參數(shù)資料
型號： MAX8557
廠商： Maxim Integrated Products, Inc.
英文描述： 3-Line To 8-Line Decoders/Demultiplexers 16-CFP -55 to 125
中文描述： 4A、超低輸入電壓LDO穩(wěn)壓器
文件頁數(shù)： 8/11頁
文件大?。?/td> 228K
代理商： MAX8557
M
4A Ultra-Low-Input-Voltage
LDO Regulators
8
_______________________________________________________________________________________
Applic ations Information
Output V oltage S elec tion
The MAX8556/MAX8557 feature an adjustable output
voltage from 0.5V to 3.4V. Set the output voltage using
an external resistor-divider from the output to GND with
FB connected to the center tap as shown in Figures 1
and 2. Choose R3
≤
1k
for light-load stability.
Determine R2 using the following equation:
where V
OUT
is the desired output voltage and V
FB
is 0.5V.
Capac itor S elec tion and
Regulator S tability
Capacitors are required at the MAX8556/MAX8557
inputs and outputs for stable operation over the full
temperature range and with load currents up to 4A.
Connect 2 x 10μF capacitors between IN and GND and
2 x 10μF low equivalent-series-resistance (ESR) capac-
itors between OUT and GND. The input capacitor (C
IN
)
lowers the source impedance of the input supply. If the
MAX8556/MAX8557s’ input is close to the output of the
source supply, a smaller input capacitance can be
used. Otherwise, 2 x 10μF ceramic input capacitors are
recommended. The output capacitor’s (C
OUT
) ESR
affects output noise and may affect output stability. Use
output capacitors with an ESR of 0.05
or less to
ensure stability and optimum transient dropout. For
good output transient performance, use the following
formula to select a minimum output capacitance:
C
OUT
= I
OUT(MAX)
x 1μF / 200mA
Noise, PS RR, and T ransient Response
The MAX8556/MAX8557 are designed to operate with
low dropout voltages and low quiescent currents while
still maintaining low noise, good transient response,
and high AC rejection (see the
Typical Operating
Characteristics
for a plot of Power-Supply Rejection
Ratio (PSRR) vs. Frequency). When operating from
noisy sources, improved supply-noise rejection and
transient response can be achieved by increasing the
values of the input and output bypass capacitors and
through passive filtering techniques. The MAX8556/
MAX8557 load-transient response graphs (see the
Typical Operating Characteristics
) show two compo-
nents of the output response: a DC shift from the output
impedance due to the load current change, and the
transient response. A typical transient overshoot for a
step change in the load current from 40mA to 4A is
40mV. Use an output capacitance from 20μF to 120μF
to attenuate the overshoot.
R
R
x
V
V
OUT
FB
2
3
1
=
IN
7–11
13
14
15
POR
POR
GND
SHUTDOWN
OUT
FB
1–6
12
R1
100k
R2
2k
R3
1k
C1
2 x 10
μ
F
C2
2 x 10
μ
F
18
N.C.
U2
EN
ENABLED
V
IN
1.7V TO3.6V
V
OUT
1.5V AT 4A
MAX8557
Figure
2. MAX8557 Typical Application Circuit
IN
7–11
13
14
15
POK
POK
GND
SHUTDOWN
OUT
FB
1–6
12
R1
100k
R2
1.4k
R3
1k
C1
2 x 10
μ
F
C2
2 x 10
μ
F
18
N.C.
U1
EN
ENABLED
V
1.425V TO3.6V
V
OUT
1.2V AT 4A
MAX8556
Figure
1. MAX8556 Typical Application Circuit
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相關代理商/技術參數(shù)
參數(shù)描述
MAX8557ETE 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX8557ETE+ 功能描述:低壓差穩(wěn)壓器 - LDO 4A Ultra-Low-Input-V LDO Regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX8557ETE+T 功能描述:低壓差穩(wěn)壓器 - LDO 4A Ultra-Low-Input-V LDO Regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX8557ETE-T 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20
MAX8559EBA11+T 功能描述:低壓差穩(wěn)壓器 - LDO Dual 300mA Low-Noise Linear Regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20
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