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参数资料
| 型号： | MAX1842EEE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 1A 16QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 1.5V，1.8V，2.5V，可调 |
| 输入电压： | 3 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 1A |
| 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： | 16-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-QSOP |
1A/2.7A, 1MHz, Step-Down Regulators with
Synchronous Rectification and Internal Switches
The constant-current source stops charging once the
voltage across the soft-start capacitor reaches 1.8V
(Figure 5).
Extended Current Limit (MAX1842)
For applications requiring occasional short bursts of
high output current (up to 2.7A), the MAX1842 provides
a higher current-limit threshold. When using the
MAX1842, choose external components capable of
withstanding its higher peak current limit.
The MAX1842 is capable of delivering large output cur-
rents for limited durations, and its thermal characteris-
tics allow it to operate at continuously higher output
currents. Figure 6 shows its maximum recommended
continuous output current versus ambient temperature.
2.70
2.65
2.60
2.55
2.50
2.45
2.40
2.35
MAX1842
MAXIMUM RECOMMENDED CONTINUOUS
OUTPUT CURRENT vs. TEMPERATURE
Figure 7 shows the maximum recommended burst cur-
rent versus the output current duty cycle at high tem-
2.30
25
35
45
55
65
75
85
peratures.
Figure 7 assumes that the output current is a square
wave with a 100Hz frequency. The duty cycle is
defined as the duration of the burst current divided by
the period of the square wave. This figure shows the
limitations for continuous bursts of output current.
Note that if the thermal limitations of the MAX1842 are
exceeded, it will enter thermal shutdown to prevent
TEMPERATURE ( ° C)
Figure 6. MAX1842 Maximum Recommended Continuous
Output Current vs. Temperature
MAXIMUM RECOMMENDED BURST CURRENT
vs. BURST CURRENT DUTY CYCLE
2.7
destructive failure.
Frequency Variation with Output Current
2.6
T A = +85 ° C
T A = +55 ° C
The operating frequency of the MAX1742/MAX1842 is
determined primarily by t OFF (set by R TOFF ), V IN , and
V OUT as shown in the following formula:
f PWM = (V IN - V OUT - V PMOS ) / [t OFF (V IN - V PMOS +
V NMOS )]
However, as the output current increases, the voltage
drop across the NMOS and PMOS switches increases
2.5
2.4
2.3
I OUT IS A 100Hz SQUARE WAVE
and the voltage across the inductor decreases. This
causes the frequency to drop. The change in frequency
can be approximated with the following formula:
2.2
0
FROM 1A TO THE BURST CURRENT
20 40 60
DUTY CYCLE (%)
80
100
Δ f PWM = -I OUT x R PMOS / (V IN x t OFF )
where R PMOS is the resistance of the internal MOSFETs
(90m Ω typ).
Circuit Layout and Grounding
Good layout is necessary to achieve the MAX1742/
MAX1842s’ intended output power level, high efficiency,
and low noise. Good layout includes the use of a ground
plane, careful component placement, and correct rout-
ing of traces using appropriate trace widths. The follow-
ing points are in order of decreasing importance:
Figure 7. MAX1842 Maximum Recommended Burst Current vs.
Burst Current Duty Cycle
1) Minimize switched-current and high-current ground
loops. Connect the input capacitor’s ground, the out-
put capacitor ’s ground, and PGND. Connect the
resulting island to GND at only one point.
2) Connect the input filter capacitor less than 5mm
away from IN. The connecting copper trace carries
large currents and must be at least 1mm wide,
preferably 2.5mm.
14
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| MAX1842EEE-TG074 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1843EGI | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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| MAX1843EGI+T | 制造商:Maxim Integrated Products 功能描述:CONV DC-DC SGL-OUT STEP DOWN 28QFN EP - Tape and Reel |
| MAX1843EGI-T | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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