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參數(shù)資料
| 型號： | MAX1559ETE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 電源管理 |
| 英文描述： | 5-Output Power-Management IC For Low-Cost PDAs |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, QCC16 |
| 封裝： | 4 X 4 MM, 0.8 MM HEIGHT, MO-220-WGGC, TQFN-16 |
| 文件頁數(shù)： | 9/14頁 |
| 文件大?。?/td> | 526K |
| 代理商： | MAX1559ETE |
MAIN and COR1 regulators are always on as long as
the IC is not in low-voltage shutdown (V
IN
< 3V). COR2
and SDIG can be turned on and off independently by
logic signals at ENC2 and ENSD, respectively, but can-
not be activated if V
IN
< 3V.
When SDIG is turned off, reverse current is blocked so
the SDIG output can be biased with an external source
when no power is present at IN. Leakage current is typ-
ically 3μA with 3.3V at SDIG.
LCD DC-DC Boost
In addition to the LDOs, the MAX1559 also includes a
low-current, high-voltage DC-DC boost converter for
LCD bias. This circuit can output at up to 28V and can
be adjusted with either an analog or PWM control sig-
nal using external components.
SW provides an input-power disconnect for the LCD
when ENLCD is low (off). The input-power disconnect
function is ideal for applications that require the output
voltage to fall to 0V in shutdown (True Shutdown). If True
Shutdown is not required, the SW switch can be
bypassed by connecting the boost inductor directly to IN
and removing the bypass cap on SW (C9 in Figure 1).
System Sleep
All regulated outputs turn off when V
IN
falls below 3V.
The MAX1559 resumes normal operation when V
IN
rises above 3.6V.
Reset Output
Reset (
RS
) asserts when V
MAIN
falls below 3.094V.
RS
is an open-drain, active-low output. Connect a 1M
resistor from
RS
to MAIN. To implement a reset
deassertion delay, add a capacitor from
RS
to GND. An
approximate 10ms delay can be generated with 1M
and 22nF. This results in a 22ms time constant, but
assumes the input threshold of the CPU reset input is
approximately 1V and is reached approximately 10ms
after
RS
goes high impedance. Timing for
RS
, 3.3V
MAIN, and 1V COR1 is shown in Figure 3.
Applications Information
LDO Output Capacitors (MAIN, SDIG,
COR1, and COR2)
Capacitors are required at each output of the MAX1559
for stable operation over the full load and temperature
range. See Figure 1 for recommended capacitor values
for each output. To reduce noise and improve load
transients, large output capacitors at up to 10μF can be
used. Surface-mount ceramic capacitors have very low
ESR and are commonly available in values up to 10μF.
X7R and X5R dielectrics are recommended. Note that
some ceramic dielectrics, such as Z5U and Y5V, exhib-
it large capacitance and ESR variation with temperature
and require larger than the recommended values to
maintain stability over temperature.
LCD Boost Output
Selecting an Inductor
The LCD boost is designed to operate with a wide range
of inductor values (4.7μH to 22μH). Smaller inductance
values typically offer smaller size for a given series
resistance or saturation current. Smaller values make LX
switch more frequently for a given load and can reduce
efficiency at low load currents. Larger values reduce
switching losses due to less frequent switching for a
given load, but higher resistance can then reduce effi-
ciency. A 10μH inductor provides a good balance and
works well for most applications. The inductor
’
s satura-
tion current rating should be greater than the peak
switching current (250mA); however, it is generally
acceptable to bias some inductors into saturation by as
much as 20%, although this slightly reduces efficiency.
Selecting a Diode
Schottky diodes rated at 250mA or more, such as the
Motorola MBRS0530 or Nihon EP05Q03L are recom-
mended. The diode reverse-breakdown voltage rating
must be greater than the LCD output voltage.
Selecting Capacitors
For most applications, use a small 1μF LCD output
capacitor. This typically provides a peak-to-peak output
ripple of 30mV. In addition, bypass IN with 1μF and SW
with 4.7μF ceramic capacitors.
An LCD feed-forward capacitor, connected from the
output to FB, improves stability over a wide range of
battery voltages. A 10pF capacitor is sufficient for most
applications; however, this value is also affected by PC
board layout.
Setting the LCD Voltage
Adjust the output voltage by connecting a voltage-
divider from the output (V
OUT
) to FB (Figure 1). Select
R2 between 10k
and 200k
. Calculate R1 with the fol-
lowing equation:
R
1
= R
2
[(V
OUT
/ V
FB
) - 1]
where V
FB
= 1.25V and V
OUT
can range from V
IN
to
28V. The input bias current of FB is typically only 5nA,
which allows large-value resistors to be used. For less
M
5-Output Power-Management IC For
Low-Cost PDAs
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| MAX1559ETE-T | 功能描述:PMIC 解決方案 Complete PMIC for PDAs RoHS:否 制造商:Texas Instruments 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-24 封裝:Reel |
| MAX155ACPI | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| MAX155ACPI+ | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 8-Bit 8Ch 250ksps 2.5V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| MAX155ACWI | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| MAX155ACWI+ | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 8-Bit 8Ch 250ksps 2.5V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
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