BLI9184

BLI9184
4.75V to 18V Input, 3.0-A Synchronous Step-Down Converter with +/-1.5% High Accuracy
Features
Applications
3.0-A Output Current
High Efficient Integrated FETs Optimized for
portable application:
85mΩ (High side) and 75mΩ (Low side)
High Efficiency
Up to 96% Efficiency @ 5V Input, 3.3V Output
Up to 94% efficiency @ 12V Input, 3.3V Output
Wide Input Voltage Range: 4.75V to 18V @
3.0-A loading
Wide Output Voltage Range: 0.923V to 14V @
3.0-A loading ( 54Watt output @max)
Low Output Ripple and Allows Ceramic Output
Capacitor
Thermal Shutdown Protection
340-KHz Switching Frequency(fsw)
Cycle By Cycle Over Current Limit
+/-1.5% High Accuracy Feedback Voltage
Wide Range of Applications for Low Voltage
System
Digital TV Power Supply
High Definition Blu-ray Disc Players
Networking Home Terminal
Digital STB
Ideal for Portable Applications
-
Descriptions
The BLI9184 is a current mode synchronous
buck converter, and has a proprietary W-mode™®
Gm curvature circuit that enables fast transient
response, enables the device to adopt to both low
ESR output capacitors, such as POSCAP or
SP-CAP, and ultra-low ESR ceramic capacitors.
The BLI9184 operates from 4.75-V to 18-V Vin
input, and the output voltage can be programmed
between 0.923V to 14v with 3.0A output current,
and +/-1.5% high accuracy output voltage.
Due to 85mΩ (High side) and 75mΩ (Low side)
integrated FETs, the BLI9184 works in high
efficiency (up to 94% @12V Input, 3.3V output) .
Typical Application
Input 4.3V – 18V
C3 10nF
R4 100K
C1
10µF/25V
Ceramic
2
1
L1 10µH
BS
IN
SW
7
EN
FB 5
8
SS COMP
C8
0.47µF
Output
3
6
4
C4
6.8nF
G
R1 26.1K
1%
R2 10K
1%
3.3V
3A
Cout
10µF/4.5V
Ceramic
X2
R3
2.2K
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V1.3
BLI9184
PIN ARRANGEMENT
PIN FUNCTIONS
PIN
Description
NAME
NO.
Details
BS
1
Supply input for high-side NFET gate driver (boost terminal). Connect capacitor from
this pin to SW pin. An internal PN diode is connected between VREG to BS pin.
IN
2
Power input and connected to high side NFET drain
SW
3
Switch node connection between high-side NFET and low-side NFET. Also serve as
inputs to current comparators.
G
4
Signal ground pin, also serve as ground returns for low-side NFET.
FB
5
Converter feedback input. Connect with feedback resistor divider.
COMP
6
Compensation Node. Used to compensate control loop. Connect a series RC
network from COMP to G. In some cases, an additional capacitor is required
EN
7
Enable control input
SS
8
Soft-start control. A external capacitor should be connected to G.
ABOSOLUTE MAXIMUM RATINGS
Over operating free-air temperature range (unless otherwise noted)
ITEMS
NAME
VALUE
UNIT
IN
-0.3 to 20
V
BS
-0.3 to 25
V
SW
-2 to 20
V
SW (10 ns transient)
-2.5 to 21
V
FB,SS,COMP
-0.3 to 5.5
V
EN
-0.3 to 8
V
TJ
Operation Junction
-40 to +150
℃
Tstg
Storage temperature
-55 to +150
℃
Voltage Range
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V1.3
BLI9184
ELECTRICAL CHARACTERISTICS
Over operating free-air temperature range(unless otherwise noted)
VIN=12V, TA=25℃
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
1.3
2.0
mA
2
4
µA
Supply Current
Iin
Operating-non-switching
supply
VIN current, TA=25℃, EN=1.8V,
current
VFB=1.0V
ISDN
Shut Down Supply Current
VEN=0V
VFB
Feedback Voltage
4.3V ≤VIN≤18V
OVP
Feedback Overvoltage Threshold
1.1
V
Aea
Error Amplifier Voltage Gain
1000
V/V
Gea
Error Amplifier Transconductance
900
µA/V
RDS(on)_1
High Side Switch ON Resistance
85
mΩ
RDS(on)_2
Low Side Switch ON Resistance
75
mΩ
Ileakgae
High Side Switch Leakage Current
VEN=0V, VSW=0V
ILM_H
High Side Switch Current Limit
Minimum Duty Cycle
ILM_L
Low Side Switch Current Limit
From Drain to Source
Gcs
0.900
△IC=+/-10µA
0.925
0.95
10
3.8
COMP Voltage to Current Sense
V
µA
4.5
A
1.0
A
3.5
A/V
340
KHz
Transconductance
Fsw_1
Switching Frequency
Fsw_2
Short Circuit Switching Frequency
VFB=0V
100
KHz
Dmax
Maximum Duty Cycle
VFB=1.0V
90
%
TON_min
Minimum ON Time
220
ns
VEN_1
EN Threshold Voltage
VHys_1
EN Threshold voltage’s Hysteresis
VEN_2
EN Lockout Threshold Voltage
VHys_2
EN Lockout Hysteresis
VUVLO
Input
Under
VEN Rising
1.1
1.5
2.0
100
1.8
2.0
mV
2.2
210
Voltage
Lockout
Voltage
Lockout
VIN Rising
3.0
3.6
V
V
mV
4.2
V
Threshold
VHys_3
Input
Under
600
mV
Threshold Hysteresis
Iss
Soft-Start Current
Vss=0V
Tss
Soft-Start Period
Css=0.1µF
TSD
Thermal Shutdown
Page3
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4.25
4.40
4.55
µA
14
ms
160
℃
V1.3
BLI9184
TYPICAL PERFORMANCE CHARACTERISTICS
Vin=12V,Vout=1.2V, L=2.2µH, Cin=10µF, Cout=2X22µF, TA=+25℃
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V1.3
BLI9184
APPLICATION SCHEMATIC (1)
1) With Electrolytic Capacitor
Input 4.75V – 18V
C1
220uF
Electrolytic
C2
10µF/25V
Ceramic
C3
R4 100K
10nF
1
7
L1
2
BS
EN
Output
5V 3.0A
3
SW
IN
5
FB
4
G
22µH
COMP
C4
6.8nF
C5
Optional
1%
SS
8
6
Co2
470Uf/10V
R1 30K
C8
0.47µF
Electrolytic
Co1
10µF/6.3V
Ceramic
R2 6.8K
1%
R3
2.2K
Figure 1
Compatible with main competitors without any external component change!
RECOMMENDED COMPONENT SELECTION
Vout
Cout
R1
R2
1.0V
1.2V
1.8V
2.5V
3.3V
5.0V
12V
470µF/6.3V/Electrolytic
470µF/6.3V/Electrolytic
470µF/6.3V/Electrolytic
470µF/6.3V/Electrolytic
470µF/6.3V/Electrolytic
470µF/10V/Electrolytic
470µF/25V/Electrolytic
1.0K
4.7K
9.7K
12.0K
26.1K
30.0K
62.0K
10K
15K
10K
6.8K
10K
6.8K
5.1K
Page5
R3
(comp)
50 Ω
100 Ω
300 Ω
1.5K Ω
2.2K Ω
2.7K Ω
3.3K Ω
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C4
(comp)
10nF
10nF
6.8nF
6.8nF
6.8nF
6.8nF
6.8nF
C5
(optional)
100pF
100pF
100pF
100pF
100pF
100pF
100pF
L(inductor)
3.3µH
3.3µH
4.7µH
6.8µH
10µH
22µH
47µH
V1.3
BLI9184
APPLICATION SCHEMATIC (2)
2) Fast Transient Response Without Electrolytic Capacitor
Input
4.75V – 18V
C3 10nF
R4 100K
C2
10µF/25V
Ceramic
2
1
L1
BS
IN
2.2µH
4A
Output
3
SW
7
EN
FB
8
SS COMP
C8
0.47µF
5
R1 6.3K
1.20V 3.0A
1%
G
6
Cff
1.0nF
4
C4
1.0nF
C6 & C7
22µF/6.3V
Ceramic
X2
R2 20K
1%
R3
3.0K
Figure 2
RECOMMENDED COMPONENT SELECTION
Vout
1.0V
1.2V
1.8V
2.5V
3.3V
5.0V
1.0V
1.2V
1.8V
2.5V
3.3V
5.0V
Page6
Cout
22µF Ceramic X2
22µF Ceramic X2
22µF Ceramic X2
22µF Ceramic X2
22µF Ceramic X2
22µF Ceramic X2
47µF SP Cap
47µF SP Cap
47µF SP Cap
47µF SP Cap
47µF SP Cap
47µF SP Cap
R1
R2
2.0K
6.3K
19.4K
34.5K
52.2K
89.5K
2.0K
6.3K
19.4K
34.5K
52.2K
89.5K
20K
20K
20K
20K
20K
20K
20K
20K
20K
20K
20K
20K
R3
(comp)
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
3.0K Ω
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C4
(comp)
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
1.0nF
Cff
2.2nF
1.0nF
680pF
680pF
680pF
390pF
2.2nF
1.0nF
680pF
680pF
680pF
390pF
L
inductor)
2.2µH
2.2µH
3.3µH
4.7µH
6.8µH
22µH
2.2µH
2.2µH
3.3µH
4.7µH
6.8µH
22µH
V1.3
BLI9184
APPLICATION NOTES
a) C2 ceramic 电容尽量靠近芯片的 PIN2 和 PIN4 放置;
b) 若使用电解电容做输入电容，C2 必须加入，且须用 100nF 或 1μF 瓷片电容。此电容容值越
大越好。
c) 使用 47µH 电感时，由于每次 switching 传输的能量大，输出需要更大的电容，以使大信号的
反馈环路稳定。使用 47µH 电感时，输出须用大于或等于 330µF 的电解电容作能量 Bulk。
d) 大电流路径尽量短，且尽量与芯片在同一 PCB 层次。避免大电流路径打过孔跨层连接。
e) 若成本可行，在高效率设计中，应尽量使用瓷片电容或较小 ESR（如：30mohm）的电解电
容，效率可有效提升 1%.
f)
EN 脚（第 7 脚）上拉电阻要求不低于 100K 欧。
g) 若多个芯片共享同一输入电容,需调节第 8 脚软起动电容的电容值分时延迟启动各芯片,以规
避多个芯片同时启动对电源输入电容产生冲击。延迟时间：每 100nF 电容延迟 15ms。
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V1.3
BLI9184
PACKAGE INFORMATION
Package
Page8
SOP8
Devices per Tube
100
Devices per reel
2500
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Unit
mm
V1.3