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参数资料
| 型号： | MAX1688ESA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/12页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST SYNC ADJ 2.5A 8SOIC |
| 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： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.25 V ~ 6 V |
| 输入电压： | 2.7 V ~ 6 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 2.5A |
| 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-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-SOIC |
Step-Up DC-DC Converters with
Precise, Adaptive Current Limit for GSM
Output (Reservoir) Capacitor
The value of the output capacitor determines the
amount of power available to deliver to the power
amplifier during the RF burst. A larger output capacitor
with low ESR reduces the amount of output voltage
droop during an RF burst. Use the following equation to
determine capacitor size when ON is synchronized to
the RF burst:
Typical Application Circuits
The current limit of the MAX1687 can be set by an exter-
nal DAC (Figure 6a), making it variable by using a micro-
controller. The MAX1687 is the choice for systems
interfacing with a microcontroller, but may also be used
with fixed current limit (Figure 6b). The MAX1688 can
monitor the droop of the output voltage to set the current
limit, maximizing battery life. The MAX1688 is suitable for
( DROOP
D
ESR
)( )
C
OUT
=
V
GSM
- I BURST ?
? I BURST ? t GSM
OUTPUT CAPACITOR
1 - tol
systems demanding variable burst currents (Figures 6a,
6b, and 7) as well as variable input voltages.
Layout
The MAX1687/MAX1688 ’s high-frequency operation
where C OUT is the output capacitor, I BURST is the peak
power amplifier burst current, t GSM is the current pulse
period, D GSM is the duty cycle, tol is the capacitor tol-
erance, and V DROOP is the acceptable drop in the out-
put during the current burst.
For example, when used in a typical GSM system,
t GSM = 4.62ms, I BURST = 2.66A for a +3.6V system
(1.42A for a +5.5V system), and with a droop of less
than 10%, the value of the capacitor is 5.3mF ±20%.
The output capacitor also determines the constant-load
(ON connected to V CC ) ripple voltage. The output rip-
ple is:
V RIPPLE = I RIPPLE · ESR (OUTPUT CAPACITOR)
where I RIPPLE is typically 0.2A.
10 μ H
LX1
LX1
and high peak currents make PC board layout critical
to minimize ground bounce and noise. Locate input
bypass and output filter capacitors as close to the
device pins as possible. All connections to OUT and FB
should also be kept as short as possible. Use a low-
inductance ground plane. Connect the ground leads of
the input capacitor, output capacitor, and PGND pins in
a star configuration to the ground plane. Table 1 lists
suggested suppliers. Refer to the MAX1687/MAX1688
evaluation kit manual for a suggested surface-mount
layout and a list of suggested components.
LX2
LX2
V IN
2.7V TO 6V
0.1 μ F
47 μ F
IN
IN
MAX1687
OUT
OUT
V OUT = 5V
2A AT 12%
DUTY CYCLE
DAC
R2
187k
2000 μ F
OUTPUT
0 TO 1V
ON
LIM
ON
FB
AGND
OFF
PGND
R1
61.9k
REF
Figure 6a. MAX1687 Typical Application Circuit (GSM Pulsed Load)
PGND
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1688EUE | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1688EUE+ | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1688EUE+T | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1688EUE-T | 功能描述:直流/直流开关转换器 StepUp w/Prec Adapt Crnt Limit for GSM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1688EUE-T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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