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參數(shù)資料
| 型號： | MAX1637EEE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Miniature, Low-Voltage, Precision Step-Down Controller |
| 中文描述： | SWITCHING CONTROLLER, 338 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 0.150 INCH, 0.025 INCH PITCH, MO-137AA, QSOP-16 |
| 文件頁數(shù)： | 13/20頁 |
| 文件大?。?/td> | 211K |
| 代理商： | MAX1637EEE |
M
Miniature, Low-Voltage,
Prec ision S tep-Down Controller
______________________________________________________________________________________
13
For prototyping or for very high-current applications, it
may be useful to wire the current-sense inputs with a
twisted pair rather than PC traces (two pieces of
wrapped wire twisted together are sufficient). This
reduces the noise picked up at CSH and CSL, which can
cause unstable switching and reduced output current.
Osc illator Frequenc y
and S ync hronization (S Y NC)
The SYNC input controls the oscillator frequency as fol-
lows: low selects 200kHz, high selects 300kHz. SYNC
can also be used to synchronize with an external 5V
CMOS or TTL clock generator. It has a guaranteed
240kHz to 340kHz capture range. A high-to-low transi-
tion on SYNC initiates a new cycle.
Operation at 300kHz optimizes the application circuit
for component size and cost. Operation at 200kHz
increases efficiency, reduces dropout, and improves
load-transient response at low input-output voltage dif-
ferences (see the Low-Voltage Operation section).
Output V oltage Ac c urac y (CC)
Output voltage error is guaranteed to be within ±2%
over all conditions of line, load, and temperature. The
MAX1637’s DC load regulation is typically better than
0.1%, due to its integrator amplifier. The device opti-
mizes transient response by providing a feedback sig-
nal with a direct path from the output to the main
summing PWM comparator. The integrated feedback
signal from the CC transconductance amplifier is also
summed into the PWM comparator, with the gain
weighted so that the signal has only enough gain to
correct the DC inaccuracies. The integrator’s response
time is determined by the time constant set by the
capacitor placed on the CC pin. The time constant
should neither be so fast that the integrator responds to
the normal V
OUT
ripple, nor too slow to negate the inte-
grator’s effect. A 470pF to 1500pF CC capacitor is suf-
ficient for 200kHz to 300kHz frequencies.
Figure 6 shows the output voltage response to a 0A to
3A load transient with and without the integrator. With
the integrator, the output voltage returns to within 0.1%
of its no-load value with only a small AC excursion.
Without the integrator, load regulation is degraded
(Figure 6b). Asymmetrical clamping at the integrator
output prevents worsening of load transients during
pulse-skipping mode.
Output Undervoltage Loc kout
The output undervoltage-lockout circuit protects
against heavy overloads and short-circuits at the main
SMPS output. This scheme employs a timer rather than
a foldback current limit. The SMPS has an undervolt-
age-protection circuit, which is activated 6144 clock
cycles after the SMPS is enabled. If the SMPS output is
under 70% of the nominal value, it is latched off and
does not restart until
SHDN
is toggled. Applications
that use the recommended RC power-on-reset circuit
will also clear the fault condition when V
CC
falls below
0.5V (typical). Note that undervoltage protection can
0
2
4
-50
50
I
OUT
(A)
V
OUT
(mV)
(100
μ
s/div)
CC = 470pF
V
OUT
= 3.3V
INTEGRATOR
ACTIVE
Figure 6a. Load-Transient Response with Integrator Active
0
2
4
-50
50
I
OUT
(A)
V
OUT
(mV)
(100
μ
s/div)
CC = REF
V
OUT
= 3.3V
INTEGRATOR
DEACTIVATED
Figure 6b. Load-Transient Response with Integrator
Deactivated
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1637EEE+ | 功能描述:DC/DC 開關(guān)控制器 Mini Precision Step Down RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1637EEE+T | 功能描述:DC/DC 開關(guān)控制器 Mini Precision Step Down RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1637EEE-T | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風格: 封裝 / 箱體:CPAK |
| MAX1637EVKIT | 制造商:Maxim Integrated Products 功能描述:MINIATURE, LOW-VOLTAGE, PRECISION STEP-DOWN C - Bulk |
| MAX1638BEAG | 制造商:MAX 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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