19-0767; Rev 1; 9/07
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
``````````````````````````````````` ᄂቶ
NBY9754BဵጙఎਈࢯஂLjᏴ1/7Wᒗ)1/:! y! WJO*
ၒ߲पᆍดభᄋᔢࡍ4BࡼঌᏲ࢟ഗăୈᔫ࢟ኹᆐ
3/46Wᒗ4/7WLjऻޟးঌᏲ࢛ਜ਼ઁᒙᆮኹᇹᄻăᏴᑳৈ
ঌᏲĂၒྜྷ࢟ኹਜ਼ᆨࣞܤછपᆍดLjୈၒ߲࢟ኹᇙތ
ࢅ᎖±2&ă
♦ ดᒙ48nΩ SETPO NPTGFU
NBY9754BݧৼࢾຫൈQXNᔫෝါLjఎਈຫൈభᄰ
ਭᅪ࢟ݝᔜᏴ611lI{ᒗ3NI{पᆍดᒙăᔫຫൈᏤ
ཝჿࠣ࢟ྏଐLjᄴဟጐᏤݧቃߛࡁᅪݝᏄୈă
♦ 4Bೌኚၒ߲࢟ഗ
♦ ᏴᑳৈঌᏲĂၒྜྷ࢟ኹਜ਼ᆨࣞपᆍดᄋ±2&ࡼ
ၒ߲றࣞ
♦ 3/46Wᒗ4/7Wᔫ࢟ኹ
♦ ၒ߲࢟ኹᏴ1/7Wᒗ)1/:! y! WJO*ᒄମభࢯ
♦ ྟࣅጴᒜၒྜྷ፻࢟ഗ
ຢดࢅࡴᄰ࢟ᔜࡼoNPTۣᑺᏴ୷ᒮঌᏲሆᄋൈLj
భဧቃࡼ࢟ঢăሤ࣪᎖ॊೂᏄୈஊऱښLjকୈ
ࡼݚገ଼ࡻࣶăܣಽࡼ࢟വݚۇਜ਼୭ᒙۣᑺ
೫ୈᏴቤଐᒦࡼጙࠨᄰਭൈă
♦ 611lI{ᒗ3NI{భࢯఎਈຫൈ
NBY9754B ด >)ࡒ߅ૹݝ25NI{*࢟ኹᇙތहࡍă࢟
ኹෝါ఼ᒜஉ৩ਜ਼ᇙތहࡍᏤဧ JJJ ቯޡݗऱښLj
ણവࡒᔢభࡉࡵఎਈຫൈࡼ31&ă୷ࡼણവຫࡒถ
৫ۣᑺႥၾზሰ።Ljᒑኊ୷ቃࡼၒ߲࢟ྏLjᏤཝჿ
ࠣ࢟ྏଐă
♦ ᅲ۸ࡼਭኹਜ਼ེۣઐถ
NBY9754Bᄋೝৈྯზ൝ၒྜྷLj᎖ኡᐋ:ᒬݙᄴࡼ
ၒ߲࢟ኹăᑚቋᎾࡼၒ߲࢟ኹᆐఱઓᄋ±2&ࡼၒ߲࢟
ኹறࣞLjᇄኊဧڜਣࡼ1/2&றම࢟ᔜăᅪLjᏴनౣ
࣡ဧೝৈᅪ࢟ݝᔜดݝ1/7WᓰĂᏴSFGJOၒྜྷ
࣡ဗଝᅪݝᓰ࢟ኹLjభጲၒ߲࢟ኹᒙᏴྀੜઓኊ
ገࡼၫᒋăNBY9754Bಽᅪྟ߈ܠྏ࢟ݝࣅဟମLjጲ
ଢ଼ࢅၒྜྷ፻࢟ഗăNBY9754Bݧ35୭Ă5nn y 5nn
ۡቯRGOᇄॖᓤă
``````````````````````````````````` ።
QPM
BTJD0DQV0ETQਖ਼࢟ᏎጲૺJ0P࢟Ꮞ
EES࢟Ꮞ
♦ ᏤဧჿࠣĂᇕጲૺ࢟ஊၒ߲࢟ྏ
♦ WJEኡᐋၒ߲࢟ኹ
1/7Ă1/8Ă1/9Ă2/1Ă2/3Ă2/6Ă2/9Ă3/1ਜ਼3/6W
♦ ڔཝࣅྜྷᎾມᒙၒ߲ᓨზ
♦ భᇢ၃0Ꮞ߲࢟ഗLjး᎖EES።
♦ 35୭Ă5nn! y! 5nnۡቯRGOᇄॖᓤ
``````````````````````````````` ࢾ৪ቧᇦ
PART
TEMP RANGE PIN-PACKAGE
MAX8643AETG+ -40°C to +85°C
PKG
CODE
24 Thin QFN-EP*
T2444-4
(4mm x 4mm)
+ܭာᇄॖᓤă
*FQ! >! ൡă
``````````````````````````` ࢜ቯᔫ࢟വ
INPUT
2.4V, 3.6V
IN
EN
BST
OUTPUT
1.8V, 3A
MAX8643A
LX
ᐶ࢟Ꮞ
VDD
OUT
࢟ቧᎧᆀ࢟Ꮞ
SBJE఼ᒜ࢟Ꮞ
PGND
CTL1
FB
CTL2
FREQ
REFIN
COMP
SS
୭ᒙᏴၫᓾ೯ࡼᔢઁ߲ă
PREBIAS
VDD
PWRGD
GND
________________________________________________________________ Maxim Integrated Products
1
۾ᆪဵNbyjnᑵါ፞ᆪᓾ೯ࡼፉᆪLjNbyjn࣪ݙडፉᒦࡀᏴࡼތፊᎅࠥޘညࡼࡇᇙঌᐊă༿ᓖፀፉᆪᒦభถࡀᏴᆪᔊᔝᒅ
डፉࡇᇙLjྙኊཀྵཱྀྀੜࠤᎫࡼᓰཀྵቶLj༿ݬఠ Nbyjnᄋࡼ፞ᆪۈᓾ೯ă
Ⴣནॅዹອਜ਼ᔢቤࡼۈၫᓾ೯Lj༿षᆰNbyjnࡼᓍǖxxx/nbyjn.jd/dpn/doă
NBY9754B
``````````````````````````````````` গၤ
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
ABSOLUTE MAXIMUM RATINGS
IN, VDD, PWRGD to GND ......................................-0.3V to +4.5V
COMP, FB, REFIN, OUT,
CTL_, EN, SS, FREQ to GND...................-0.3V to (VDD + 0.3V)
LX Current (Note 1) .....................................................-4A to +4A
BST to LX..................................................................-0.3V to +4V
PGND to GND .......................................................-0.3V to +0.3V
Continuous Power Dissipation (TA = +70°C)
24-Pin TQFN-EP
(derated 27.8mW/°C above +70°C)........................2222.2mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should take care not to exceed
the IC’s package power dissipation limits.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = VDD = 3.3V, VFB = 0.5V, TA = -40°C to +85°C. Typical values are at TA = +25°C, circuit of Figure 1, unless otherwise noted.) (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
3.60
V
IN/VDD
IN and VDD Voltage Range
2.35
VIN = 2.5V
4
VIN = 3.3V
5.5
VIN = 2.5V
1.4
VIN = 3.3V
2
IN Supply Current
fS = 1MHz, no load
(includes gate-drive current)
VDD Supply Current
fS = 1MHz
Total Shutdown Current from IN
and VDD
VIN = VDD = VBST - VLX = 3.6V, VEN = 0V
VDD Undervoltage Lockout
Threshold
LX starts/stops switching
2.3
13
VDD rising
VDD falling
4.6
2
1.8
Deglitching
2.1
1.9
2
mA
mA
μA
V
μs
BST
BST Supply Current
VBST = VDD = VIN = 3.6V,
VLX = 3.6V or 0V, VEN = 0V
TA = +25°C
5
TA = +85°C
10
μA
PWM COMPARATOR
PWM Comparator Propagation
Delay
10mV overdrive
20
ns
VIN = 2.35V to 3.6V
2
V
1.4
V/μs
COMP
COMP Clamp Voltage, High
COMP Slew Rate
PWM Ramp Amplitude
COMP Shutdown Resistance
From COMP to GND, VEN = VSS = 0V
1
V
8
Ω
ERROR AMPLIFIER
Preset Output-Voltage Accuracy
REFIN = SS
FB Regulation Accuracy Using
External Resistors
CTL1 = CTL2 = GND
FB to OUT Resistor
All VID settings except CTL1 = CTL2 = GND
2
-1
Select
from
Table 1
+1
%
0.594
0.600
0.606
V
5
8
11
kΩ
_______________________________________________________________________________________
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
(VIN = VDD = 3.3V, VFB = 0.5V, TA = -40°C to +85°C. Typical values are at TA = +25°C, circuit of Figure 1, unless otherwise noted.) (Note 2)
PARAMETER
CONDITIONS
MIN
Open-Loop Voltage Gain
1kΩ from COMP to GND
Error-Amplifier Unity-Gain
Bandwidth
Parallel 10kΩ, 40pF from COMP to GND (Note 3)
Error-Amplifier Common-Mode
Input Range
14
TYP
MAX
dB
26
MHz
VDD = 2.35V to 2.6V
0
VDD - 1.65
VDD = 2.6V to 3.6V
0
VDD - 1.7
Error-Amplifier Minimum Output
Current
VCOMP = 1V
FB Input Bias Current
VFB = 0.7V, CTL1 = CTL2 =
Sourcing
1000
Sinking
-500
TA = +25°C
-200
UNITS
115
V
μA
-40
nA
CTL_
CTL_ Input Bias Current
VCTL_ = 0V
-7
VCTL_ = VDD
+7
Rising
High-Impedance Threshold
Hysteresis
μA
0.75
V
VDD
- 1.2V
Falling
All VID transitions
50
mV
-100
nA
REFIN
REFIN Input Bias Current
REFIN Common-Mode Range
REFIN Offset Voltage
VREFIN = 0.6V
TA = +25°C
-500
VDD = 2.3V to 2.6V
0
VDD - 1.65
VDD = 2.6V to 3.6V
0
VDD - 1.7
CTL1 = CTL2 = GND, TA = +25°C
-3
+3
V
mV
LX (ALL PINS COMBINED)
LX On-Resistance, High Side
ILX = -2A
LX On-Resistance, Low Side
ILX = 2A
LX Current-Limit Threshold
VIN = 2.5V, high-side sourcing
VIN = VBST - VLX = 2.5V
39
VIN = VBST - VLX = 3.3V
37
VIN = 2.5V
36
VIN = 3.3V
34
4
TA = +25°C
LX Leakage Current
VIN = 3.6V, VEN = VSS = 0V
TA = +85°C
LX Switching Frequency
VIN = 2.5V to 3.3V
Frequency Range
VLX = 0V
VIN = 2.5V to 3.3V
LX Maximum Duty Cycle
RFREQ = 50kΩ, VIN = 2.5V to 3.3V
5.5
VLX = 3.6V
mΩ
A
+2
VLX = 0V
1
VLX = 3.6V
1
RFREQ = 50kΩ
0.9
1
1.1
RFREQ = 23.2kΩ
1.8
2.0
2.2
40
93
LX Minimum On-Time
RMS LX Output Current
55
mΩ
-2
500
LX Minimum Off-Time
58
3
μA
MHz
2000
kHz
75
ns
96
%
80
ns
A
_______________________________________________________________________________________
3
NBY9754B
ELECTRICAL CHARACTERISTICS (continued)
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VDD = 3.3V, VFB = 0.5V, TA = -40°C to +85°C. Typical values are at TA = +25°C, circuit of Figure 1, unless otherwise noted.) (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
1.2
0.7
V
ENABLE
EN Input Logic-Low, Falling
EN Input Logic-High, Rising
1.7
EN Hysteresis
VEN = 0V or 3.6V,
VDD = 3.6V
EN, Input Current
1.4
V
200
mV
TA = +25°C
1
TA = +85°C
0.01
μA
SS
SS Charging Current
VSS = 0.45V
7
8
9
μA
500
Ω
Thermal-Shutdown Threshold
+165
°C
Thermal-Shutdown Hysteresis
20
°C
SS Discharge Resistance
THERMAL SHUTDOWN
POWER-GOOD (PWRGD)
Power-Good Threshold Voltage
VFB falling, 3mV hysteresis
87
Power-Good Falling-Edge Deglitch
90
93
%
Clock
cycles
48
PWRGD Output-Voltage Low
IPWRGD = 4mA
0.03
PWRGD Leakage Current
0.15
V
VDD = VPWRGD = 3.6V, VFB = 0.9V
0.01
μA
Current-Limit Startup Blanking
128
Clock
cycles
Restart Time
1024
Clock
cycles
OVERCURRENT LIMIT
Note 2: Specifications are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by
design and characterization.
Note 3: Guaranteed by design.
`````````````````````````````````````````````````````````````````````` ࢜ቯᔫᄂቶ
(Typical values are at VIN = VDD = 3.3V, VOUT = 1.8V, RFREQ = 50kΩ, IOUT = 3A, and TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT
EFFICIENCY vs. OUTPUT CURRENT
90
80
VOUT = 1.8V
70
VOUT = 1.2V
60
95
90
EFFICIENCY (%)
VOUT = 2.5V
MAX8643A toc02
100
MAX8643A toc01
100
EFFICIENCY (%)
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
85
VOUT = 1.88V
80
VOUT = 1.5V
75
70
50
65
VIN = VDD = 3.3V
40
4
0.1
1
OUTPUT CURRENT (A)
VOUT = 1.2V
10
VIN = VDD = 2.5V
60
0.1
1
OUTPUT CURRENT (A)
_______________________________________________________________________________________
10
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
1800
85
FREQUENCY (kHz)
EFFICIENCY (%)
90
VOUT = 1.8V
80
VOUT = 1.5V
75
VOUT = 1.2V
70
60
0.1
+25°C
+85°C
1650
1500
1350
1200
VIN = 2.5V
VDD = 3.3V
65
-40°C
-40°C
+25°C
+85°C
1050
10
LOAD TRANSIENT
-0.04
VOUT = 2.5V
-0.06
VOUT = 1.8V
-0.08
-0.10
-0.12
-0.14
VOUT = 1.2V
-0.16
900
1
OUTPUT CURRENT (A)
VIN = VDD = 3.3V
-0.02
MAX8643A toc05
1950
0
OUTPUT VOLTAGE CHARGE (%)
MAX8643A toc03
95
LOAD REGULATION
FREQUENCY vs. INPUT VOLTAGE
MAX8643A toc04
EFFICIENCY vs. OUTPUT CURRENT
100
2.2
2.6
3.0
3.4
INPUT VOLTAGE (V)
0
3.8
1
2
3
LOAD CURRENT (A)
4
5
SWITCHING WAVEFORMS
MAX8643A toc07
MAX8643A toc06
VIN = VDD = 3.3V
AC-COUPLED
50mV/div
VOUT
AC-COUPLED
20mV/div
VOUT
2A/div
ILX
0A
VLX
IOUT
2V/div
1A/div
0V
0A
100ns/div
40μs/div
SOFT-START WAVEFORMS
SHUTDOWN WAVEFORMS
MAX8643A toc08
VEN
MAX8643A toc09
2V/div
VEN
2V/div
0V
VOUT
1V/div
0V
VOUT
1V/div
RLOAD = 1Ω
400μs/div
0V
0V
RLOAD = 1Ω
10μs/div
_______________________________________________________________________________________
5
NBY9754B
``````````````````````````````````````````````````````````````````` ࢜ቯᔫᄂቶ)ኚ*
(Typical values are at VIN = VDD = 3.3V, VOUT = 1.8V, RFREQ = 50kΩ, IOUT = 3A, and TA = +25°C, unless otherwise noted.)
````````````````````````````````````````````````````````````````````` ࢜ቯᔫᄂቶ)ኚ*
(Typical values are at VIN = VDD = 3.3V, VOUT = 1.8V, RFREQ = 50kΩ, IOUT = 3A, and TA = +25°C, unless otherwise noted.)
6
6
5
4
3
IOUT
5A/div
3
0A
2
IIN
1
1
1A/div
0A
0
2.4
2.6 2.8 3.0 3.2
INPUT VOLTAGE (V)
3.4
3.6
0.5
1.0
0.30
0.25
0.20
0.15
0.10
90
80
70
60
50
40
30
0.05
20
0
10
2.0
2.5
3.0
3.5
INPUT VOLTAGE (V)
VOUT = 1.8V
3A LOAD
100
0.63
0.62
0.61
0.60
0.59
0.58
0.57
MEASURED ON A MAX8643EVKIT
0
4.0
20
40
60
TEMPERATURE (°C)
SOFT-START WITH REFIN
80
100
0.56
-40
-15
10
35
TEMPERATURE (°C)
STARTING INTO PREBIAS OUTPUT
MAX8643A toc16
IIN
FEEDBACK VOLTAGE vs. TEMPERATURE
0.64
FEEDBACK VOLTAGE (V)
0.35
110
EXPOSED PAD TEMPERATURE (°C)
MAX8643A toc13
0.40
400μs/div
2.5
EXPOSED PAD TEMPERATURE
vs. AMBIENT TEMPERATURE
RMS INPUT CURRENT DURING SHORT CIRCUIT
vs. INPUT VOLTAGE (C4 = 0.022μF)
VOUT = 0V
1.5
2.0
OUTPUT VOLTAGE (V)
MAX8643A toc14
2.2
MAX8643A toc15
0
0.45
1V/div
0V
4
2
0.50
VOUT
5
CURRENT LIMIT (A)
7
MAX8643A toc12
MAX8643A toc11
8
INPUT CURRENT (μA)
7
MAX8643A toc10
VEN = 0V
9
HICCUP CURRENT LIMIT
CURRENT LIMIT vs. OUTPUT VOLTAGE
INPUT CURRENT vs. INPUT VOLTAGE
10
RMS INPUT CURRENT (A)
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
MAX8643A toc17
1A/div
2V/div
VEN
0V
0A
0.5V/div
0V
VREFIN
VOUT
1V/div
0V
VOUT
1V/div
0V
VPWRGD
2V/div
0V
2V/div
VPWRGD
0V
200μs/div
100μs/div
CSS = 6800pF, CO = 122μF, L = 0.56μH, VOUT = 2.5V
6
_______________________________________________________________________________________
60
85
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
୭
߂
ถ
1
PREBIAS
ক୭ኞహLjጲܜྟࣅਭ߈ᒦၒ߲࢟ྏह࢟Ǘ॥ᐌೌᒗHOE! )ݬྟࣅྜྷᎾມᒙၒ߲ ݝॊ*ă
2
VDD
3, 4
CTL1,
CTL2
ၒ߲࢟ኹኡᐋၒྜྷăDUM2ਜ਼DUM3ኡᐋ:ᒬݙᄴࡼᎾၒ߲࢟ኹLjᎾၒ߲࢟ኹݬܭ2ă
5
REFIN
ᅪݝᓰၒྜྷăSFGJOTTဟLjဧดݝ1/7WᓰăSFGJOᅪݝᓰဟLjࢯஂGCᆮࢾᏴSFGJO࢟ኹă
JDࠀ᎖ਈࣥෝါဟLjSFGJOดݝ౯ᒗHOEă
6
SS
7
GND
8
COMP
࢟ኹᇙތहࡍࡼၒ߲ăᏴDPNQᎧGCᒄମೌܘገࡼޡݗᆀLjJDࠀ᎖ਈࣥෝါဟLjDPNQᏴดݝ౯ᒗ
HOEă
9
FB
नౣၒྜྷăGCೌᒗၒ߲ਜ਼HOEᒄମࡼ࢟ᔜॊኹᆀᒦቦߥᄿLjၒ߲࢟ኹభጲᏴ1/7Wᒗ):1& y WJO*पᆍ
ดᒙăDUM2ਜ਼DUM3ኡᐋ:ᒬݙᄴࡼᎾၒ߲࢟ኹဟLjGCᎧၒ߲ᒄମೌSDᆀă
10
OUT
ၒ߲࢟ኹଶހLjೌᒗၒ߲ăဧᅪ࢟ݝᔜॊኹဟLjPVUኞహă
11
FREQ
ᑩຫൈኡᐋăᏴGSFRਜ਼HOEᒄମೌጙৈ࢟ᔜLj᎖ኡᐋఎਈຫൈă
12
PWRGD
13
BST
࢟Ꮞ࢟ኹਜ਼വၒྜྷăᄰਭጙৈ21Ω࢟ᔜೌWEE ᒗJOLjWEE ᒗHOEମೌጙᒑ2μGჿࠣ࢟ྏă
ྟࣅၒྜྷăᏴTTਜ਼HOEᒄମೌጙᒑ࢟ྏLjᒙࣅဟମăᎌਈྟࣅဟମࡼᒙLj༿ݬఠྟࣅਜ਼
SFGJO ݝॊă
ෝผă
࢟Ꮞኙၒ߲LjࡩWGC ≥ WSFGJO ࡼ:1&1/7WဟLjఎധၒ߲ᆐᔜზăWGC ࢅ᎖ࢯஂ࢛ࡼ:1&ဟLj
QXSHEดݝ౯ᒗࢅ࢟ຳăJDࠀ᎖ਈࣥෝါĂWEE WJO ࢅ᎖VWMPඡሢLjᑗJDࠀ᎖ེਈࣥෝါဟLj
QXSHEۻดݝ౯ࢅă
ܟNPTGFUདࣅ࢟ᏎLjݧጙᒑ1/2μG࢟ྏവCTUᒗMYă
࢟ঢೌăჅᎌMY୭ᏴดೌݝᏴጙLjჅᎌMY୭ೌᒗၒ߲࢟ঢăJDࠀ᎖ਈࣥෝါဟLj
MYᆐᔜზă
14, 15, 16
LX
17–20
PGND
21, 22, 23
IN
࢟ᏎၒྜྷLjၒྜྷ࢟Ꮞपᆍᆐ3/46Wᒗ4/7Wăݧጙᒑ33μGჿࠣ࢟ྏᅪݝവᒗQHOELjݬ࢜ቯ።࢟വă
24
EN
ဧถၒྜྷLj൝ၒྜྷ᎖ဧถ0ணᒏNBY9754Bă
—
EP
ൡLjೌᒗࡍෂ૩ށLjጲখ࿖ྲེᄟୈă
ൈLj࠭ᅪݝჅᎌQHOE୭ೌᒗൈă
_______________________________________________________________________________________
7
NBY9754B
````````````````````````````````````````````````````````````````````````````` ୭ႁී
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
``````````````````````````````````````````````````````````````````````````````` ऱౖᅄ
VDD
MAX8643A
UVLO
CIRCUITRY
SHUTDOWN
CONTROL
EN
CURRENT-LIMIT
COMPARATOR
BIAS
GENERATOR
LX
ILIM THRESHOLD
IN
VOLTAGE
REFERENCE
SS
BST
BST CAPACITOR
CHARGING SWITCH
SOFT-START
CONTROL
LOGIC
LX
IN
THERMAL
SHUTDOWN
REFIN
PGND
OUT
ERROR
AMPLIFIER
8kΩ
PWM
COMPARATOR
PREBIAS
FB
CTL1
CTL2
VID
VOLTAGECONTROL
CIRCUITRY
FREQ
1VP-P
OSCILLATOR
COMP
SHDN
COMP LOW
DETECTOR
FB
0.9 x VREFIN
8
PWRGD
_______________________________________________________________________________________
GND
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
INPUT
2.4V TO 3.6V
R1
10Ω
C1
22μF
23
C3
0.1μF
22
VDD
21
2
C5
1μF
IN
BST
IN
IN
MAX8643A
LX
LX
VDD
LX
OUT
C6
0.01μF
PGND
EN
PGND
PGND
GND
3
4
5
6
C8
6800pF
C9
0.1μF
U1
R2
10kΩ
24
13
FB
CTL1
16
15
COMP
SS
PWRGD
PREBIAS
1
GND
7
FREQ
C15
1000pF
L1
0.56μH
14
OUTPUT
1.8V/3A
10
20
R6
100Ω
1%
C10
1500pF
19
18, 17
7
C2
100μF
C4
0.01μF
C14
22μF
9
CTL2
REFIN
R10
2.2Ω
NBY9754B
````````````````````````````````````````````````````````````````````````` ࢜ቯ።࢟വ
8
C11
560pF
R4
18kΩ
VDD
C12
10pF
12
11
R7
24kΩ
1%
R5
20kΩ
ᅄ2/! 2NI{ĂWPVU >! 2/9Wဟࡼཝჿࠣ࢟ྏଐă
``````````````````````````````` ሮᇼႁී
NBY9754BᆐĂ࢟ኹෝါఎਈࢯஂLjభᄋ4Bၒ
߲࢟ഗăNBY9754BᔫᏴ3/46Wᒗ4/7Wၒྜྷ࢟ኹपᆍLj
భጲᄋ 1/7Wᒗ)1/:! y! WJO*ࡼၒ߲࢟ኹLjऻޟးঌᏲ࢛
።ăᏴᑳৈঌᏲĂၒྜྷ࢟ኹਜ਼ᆨࣞܤછपᆍดLjୈ
ၒ߲࢟ኹறࣞᎁ᎖±2&ă
NBY9754Bᎌ୷ࡼఎਈຫൈपᆍLjభጲဣሚཝჿࠣ࢟
ྏଐጲૺႥၾზሰ።ă୷ࡼఎਈຫൈᏤဧቃ
ߛࡁᅪݝᏄୈă NBY9754Bݧቃߛࡁ)5nn! y! 5nn*Ăᇄ
Ă35୭ۡቯRGOॖᓤăSFGJOဧNBY9754Bభಯሯ
᎖EESਜ਼ৌᔍ࢟ᏎLjܟਜ਼ࢅܟఎਈݧดࢅݝS ETPO
)48nΩ*! oࡸNPTGFULjۣߒᏴᒮᏲਜ਼ఎਈຫൈሆᎌ
ൈă
NBY9754Bݧ࢟ኹෝါ఼ᒜஉ৩Ljดᒙࡒ)? 25NI{*ᇙ
ތहࡍă࢟ኹ఼ᒜஉ৩Ꮴࡉ3NI{ࡼఎਈຫൈLjି
ቃ೫࢟വۇෂ૩ă࢟ኹᇙތहࡍݧ JJJ ቯޡݗऱښLj
ߠॊಽఎਈຫൈࡼࡒᎁဴLjࡻႥၾზሰ።ă
భࢯஂࡼྟࣅဟମܣ᎖ഉᒙLjିቃ೫ၒྜྷࣅਭ
߈ࡼ፻࢟ഗăࡩWGC ࡉࡵWSFGJO ࡼ:1&ࢀ᎖1/65WဟLj
࢟Ꮞኙ)QXSHE*ఎധၒ߲ܤᆐ࢟ຳă
఼ᒜถ
఼ᒜ൝࢟വဵࠀಯࡼਖ਼ቦLjࢾݙᄴၒྜྷ࢟
ኹĂঌᏲਜ਼ᆨࣞᄟୈሆܟNPTGFUࡼᐴహ܈ăᑵޟᔫ
ෝါሆLjᎌࡉࡵ࢟ഗሢᒜਜ਼ᆨۣࣞઐᄟୈဟLj఼ᒜ
൝࢟വ၃ QXN ୷܈ࡼၒ߲Ljޘညܟਜ਼ࢅܟ
NPTGFUདࣅቧăሌࣥઁ൝ਜ਼ᔈ࢟ྏࡼߠ࢟ဟኔ
၊఼᎖఼ᒜ൝࢟വă࢟ኹᇙތहࡍޘညࡼᇙތቧ
ᎧᑩޘညࡼቓຸቧᄰਭQXN୷܈ቲ୷܈Lj
ᎅࠥޘညჅኊࡼQXNቧăܟఎਈᏴᑩᒲ໐ࡼఎဪ
ࡴᄰLjࡩቓຸ࢟ኹިਭWDPNQ ࢟ኹި߲ሢഗඡሢဟਈܕă
ႲઁLjᏴᑩࡼထᒲ໐ดLjࢅܟఎਈۣߒࡴᄰă
_______________________________________________________________________________________
9
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
࢟ഗሢᒜ
ดݝܟNPTGFUᎌ6/6B! )࢜ቯᒋ*ख़ᒋ࢟ഗඡሢăࡩ࠭
MYഗ߲ࡼ࢟ഗި߲ࠥඡሢဟLjܟNPTGFUਈܕLjᄴဟ
ࡌఎᄴݛᑳഗăᄴݛᑳഗጙᒇۣߒఎᓨზLjᒇ
ࡵ࢟ঢ࢟ഗࢰൢᒗࢅܟఎਈሢഗඡሢăᑚଢ଼ࢅᐴహ܈
݀ଢ଼ࢅၒ߲࢟ኹLjᒇᒗݙᏳި߲࢟ഗඡሢăNBY9754Bᄰ
ਭࡌᡅෝါܜၒ߲വဟበຢਭེă
ሢഗ໐ମLjྙਫWGC ࢅ᎖531nW݀༦ࢅ᎖ক࢟ຳࡼဟମި
ਭ23μtLjୈྜྷࡌᡅෝါăܟNPTGFUਜ਼ᄴݛᑳഗ
ਈܕLjᄴဟDPNQਜ਼SFGJO࠭ดݝ౯ࢅăྙਫSFGJOਜ਼TT
ೌᏴጙLjᑚೝৈ୭ۻ౯ࢅăୈۣߒকᓨზ2135
ৈဟᒩᒲ໐LjႲઁᏴ239ৈဟᒩᒲ໐ดޞ၂ᒮăྙਫࡴ
ᒘሢഗࡼ৺ᑇጯளஊ߹Ljୈૂআᑵޟᔫă॥ᐌLj
ୈᏳࠨྜྷࡌᡅෝါă
ྟࣅਜ਼SFGJO
NBY9754Bಽభྟ߈ܠࣅሢᒜࣅਭ߈ᒦࡼ፻࢟
ഗă 9μB! )࢜ቯᒋ*࢟ഗᏎ࣪ೌᏴ TT ࡼᅪ࢟ߠྏ࢟ݝă
ྟࣅဟମᎅೌᏴTTᎧHOEᒄମࡼᅪஂࢯྏ࢟ݝLjჅ
ኊ࢟ྏᒋᎅሆါࢾǖ
C=
་ኹჄࢾ)VWMP*
WEE ଢ଼ࢅᒗ3W )࢜ቯᒋ*ጲሆဟLjVWMP࢟വணᒏఎਈࣅ
ᔫăጙࡡWEE ဍᒗ3W )࢜ቯᒋ*ጲLjVWMPஊ߹LjᏳ
ࠨఎဪྟࣅਭ߈ăดᒙ211nWᒣૄLj᎖ጴᒜ൴ߡছཷă
CTU
ܟĂoࡸఎਈࡼᐜདࣅ࢟ኹᎅऽ࢟ྏᔈ࢟വޘညă
ࢅܟNPTGFUࡴᄰဟLjೌᏴCTU୭ਜ਼MY୭ᒄମࡼ
࢟ྏᎅWJO ࢟Ꮞߠ࢟ăࢅܟNPTGFUਈܕဟLjऽ࢟ྏࡼ
࢟ኹࢶଝࡵMY࣡LjᆐดݝܟNPTGFUᄋܘገࡼࡴᄰ
࢟ኹă
ຫൈኡᐋ)GSFR*
ఎਈຫൈభᄰਭ࢟ᔜᏴ611lI{ᒗ3NI{पᆍด߈ܠࢾă
ಽೌᏴGSFRਜ਼HOEᒄମࡼ࢟ᔜ)SGSFR*ᒙJDࡼఎਈ
ຫൈLjSGSFR ଐႯါྙሆǖ
RFREQ =
50kΩ
0.95μs
×(
1
fS
− 0.05μs)
ᒦLjgT ᆐჅገཇࡼఎਈຫൈLjᆡᆐI{ă
8μA × t SS
࢟Ꮞኙၒ߲)QXSHE*
0.6V
ᒦLjuTT ᆐჅኊࡼྟࣅဟମLjᆡᆐăNBY9754Bથ
భጲᅪᓰၒྜྷ)SFGJO*ăJDࢯஂGC࢟ኹLjဧᆮࢾᏴ
SFGJO࢟ኹăݧᅪݝᓰဟLjดྟݝࣅᇄăᅄ3Ⴥ
ာᆐݧᅪݝᓰဟLjဧྟࣅࡼऱजăೌSFGJOᒗ
TTLjጲဧดݝ1/7Wᓰă
QXSHEᆐఎധၒ߲LjࡩWGC ިਭ1/: y WSFGJO ဟܤᆐᔜ
ზăࡩWGC ࢅ᎖ᆮࢾ࢟ኹࡼ:1&݀༦ߒኚᒗ59ৈဟᒩ
ᒲ໐ဟLjQXSHE౯ᒗࢅ࢟ຳăਈࣥෝါሆLjQXSHEᆐࢅ
࢟ຳă
ၒ߲࢟ኹ)߈ܠDUM2ĂDUM3*
ྙܭ2ჅာLjၒ߲࢟ኹᎅDUM2ਜ਼DUM3୭ࡼ൝ᓨზܠ
߈ᒙăDUM2ਜ਼DUM3ᆐྯზၒྜྷǖW EEĂኞహਜ਼HOEă
R1
ܭ2/! DUM2ਜ਼DUM3ၒ߲࢟ኹኡᐋ
REFIN
R2
C
MAX8643A
ᅄ3/! ݧᅪݝᓰဟLj࢜ቯࡼྟࣅဣሚऱज
10
CTL1
CTL2
VOUT (V)
GND
GND
0.6
0.7
VDD
VDD
GND
Unconnected
0.8
GND
VDD
1.0
Unconnected
GND
1.2
Unconnected
Unconnected
1.5
Unconnected
VDD
1.8
VDD
GND
2.0
VDD
Unconnected
2.5
______________________________________________________________________________________
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
ਈࣥෝါ
དࣅFOᒗHOELjጲਈࣥJDLjࠥဟஸზ࢟ഗଢ଼ᒗ23μBጲ
ሆăਈࣥ໐ମLjMY ᆐᔜზăདࣅ FO ᒗ࢟ຳLjဧถ
NBY9754Bă
ེۣઐ
ེਭᏲۣઐ࢟വሢᒜୈࡼᔐLjࡩஉᆨިਭ U K >
,276°DဟLjᆨࣞଶ࢟ހവ༓ᒜୈྜྷਈࣥᓨზLjጲଢ଼
ࢅበᆨࣞăࡩஉᆨሆଢ଼31°DጲઁLjᆨࣞଶ࢟ހവᏳࠨ
ࣅୈLjᏴೌኚਭᏲᄟୈሆޘည൴ߡၒ߲ăེਈࣥ
ਭ߈உၦઁLjᒮቤఎဪྟࣅਭ߈ă
``````````````````````````````` ።ቧᇦ
JOਜ਼WEE བྷẮ
ᆐିᎅ᎖ఎਈຫൈࡴᒘࡼᐅဉLjۣ݀ߒᔢࡼ
NBY9754Bၒ߲றࣞLjᏴWJO ਜ਼QHOEᒄମೌጙᒑ33μG
࢟ྏ࣪ W JO ቲབྷẮLjᄴဟLjᏴ W EE ਜ਼ HOE ᒄମೌ
ጙᒑ2μG࢟ྏ࣪W EE ቲབྷẮăᑚቋ࢟ྏభถణதJD
हᒙă
࢟ঢኡᐋ
ږᑍሆါኡᐋ࢟ঢǖ
L=
VOUT × (VIN − VOUT )
fS × VIN × LIR × IOUT(MAX)
ᒦLjMJSᆐᔢቃᐴహ܈ሆ࢟ঢᆬ݆࢟ഗᎧ൸ঌ࢟ഗࡼ
܈ᒋăገࡻᔢଛቶถਜ਼ᆮࢾቶLjኡᐋMJSဧ᎖31&
ᒗ51&ă
ᏴࢾߛࡁሆLjኡᐋᒇഗ࢟ᔜభถቃࡼ࢟ঢăఠࡵ
ቶถLjᄰޟᄤድᄏࠟበ࢟ঢဵᔢଛኡᐋăݙ൙ݧੜᒬ
ࠟበLjࠟበܘኍᔗ৫ࡍጲۣᑺᏴNBY9754Bࡼ࢟ഗሢᒜ࢛
ۥݙਜ਼ă
ၒ߲࢟ྏኡᐋ
ኡᐋၒ߲࢟ྏࡼਈݬၫᆐ࢟ྏᒋĂFTSĂFTMਜ਼ऄࢾ࢟
ኹࢀăᑚቋݬၫ፬ሰED.EDᓞધࡼᑳᄏᆮࢾቶĂၒ߲
ᆬ݆࢟ኹਜ਼ၾზሰ።ăၒ߲ᆬ݆ဵᎅ᎖ࡀᏴၒ߲࢟ྏ
ᒦࡼ࢟ܤછĂ࢟ྏFTSࡼኹଢ଼ጲૺFTMࡼኹଢ଼ޘည
ࡼăଐႯᎅ᎖ၒ߲࢟ྏĂFTSਜ਼FTMࡼၒ߲࢟ኹᆬ݆ǖ
VRIPPLE = VRIPPLE(C) +
VRIPPLE(ESR) + VRIPPLE(ESL)
ᒦLjᎅ᎖ၒ߲࢟ྏĂFTSਜ਼FTMࡼၒ߲ᆬ݆ॊܰᆐǖ
IP−P
VRIPPLE(C) =
8 x COUT x fS
VRIPPLE(ESR) = IP−P x ESR
I
VRIPPLE(ESL) = P−P x ESL
t ON
I
VRIPPLE(ESL) = P−P x ESL
t OFF
ᒦᔢࡍࡼጙሲă
ख़ᒋ࢟ঢ࢟ഗ)JQ.Q*ྙሆǖ
V − VOUT
V
IP−P = IN
x OUT
fS × L
VIN
ಽᑚቋါኡᐋ߱ဪ࢟ྏLjࡣᔢᒫནᒋገᄰਭ࣪Ꮗቯ
࢟വຶৰ࢟വހ၂ཀྵࢾăᄰޟLjᆬ݆࢟ഗᏗቃࡻࡵࡼ
ၒ߲࢟ኹᆬ݆ጐᏗቃăᎅ᎖࢟ঢᒋဵࢾ࢟ঢᆬ݆࢟ഗ
ࡼፐႤᒄጙLjჅጲݧ୷ࡍࡼ࢟ঢᒋଢ଼ࢅၒ߲࢟ኹᆬ
݆ăဧჿࠣ࢟ྏభጲᏴᓞધఎਈຫൈሆࡻ୷ࢅࡼ
FTSਜ਼FTMăဧჿࠣ࢟ྏဟLjᎅ᎖FTMჅࡼᆬ݆࢟
ኹభጲݙଐă
ঌᏲၾზሰ።ጞ౷᎖Ⴥኡᐋࡼၒ߲࢟ྏăᏴঌᏲၾზሰ
።໐ମLjFTS! y! ΔJ MPBE ᆐၒ߲ၾମܤછăᏴ఼ᒜᔪ
߲न።ᒄ༄Ljၒ߲ມތጙݛ౫ࡍLjན᎖࢟ঢਜ਼ၒ
߲࢟ྏᒋăႲઁLj఼ᒜቲሰ።Ljၒ߲࢟ኹࢯஂᒗ
Ꮎ࢟ኹᒋă఼ᒜሰ።ဟମན᎖ܕણࡒLjৎࡼ
ࡒᎌৎࡼሰ።ဟମLjܜ࢟ኹਭࣶມಭᆮኹᒋLj
ሮᇼดྏ༿ݬఠޡݗଐ ݝॊă
______________________________________________________________________________________
11
NBY9754B
DUM2ਜ਼DUM3ࡼ൝ᓨზܘኍᏴ࢟ᒄ༄ᅲ߅ᒙăጙࡡ
ୈဧถLjݙገখܤDUM2ਜ਼DUM3ăྙਫኊገ࣪ၒ߲࢟ኹ
ቲᒮቤᒙLjኊᒮቤࣅ࢟ᏎFOLj݀ᏴᏳࠨဧถ༄
ᅲ߅ᒮቤ߈ܠă
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
ၒྜྷ࢟ྏኡᐋ
ၒྜྷ࢟ྏᎌᓐ᎖ଢ଼ࢅᔈၒྜྷ࢟Ꮞࡼ࢟ഗख़ᒋLjି೫
JDᒦࡼఎਈᐅဉăᔐၒྜྷ࢟ྏܘኍࢀ᎖ࡍ᎖ሆါଐႯ
ᒋLjጲۣߒၒྜྷᆬ݆࢟ኹᏴᒎࢾपᆍดLj݀༦ဧनౣࡵ
ၒྜྷ࢟Ꮞࡼຫᆬ݆࢟ഗᔢቃǖ
CIN _ MIN =
D x t S x IOUT
VIN − RIPPLE
NBY9754BࡼఎਈຫൈᏤݧჿࠣၒ߲࢟ྏăᎅ᎖ჿ
ࠣ࢟ྏࡼFTSᄰޟ੪ࢅLj࣪።ࠅၒၫഃ࢛ࡼຫൈ᎖
ᆡᐐፄຫൈgDLj݀༦কഃ࢛ݙถޡݗᎅ݆࢟ঢਜ਼ၒ߲࢟
ྏޘညࡼၷ࢛ăၷ࢛ޘညጙৈ51eC0လ۶ຫ߈ࡼᐐፄ
ၱିਜ਼ጙৈ291°0လ۶ຫ߈ࡼሤጤăᇙތहࡍܘኍޡݗ
কᐐፄၱିਜ਼ሤጤLjጲࡻᆮࢾࡼࡒܕણᇹᄻăፐࠥLj
ݧᅄ4ਜ਼ᅄ5ᒦჅာࡼJJJቯޡݗᆀăJJJቯޡݗᎌྯ
ৈ࢛ਜ਼ೝৈഃ࢛Ljᒦጙৈ࢛gQ2`FB ࠀ᎖ഃຫ)ED*Lj
JJJቯࡼޡݗ࢛ਜ਼ഃ࢛ᆡᒙᎅሆါ߲ǖ
ᒦLjWJO.SJQQMF ᆐၒྜྷ࢟ྏჅᏤࡼᔢࡍၒྜྷᆬ݆࢟ኹLj
ፇকᒋࢅ᎖ᔢቃၒྜྷ࢟ኹࡼ3&ăEᆐᐴహ)܈WPVU0WJO*Lj
uT ᆐఎਈᒲ໐)20gT*ă
fZ1_ EA =
Ᏼఎਈຫൈሆࡼၒྜྷ࢟ྏᔜఝ።ቃ᎖ၒྜྷ࢟ᏎࡼᔜఝLj
ဧຫఎਈ࢟ഗ્ݙᄰਭၒྜྷᏎLjऎဵᎅၒྜྷ࢟ྏവă
ᔜఝ࢟Ꮞኊገৎࡍࡼၒྜྷ࢟ྏLjၒྜྷ࢟ྏܘኍߌ၊ఎ
ਈ࢟ഗჅࡼᆬ݆࢟ഗࡼገཇăSNTၒྜྷᆬ݆࢟ഗᎅ
ሆါࢾǖ
IRIPPLE = ILOAD ×
1
2π x R1 x C1
L
COUT
MAX8643A
R3
OUT
C3
CTL1
VOUT × (VIN − VOUT )
VIN
COMP
R4
C2
a) EXTERNAL RESISTOR-DIVIDER
࢟Ꮞࠅၒၫᎅၷ࢛ਜ਼ጙৈഃ࢛ᔝ߅ăၷ࢛ᎅၒ߲
݆࢟ঢMਜ਼ၒ߲݆࢟ྏD P ޘညLjၒ߲݆࢟ྏࡼ
FTSࢾഃ࢛ăၷ࢛ਜ਼ഃ࢛ຫൈᎅሆါ߲ǖ
L
COUT
MAX8643A
R2
OUT
⎛ R + ESR ⎞
2π x L x C O x ⎜ O
⎟
⎝ RO + RL ⎠
1
2π x ESR x CO
VOUT
LX
1
ᒦLjSM ᆐၒ߲࢟ঢࡼEDSਜ਼ดݝఎਈ࢟ᔜSETPO ࡼᔐਜ਼ă
SETPO ࡼ࢜ቯᒋᆐ48nΩăSP ᆐၒ߲ঌᏲ࢟ᔜLjᒋࢀ᎖
ऄࢾၒ߲࢟ኹ߹ጲऄࢾၒ߲࢟ഗăFTSᆐၒ߲݆࢟ྏࡼ
ᔐࢀࠈೊ࢟ᔜăྙਫᎌࣶৈሤᄴࡼၒ߲࢟ྏ݀ೊLj
ါᒦFTSࢀ᎖ৈၒ߲࢟ྏࡼFTS߹ጲၒ߲࢟ྏၫă
12
C1
R1
CTL2
ޡݗଐ
fZ _ ESR =
R2
FB
ᒦLjJSJQQMF ᆐၒྜྷSNTᆬ݆࢟ഗă
fP1_ LC = fP2 _ LC =
VOUT
LX
R3
8kΩ
C3
FB
VOLTAGE
SELECT
CTL1
CTL2
R1
C1
COMP
C2
b) INTERNAL PRESET VOLTAGE
ᅄ4/! JJJቯޡݗᆀ
______________________________________________________________________________________
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
OPEN-LOOP
GAIN
THIRD
POLE
DOUBLE POLE
ᎅ᎖ၒ߲MDၷ࢛ࡼ་ᔜปᄂቶLjJJJቯࡼޡݗೝৈഃ
࢛ຫൈᒙᆐࢅ᎖MDၷ࢛ຫൈLjጲܣᄋᔗ৫ࡼሤᆡ
ᄋဍăೝৈഃ࢛ຫൈᒙᏴMDၷ࢛ຫൈࡼ91&Ljభ
ጲࡻࡵǖ
R1 =
GAIN (dB)
SECOND
POLE
POWER-STAGE
TRANSFER
FUNCTION
C3 =
FIRST AND SECOND ZEROS
1
0.8 x C1
1
0.8 x R 3
x
L x CO x (RO + ESR)
x
L x CO x (RO + ESR)
RL + RO
RL + RO
औৈ࢛ޡݗgQ3`FB ᒙࡵg[`FTSLjࡻࡵǖ
ᅄ5/! JJJቯޡݗာಿ
1
fZ2_EA =
2π x R 3 x C 3
fP3 _ EA =
1
2π x R1 x C2
1
fP2 _ EA =
2π x R2 x C 3
ၤऱ߈᎖D2??D3ਜ਼S4??S3ࡼଣLjকଣᏴࣶၫ።
ᒦ߅ೂăᑚቋ࢛ਜ਼ഃ࢛ࡼᆡᒙᎅ࢟Ꮞࠅၒၫࡼၷ
࢛ਜ਼FTSഃ࢛ࡼຫൈࢾăથဵჅገཇࡼܕણࡒࡼ
ၫăጲሆগၤ೫ଐႯNBY9754BޡݗᏄୈࡼሮᇼݛᒾă
ࡩNBY9754Bࡼၒ߲࢟ኹᆐᎾᒙ࢟ኹဟLjS4ᆐJDด࢟ݝ
ᔜLjS5ࡀݙᏴ)ᅄ4c*ă
Ᏼ࣪NBY9754Bቲᅪ߈ܠݝᒙဟ)ᅄ4b*Ljၒ߲࢟ኹᎅ
ሆါࢾǖ
R4 =
0.6 × R3
(VOUT − 0.6)
ܕણਭഃຫൈgD ።ᏴఎਈຫൈgT ࡼ21&ᒗ31&ᒄମă୷
ࡼਭഃຫൈభጲࡻࡵৎࡼၾზሰ።ăጙࡡg D ኡࢾLjD2
ږᑍሆऱ߈ଐႯǖ
C1 =
1.5625 VIN
R
2 x π x R3 x (1 + L ) × fC
RO
R2 =
CO x ESR
C3
ྯৈ࢛ޡݗᒙࡵఎਈຫൈࡼ203Ljጲࡻጙቋሤ
ᆡᎽăږᑍሆါଐႯD3ǖ
C2 =
1
π x R1 x fS × 2
ࡩਭഃຫൈීመ᎖ၷ࢛ຫൈဟLjၤऱ߈భᄋற
ཀྵࡼޡݗăࡩਭഃຫൈத႒ࢀ᎖ၷ࢛ຫൈဟLjဣଔࡼ
ਭഃຫൈገ᎖ଐႯࡻ߲ࡼຫൈᒋăᏴᑚᒬ༽ౚሆLjଢ଼
ࢅS2ࡼ࢟ᔜᒋభିቃਭഃຫൈăࠥᅪLjྙਫਭഃຫൈࡍ
᎖311lI{ဟLjJJJቯྯࡼޡݗৈ࢛ᒙᏴణதఎਈ
ຫൈࠀLjጲᐐଝሤᆡᎽăS4ࡼᅎୀᒋᆐ3lΩᒗ21lΩă
ᓖፀLjྙਫᒑখܤS5ᔜᒋᒙݙᄴၒ߲Ljણവۣޡݗ
ߒܤݙă
ྟࣅྜྷᎾມᒙၒ߲
QSFCJBT୭ኞహဟLjNBY9754BభྟࣅྜྷᎾມᒙၒ
߲Ljᇄၒ߲࢟ྏह࢟ăᑚᒬݷᔫጐᔫࢯࣅăᆐܜ
ྟࣅਭ߈ᒦ߲ሚၒ߲࢟ኹ൴ߡছཷLj።ཀྵۣ࢟ঢ࢟
ഗᏴྟࣅஉၦઁࠀ᎖ೌኚࡴᄰෝါăᄰਭ൸ᔗሆऱ
߈ဣሚǖ
V
I
CO × O ≥ P−P
t SS
2
______________________________________________________________________________________
13
NBY9754B
COMPENSATION
TRANSFER
FUNCTION
ᒦLjDP ᆐၒ߲࢟ྏĂWP ᆐၒ߲࢟ኹĂuTT ᆐྟࣅဟମLj
ᄰਭྟࣅ࢟ྏDTT ᒙǗJQ.Q ᆐ࢟ঢᆬ݆࢟ഗख़ख़ᒋ)ᎅ
ၒ߲࢟ྏኡᐋ ݝॊཀྵࢾ*ăোݙᄴ።Ljཀྵࢾ೫ᑚቋݬ
ၫᒦࡼጙৈ્፬ሰࡵݬၫࡼኡᐋă ࢜ቯᔫᄂቶ
ݝॊᒦࡼ Tubsujoh! joup! Qsfcjbt! Pvuqvu݆ተ߲೫ၤݬၫ
ኡᐋࡼဣಿăೌQSFCJBT୭ᒗHOELjணᒏᎾມᒙྟ
ࣅถLj݀ဧNBY9754B࣪ၒ߲࢟ྏࡼ࢟ኹቲह࢟Lj
ઁఎဪྟࣅਭ߈ă
5* JOĂMYਜ਼QHOEॊܰೌᒗጙৈ୷ࡍࡼ१ᄵཌᎮLj
ጲۑᓐJDྲེLjጙݛᄋൈਜ਼ޠ໐భణቶă
6* ཀྵۣჅᎌࡼनౣೌሣభถLj݀ᒇೌLjनౣ࢟
ᔜਜ਼ޡݗᏄୈ።భถణதJDहᒙă
7* ຫఎਈஂ࢛ࡼᔓሣ)ྙMY*።কᏐಭැঢࡼෝผཌᎮ
)GCĂDPNQ*ă
``````````````````````````````` ୭ᒙ
QDCݚఠਜ਼ྲེ
PGND
LX
LX
LX
BST
TOP VIEW
PGND
றᇼࡼQDCݚ࣪ࡻࢅᐅĂᆮࢾࡼᔫᓨზऻޟᒮገă
ᆐ೫ࡉࡵᔢଛቶถLjᅎୀݬᑍNBY9754ຶৰݚۇăᆐ
ࡻ୷ੑࡼQDCݚLjኍᔥክሆਖᐌǖ
18
17
16
15
14
13
2* ၒྜྷਜ਼ၒ߲࢟ྏೌᒗൈǗჅᎌ࢟ྏೌ
ᒗቧă
PGND 19
12 PWRGD
PGND 20
11 FREQ
3* W EEĂW JO ਜ਼TT࣡ࡼ࢟ྏభถణதJDहᒙLjሤ።
୭ݧᒇᔓሣăۣߒࣖೂࡼൈ)ೌᒗQHOE*
ਜ਼ቧ)ೌᒗHOE*ă
IN 21
IN 23
2
3
4
5
6
SS
1
REFIN
+
CTL2
*EP
CTL1
EN 24
VDD
4* భถۣߒ༦ࡼࡍ࢟ഗവLjჁఎਈ࢟ഗവLj
݀భถჁቃᎅMYĂၒ߲࢟ྏਜ਼ၒྜྷ࢟ྏተ߅ࡼ
ૄവă
10 OUT
MAX8643A
IN 22
PREBIAS
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
9
FB
8
COMP
7
GND
THIN QFN
*EP = EXPOSED PAD.
``````````````````````````````` በຢቧᇦ
PROCESS: BiCMOS
14
______________________________________________________________________________________
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
24L QFN THIN.EPS
______________________________________________________________________________________
15
NBY9754B
``````````````````````````````````````````````````````````````````````````````````````` ॖᓤቧᇦ
(۾ၫᓾ೯ᄋࡼॖᓤᅄభถဵݙᔢதࡼਖৃLjྙኊᔢதࡼॖᓤᅪተቧᇦLj༿އኯ www.maxim-ic.com.cn/packagesă)
NBY9754B
4BĂ3NI{Ăଢ଼ኹቯࢯஂLjดᒙఎਈ
`````````````````````````````````````````````````````````````````````````````ॖᓤቧᇦ)ኚ*
(۾ၫᓾ೯ᄋࡼॖᓤᅄభถဵݙᔢதࡼਖৃLjྙኊᔢதࡼॖᓤᅪተቧᇦLj༿އኯ www.maxim-ic.com.cn/packagesă)
``````````````````````````````` ኀࢿ಼ဥ
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