參數(shù)資料
型號: MAX1830-MAX1831
廠商: Maxim Integrated Products, Inc.
英文描述: 3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal Switches
中文描述: 第3A,1MHz的,低電壓,降壓型穩(wěn)壓器與同步整流和內(nèi)部開關(guān)
文件頁數(shù): 11/13頁
文件大?。?/td> 278K
代理商: MAX1830-MAX1831
M
3A, 1MHz, Low-Voltage, Step-Down Regulators with
Synchronous Rectification and Internal Switches
______________________________________________________________________________________
11
Integrator Amplifier
An internal transconductance amplifier fine tunes the
output DC accuracy. A capacitor, C
COMP
, from COMP
to V
CC
compensates the transconductance amplifier.
For stability, choose C
COMP
= 470pF.
A large capacitor value maintains a constant average
output voltage but slows the loop response to changes
in output voltage. A small capacitor value speeds up
the loop response to changes in output voltage but
decreases stability.
High-Current Thermal Considerations
High ambient temperatures can limit the maximum
current or duty factor of the output current, depending
on the total copper, are connected to the MAX1830/
MAX1831 and available airflow.
Figure 5 shows the maximum recommended continuous
output current vs. ambient temperature. Figure 6 shows
the maximum recommended output current vs. the out-
put current duty cycle at high temperatures. These fig-
ures are based on 0.7in
2
of 1oz copper in free air.
Figure 6 assumes that the output current is a square
wave with a 100Hz frequency. The duty cycle is
defined as the duration of the burst current divided by
the period of the square wave. This figure shows the
limitations for continuous bursts of output current.
Note that if the thermal limitations of the MAX1830/
MAX1831 are exceeded, it enters thermal shutdown to
prevent destructive failure.
Frequency Variation with
Output Current
The operating frequency of the MAX1830/MAX1831 is
determined primarily by t
OFF
(set by R
TOFF
), V
IN
, and
V
OUT
as shown in the following formula:
(
(
However, as the output current increases, the voltage
drop across the NMOS and PMOS switches increases
and the voltage across the inductor decreases. This
causes the frequency to drop. The change in frequency
can be approximated with the following formula:
f
PWM
= -I
OUT
x R
PMOS
/ (V
IN
x t
OFF
)
where R
PMOS
is the resistance of the internal MOSFETs
(50m
typ).
Circuit Layout and Grounding
Good layout is necessary to achieve the MAX1830/
MAX1831s
intended output power level, high efficien-
cy, and low noise. Good layout includes the use of a
ground plane, careful component placement, and cor-
rect routing of traces using appropriate trace widths.
f
V
V
V
t
V
V
V
PWM
IN
OUT
PMOS
+
OFF
IN
PMOS
NMOS
=
)
)
[
]
2.40
2.50
2.60
2.70
2.80
3.00
2.90
3.10
3.30
3.20
3.40
3.50
25
45
TEMPERATURE (
°
C)
35
55
65
75
85
MAX1830/MAX1831
MAXIMUM RECOMMENDED CONTINUOUS
OUTPUT CURRENT vs. TEMPERATURE
O
0.7IN
2
OF 1-OZ COPPER
Figure 5. Maximum Recommended Continuous Output Current
vs.Temperature
2.40
2.60
3.00
2.80
3.20
3.40
0
40
20
60
80
100
MAXIMUM RECOMMENDED BURST CURRENT
vs. BURST CURRENT DUTY CYCLE
DUTY CYCLE (%)
B
I
OUT
IS A 100Hz SQUARE WAVE
FROM 1A TO THE BURST CURRENT
T
A
= +55
°
C
T
A
= +85
°
C
Figure 6. Maximum Recommended Burst Current vs. Burst
Current Duty Cycle
相關(guān)PDF資料
PDF描述
MAX1830 Replaced by TMS320BC52 :
MAX1831EEE 3A, 1MHz, Low-Voltage, Step-Down Regulators with Synchronous Rectification and Internal Switches
MAX1833ETT30-T High-Efficiency Step-Up Converters with Reverse Battery Protection
MAX1834 High-Efficiency Step-Up Converters with Reverse Battery Protection
MAX1832EUT-T High-Efficiency Step-Up Converters with Reverse Battery Protection
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1831EEE 功能描述:直流/直流開關(guān)調(diào)節(jié)器 RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
MAX1831EEE+ 功能描述:直流/直流開關(guān)調(diào)節(jié)器 3A 1MHz Step-Down RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
MAX1831EEE+T 功能描述:直流/直流開關(guān)調(diào)節(jié)器 3A 1MHz Step-Down RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
MAX1831EEE-T 功能描述:直流/直流開關(guān)調(diào)節(jié)器 RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
MAX1832EUT 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY STEP-UP CONVERTER - Rail/Tube