
29
AGND
30
BP
31
ADDR
32
VSEL
33
MODE
34
PGOOD
35
ILIM
36
RESV_TRK
37
RSN 38
RSP 39
VOSNS 40
PAD 41
U1
TPS549B22RVFR
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Schematic www.ti.com
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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With Full
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4 Schematic
Figure 1 illustrates the PWR-847EVM schematic.
Figure 1. PWR-847EVM Schematic

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5 Test Setup
5.1 Test and Configuration Software
To change any of the default configuration parameters on the EVM, it is necessary to obtain the TI Fusion
Digital Power Designer software. This can be downloaded from the TI website.
5.1.1 Description
The Fusion Digital Power Designer is the graphical user interface (GUI) used to configure and monitor the
Texas Instruments TPS549B22 power converter installed on this evaluation module. The application uses
the PMBus protocol to communicate with the controller over serial bus by way of a TI USB adapter. This
adapter can be purchased at http://www.ti.com/tool/usb-to-gpio.
NOTE: The TI USB adapter must be purchased separately. It is not included with this EVM kit.
5.1.2 Features
Some of the tasks performed with the GUI include:
• Turn on or off the power supply output, either through the hardware control line or the PMBus
operation command.
• Monitor status registers. Items such as input voltage, output voltage, output current, temperature, and
warnings and faults are continuously monitored and displayed by the GUI.
• Configure common operating characteristics such as VOUT, UVLO, soft-start time, warning and fault
thresholds, fault response, and ON/OFF.
This software is available for download at http://www.ti.com/tool/fusion_digital_power_designer.

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
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6 Test Equipment
Voltage Source: The input voltage source VIN must be a 0-V to 18-V variable DC source capable of
supplying at least 12 ADC.
Multimeters: It is recommended to use two separate multimeters Figure 2. One meter is used to measure
VIN and one to measure VOUT.
Output Load: A variable electronic load is recommended for testing Figure 2. It must be capable of 25 A
at voltages as low as 0.6 V.
Oscilloscope: An oscilloscope is recommended for measuring output noise and ripple. Output ripple must
be measured using a tip-and-barrel method or better as shown in Figure 3.The scope must be adjusted to
20-MHz bandwidth, AC coupling at 50 mV/division, and must be set to 1-µs/division.
Fan: During prolonged operation at high loads, it may be necessary to provide forced air cooling with a
small fan aimed at the EVM. Temperature of the devices on the EVM must be maintained below 105°C.
USB-to-GPIO Interface Adapter: A communications adapter is required between the EVM and the host
computer. This EVM was designed to use TI's USB-to-GPIO adapter. Purchase this adapter at
http://www.ti.com/tool/usb-to-gpio.
Recommended Wire Gauge: The voltage drop in the load wires must be kept as low as possible in order
to keep the working voltage at the load within its operating range. Use the AWG 14 wire (2 wires parallel
for VOUT positive and 2 wires parallel for the VOUT negative) of no more than 1.98 feet between the EVM
and the load. This recommended wire gauge and length should achieve a voltage drop of no more than
0.2 V at the maximum 25-A load.

Metal Ground
Barrel
Probe
Tip
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7 PWR-847EVM
Figure 2 and Figure 3 illustrate the PWR-847EVM overview, tip and barrel measurement.
Figure 2. PWR-847EVM Overview
Figure 3. Tip and Barrel Measurement

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Figure 4 illustrates the EVM and USB interface adapter.
Figure 4. EVM and USB Interface Adapter

www.ti.com List of Test Points, Jumpers, and Switch
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8 List of Test Points, Jumpers, and Switch
Table 2 lists the test points and their descriptions.
Table 2. Test Point Functions
Item Type Name Description
TP5 T-H loop SW Power supply Switch node
TP7 T-H loop CH-A Measure loop stability
TP6 T-H loop CH-B Measure loop stability
TP2 T-H loop LocS+ Sense VOUT + locally across C25. Use for efficiency and ripple
measurements
TP10 T-H loop LocS- Sense VOUT– locally across C25. Use for efficiency and ripple
measurements
TP3 T-H loop RemS+ Remote sense +
TP11 T-H loop RemS- Remote sense –
TP4 T-H loop PVIN Sense VIN + across C10
TP13 T-H loop PGND Sense VIN – across C10
TP1 T-H loop VDD Supplies the internal circuitry
TP17 T-H loop ADDR Monitor the ADDR external resistor divider ratio during initial power up.
TP15 T-H loop VSEL Monitor the VSEL external resistor divider ratio during initial power up.
TP9 T-H loop BP LDO output
TP8 T-H loop PG Power good
TP16 T-H loop MODE Monitor the MODE external resistor divider ratio during initial power up.
TP12 T-H loop ILIM Program over-current limit.
TP14 T-H loop RESV_TRK Do not connect.
TP19 T-H loop PGND Common GND
TP18 T-H loop PGND Common GND
TP20 T-H loop PMB_CLK Clock input for the PMBus interface.
TP21 T-H loop PMB_DATA Data I/O for the PMBus interface.
TP22 T-H loop SMB_ALRT# Alert output for the PMBus interface.
JP4 2-pin jumper CNTL Shunts control pin to GND

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9 EVM Configuration Using the Fusion GUI
The TPS549B22 installed on this EVM leave the factory pre-configured. See Table 3 for a short list of key
factory configuration parameters as obtained from the configuration file.
Table 3. Key Factory Configuration Parameters
Cmd ID With Phase Cmd Code Hex Encoded Hex
[HiByte|LoByte] Comments
CAPABILITY 0x19 0xD0 Max Bus: 1000 kHz; PEC: Yes; SMBALERT#: Yes
MFR_00 0xD0 0x00 0
MFR_01 (PGOOD_DLY) 0xD1 0x12 PGD:1024?s [010b], POD:1024?s [010b]
MFR_02 0xD2 0x13 CM: True, HICLOFF: True, SST: 0x00, FORCESKIPSS:
True, SEQ: False, TRK: False
MFR_03 0xD3 0x93 FS:650 kHz [011b], RCSP:R ? 1 [01b], DCAP3:True
MFR_04 0xD4 0x80 DCAP3_Offset:0mV [00b], DCAP3_Offset_Sel:True
MFR_06 0xD6 0x05 VDDUVLO:4.25V [101b]
MFR_07 0xD7 0x8F VTRKIN:1.25V [1111b], TRKOPTION:False,
SPARE:False, VPBAD:True
MFR_33 0xF1 0x00 0
MFR_42 0xFA 0x00 0
MFR_44 0xFC 0x0201 ID: 0x020 (TPS549B22), Revision: 0x8
ON_OFF_CONFIG 0x02 0x17 Mode: CONTROL Pin Only; Control: Active High, Turn off
Immediately
OPERATION 0x01 0x00 Operation is not used to enable regulatio; Unit:
ImmediateOff; Margin: None
STATUS_BYTE 0x78 0x00 Status: Output Off, Vout OV Fault, IOUT OC Fault, Vin
UV Fault, Temperature, CML
STATUS_CML 0x7E 0x00 Status: Invalid Command, Invalid Data, PEC Fault, Other
Comms Fault
STATUS_IOUT 0x7B 0x00 Status: Iout OC Fault, Iout OC Fault with LV Shutdown,
Iout UC Fault
STATUS_VOUT 0x7A 0x00 Status: Vout OV Fault, OV Warning, UV Fault, UV
Warning
VOUT_COMMAND 0x21 0x01CD VOUT_COMMAND=0.900 V
VOUT_MARGIN_HIGH 0x25 0x0266 VOUT_MARGIN_HIGH=1.199 V
VOUT_MARGIN_LOW 0x26 0x0266 VOUT_MARGIN_LOW=1.199 V
WRITE_PROTECT 0x10 0x00 Enable Writes To All Commands
If it is desired to configure the EVM to settings other than the factory settings shown in Table 3, the TI
Fusion Digital Power Designer software can be used for reconfiguration. It is necessary to have input
voltage applied to the EVM prior to launching the software so that the TPS549B22 installed is active and
able to respond to the GUI and the GUI can recognize the device.

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10 Test Procedure
10.1 Line and Load Regulation Measurement Procedure
Use the following procedures for line and load regulation measurement.
1. Connect VOUT to J3 and VOUT_GND to J5 Figure 2.
2. Ensure that the electronic load is set to draw 0 ADC.
3. Connect VIN to J1 and VIN_GND to J2 Figure 2.
4. Connect the USB interface adapter as shown in Figure 4.
5. Increase VIN from 0 V to 12 V using the digital multimeter to measure input voltage.
6. Launch the Fusion GUI software. See the screen shots in Section 12 for more information.
7. Configure the EVM operating parameters as desired.
8. Use the other digital multimeter or the oscilloscope to measure output voltage VOUT at TP2 and TP10
as you vary the external voltage source.
Table 4. List of Test Points for Line and Load Measurements
Test Point Node Name Description
TP2 LocS+ Sense VOUT + locally across C5. Use for efficiency and ripple measurements
TP10 LocS– Sense VOUT - locally across C5. Use for efficiency and ripple measurements
TP4 PVIN Sense VIN + across C10
TP13 PGND Sense VIN - across C10
9. Vary the load from 0 ADC to maximum rated output 25 ADC. VOUT must remain in regulation as defined in
Table 1.
10. Vary VIN from 5 V to 14 V. VOUT must remain in regulation as defined in Table 1.
11. Decrease the load to 0 A.
12. Decrease VIN to 0 V or turn off the supply.
10.2 Efficiency
To measure the efficiency of the power train on the EVM, it is important to measure the voltages at the
correct location. This is necessary because otherwise the measurements will include losses in efficiency
that are not related to the power train itself. Losses incurred by the voltage drop in the copper traces and
in the input and output connectors are not related to the efficiency of the power train, and they must not be
included in efficiency measurements.
Table 5. List of Test Points for Efficiency Measurements
Test Point Node Name Description
TP2 LocS+ Sense VOUT + locally across C25. Use for efficiency and ripple measurements
TP10 LocS- Sense VOUT - locally across C25. Use for efficiency and ripple measurements
TP4 PVIN Sense VIN + across C10
TP13 PGND Sense VIN - across C10
Input current can be measured at any point in the input wires, and output current can be measured
anywhere in the output wires of the output being measured. Using these measurement points result in
efficiency measurements that do not include losses due to the connectors and PCB traces.
10.3 Equipment Shutdown
1. Reduce the load current to 0 A.
2. Reduce input voltage to 0 V.
3. Shut down the external fan if in use.
4. Shut down equipment.

Load Current (A)
Converter Power Loss (W)
0 5 10 15 20 25
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
D002
VIN = 5 V
VIN = 12 V
VIN = 14 V
VIN = 18 V
Load Current (A)
Efficiency (%)
0 5 10 15 20 25
60
65
70
75
80
85
90
95
100
D001
VIN = 5 V
VIN = 12 V
VIN = 14 V
VIN = 18 V
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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
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11 Performance Data and Typical Characteristic Curves
Figure 5 through Figure 18 present typical performance curves for the PWR-847EVM.
SPACE
11.1 Efficiency
Figure 5. Efficiency vs Output Current SKIP Mode
11.2 Load Regulation
Figure 6. Power Loss vs Output Current SKIP Mode

Load Current (A)
Output Voltage Regulation (V)
0 5 10 15 20 25
0.99
0.995
1
1.005
1.01
D003
VIN = 5 V
VIN = 12 V
VIN = 14 V
VIN = 18 V
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11.3 Line Regulation
Figure 7. Line Regulation of 1-V Output
Figure 8. PMBus VOUT Step-Up = 0.6 V to 1.2 V at 0 A

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
Figure 9. PMBus VOUT Step-Down = 1.2 V to 0.6 V at 0 A
Figure 10. PMBus VOUT Step-Up = 0.6 V to 1.2 V at 25 A

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
Figure 11. PMBus VOUT Step-Down = 1.2 V to 0.6 V at 25 A
Figure 12. PMBUS Multiple Commands

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
11.4 Transient Response
Figure 13. Transient Response of 1-V Output at 12 VIN, Transient is 0.5 A to 15.5 A,
the Step is 15 A at 40 A/µs
11.5 Output Ripple
Figure 14. Output Ripple and SW Node of 1-V Output at 12 VIN, 25-A Output

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
Figure 15. Output Ripple and SW Node of 1-V Output at 12 VIN, 0-A Output
11.6 Control On
Figure 16. Start up from Control, 1-V Output at 12 VIN, 0-A Output

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TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
Figure 17. 0.5-V Pre-bias start up from Control, 1-V Output at 12 VIN, 10-A Output
11.7 Control Off
Figure 18. Start-Up and Shutdown, 1-V Output at 12 VIN, 0.5-A Output