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參數(shù)資料
| 型號(hào)： | MAX1692EUB |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Low-Noise, 5.5V-Input, PWM Step-Down Regulator |
| 中文描述： | 1.6 A SWITCHING REGULATOR, 840 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | 1.11 MM HEIGHT, UMAX-10 |
| 文件頁(yè)數(shù)： | 9/12頁(yè) |
| 文件大?。?/td> | 150K |
| 代理商： | MAX1692EUB |
M
Low-Noise, 5.5V-Input,
PWM S tep-Down Regulator
_______________________________________________________________________________________
9
Capac itor S elec tion
Choose input- and output-filter capacitors to service
inductor currents with acceptable voltage ripple. The
input-filter capacitor also reduces peak currents and
noise at the voltage source. In addition, connect a low-
ESR bulk capacitor (>10μF suggested) to the input.
Select this bulk capacitor to meet the input ripple
requirements and voltage rating, rather than capacitor
size. Use the following equation to calculate the maxi-
mum RMS input current:
I
RMS
OUT
[V
OUT
(V
IN
- V
OUT
)]
1/2
·
V
IN
When selecting an output capacitor, consider the out-
put-ripple voltage and approximate it as the product of
the ripple current and the ESR of the output capacitor.
V
RIPPLE
=
[V
OUT
(V
IN
- V
OUT
)] /
[2
·
f
OSC
(L) (V
IN
)]
·
ESR
C2
where ESR
C2
is the equivalent-series resistance of the
output capacitor.
The MAX1692’s loop gain is relatively low, enabling the
use of small, low-value output filter capacitors. Higher
values provide improved output ripple and transient
response. Lower oscillator frequencies require a larger-
value output capacitor. When PWM/PFM is used, verify
capacitor selection with light loads during PFM opera-
tion, since output ripple is higher under these condi-
tions. Low-ESR capacitors are recommended.
Capacitor ESR is a major contributor to output ripple
(usually more than 60%). Ordinary aluminum-electrolyt-
ic capacitors have high ESR and should be avoided.
Low-ESR aluminum-electrolytic capacitors are accept-
able and relatively inexpensive. Low-ESR tantalum
capacitors are better and provide a compact solution
for space-constrained surface-mount designs. Do not
exceed the ripple-current ratings of tantalum capaci-
tors. Ceramic capacitors have the lowest ESR overall,
and OS-CON
capacitors have the lowest ESR of the
high-value electrolytic types.
It is generally not necessary to use ceramic or OS-CON
capacitors for the MAX1692; consider them only in very
compact, high-reliability, or wide-temperature applica-
tions where the expense is justified. When using very-
low-ESR capacitors, such as ceramic or OS-CON,
check for stability while examining load-transient
response. The output capacitor is determined by ensur-
ing that the minimum capacitance value and maximum
ESR values are met:
C2 > 2V
REF
(1 + V
OUT
/V
IN(MIN)
) / (V
OUT
·
R
SENSE
·
f
OSC
)
R
ESR
< (R
SENSE
)(V
OUT
) / (V
REF
)
where C2 is the output filter capacitor, V
REF
is the inter-
nal reference voltage of 1.25V, V
IN
(min) is the minimum
input voltage (2.7V), R
SENSE
is the internal sense resis-
tance of 0.1
, and f
OSC
is the internal oscillator fre-
quency (typically 750kHz). These equations provide the
minimum requirements. The value of C2 may need to
be increased for operation at duty-cycle extremes.
Tables 1 and 2 provide recommended inductor and
capacitor sizes at various external sync frequencies.
Table 3 lists suppliers for the various components used
with the MAX1692.
S tandard Applic ation Circ uits
Figures 2 and 3 are standard application circuits opti-
mized for power and board space respectively. The cir-
cuit of Figure 2 is the most general of the two, and
generates 1.8V at 600mA.
The circuit of Figure 3 is optimized for smallest overall
size. Cellular phones are using low voltage for base-
band logic and have critical area and height restric-
tions. This circuit operates from a single Li-ion battery
(2.9V to 4.5V) and delivers up to 200mA at 1.8V. It uses
small ceramic capacitors at the input and output and a
tiny chip inductor such as the NLC322522T series from
TDK. With the MAX1692 in a 10-pin μMAX package, the
entire circuit can fit in only 60mm
2
and have less than
2.4mm height.
LX
FB
IN
BP
REF
LIM
MAX1692
C5
4.7
μ
F
V
IN
+2.9V TO+4.5V
L1
10
μ
H
V
OUT
= 1.8V @ 200mA
C5
47pF
R1
138k
R2
301k
10
μ
F
10
μ
F
ON
/
OFF
C4
0.1
μ
F
GND
PGND
SYNC/
PWM
SHDN
C2
Figure 3. Miniaturized 200mA Output Circuit Fits in 60mm
2
OS-CON is a trademark of Sanyo Corp.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1692EUB+ | 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 5.5V PWM Step-Down Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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 |
| MAX1692EUB+T | 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 5.5V PWM Step-Down Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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 |
| MAX1692EUB-T | 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 5.5V PWM Step-Down Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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 |
| MAX1692EVKIT | 制造商:Maxim Integrated Products 功能描述:LOW-NOISE, 5.5V-INPUT, PWN STEP-DOWN REGULATO - Bulk |
| MAX16930ATLR/V+ | 制造商:Maxim Integrated Products 功能描述:2MHZ, 36V, DUAL BUCK WITH PRE-BOOST AND 40A QUIESCENT CURREN - Rail/Tube |
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