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參數(shù)資料
| 型號(hào)： | MAX8553 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | 4.5V to 28V Input. Synchronous PWM Buck Controllers for DDR Termination and Point-of-Load Applications |
| 中文描述： | 4.5V至28V輸入、同步PWM buck控制器，適合DDR端接和負(fù)載點(diǎn)應(yīng)用 |
| 文件頁數(shù)： | 15/24頁 |
| 文件大小： | 483K |
| 代理商： | MAX8553 |
M
4.5V to 28V Input, Synchronous PWM Buck Controllers
for DDR Termination and Point-of-Load Applications
______________________________________________________________________________________
15
Detailed Description
Internal Linear Regulator
An internal regulator produces the +5V supply (VL) that
powers the PWM controller, MOSFET driver, logic, refer-
ence, and other blocks within the IC. This +5V low-
dropout (LDO) linear regulator supplies up to 35mA for
MOSFET gate-drive and external loads. For supply volt-
ages between +4.5V and +5.5V, connect VL to V+. This
bypasses the VL regulator, which improves efficiency
and allows the IC to function at lower input voltages.
On-Time One-Shot and
Switching Frequency
The heart of the PWM is the one-shot that sets the high-
side switch on-time. This fast, low-jitter, adjustable one-
shot includes circuitry that varies the on-time in
response to both input and output voltages. The high-
side switch on-time is inversely proportional to the input
voltage as measured by the EN/HSD (HSD for the
MAX8554) input, and is directly proportional to the out-
put voltage. This algorithm results in a nearly constant
switching frequency despite the lack of a fixed-fre-
quency clock generator. The switching frequency can
be selected to avoid noise-sensitive regions such as
the 455kHz IF band. Also, with a constant switching fre-
quency, the inductor ripple-current operating point
remains relatively constant, resulting in easy design
methodology and predictable output voltage ripple.
The general formula for the MAX8553 on-time (t
ON
) is:
where V
EN/HSD
and V
OUT
are the voltages measured at
EN/HSD and the output, respectively, and K = 1.7μs.
The value of N depends on the configuration of FSEL
and is listed in
Table
1.
For the MAX8554, the general formula for on-time (t
ON
) is:
where V
HSD
and V
OUT
are the voltages measured at
HSD and the output, respectively, and K = 1.7μs. The
value of N depends on the configuration of FSEL and is
listed in
Table
2.
t
K N
V
V
ON
HSD
OUT
=
×
×
1
t
K N
V
V
ON
EN HSD
/
OUT
=
×
×
1
C4
0.47
μ
F
10V
Q1
IRF7807V
Q2
IRF7821
L1
2.5
μ
H
10A
R6
3
C8
2200pF
R2
12.1k
R3
6.04k
C6
2x470
μ
F
4V
C5
10
μ
F
6.3V
VOUT
PGND
C3
4.7
μ
F
6.3V
D1
CMPSH-3
1.8V AT
8A
17V TO 21V
VIN
C2
470
μ
F
16V
C1
10
μ
F
16V
MAX8554
VL
POK
R1
20k
ON
OFF
C7
0.22
μ
F
10V
R4
61.9k
R5
80.6k
POK
V+
EN
HSD
REF
ILIM
GND
FSEL
VL
BST
DH
LX
DL
PGND
OUT
FB
Figure
3. Typical Application Circuit 3: 19V Input, 1.8V Output at Up to 8A with 300kHz Switching Frequency
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX8553EEE | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX8553EEE+ | 功能描述:電流型 PWM 控制器 4.5-28V Input Synch Buck Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX8553EEE+T | 功能描述:電流型 PWM 控制器 4.5-28V Input Synch Buck Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX8553EEE-T | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| MAX8554EEE | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
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