參數(shù)資料
型號: MAX1688ESA
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: 穩(wěn)壓器
英文描述: Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM
中文描述: 0.9 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8
封裝: SOP-8
文件頁數(shù): 6/12頁
文件大?。?/td> 210K
代理商: MAX1688ESA
M
Detailed Desc ription
The MAX1687 and MAX1688 ICs supply power ampli-
fiers in GSM applications where limited input current
surge is desirable. For example, GSM systems require
high-power, 12% duty-cycle RF bursts. Synchronizing
the MAX1687/MAX1688 to enter standby mode during
these RF bursts eliminates battery surge current and
minimizes switching noise to the power amplifier. In
standby mode, the charged output reservoir capacitor
delivers power to the power amplifier. Between each
burst, the DC-DC converter switches on to charge the
output capacitor. To improve efficiency and reduce peak
battery current, the MAX1687/MAX1688 provide a volt-
age-controlled current limit. The MAX1688 is a MAX1687
with added self-regulating circuitry that recharges the
reservoir capacitor in a fixed time (Figure 1).
S tart-Up S equenc e
In a conventional DC-DC converter, when high current
is required by the load, the battery voltage droops due
to battery series resistance. This may cause other cir-
cuitry that depends on the battery to malfunction or be
reset. The MAX1687/MAX1688 prevent battery voltage
droop by charging the reservoir capacitor during sys-
tem off-time and isolate the battery from the output dur-
ing high current demand. The MAX1687/MAX1688 are
gentle to the battery during initial power-up, as well.
S tep-Up DC-DC Converters with
Prec ise, Adaptive Current Limit for GS M
6
_______________________________________________________________________________________
Pin Desc ription
PIN
NAME
FUNCTION
MAX1688
MAX1687
10
11, 12
13, 14
15, 16
6
7
8
9
5
3, 4
1, 2
TSSOP
GND
AGND
PGND
LX2
OUT
FB
REF
N.C.
ON
CHG
LIM
LX1
IN
Ground
Analog Ground
Power Ground
N-Channel and P-Channel MOSFET Drain
Output
Feedback Input. Connect a resistor-divider from OUT to GND to
set the output voltage. FB regulates to a nominal 1.25V.
Reference Voltage Output. 1.25V nominal.
No Connection. Not internally connected.
Logic ON/OFF Input. When ON is high, the device operates in
normal mode. When ON goes low, the device goes into standby
mode. If ON remains low for greater than 1.2ms, the device shuts
down (see Standby/Shutdownsection). The supply current falls to
3μA in shutdown mode.
Constant-Recharge-Time Input. Set the recharge time of the out-
put reservoir capacitor by connecting a resistor from CHG to GND
(see Applications Informationsection).
Voltage-Controlled Current-Limit Adjust Input. Apply a voltage
between 0 and 1V to vary the current limit. LIM is internally
clamped to 1.25V.
Internal Current-Sense Resistor Output. Connect the inductor
between LX1 and LX2.
Supply Voltage Input. Connect Battery to IN. Bypass to GND with
a 47μF minimum capacitor.
6
6
10
11, 12
7
13, 14
7
8
15, 16
8
4
6
4
7
8
5
9
5
3
5
3
SO
2
3, 4
2
1
1, 2
1
SO
TSSOP
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1688ESA+ 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
MAX1688ESA+T 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
MAX1688ESA-T 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
MAX1688EUE 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
MAX1688EUE+ 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT