TPS54618C-Q1 [TI]

汽车 2.95V 至 6V、6A、2MHz 同步降压转换器;
TPS54618C-Q1
型号: TPS54618C-Q1
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

汽车 2.95V 至 6V、6A、2MHz 同步降压转换器

转换器
文件: 总41页 (文件大小:2505K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
TPS54618C-Q1  
ZHCSLU7A SEPTEMBER 2020 REVISED AUGUST 2021  
TPS54618C-Q1 汽车2.95V 6V6A 同步降压转换器  
TPS54618C-Q1 借助以下功能实现了小尺寸设计集  
MOSFET实现可减少外部组件数量的电流模式控  
通过启用高达 2MHz 的开关频率来减小电感器尺  
借助小型 3mm × 3mm 热增强型 WQFN 封装尽量  
IC 封装尺寸。  
1 特性  
• 符合面向汽车应用AEC-Q100 标准:  
– 温度等1-40°C +125°CTA  
提供功能安全  
可帮助进行功能安全系统设计的文档  
• 两个可6A 负载下获得高效率12mΩ(典型  
MOSFET  
TPS54618C-Q1 可在工作温度范围内为各种负载提供  
±1% 精确电压基(VREF) 的准确调节。  
通过集12mMOSFET 和典型值  
300kHz 2MHz 开关频率  
515μA 的电源电流有效提升效率。通过使用使能  
引脚进入关断模式关断电流被减少5.5µA。  
• 在工作温度范围-40°C +150°C内  
0.8V ±1% 电压基准  
• 与外部时钟同步  
欠压闭锁被内部设定在 2.6V 但是可通过一个使能  
引脚上的电阻器网络来编辑阈值以增加此电压值。输  
出电压启动斜坡由慢启动引脚控制。一个开漏电源正常  
信号表示输出处于其标称电压值的 93% 107% 之  
内。  
• 可调缓启动和排序  
• 欠(UV) 和过(OV) 电源正常输出  
• 推出的新产品TPS62816-Q1 采用具有可湿性侧  
2mm x 3mm QFN 封装6V 降压转换器  
• 热增强3mm × 3mm16 WQFN 封装  
频率折返和热关断功能可在过流情况下保护器件。  
2 应用  
器件信息  
汽车音响主机  
汽车仪表组  
ADAS 摄像头  
器件型号(1)  
封装尺寸标称值)  
封装  
WQFN (16)  
TPS54618C-Q1  
3.00mm × 3.00mm  
(1) 如需了解所有可用封装请参阅数据表末尾的可订购产品附  
录。  
3 说明  
TPS54618C-Q1 器件是一款具有两个集成 MOSFET  
的全功6V6A、同步降压电流模式转换器。  
VIN  
100  
C
BOOT  
3 Vin  
VIN  
95  
BOOT  
C
5 Vin  
I
R
R
4
5
90  
TPS54618C-Q1  
EN  
L
O
VOUT  
PH  
85  
C
O
80  
75  
R
1
2
PWRGD  
VSENSE  
70  
65  
60  
R
SS/TR  
RT /CLK  
COMP  
GND  
f
= 500kHz  
AGND  
s
55  
50  
C
POWERPAD  
ss  
Vout = 1.8V  
R
R
T
3
0
1
2
3
4
5
6
I
- Output Current - A  
O
C
1
效率与输出电流间的关系  
简化原理图  
本文档旨在为方便起见提供有TI 产品中文版本的信息以确认产品的概要。有关适用的官方英文版本的最新信息请访问  
www.ti.com其内容始终优先。TI 不保证翻译的准确性和有效性。在实际设计之前请务必参考最新版本的英文版本。  
English Data Sheet: SLVSEW2  
 
 
 
 
TPS54618C-Q1  
ZHCSLU7A SEPTEMBER 2020 REVISED AUGUST 2021  
www.ti.com.cn  
Table of Contents  
7.4 Device Functional Modes..........................................20  
8 Application and Implementation..................................24  
8.1 Application Information............................................. 24  
8.2 Typical Application.................................................... 24  
9 Power Supply Recommendations................................32  
10 Layout...........................................................................33  
10.1 Layout Guidelines................................................... 33  
10.2 Layout Example...................................................... 34  
10.3 Power Dissipation Estimate.................................... 34  
11 Device and Documentation Support..........................36  
11.1 Device Support........................................................36  
11.2 接收文档更新通知................................................... 36  
11.3 支持资源..................................................................36  
11.4 Trademarks............................................................. 36  
11.5 静电放电警告...........................................................36  
11.6 术语表..................................................................... 36  
12 Mechanical, Packaging, and Orderable  
1 特性................................................................................... 1  
2 应用................................................................................... 1  
3 说明................................................................................... 1  
4 Revision History.............................................................. 2  
5 Pin Configuration and Functions...................................3  
Pin Functions.................................................................... 3  
6 Specifications.................................................................. 5  
6.1 Absolute Maximum Ratings ....................................... 5  
6.2 ESD Ratings .............................................................. 5  
6.3 Recommended Operating Conditions ........................5  
6.4 Thermal Information ...................................................5  
6.5 Electrical Characteristics ............................................6  
6.6 Timing Requirements .................................................7  
6.7 Typical Characteristics................................................8  
7 Detailed Description......................................................12  
7.1 Overview...................................................................12  
7.2 Functional Block Diagram.........................................13  
7.3 Feature Description...................................................13  
Information.................................................................... 36  
4 Revision History  
以前版本的页码可能与当前版本的页码不同  
Changes from Revision * (September 2020) to Revision A (August 2021)  
Page  
• 添加TPS62816-Q1 促销要点..........................................................................................................................1  
Changed "Start with 100 kΩfor the R1 resistor and use equation 1..." to "Pick a suitable value for R1 and  
use equation 1..."..............................................................................................................................................14  
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5 Pin Configuration and Functions  
16  
15  
14  
13  
VIN  
VIN  
1
PH  
PH  
12  
11  
10  
9
2
3
4
Thermal  
Pad  
GND  
GND  
PH  
SS/TR  
5
6
7
8
5-1. 16-Pin WQFN With Exposed Thermal Pad RTE Package (Top View)  
5-1. Pin Functions  
PIN  
TYPE(1)  
DESCRIPTION  
NAME  
NO.  
AGND  
5
G
I
Analog ground must be electrically connected to GND close to the device.  
A bootstrap capacitor is required between BOOT and PH. If the voltage on this capacitor is below the  
minimum required by the BOOT UVLO, the output is forced to switch off until the capacitor is refreshed.  
BOOT  
COMP  
EN  
13  
7
Error amplifier output, and input to the output switch current comparator. Connect frequency  
compensation components to this pin.  
O
I
Enable pin and internal pullup current source. Pull below 1.2 V to disable. Float to enable. Can be used  
to set the on/off threshold (adjust UVLO) with two additional resistors.  
15  
3
GND  
PH  
G
O
Power ground. This pin must be electrically connected directly to the power pad under the device.  
4
10  
11  
12  
The source of the internal high-side power MOSFET, and drain of the internal low-side (synchronous)  
rectifier MOSFET.  
An open-drain output, asserts low if output voltage is low due to thermal shutdown, overcurrent,  
overvoltage and undervoltage, or EN shutdown.  
PWRGD  
RT/CLK  
SS/TR  
14  
8
O
I/O  
I/O  
Resistor timing or external clock input pin  
Slow start and tracking. An external capacitor connected to this pin sets the output voltage rise time.  
This pin can also be used for tracking.  
9
1
2
VIN  
I
Input supply voltage: 2.95 V to 6 V  
16  
6
VSENSE  
I
Inverting node of the transconductance (gm) error amplifier  
Thermal  
Pad  
GND pin must be connected to the exposed power pad for proper operation. This power pad must be  
connected to any internal PCB ground plane using multiple vias for good thermal performance.  
G
(1) I = Input, O = Output, G = Ground  
Pin Functions  
PIN  
TYPE(1)  
DESCRIPTION  
NAME  
NO.  
AGND  
5
G
Analog ground must be electrically connected to GND close to the device.  
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PIN  
TYPE(1)  
DESCRIPTION  
NAME  
NO.  
A bootstrap capacitor is required between BOOT and PH. If the voltage on this capacitor is below the  
minimum required by the BOOT UVLO, the output is forced to switch off until the capacitor is refreshed.  
BOOT  
13  
I
O
I
Error amplifier output, and input to the output switch current comparator. Connect frequency  
compensation components to this pin.  
COMP  
EN  
7
Enable pin and internal pullup current source. Pull below 1.2 V to disable. Float to enable. Can be used  
to set the on/off threshold (adjust UVLO) with two additional resistors.  
15  
3
GND  
PH  
G
O
Power ground. This pin must be electrically connected directly to the power pad under the device.  
4
10  
11  
12  
The source of the internal high-side power MOSFET, and drain of the internal low-side (synchronous)  
rectifier MOSFET.  
An open-drain output, asserts low if output voltage is low due to thermal shutdown, overcurrent,  
overvoltage and undervoltage, or EN shutdown.  
PWRGD  
RT/CLK  
SS/TR  
14  
8
O
I/O  
I/O  
Resistor timing or external clock input pin  
Slow start and tracking. An external capacitor connected to this pin sets the output voltage rise time.  
This pin can also be used for tracking.  
9
1
2
VIN  
I
Input supply voltage: 2.95 V to 6 V  
16  
6
VSENSE  
I
Inverting node of the transconductance (gm) error amplifier  
Thermal  
Pad  
GND pin must be connected to the exposed power pad for proper operation. This power pad must be  
connected to any internal PCB ground plane using multiple vias for good thermal performance.  
G
(1) I = Input, O = Output, G = Ground  
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ZHCSLU7A SEPTEMBER 2020 REVISED AUGUST 2021  
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6 Specifications  
6.1 Absolute Maximum Ratings  
over operating free-air temperature range (unless otherwise noted)(1)  
MIN  
0.3  
0.3  
0.3  
MAX  
7
UNIT  
PWRGD, VIN  
EN, RT/CLK  
Input voltage  
4
V
COMP, SS, VSENSE  
3
BOOT  
VPH+ 7  
7
BOOT-PH  
PH  
7
Output voltage  
0.6  
2  
V
PH (10-ns transient)  
EN, RT/CLK  
COMP, SS  
PWRGD  
10  
Source current  
Sink current  
100  
100  
10  
µA  
µA  
mA  
°C  
Operating junction temperature, TJ  
Storage temperature, Tstg  
150  
150  
40  
65  
°C  
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings  
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under 6.3.  
Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.  
6.2 ESD Ratings  
VALUE  
UNIT  
Human-body model (HBM), per AEC Q100-002(1)  
HBM ESD classification level XX  
±2000  
V(ESD)  
Electrostatic discharge  
V
Charged-device model (CDM), per AEC Q100-011  
CDM ESD classification level XX  
±750  
(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.  
6.3 Recommended Operating Conditions  
over operating free-air temperature range (unless otherwise noted)  
MIN  
3
MAX  
UNIT  
V
VVIN  
TA  
Input voltage  
6
Operating ambient temperature  
125  
°C  
40  
6.4 Thermal Information  
TPS54618C-Q1  
RTE (WQFN)  
16 PINS  
44.38  
THERMAL METRIC(2) (1)  
UNIT  
RθJA  
Junction-to-ambient thermal resistance  
Junction-to-case (top) thermal resistance  
°C/W  
°C/W  
°C/W  
°C/W  
°C/W  
°C/W  
RθJC(top)  
RθJB  
46.09  
Junction-to-board thermal resistance  
15.96  
Junction-to-top characterization parameter  
Junction-to-board characterization parameter  
Junction-to-case (bottom) thermal resistance  
0.69  
ψJT  
15.91  
ψJB  
RθJC(bot)  
4.55  
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application  
report.  
(2) Unless otherwise specified, metrics listed in this table refer to JEDEC high-K board measurements  
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6.5 Electrical Characteristics  
at TJ = 40°C to +125°C, VIN = 2.95 to 6 V (unless otherwise noted)  
PARAMETER  
SUPPLY VOLTAGE (VIN PIN)  
Operating input voltage  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNIT  
2.95  
6
2.5  
2.6  
15  
V
V
VIN UVLO STOP  
VIN UVLO START  
2.28  
2.45  
5.5  
Internal undervoltage lockout  
threshold  
Shutdown supply current  
Quiescent current, IQ  
EN = 0 V, 25°C, 2.95 V VIN 6 V  
μA  
μA  
515  
650  
VSENSE = 0.9 V, VIN = 5 V, 25°C, RT = 400 kΩ  
ENABLE AND UVLO (EN PIN)  
Rising  
1.25  
1.18  
Enable threshold  
Input current  
V
Falling  
Enable threshold + 50 mV  
3.5  
1.9  
μA  
Enable threshold 50 mV  
VOLTAGE REFERENCE (VSENSE PIN)  
Voltage reference  
0.791  
0.799  
0.807  
V
2.95 V VIN 6 V, 40°C <TJ < 150°C  
MOSFET  
BOOT-PH = 5 V  
BOOT-PH = 2.95 V  
VIN = 5 V  
12  
16  
13  
17  
25  
33  
25  
33  
High-side switch resistance  
Low-side switch resistance  
mΩ  
mΩ  
VIN = 2.95 V  
ERROR AMPLIFIER  
Input current  
2
nA  
Error amplifier transconductance  
(gm)  
245  
2 μA < I(COMP) < 2 μA, V(COMP) = 1 V  
μmhos  
Error amplifier transconductance  
(gm)  
during slow start  
2 μA < I(COMP) < 2 μA, V(COMP) = 1 V,  
VSENSE = 0.4 V  
79  
μmhos  
Error amplifier source/sink  
COMP to Iswitch gm  
V(COMP) = 1 V, 100-mV overdrive  
±20  
25  
μA  
A/V  
CURRENT LIMIT  
VIN = 6 V, 25°C < TJ < 150°C  
7.46  
7.68  
10.6  
10.2  
15.3  
13.5  
Current limit threshold  
A
VIN = 2.95 V, 25°C < TJ < 150°C  
THERMAL SHUTDOWN  
Thermal shutdown  
Hysteresis  
168  
20  
°C  
°C  
BOOT (BOOT PIN)  
BOOT charge resistance  
BOOT-PH UVLO  
VIN = 5 V  
16  
VIN= 2.95 V  
2.1  
V
SLOW-START AND TRACKING (SS/TR PIN)  
Charge current  
V(SS/TR) = 0.4 V  
2
54  
μA  
mV  
V
SS/TR to VSENSE matching  
SS/TR to reference crossover  
V(SS/TR) = 0.4 V  
98% normal  
1.1  
61  
SS/TR discharge voltage (overload) VSENSE = 0 V  
mV  
µA  
SS/TR discharge current (overload) VSENSE = 0 V, V(SS/TR) = 0.4 V  
350  
SS discharge current (UVLO, EN,  
VIN = 5 V, V(SS) = 0.5 V  
Thermal fault)  
1.9  
mA  
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at TJ = 40°C to +125°C, VIN = 2.95 to 6 V (unless otherwise noted)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX  
UNIT  
POWER GOOD (PWRGD PIN)  
VSENSE falling (Fault)  
91%  
93%  
109%  
107%  
2%  
VSENSE rising (Good)  
VSENSE rising (Fault)  
VSENSE falling (Good)  
VSENSE falling  
VSENSE threshold  
Vre  
Hysteresis  
Vref  
nA  
Output high leakage  
ON-resistance  
VSENSE = VREF, V(PWRGD) = 5.5 V  
7
56  
100  
0.3  
1.5  
Output low  
I(PWRGD) = 3 mA  
0.2  
V
Minimum VIN for valid output  
0.65  
V
V(PWRGD) < 0.5 V at 100 μA  
6.6 Timing Requirements  
MIN NOM MAX  
UNIT  
TIMING RESISTOR AND EXTERNAL CLOCK (RT/CLK PIN)  
Switching frequency range using RT mode  
200  
400  
300  
75  
2000  
600  
kHz  
kHz  
kHz  
ns  
Switching frequency  
500  
Rt = 400 kΩ  
Switching frequency range using CLK mode  
Minimum CLK pulse width  
RT/CLK voltage  
2000  
0.5  
1.6  
0.6  
90  
V
R(RT/CLK) = 400 kΩ  
RT/CLK high threshold  
RT/CLK low threshold  
2.2  
V
0.4  
V
RT/CLK falling edge to PH rising edge delay  
PLL lock in time  
Measure at 500 kHz with RT resistor in series  
Measure at 500 kHz  
ns  
42  
μs  
PH (PH PIN)  
Measured at 50% points on PH, IOUT = 3 A  
75  
Minimum ON-time  
ns  
Measured at 50% points on PH, VIN = 6 V,  
IOUT = 0 A  
120  
Prior to skipping off pulses, BOOT-PH = 2.95 V,  
IOUT = 3 A  
Minimum OFF-time  
60  
ns  
Rise time  
Fall time  
VIN = 6 V, 6 A  
VIN = 6 V, 6 A  
2.25  
2
V/ns  
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6.7 Typical Characteristics  
0.025  
0.023  
525  
520  
RT = 400 kW,  
Vin = 5 V  
High Side Rdson Vin = 3.3 V  
515  
510  
505  
500  
495  
490  
485  
0.021  
0.019  
0.017  
0.015  
0.013  
0.011  
0.009  
0.007  
0.005  
Low Side Rdson Vin = 3.3 V  
High Side Rdson Vin = 5 V  
Low Side Rdson Vin = 5 V  
480  
475  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
T
- Junction Temperature - °C  
J
J
6-2. Switching Frequency vs Junction  
6-1. High-Side and Low-Side ON-Resistance  
Temperature  
vs Junction Temperature  
12  
0.807  
Vin = 3.3 V  
Vin = 6 V  
11.5  
0.805  
0.803  
0.801  
0.799  
0.797  
0.795  
0.793  
0.791  
11  
10.5  
Vin = 2.95 V  
10  
9.5  
9
8.5  
8
25  
75  
- Junction Temperature - °C  
50  
100  
125  
150  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
T
T
- Junction Temperature - °C  
J
J
6-3. High-Side Current Limit vs Junction  
6-4. Voltage Reference vs Junction Temperature  
Temperature  
100  
2000  
1800  
1600  
1400  
1200  
1000  
800  
Vsense Falling  
75  
Vsense Rising  
50  
600  
25  
0
400  
200  
100 200 300 400 500 600 700 800  
Resistance (k)  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
G000  
Vsense - V  
6-5. Switching Frequency vs RT Resistance  
6-6. Switching Frequency vs Vsense  
Low Frequency Range  
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105  
100  
95  
310  
Vin = 3.3 V  
Vin = 3.3 V  
290  
270  
250  
230  
210  
90  
85  
80  
75  
70  
65  
190  
170  
60  
55  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
-50  
-25  
0
25  
T - Junction Temperature - °C  
J
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
J
6-7. Transconductance vs Junction Temperature  
6-8. Transconductance (Soft-Start)  
vs Junction Temperature  
-3  
1.3  
1.29  
1.28  
Vin = 5 V,  
Ven = Threshold +50 mV  
-3.1  
Vin = 3.3 V, rising  
1.27  
-3.2  
-3.3  
-3.4  
-3.5  
-3.6  
-3.7  
-3.8  
1.26  
1.25  
1.24  
1.23  
1.22  
1.21  
1.2  
Vin = 3.3 V, falling  
1.19  
1.18  
1.17  
-3.9  
-4  
1.16  
1.15  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
T
- Junction Temperature - °C  
J
J
6-10. EN Pin Current vs Junction Temperature  
6-9. Enable Pin Voltage vs Junction  
Temperature  
-1  
-1.4  
Vin = 5 V  
Vin = 5 V,  
Ven = Threshold -50 mV  
-1.2  
-1.4  
-1.6  
-1.8  
-2  
-1.6  
-1.8  
-2  
-2.2  
-2.4  
-2.6  
-2.2  
-2.4  
-2.6  
-2.8  
-3  
-2.8  
-3  
-50  
-30  
-10  
10  
30  
50  
70  
90  
110  
130  
150  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
T
- Junction Temperature - °C  
J
J
6-12. Charge Current vs Junction Temperature  
6-11. EN Pin Current vs Junction Temperature  
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2.8  
2.7  
2.6  
8
7
6
5
4
3
2
Vin = 3.3 V  
UVLO Stop Switching  
2.5  
2.4  
2.3  
2.2  
UVLO Start Switching  
1
0
2.1  
2
-50  
-25  
0
25  
50  
75  
100  
125  
150  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
T
- Junction Temperature - °C  
J
J
6-14. Shutdown Supply Current  
6-13. Input Voltage vs Junction Temperature  
vs Junction Temperature  
800  
700  
600  
500  
400  
8
T
= 25°C  
Vin = 3.3 V  
J
7
6
5
4
3
2
300  
200  
1
0
-50  
-25  
0
25  
50  
75  
100  
125  
150  
3
3.5  
4
4.5  
V - Input Voltage - V  
I
5
5.5  
6
T
- Junction Temperature - °C  
J
6-15. Shutdown Supply Current vs Input Voltage  
6-16. Supply Current vs Junction Temperature  
800  
110  
108  
106  
T
= 25°C  
J
700  
600  
500  
400  
Vsense Rising, Vin = 5 V  
Vsense Falling  
104  
102  
100  
98  
96  
94  
92  
Vsense Rising  
Vsense Falling  
300  
200  
90  
88  
-50  
-25  
0
25  
50  
75  
100  
125  
150  
3
3.5  
4
4.5  
V - Input Voltage - V  
I
5
5.5  
6
T
- Junction Temperature - °C  
J
6-17. Supply Current vs Input Voltage  
6-18. PWRGD Threshold vs Junction  
Temperature  
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100  
100  
90  
80  
70  
60  
50  
40  
30  
20  
Vin = 5 V,  
SS = 0.4 V  
Vin = 3.3 V  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
10  
0
-50  
-25  
0
25  
50  
75  
100  
125  
150  
-50  
-25  
0
25  
T - Junction Temperature - °C  
J
50  
75  
100  
125  
150  
T
- Junction Temperature - °C  
J
6-19. PWRGD ON-Resistance  
6-20. SS/TR to VSENSE Offset  
vs Junction Temperature  
vs Junction Temperature  
100  
100  
95  
90  
85  
80  
75  
70  
65  
60  
95  
90  
85  
80  
75  
70  
65  
60  
55  
Vout = 3.3 V  
Vout = 1.8 V  
Vout = 1.8 V  
Vout = 1.05 V  
Vout = 1.05 V  
Vin = 5 V,  
f
Vin = 3.5 V,  
= 1 MHz,  
f
= 1 MHz,  
T = 25°C  
J
s
s
55  
50  
T
= 25°C  
J
50  
0
1
2
3
4
5
6
0
1
2
3
4
5
6
Output Current - A  
Output Current - A  
6-21. Efficiency vs Load Current  
6-22. Efficiency vs Load Current  
100  
95  
90  
85  
80  
75  
70  
65  
60  
100  
95  
90  
85  
80  
75  
70  
65  
60  
Vout = 3.3 V  
Vout = 1.8 V  
Vout = 1.8 V  
Vout = 1.05 V  
Vout = 1.05 V  
Vin = 5 V,  
= 500 kHz,  
Vin = 3.5 V,  
f
f
= 500 kHz,  
T = 25°C  
J
s
s
55  
50  
55  
50  
T
= 25°C  
J
0
1
2
3
4
5
6
0
1
2
3
4
5
6
Output Current - A  
Output Current - A  
6-23. Efficiency vs Load Current  
6-24. Efficiency vs Load Current  
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7 Detailed Description  
7.1 Overview  
The TPS54618C-Q1 is a 6-V, 6-A, synchronous step-down (buck) converter with two integrated n-channel  
MOSFETs. To improve performance during line and load transients, the device implements a constant frequency,  
peak current mode control which reduces output capacitance and simplifies external frequency compensation  
design. The wide switching frequency range of 200 kHz to 2000 kHz allows for efficiency and size optimization  
when selecting the output filter components. The switching frequency is adjusted using a resistor to ground on  
the RT/CLK pin. The device has an internal phase lock loop (PLL) on the RT/CLK pin that is used to synchronize  
the power switch turnon to a falling edge of an external system clock.  
The TPS54618C-Q1 has a typical default start-up voltage of 2.45 V. The EN pin has an internal pullup current  
source that can be used to adjust the input voltage undervoltage lockout (UVLO) with two external resistors. In  
addition, the pullup current provides a default condition when the EN pin is floating for the device to operate. The  
total operating current for the TPS54618C-Q1 is typically 515 μA when not switching and under no load. When  
the device is disabled, the supply current is less than 5.5 μA.  
The integrated 12-mMOSFETs allow for high efficiency power supply designs with continuous output currents  
up to 6 A.  
The TPS54618C-Q1 reduces the external component count by integrating the boot recharge diode. The bias  
voltage for the integrated high-side MOSFET is supplied by a capacitor between the BOOT and PH pins. The  
boot capacitor voltage is monitored by an UVLO circuit and turns off the high-side MOSFET when the voltage  
falls below a preset threshold. This BOOT circuit allows the TPS54618C-Q1 to operate approaching 100%. The  
output voltage can be stepped down to as low as the 0.799-V reference.  
The TPS54618C-Q1 has a power-good comparator (PWRGD) with 2% hysteresis.  
The TPS54618C-Q1 minimizes excessive output overvoltage transients by taking advantage of the overvoltage  
power-good comparator. When the regulated output voltage is greater than 109% of the nominal voltage, the  
overvoltage comparator is activated, and the high-side MOSFET is turned off and masked from turning on until  
the output voltage is lower than 107%.  
The SS/TR (slow start/tracking) pin is used to minimize inrush currents or provide power supply sequencing  
during power up. A small value capacitor must be coupled to the pin for slow start. The SS/TR pin is discharged  
before the output power up to ensure a repeatable restart after an overtemperature fault, UVLO fault, or disabled  
condition.  
The use of a frequency foldback circuit reduces the switching frequency during start-up and over current fault  
conditions to help limit the inductor current.  
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7.2 Functional Block Diagram  
PWRGD EN  
VIN  
Thermal  
UVLO  
i1  
iHYS  
Shutdown  
93%  
Logic  
Enable  
Comparator  
107%  
Shutdown  
Logic  
Boot  
Charge  
Voltage  
Reference  
Enable  
Threshold  
Boot  
UVLO  
VSENSE  
SS  
+
+
BOOT  
Minimum  
COMP Clamp  
Shutdown  
Logic  
PWM  
Comparator  
Logic and  
PWM Latch  
COMP  
PH  
Slope  
Compensation  
Frequency  
Shift  
GND  
Overload  
Recovery  
Maximum  
Clamp  
OSC with  
PLL  
AGND  
PowerPad  
RT/CLK  
7.3 Feature Description  
7.3.1 Fixed Frequency PWM Control  
The TPS54618C-Q1 uses an adjustable, fixed frequency, peak current mode control. The output voltage is  
compared through external resistors on the VSENSE pin to an internal voltage reference by an error amplifier  
which drives the COMP pin. An internal oscillator initiates the turnon of the high-side power switch. The error  
amplifier output is compared to the high-side power switch current. When the power switch current reaches the  
COMP voltage level, the high-side power switch is turned off and the low-side power switch is turned on. The  
COMP pin voltage increases and decreases as the output current increases and decreases. The device  
implements a current limit by clamping the COMP pin voltage to a maximum level and also implements a  
minimum clamp for improved transient response performance.  
7.3.2 Slope Compensation and Output Current  
The TPS54618C-Q1 adds a compensating ramp to the switch current signal. This slope compensation prevents  
subharmonic oscillations as duty cycle increases. The available peak inductor current remains constant over the  
full duty cycle range.  
7.3.3 Bootstrap Voltage (Boot) and Low Dropout Operation  
The TPS54618C-Q1 has an integrated boot regulator and requires a small ceramic capacitor between the BOOT  
and PH pin to provide the gate drive voltage for the high-side MOSFET. The value of the ceramic capacitor must  
be 0.1 μF. A ceramic capacitor with an X7R or X5R grade dielectric with a voltage rating of 10 V or higher is  
recommended because of the stable characteristics over temperature and voltage.  
To improve dropout, the TPS54618C-Q1 is designed to operate at 100% duty cycle as long as the BOOT-to-PH  
pin voltage is greater than 2.2 V. The high-side MOSFET is turned off using a UVLO circuit, allowing for the low-  
side MOSFET to conduct when the voltage from BOOT to PH drops below 2.2 V. Because the supply current  
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sourced from the BOOT pin is very low, the high-side MOSFET can remain on for more switching cycles than are  
required to refresh the capacitor, thus the effective duty cycle of the switching regulator is very high.  
7.3.4 Error Amplifier  
The TPS54618C-Q1 has a transconductance amplifier. The error amplifier compares the VSENSE voltage to the  
lower of the SS/TR pin voltage or the internal 0.799-V voltage reference. The transconductance of the error  
amplifier is 245 μA/V during normal operation. When the voltage of VSENSE pin is below 0.799 V and the  
device is regulating using the SS/TR voltage, the gm is typically greater than 79 μA/V, but less than 245 μA/V.  
The frequency compensation components are placed between the COMP pin and ground.  
7.3.5 Voltage Reference  
The voltage reference system produces a precise ±1% voltage reference over temperature by scaling the output  
of a temperature-stable bandgap circuit. The bandgap and scaling circuits produce 0.799 V at the noninverting  
input of the error amplifier.  
7.3.6 Adjusting the Output Voltage  
The output voltage is set with a resistor divider from the output node to the VSENSE pin. TI recommends using  
divider resistors with 1% tolerance or better. Pick a suitable value for the R1 resistor and use 方程式 1 to  
calculate R2. To improve efficiency at very light loads, consider using larger value resistors. If the values are too  
high, the regulator is more susceptible to noise and voltage errors from the VSENSE input current are  
noticeable.  
æ
ç
è
ö
÷
ø
0.799 V  
R2 = R1 ´  
VO - 0.799 V  
(1)  
TPS54618C-Q1  
VOUT  
R1  
VSENSE  
+
0.799 V  
R2  
7-1. Voltage Divider Circuit  
7.3.7 Enable and Adjusting Undervoltage Lockout  
The TPS54618C-Q1 is disabled when the VIN pin voltage falls below 2.28 V. If an application requires a higher  
undervoltage lockout (UVLO), use the EN pin as shown in 7-2 to adjust the input voltage UVLO by using two  
external resistors. TI recommends using the EN resistors to set the UVLO falling threshold (VSTOP) above 2.6 V.  
The rising threshold (VSTART) must be set to provide enough hysteresis to allow for any input supply variations.  
The EN pin has an internal pullup current source that provides the default condition of the TPS54618C-Q1  
operating when the EN pin floats. Once the EN pin voltage exceeds 1.25 V, an additional 1.6 μA of hysteresis is  
added. When the EN pin is pulled below 1.18 V, the 1.6 μA is removed. This additional current facilitates input  
voltage hysteresis.  
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TPS54618C-Q1  
Ih 1.6 µA  
Ip 1.9  
µA  
VIN  
EN  
R1  
R2  
+
7-2. Adjustable Undervoltage Lockout  
- VSTOP  
æ
ç
è
ö
÷
ø
VENFALLING  
VENRISING  
VSTART  
R1 =  
æ
ö
÷
ø
VENFALLING  
I
1-  
+I  
p ç  
h
VENRISING  
è
(2)  
(3)  
vertical spacer  
R1´ VENFALLING  
VSTOP - VENFALLING + R1(Ip + Ih )  
R2 =  
where  
R1 and R2 are in Ω  
Ih = 1.6 µA  
Ip = 1.9 µA  
VENRISING = 1.25 V  
VENFALLING = 1.18 V  
7.3.8 Soft-Start Pin  
The TPS54618C-Q1 regulates to the lower of the SS/TR pin and the internal reference voltage. A capacitor on  
the SS/TR pin to ground implements a slow-start time. The TPS54618C-Q1 has an internal pullup current source  
of 2 μA, which charges the external slow-start capacitor. 方程式 4 calculates the required slow-start capacitor  
value.  
Tss(mS) ´ Iss(mA)  
Css(nF) =  
Vref(V)  
(4)  
where  
Tss is the desired slow-start time in ms  
Iss is the internal slow-start charging current of 2 μA  
Vref is the internal voltage reference of 0.799 V  
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If, during normal operation, the VIN goes below UVLO, the EN pin pulls below 1.2 V, or a thermal shutdown  
event occurs, the TPS54618C-Q1 stops switching. When the VIN goes above UVLO, EN is released or pulled  
high, or a thermal shutdown is exited, then SS/TR is discharged to below 40 mV before reinitiating a powering-  
up sequence. The VSENSE voltage follows the SS/TR pin voltage with a 54-mV offset up to 85% of the internal  
voltage reference. When the SS/TR voltage is greater than 85% on the internal reference voltage, the offset  
increases as the effective system reference transitions from the SS/TR voltage to the internal voltage reference.  
7.3.9 Sequencing  
Many of the common power supply sequencing methods can be implemented using the SS/TR, EN, and  
PWRGD pins. The sequential method can be implemented using an open-drain or collector output of a power-on  
reset pin of another device. 7-3 shows the sequential method. The power good is coupled to the EN pin on  
the TPS54618C-Q1 which enables the second power supply once the primary supply reaches regulation.  
Ratio-metric start-up can be accomplished by connecting the SS/TR pins together. The regulator outputs ramp  
up and reach regulation at the same time. When calculating the slow-start time, the pullup current source must  
be doubled in 方程4. The ratio-metric method is shown in 7-5.  
TPS54618C-Q1  
PWRGD  
TPS54618C-Q1  
EN1  
EN  
SS  
EN  
SS/TR  
PWRGD  
EN2  
CSS  
CSS  
VO1  
VO2  
7-3. Sequential Start-Up Sequence  
7-4. Sequential Start-Up  
Using EN and PWRGD  
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TPS54618C-Q1  
EN  
EN  
SS  
SS  
CSS  
PWRGD  
VO1  
VO2  
TPS54618C-Q1  
EN  
SS  
PWRGD  
7-6. Ratio-Metric Start-Up  
7-5. Schematic for Ratio-Metric Start-Up  
Sequence  
space  
Ratio-metric and simultaneous power supply sequencing can be implemented by connecting the resistor network  
of R1 and R2 shown in 7-7 to the output of the power supply that needs to be tracked or another voltage  
reference source. Using 方程式 5 and 方程式 6, the tracking resistors can be calculated to initiate the Vout2  
slightly before, after, or at the same time as Vout1. 方程式 7 is the voltage difference between Vout1 and Vout2.  
The ΔV variable is zero volts for simultaneous sequencing. To minimize the effect of the inherent SS/TR to  
VSENSE offset (Vssoffset) in the slow-start circuit and the offset created by the pullup current source (Iss) and  
tracking resistors, the Vssoffset and Iss are included as variables in the equations. To design a ratio-metric start-  
up in which the Vout2 voltage is slightly greater than the Vout1 voltage when Vout2 reaches regulation, use a  
negative number in 方程式 5 through 方程式 7 for ΔV. 方程式 7 results in a positive number for applications  
which the Vout2 is slightly lower than Vout1 when Vout2 regulation is achieved. Because the SS/TR pin must be  
pulled below 40 mV before starting after an EN, UVLO, or thermal shutdown fault, careful selection of the  
tracking resistors is needed to ensure the device restarts after a fault. Make sure the calculated R1 value from 方  
程式 5 is greater than the value calculated in 方程式 8 to ensure the device can recover from a fault. As the  
SS/TR voltage becomes more than 85% of the nominal reference voltage the Vssoffset becomes larger as the  
slow-start circuits gradually handoff the regulation reference to the internal voltage reference. The SS/TR pin  
voltage needs to be greater than 1.1 V for a complete hand off to the internal voltage reference as shown in 图  
7-6.  
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space  
Vout2 + DV  
Vssoffset  
Iss  
R1 =  
´
Vref  
(5)  
space  
R2 =  
Vref ´ R1  
Vout2 + DV - Vref  
(6)  
(7)  
(8)  
space  
DV = Vout1 - Vout2  
space  
R1> 2930´ Vout1-145´DV  
space  
TPS54618C-Q1  
EN  
VOUT(1)  
EN1  
SS/TR  
PWRGD  
CSS  
SS2  
Vout1  
Vout2  
TPS54618C-Q1  
VOUT(2)  
EN  
R1  
SS/TR  
R2  
PWRGD  
7-8. Ratio-Metric Start-Up Using Coupled SS/TR  
7-7. Ratio-Metric and Simultaneous Start-Up  
Pins  
Sequence  
7.3.10 Constant Switching Frequency and Timing Resistor (RT/CLK Pin)  
The switching frequency of the TPS54618C-Q1 is adjustable over a wide range from 300 kHz to 2000 kHz by  
placing a maximum of 700 kand minimum of 85 k, respectively, on the RT/CLK pin. An internal amplifier  
holds this pin at a fixed voltage when using an external resistor to ground to set the switching frequency. The  
RT/CLK is typically 0.5 V. To determine the timing resistance for a given switching frequency, use the curve in 方  
9 or 方程10.  
235892  
RT kW =  
( )  
1.027  
fSW kHz  
(
)
(9)  
space  
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171032  
f
kHz =  
( )  
SW  
0.974  
RT kW  
( )  
(10)  
To reduce the solution size, you would typically set the switching frequency as high as possible, but tradeoffs of  
the efficiency, maximum input voltage, and minimum controllable ON-time must be considered.  
The minimum controllable ON-time is typically 75 ns at full current load and 120 ns at no load, and limits the  
maximum operating input voltage or output voltage.  
7.3.11 Overcurrent Protection  
The TPS54618C-Q1 implements a cycle-by-cycle current limit. During each switching cycle, the high-side switch  
current is compared to the voltage on the COMP pin. When the instantaneous switch current intersects the  
COMP voltage, the high-side switch is turned off. During overcurrent conditions that pull the output voltage low,  
the error amplifier responds by driving the COMP pin high, increasing the switch current. The error amplifier  
output is clamped internally. This clamp functions as a switch current limit.  
7.3.12 Frequency Shift  
To operate at high switching frequencies and provide protection during overcurrent conditions, the TPS54618C-  
Q1 implements a frequency shift. If frequency shift was not implemented during an overcurrent condition, the  
low-side MOSFET may not be turned off long enough to reduce the current in the inductor, causing a current  
runaway. With frequency shift during an overcurrent condition, the switching frequency is reduced from 100%,  
then 50%, then 25%, as the voltage decreases from 0.799 to 0 V on VSENSE pin to allow the low-side MOSFET  
to be off long enough to decrease the current in the inductor. During start-up, the switching frequency increases  
as the voltage on VSENSE increases from 0 to 0.799 V.  
7.3.13 Reverse Overcurrent Protection  
The TPS54618C-Q1 implements low-side current protection by detecting the voltage across the low-side  
MOSFET. When the converter sinks current through its low-side FET, the control circuit turns off the low-side  
MOSFET if the reverse current is typically more than 4.5 A. By implementing this additional protection scheme,  
the converter is able to protect itself from excessive current during power cycling and start-up into prebiased  
outputs.  
7.3.14 Synchronize Using the RT/CLK Pin  
The RT/CLK pin is used to synchronize the converter to an external system clock. See 7-9. To implement the  
synchronization feature in a system, connect a square wave to the RT/CLK pin with an ON-time of at least  
75 ns. If the pin is pulled above the PLL upper threshold, a mode change occurs and the pin becomes a  
synchronization input. The internal amplifier is disabled and the pin is a high impedance clock input to the  
internal PLL. If clocking edges stop, the internal amplifier is re-enabled and the mode returns to the frequency  
set by the resistor. The square wave amplitude at this pin must transition lower than 0.6 V and higher than 1.6 V  
typically. The synchronization frequency range is 300 kHz to 2000 kHz. The rising edge of the PH is  
synchronized to the falling edge of RT/CLK pin.  
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TPS54618C-Q1  
PLL  
SYNC Clock  
RT/CLK  
RRT  
PH  
7-9. Synchronizing to a System Clock  
7-10. Plot of Synchronizing to System Clock  
7.3.15 Power Good (PWRGD Pin)  
The PWRGD pin output is an open-drain MOSFET. The output is pulled low when the VSENSE voltage enters  
the fault condition by falling below 91% or rising above 109% of the nominal internal reference voltage. There is  
a 2% hysteresis on the threshold voltage, so when the VSENSE voltage rises to the good condition above 93%  
or falls below 107% of the internal voltage reference, the PWRGD output MOSFET is turned off. TI recommends  
using a pullup resistor between the values of 1 kand 100 kto a voltage source that is 6 V or less. The  
PWRGD is in a valid state once the VIN input voltage is greater than 1.5 V.  
7.3.16 Overvoltage Transient Protection  
The TPS54618C-Q1 incorporates an overvoltage transient protection (OVTP) circuit to minimize voltage  
overshoot when recovering from output fault conditions or strong unload transients. The OVTP feature minimizes  
the output overshoot by implementing a circuit to compare the VSENSE pin voltage to the OVTP threshold which  
is 109% of the internal voltage reference. If the VSENSE pin voltage is greater than the OVTP threshold, the  
high-side MOSFET is disabled, preventing current from flowing to the output and minimizing output overshoot.  
When the VSENSE voltage drops lower than the OVTP threshold, the high-side MOSFET is allowed to turn on  
the next clock cycle.  
7.3.17 Thermal Shutdown  
The device implements an internal thermal shutdown to protect itself if the junction temperature exceeds 168°C.  
The thermal shutdown forces the device to stop switching when the junction temperature exceeds the thermal  
trip threshold. Once the die temperature decreases below 150°C, the device reinitiates the power-up sequence  
by discharging the SS pin to below 40 mV. The thermal shutdown hysteresis is 20°C.  
7.4 Device Functional Modes  
7.4.1 Simple Small Signal Model for Peak Current Mode Control  
7-11 shows an equivalent model for the TPS54618C-Q1 control loop which can be modeled in a circuit  
simulation program to check frequency response and dynamic load response. The error amplifier is a  
transconductance amplifier with a gm of 245 μA/V. The error amplifier can be modeled using an ideal voltage  
controlled current source. The resistor R0 and capacitor Co model the open loop gain and frequency response  
of the amplifier. The 1-mV AC voltage source between the nodes a and b effectively breaks the control loop for  
the frequency response measurements. Plotting a/c shows the small signal response of the frequency  
compensation. Plotting a/b shows the small signal response of the overall loop. The dynamic loop response can  
be checked by replacing the RL with a current source with the appropriate load step amplitude and step rate in a  
time domain analysis.  
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TPS54618C-Q1  
PH  
VOUT  
Power Stage  
25 A/V  
a
RESR  
b
R1  
RLOAD  
VSENSE  
COUT  
COMP  
c
+
gM 245 µA/V  
0.799V  
R2  
COUT(ea)  
R3  
C1  
C2  
ROUT(ea)  
7-11. Small Signal Model for Loop Response  
7-11 is a simple, small-signal model that can be used to understand how to design the frequency  
compensation. The TPS54618C-Q1 power stage can be approximated to a voltage-controlled current source  
(duty cycle modulator) supplying current to the output capacitor and load resistor. The control to output transfer  
function is shown in 方程11 and consists of a DC gain, one dominant pole, and one ESR zero. The quotient of  
the change in switch current and the change in COMP pin voltage (node c in 7-11) is the power stage  
transconductance. The gm for the TPS54618C-Q1 is 25 A/V. The low frequency gain of the power stage  
frequency response is the product of the transconductance and the load resistance as shown in 方程式 12. As  
the load current increases and decreases, the low frequency gain decreases and increases, respectively. This  
variation with load can seem problematic at first glance, but the dominant pole moves with load current. The  
combined effect is highlighted by the dashed line in the right half of 7-13. As the load current decreases, the  
gain increases and the pole frequency lowers, keeping the 0-dB crossover frequency the same for the varying  
load conditions which makes it easier to design the frequency compensation.  
space  
VC  
RESR  
Adc  
RLOAD  
COUT  
gm(ps)  
f
P
f
Z
Frequency  
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7-13. Frequency Response Model for Peak  
7-12. Small Signal Model for Peak Current Mode  
Current Mode Control  
Control  
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æ
ç
è
æ
ç
è
s
ö
÷
ø
ö
÷
ø
1+  
1+  
2p × ¦z  
vo  
vc  
= Adc ´  
s
2p × ¦p  
(11)  
(12)  
Adc = gmps ´ RL  
1
¦p =  
COUT ´ RL ´ 2p  
(13)  
space  
¦z =  
1
COUT ´ RESR ´ 2p  
(14)  
7.4.2 Small Signal Model for Frequency Compensation  
The TPS54618C-Q1 uses a transconductance amplifier for the error amplifier and readily supports two of the  
commonly used frequency compensation circuits. The compensation circuits are shown in 7-14. The Type-2  
circuits are most likely implemented in high-bandwidth power supply designs using low-ESR output capacitors.  
In Type 2A, one additional high-frequency pole is added to attenuate high-frequency noise.  
VOUT  
TPS54618C-Q1  
R1  
VSENSE  
gM(ea)  
COMP  
VREF  
+
R2  
R3  
C1  
R3  
C2  
ROUT(ea)  
COUT(ea)  
5 pF  
C1  
Type IIA  
Type IIB  
7-14. Types of Frequency Compensation  
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The design guidelines for TPS54618C-Q1 loop compensation are as follows:  
1. The modulator pole, fpmod, and the esr zero, fz1, must be calculated using 方程15 and 方程16.  
Derating the output capacitor (COUT) can be needed if the output voltage is a high percentage of the  
capacitor rating. Use the capacitor manufacturer information to derate the capacitor value. Use 方程17  
and 方程18 to estimate a starting point for the crossover frequency, fc. 方程17 is the geometric mean  
of the modulator pole and the esr zero and 方程18 is the mean of modulator pole and the switching  
frequency. Use the lower value of 方程17 or 方程18 as the maximum crossover frequency.  
Ioutmax  
¦p mod =  
2p ´ Vout ´ Cout  
(15)  
space  
1
¦z mod =  
2p ´ Resr ´ Cout  
(16)  
space  
¦
=
¦p mod´ ¦z mod  
C
(17)  
(18)  
space  
¦sw  
¦p mod´  
2
¦
=
C
space  
2. R3 can be determined by 方程19:  
2p × ¦c ´ Vo ´ COUT  
R3 =  
gmea ´ Vref ´ gmps  
(19)  
where  
the gmea amplifier gain (245 μA/V)  
gmps is the power stage gain (25 A/V)  
vertical spacer  
3. Place a compensation zero at the dominant pole:  
1
¦p =  
COUT ´ RL ´ 2p  
C1 can be determined by 方程20:  
RL ´ COUT  
C1 =  
R3  
(20)  
space  
4. C2 is optional. It can be used to cancel the zero from the ESR of COUT  
.
Resr ´ COUT  
C2 =  
R3  
(21)  
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8 Application and Implementation  
Note  
以下应用部分的信息不属TI 组件规范TI 不担保其准确性和完整性。客户应负责确定 TI 组件是否适  
用于其应用。客户应验证并测试其设计以确保系统功能。  
8.1 Application Information  
This design example describes a high-frequency switching regulator design using ceramic output capacitors.  
This design is available as the HPA606 evaluation module (EVM).  
8.2 Typical Application  
This section details a high-frequency, 1.8-V output power supply design application with adjusted UVLO.  
8-1. Typical Application Schematic TPS54618C-Q1  
8.2.1 Design Requirements  
The design parameters for the TPS54618C-Q1 are listed in 8-1.  
8-1. Design Parameters  
PARAMETER  
CONDITIONS  
MIN  
TYP  
3.3  
MAX UNIT  
VIN  
Input voltage  
Operating  
3
6
V
V
VOUT  
Output voltage  
1.8  
Transient response  
Maximum output current  
1.5-A to 4.5-A load step  
4%  
ΔVOUT  
IOUT(max)  
6
A
VOUT(ripple) Output voltage ripple  
fSW Switching frequency  
30 mVP-P  
kHz  
1000  
8.2.2 Detailed Design Procedure  
8.2.2.1 Step One: Select the Switching Frequency  
The first step is to decide on a switching frequency for the regulator. Typically, you want to choose the highest  
switching frequency possible because this produces the smallest solution size. The high-switching frequency  
allows for lower valued inductors and smaller output capacitors compared to a power supply that switches at a  
lower frequency. However, the highest switching frequency causes extra switching losses, which hurt the  
performance of the converter. The converter is capable of running from 300 kHz to 2 MHz. Unless a small  
solution size is an ultimate goal, a moderate switching frequency of 1 MHz is selected to achieve both a small  
solution size and a high-efficiency operation. Using 方程式 9, R4 is calculated to be 180 k. A standard 1% 182-  
kvalue was chosen in the design.  
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8.2.2.2 Step Two: Select the Output Inductor  
The inductor selected works for the entire TPS54618C-Q1 input voltage range. To calculate the value of the  
output inductor, use 方程式 22. KIND is a coefficient that represents the amount of inductor ripple current relative  
to the maximum output current. The inductor ripple current is filtered by the output capacitor. Therefore, choosing  
high inductor ripple currents impacts the selection of the output capacitor because the output capacitor must  
have a ripple current rating equal to or greater than the inductor ripple current. In general, the inductor ripple  
value is at the discretion of the designer; however, KIND is normally from 0.1 to 0.3 for the majority of  
applications.  
For this design example, use KIND = 0.3 and the inductor value is calculated to be 0.7 μH. For this design, a  
nearest standard value was chosen: 0.75 μH. For the output filter inductor, it is important that the RMS current  
and saturation current ratings not be exceeded. The RMS and peak inductor current can be found from 方程式  
24 and 方程25.  
For this design, the RMS inductor current is 6.01 A and the peak inductor current is 6.84 A. The chosen inductor  
is a Toko FDV0630-R75M. It has a saturation current rating of 10 A and a RMS current rating of 8.9 A.  
The current flowing through the inductor is the inductor ripple current plus the output current. During power up,  
faults, or transient load conditions, the inductor current can increase above the calculated peak inductor current  
level calculated above. In transient conditions, the inductor current can increase up to the switch current limit of  
the device. For this reason, the most conservative approach is to specify an inductor with a saturation current  
rating equal to or greater than the switch current limit rather than the peak inductor current.  
Vinmax - Vout  
Io ´ Kind  
Vout  
L1 =  
´
Vinmax ´ ¦sw  
(22)  
(23)  
space  
Iripple =  
Vinmax - Vout  
Vout  
´
L1  
Vinmax ´ ¦sw  
space  
æ
ö2  
÷
1
Vo ´ (Vinmax - Vo)  
Vinmax ´ L1 ´ ¦sw  
ILrms = Io2  
+
´
ç
12  
è
ø
(24)  
(25)  
space  
ILpeak = Iout +  
Iripple  
2
8.2.2.3 Step Three: Choose the Output Capacitor  
There are three primary considerations for selecting the value of the output capacitor. The output capacitor  
determines the modulator pole, the output voltage ripple, and how the regulator responds to a large change in  
load current. The output capacitance needs to be selected based on the more stringent of these three criteria.  
The desired response to a large change in the load current is the first criteria. The output capacitor needs to  
supply the load with current when the regulator can not. This situation would occur if there are desired holdup  
times for the regulator where the output capacitor must hold the output voltage above a certain level for a  
specified amount of time after the input power is removed. The regulator is temporarily not able to supply  
sufficient output current if there is a large, fast increase in the current needs of the load such as transitioning  
from no load to a full load. The regulator usually needs two or more clock cycles for the control loop to see the  
change in load current and output voltage and adjust the duty cycle to react to the change. The output capacitor  
must be sized to supply the extra current to the load until the control loop responds to the load change. The  
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output capacitance must be large enough to supply the difference in current for two clock cycles while only  
allowing a tolerable amount of droop in the output voltage. 方程式 26 shows the minimum output capacitance  
necessary to accomplish this.  
For this example, the transient load response is specified as a 3% change in Vout for a load step from 1.5 A  
(25% load) to 4.5 A (75% load). For this example, ΔIout = 4.5 1.5 = 3.0 A and ΔVout = 0.04 × 1.8 = 0.072 V.  
Using these numbers gives a minimum capacitance of 83 μF. This value does not take the ESR of the output  
capacitor into account in the output voltage change. For ceramic capacitors, the ESR is usually small enough to  
ignore in this calculation.  
方程式 27 calculates the minimum output capacitance needed to meet the output voltage ripple specification.  
Where fsw is the switching frequency, Vripple is the maximum allowable output voltage ripple, and Iripple is the  
inductor ripple current. In this case, the maximum output voltage ripple is 30 mV. Under this requirement, 方程式  
27 yields 7 μF.  
space  
2 ´ DIout  
Co >  
¦sw ´ DVout  
(26)  
space  
1
1
Co >  
´
Voripple  
8 ´ ¦sw  
Iripple  
(27)  
where  
• ΔIout is the change in output current  
fsw is the regulators switching frequency  
and ΔVout is the allowable change in the output voltage  
space  
方程式 28 calculates the maximum ESR an output capacitor can have to meet the output voltage ripple  
specification. 方程式 28 indicates the ESR should be less than 18 m. In this case, the ESR of the ceramic  
capacitor is much less than 18 m.  
Additional capacitance de-ratings for aging, temperature and DC bias must be factored in which increases this  
minimum value. For this example, five 22-μF, 10-V X5R ceramic capacitors with 3 mof ESR are used. The  
estimated capacitance after derating by a factor 0.75 is 82.5 µF.  
Capacitors generally have limits to the amount of ripple current they can handle without failing or producing  
excess heat. An output capacitor that can support the inductor ripple current must be specified. Some capacitor  
data sheets specify the RMS (Root Mean Square) value of the maximum ripple current. 方程式 29 can be used  
to calculate the RMS ripple current the output capacitor needs to support. For this application, 方程式 29 yields  
520 mA.  
Voripple  
Resr <  
Iripple  
(28)  
space  
Vout ´ (Vinmax - Vout)  
Icorms =  
12 ´ Vinmax ´ L1 ´ ¦sw  
(29)  
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8.2.2.4 Step Four: Select the Input Capacitor  
The TPS54618C-Q1 requires a high-quality ceramic, type X5R or X7R, input decoupling capacitor of at least 10  
μF of effective capacitance and in some applications, a bulk capacitance. The effective capacitance includes  
any DC bias effects. The voltage rating of the input capacitor must be greater than the maximum input voltage.  
The capacitor must also have a ripple current rating greater than the maximum input current ripple of the  
TPS54618C-Q1. The input ripple current can be calculated using 方程30.  
The value of a ceramic capacitor varies significantly over temperature and the amount of DC bias applied to the  
capacitor. The capacitance variations due to temperature can be minimized by selecting a dielectric material that  
is stable over temperature. X5R and X7R ceramic dielectrics are usually selected for power regulator capacitors  
because they have a high capacitance to volume ratio and are fairly stable over temperature. The output  
capacitor must also be selected with the DC bias taken into account. The capacitance value of a capacitor  
decreases as the DC bias across a capacitor increases.  
For this example design, a ceramic capacitor with at least a 10-V voltage rating is required to support the  
maximum input voltage. For this example, two 10-μF and one 0.1-μF 10-V capacitors in parallel have been  
selected. The input capacitance value determines the input ripple voltage of the regulator. The input voltage  
ripple can be calculated using 方程式 31. Using the design example values (Ioutmax = 6 A, Cin = 20 μF, Fsw =  
1 MHz) yields an input voltage ripple of 149 mV and an RMS input ripple current of 2.94 A.  
Vinmin - Vout  
(
)
Vout  
Icirms = Iout ´  
´
Vinmin  
Vinmin  
(30)  
space  
DVin =  
Ioutmax ´ 0.25  
Cin ´ ¦sw  
(31)  
8.2.2.5 Step Five: Choose the Soft-Start Capacitor  
The slow-start capacitor determines the minimum amount of time it takes for the output voltage to reach its  
nominal programmed value during power up. This is useful if a load requires a controlled voltage slew rate. This  
is also used if the output capacitance is very large and would require large amounts of current to quickly charge  
the capacitor to the output voltage level. The large currents necessary to charge the capacitor may make the  
TPS54618C-Q1 reach the current limit or excessive current draw from the input power supply can cause the  
input voltage rail to sag. Limiting the output voltage slew rate solves both of these problems.  
The slow-start capacitor value can be calculated using 方程式 32. For the example circuit, the slow-start time is  
not too critical because the output capacitor value is 110 μF which does not require much current to charge to  
1.8 V. The example circuit has the slow-start time set to an arbitrary value of 4 ms which requires a 10-nF  
capacitor. In TPS54618C-Q1, Iss is 2.2 μA and Vref is 0.799 V.  
Tss(ms) ´ Iss(mA)  
Css(nF) =  
Vref(V)  
(32)  
8.2.2.6 Step Six: Select the Bootstrap Capacitor  
A 0.1-μF ceramic capacitor must be connected between the BOOT to PH pin for proper operation. TI  
recommends using a ceramic capacitor with X5R or better grade dielectric. The capacitor must have 10-V or  
higher voltage rating.  
8.2.2.7 Step Eight: Select Output Voltage and Feedback Resistors  
For the example design, 100 kwas selected for R6. Using 方程式 33, R7 is calculated as 80 k. The nearest  
standard 1% resistor is 80.6 k.  
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Vref  
R7 =  
R6  
Vo - Vref  
(33)  
8.2.2.7.1 Output Voltage Limitations  
Due to the internal design of the TPS54618C-Q1, there is a minimum output voltage limit for any given input  
voltage. The output voltage can never be lower than the internal voltage reference of 0.799 V. Above 0.799 V,  
the output voltage can be limited by the minimum controllable ON-time. The minimum output voltage in this case  
is given by 方程34.  
Voutmin = Ontimemin´Fsmax ´ Vinmax - loutmin´RDSmin -Ioutmin´ RL + RDSmin  
(
(
)
)
(34)  
where  
Voutmin = minimum achievable output voltage  
Ontimemin = minimum controllable ON-time (75 ns typical. 120 ns no load)  
Fsmax = maximum switching frequency including tolerance  
Vinmax = maximum input voltage  
Ioutmin = minimum load current  
RDSmin = minimum high-side MOSFET ON-resistance (see 6.5)  
RL = series resistance of output inductor  
There is also a maximum achievable output voltage which is limited by the minimum OFF-time. The maximum  
output voltage is given by 方程35.  
Offtimemax  
ts  
tdead  
ts  
æ
ö
æ
ö
Voutmax = Vin´ 1-  
-Ioutmax ´ RDSmax + RI - 0.7 -Ioutmax ´RDSmax ´  
(
) (  
)
ç
÷
ç
÷
è
ø
è
ø
(35)  
where  
Voutmax = maximum achievable output voltage  
Vin = minimum input voltage  
Offtimemax = maximum OFF-time (90 ns typical for adequate margin)  
ts = 1/Fs  
Ioutmax = maximum current  
RDSmax = maximum high-side MOSFET ON-resistance (see 6.5)  
RI = DCR of the inductor  
tdead = dead time (60 ns)  
8.2.2.8 Step Nine: Select Loop Compensation Components  
There are several industry techniques used to compensate DCDC regulators. The method presented here is  
easy to calculate and yields high phase margins. For most conditions, the regulator has a phase margin between  
60 and 90 degrees. The method presented here ignores the effects of the slope compensation that is internal to  
the TPS54618C-Q1. Because the slope compensation is ignored, the actual cross over frequency is usually  
lower than the cross over frequency used in the calculations. Use SwitcherProsoftware for a more accurate  
design.  
To get started, the modulator pole, fpmod, and the esr zero, fz1, must be calculated using 方程式 36 and 方程式  
37. For COUT, the derated capacitance value is 82.5 µF. Use 方程38 and 方程39 to estimate a starting point  
for the crossover frequency, fc. For the example design, fpmod is 6.43 kHz and fzmod is 643 kHz. 方程式 38 is  
the geometric mean of the modulator pole and the esr zero and 方程39 is the mean of modulator pole and the  
switching frequency. 方程式 38 yields 64.3 kHz and 方程式 39 gives 56.7 kHz. The lower value of 方程式 38 or  
方程式 39 is the maximum recommended crossover frequency. For this example, a lower fc value of 40 kHz is  
specified. Next, the compensation components are calculated. A resistor in series with a capacitor is used to  
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create a compensating zero. A capacitor in parallel to these two components forms the compensating pole (if  
needed).  
Ioutmax  
¦p mod =  
2p ´ Vout ´ Cout  
(36)  
space  
1
¦z mod =  
2p ´ Resr ´ Cout  
(37)  
space  
¦
=
¦p mod´ ¦z mod  
C
(38)  
(39)  
space  
¦sw  
¦p mod´  
2
¦
=
C
space  
The compensation design takes the following steps:  
1. Set up the anticipated crossover frequency. Use 方程40 to calculate the resistor value of the  
compensation network. In this example, the anticipated crossover frequency (fc) is 40 kHz. The power stage  
gain (gmps) is 25 A/V and the error amplifier gain (gmea) is 245 μA/V.  
2p × ¦c ´ Vo ´ Co  
R3 =  
Gm ´ Vref ´ VIgm  
(40)  
2. Place compensation zero at the pole formed by the load resistor and the output capacitor. The capacitor of  
the compensation network can be calculated from 方程41.  
Ro ´ Co  
C4 =  
R3  
(41)  
3. An additional pole can be added to attenuate high-frequency noise. In this application, it is not necessary to  
add it.  
From the previously listed procedures, the compensation network includes a 7.50-kresistor and a  
3300-pF capacitor.  
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8.2.3 Application Curves  
100  
90  
100  
90  
Vin = 3.3 V  
Vin = 5 V  
80  
80  
70  
60  
50  
40  
30  
20  
10  
0
Vin = 3 V  
70  
60  
50  
40  
30  
20  
Vin = 5 V  
10  
0
0
1
2
3
4
5
6
0.01  
0.1  
1
10  
Output Current - A  
Output Current - A  
8-2. Efficiency vs Load Current  
8-3. Efficiency vs Load Current  
Vout = 50 mV / div (ac coupled)  
Vin = 2 V / div  
Iout = 2 A / div (1.5 A to 4.5 A load step)  
Vout = 1 V / div  
PWRGD = 2 V / div  
Time = 200 usec / div  
Time = 2 msec / div  
1-A Load Step  
8-4. Transient Response  
8-5. Power Up, VOUT, VIN  
Vout = 10 mV / div (ac coupled)  
EN = 2 V / div  
Vout = 1 V / div  
PH = 2 V / div  
PWRGD = 2 V / div  
Time = 2 msec / div  
Time = 500 nsec / div  
IOUT = 0 A  
8-7. Output Ripple  
8-6. Power Up, VOUT, EN  
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60  
50  
40  
180  
150  
120  
Vin = 100 mV / div (ac coupled)  
30  
20  
90  
60  
10  
30  
0
0
–10  
–30  
PH = 2 V / div  
–20  
–30  
–40  
–50  
–60  
–60  
–90  
–120  
–150  
Gain  
Phase  
–180  
100  
1000  
10k  
Frequency - Hz  
100k  
1M  
Time = 500 nsec / div  
VIN = 3.3. V  
IOUT = 2 A  
IOUT = 2A  
8-9. Closed-Loop Response  
8-8. Input Ripple  
0.4  
0.4  
0.3  
0.3  
0.2  
0.1  
Iout = 3 A  
Vin = 5 V  
0.2  
0.1  
Vin = 3.3 V  
0
-0.1  
-0.2  
-0.3  
-0.4  
0
-0.1  
-0.2  
-0.3  
-0.4  
0
1
2
3
4
5
6
3
3.5  
4
4.5  
5
5.5  
6
Output Current - A  
Input Voltage-V  
8-10. Load Regulation vs Load Current  
8-11. Regulation vs Input Voltage  
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9 Power Supply Recommendations  
These devices are designed to operate from an input voltage supply between 2.95 V and 6 V. This supply must  
be well regulated. Proper bypassing of input supplies and internal regulators is also critical for noise  
performance, as is PCB layout and grounding scheme. See the recommendations in 10.1.  
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TPS54618C-Q1  
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10 Layout  
10.1 Layout Guidelines  
Layout is a critical portion of good power supply design. There are several signal paths that conduct fast  
changing currents or voltages that can interact with stray inductance or parasitic capacitance to generate noise  
or degrade the power supplies performance.  
Minimize the loop area formed by the bypass capacitor connections and the VIN pins. See 10-1 for a PCB  
layout example.  
The GND pins and AGND pin should be tied directly to the power pad under the TPS54618C-Q1 device. The  
power pad must be connected to any internal PCB ground planes using multiple vias directly under the  
device. Additional vias can be used to connect the top-side ground area to the internal planes near the input  
and output capacitors. For operation at full rated load, the top-side ground area along with any additional  
internal ground planes must provide adequate heat dissipating area.  
Place the input bypass capacitor as close to the device as possible.  
Route the PH pin to the output inductor. Because the PH connection is the switching node, place the output  
inductor close to the PH pins. Minimize the area of the PCB conductor to prevent excessive capacitive  
coupling.  
The boot capacitor must also be located close to the device.  
The sensitive analog ground connections for the feedback voltage divider, compensation components, soft-  
start capacitor, and frequency set resistor must be connected to a separate analog ground trace as shown in  
10-1.  
The RT/CLK pin is particularly sensitive to noise so the RT resistor must be located as close as possible to  
the device and routed with minimal trace lengths.  
The additional external components can be placed approximately as shown. It is possible to obtain  
acceptable performance with alternate PCB layouts, however, this layout has been shown to produce good  
results and can be used as a guide.  
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10.2 Layout Example  
VIA to  
Ground  
Plane  
UVLO SET  
RESISTRORS  
VIN  
BOOT  
CAPACITOR  
VIN  
INPUT  
OUTPUT  
INDUCTOR  
VIN  
PH  
PH  
PH  
SS  
VOUT  
BYPASS  
CAPACITOR  
VIN  
OUTPUT  
FILTER  
EXPOSED  
POWERPAD  
AREA  
CAPACITOR  
GND  
GND  
PH  
SLOW START  
CAPACITOR  
FEEDBACK  
RESISTORS  
ANALOG  
GROUND  
TRACE  
FREQUENCY  
SET  
RESISTOR  
COMPENSATION  
NETWORK  
TOPSIDE  
GROUND  
AREA  
VIA to Ground Plane  
10-1. PCB Layout Example  
10.3 Power Dissipation Estimate  
The following formulas show how to estimate the IC power dissipation under continuous conduction mode  
(CCM) operation. The power dissipation of the IC (Ptot) includes conduction loss (Pcon), dead time loss (Pd),  
switching loss (Psw), gate drive loss (Pgd), and supply current loss (Pq).  
Pcon = Io2 × RDS_on_Temp  
(42)  
(43)  
(44)  
where  
IO is the output current (A)  
RDS_on_Temp is the ON-resistance of the high-side MOSFET with given temperature ()  
Pd = ƒsw × Io × 0.7 × 40 × 109  
where  
IO is the output current (A)  
• ƒsw is the switching frequency (Hz)  
Psw = 1/2 × Vin × Io × ƒsw× 13 × 109  
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where  
IO is the output current (A)  
Vin is the input voltage (V)  
• ƒsw is the switching frequency (Hz)  
Pgd = 2 × Vin × ƒsw× 10 × 109  
(45)  
where  
Vin is the input voltage (V)  
• ƒsw is the switching frequency (Hz)  
Pq = Vin × 515 × 106  
(46)  
(47)  
where  
Vin is the input voltage (V)  
Ptot = Pcon + Pd + Psw + Pgd + Pq  
where  
Ptot is the total device power dissipation (W)  
For given TA:  
TJ = TA + Rth × Ptot  
where  
(48)  
TA is the ambient temperature (°C)  
TJ is the junction temperature (°C)  
Rth is the thermal resistance of the package (°C/W)  
For given TJmax = 150°C:  
TAmax = TJmax Rth × Ptot  
where  
(49)  
Ptot is the total device power dissipation (W)  
Rth is the thermal resistance of the package (°C/W)  
TJmax is maximum junction temperature (°C)  
TAmax is maximum ambient temperature (°C)  
There are additional power losses in the regulator circuit due to the inductor AC and DC losses and trace  
resistance that impact the overall efficiency of the regulator.  
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11 Device and Documentation Support  
11.1 Device Support  
11.1.1 Developmental Support  
For developmental support, see the following:  
Evaluation Module for TPS54618C-Q1 Synchronous Step-Down SWIFT™ DC/DC Converter, HPA606  
11.2 接收文档更新通知  
要接收文档更新通知请导航至 ti.com 上的器件产品文件夹。点击订阅更新 进行注册即可每周接收产品信息更  
改摘要。有关更改的详细信息请查看任何已修订文档中包含的修订历史记录。  
11.3 支持资源  
TI E2E中文支持论坛是工程师的重要参考资料可直接从专家处获得快速、经过验证的解答和设计帮助。搜索  
现有解答或提出自己的问题获得所需的快速设计帮助。  
链接的内容由各个贡献者“按原样”提供。这些内容并不构成 TI 技术规范并且不一定反映 TI 的观点请参阅  
TI 使用条款。  
11.4 Trademarks  
SwitcherProand TI E2Eare trademarks of Texas Instruments.  
所有商标均为其各自所有者的财产。  
11.5 静电放电警告  
静电放(ESD) 会损坏这个集成电路。德州仪(TI) 建议通过适当的预防措施处理所有集成电路。如果不遵守正确的处理  
和安装程序可能会损坏集成电路。  
ESD 的损坏小至导致微小的性能降级大至整个器件故障。精密的集成电路可能更容易受到损坏这是因为非常细微的参  
数更改都可能会导致器件与其发布的规格不相符。  
11.6 术语表  
TI 术语表  
本术语表列出并解释了术语、首字母缩略词和定义。  
12 Mechanical, Packaging, and Orderable Information  
The following pages include mechanical, packaging, and orderable information. This information is the most  
current data available for the designated devices. This data is subject to change without notice and revision of  
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.  
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PACKAGE OPTION ADDENDUM  
www.ti.com  
8-Apr-2021  
PACKAGING INFORMATION  
Orderable Device  
Status Package Type Package Pins Package  
Eco Plan  
Lead finish/  
Ball material  
MSL Peak Temp  
Op Temp (°C)  
Device Marking  
Samples  
Drawing  
Qty  
(1)  
(2)  
(3)  
(4/5)  
(6)  
TPS54618CQRTERQ1  
ACTIVE  
WQFN  
RTE  
16  
3000 RoHS & Green  
NIPDAU  
Level-3-260C-168 HR  
-40 to 125  
618CQ  
(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 <=1000ppm threshold. Antimony trioxide based  
flame retardants must also meet the <=1000ppm threshold requirement.  
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.  
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.  
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation  
of the previous line and the two combined represent the entire Device Marking for that device.  
(6)  
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two  
lines if the finish value exceeds the maximum column width.  
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information  
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and  
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.  
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.  
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.  
Addendum-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
3-Jun-2022  
TAPE AND REEL INFORMATION  
REEL DIMENSIONS  
TAPE DIMENSIONS  
K0  
P1  
W
B0  
Reel  
Diameter  
Cavity  
A0  
A0 Dimension designed to accommodate the component width  
B0 Dimension designed to accommodate the component length  
K0 Dimension designed to accommodate the component thickness  
Overall width of the carrier tape  
W
P1 Pitch between successive cavity centers  
Reel Width (W1)  
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE  
Sprocket Holes  
Q1 Q2  
Q3 Q4  
Q1 Q2  
Q3 Q4  
User Direction of Feed  
Pocket Quadrants  
*All dimensions are nominal  
Device  
Package Package Pins  
Type Drawing  
SPQ  
Reel  
Reel  
A0  
B0  
K0  
P1  
W
Pin1  
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant  
(mm) W1 (mm)  
TPS54618CQRTERQ1  
WQFN  
RTE  
16  
3000  
330.0  
12.4  
3.3  
3.3  
1.1  
8.0  
12.0  
Q2  
Pack Materials-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
3-Jun-2022  
TAPE AND REEL BOX DIMENSIONS  
Width (mm)  
H
W
L
*All dimensions are nominal  
Device  
Package Type Package Drawing Pins  
WQFN RTE 16  
SPQ  
Length (mm) Width (mm) Height (mm)  
367.0 367.0 35.0  
TPS54618CQRTERQ1  
3000  
Pack Materials-Page 2  
GENERIC PACKAGE VIEW  
RTE 16  
3 x 3, 0.5 mm pitch  
WQFN - 0.8 mm max height  
PLASTIC QUAD FLATPACK - NO LEAD  
This image is a representation of the package family, actual package may vary.  
Refer to the product data sheet for package details.  
4225944/A  
www.ti.com  
重要声明和免责声明  
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