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| 型号： | MAX1678EUA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST SYNC 3.3V/ADJ 8UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 升压（升压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 3.3V，2 V ~ 5.5 V |
| 输入电压： | 0.7 V ~ 5.5 V |
| 电流 - 输出： | 90mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-uMAX |
1-Cell to 2-Cell, Low-Noise,
High-Efficiency, Step-Up DC-DC Converter
Shutdown Mode
Pulling the SHDN pin low places the MAX1678 in shut-
down mode (I SHDN = 2μA typical). In shutdown, the
internal switching MOSFET turns off, PFO goes high
impedance, and the synchronous rectifier turns off to
OUT
V OUT
V IN
prevent the flow of reverse current from the output back
to the input. However, there is still a forward current
path through the synchronous-rectifier body diode from
MAX1678
PDRV
P
BATT
the input to the output. Thus, in shutdown, the output
remains one diode drop below the battery voltage
(V BATT ).
To disable the shutdown feature, connect SHDN (a
logic input) to BATT or OUT.
Reverse-Battery Protection
The MAX1678 can sustain/survive battery reversal up to
the package power-dissipation limit. An internal 5 ?
resistor in series with a diode limits reverse current to
less than 220mA, preventing damage. Prolonged oper-
ation above 220mA reverse-battery current can
TIMING
CIRCUIT
DAMP
NDRV
N
GND
DAMPING
SWITCH
P
LX
R3 = R4 x ? TH ? 1 ?
degrade the device’s performance.
Power-Fail Comparator
The MAX1678 has an on-chip comparator for power-fail
detection. This comparator can detect a loss of power
at the input or output (Figures 7 and 8). If the voltage at
the power-fail input (PFI) falls below 614mV, the PFO
output sinks current to GND. Hysteresis at PFI is 2%.
The power-fail monitor threshold is set by two resistors,
R3 and R4, using the following equation:
? V ?
? V PFI ?
where V TH is the desired threshold of the power-fail
detector, and V PFI is the 614mV threshold of the power-
fail comparator. Since PFI leakage is 10nA max, select
feedback resistor R4 in the 100k ? to 1M ? range.
Damping Switch
The MAX1678 is designed with an internal damping
switch to minimize ringing at the LX node. The damping
switch (Figure 4) connects the LX node to BATT, effec-
tively depleting the inductor’s remaining energy. When
the energy in the inductor is insufficient to supply cur-
rent to the output, the capacitance and inductance at
LX form a resonant circuit that causes ringing. The
damping switch supplies a path to quickly dissipate
Figure 4. Simplified Diagram of Damping Switch
V BATT = 2.5V
V OUT = 3.3V
L1 = 47 μ H
2 μ s/div
Figure 5. LX Ringing Without Damping Switch (example only)
this energy, suppressing the ringing at LX. This does
not reduce the output ripple, but does reduce EMI.
Figures 5 and 6 show the LX node voltage waveform
without and with the damping switch.
2 μ s/div
V BATT = 1.8V
V OUT = 3.3V
L1 = 47 μ H
Figure 6. LX Ringing With Damping Switch
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1678EVKIT | 功能描述:电源管理IC开发工具 Evaluation Kit for the MAX1678 RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX1679EUA | 功能描述:电池管理 Battery Charger Current-Limited Sply RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1679EUA+ | 功能描述:电池管理 Battery Charger Current-Limited Sply RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1679EUA+T | 功能描述:电池管理 Battery Charger Current-Limited Sply RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX1679EUA-T | 功能描述:电池管理 Battery Charger Current-Limited Sply RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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