参数资料
型号: MAX1765EEE+
厂商: Maxim Integrated
文件页数: 16/19页
文件大小: 867K
描述: IC REG DL BST/LINEAR SYNC 16QSOP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 100
拓扑: 升压(升压)同步(1),线性(LDO)(1)
功能: 任何功能
输出数: 2
频率 - 开关: 1MHz
电压/电流 - 输出 1: 2.5 V ~ 5.5 V,800mA
电压/电流 - 输出 2: 2.85V/可调,500mA
带 LED 驱动器:
带监控器:
带序列发生器:
电源电压: 0.7 V ~ 5.5 V
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)
供应商设备封装: 16-QSOP
包装: 管件
should have a saturation current rating exceeding the
N-channel switch current limit; however, it is accept-
able to bias the inductor current into saturation by as
much as 20% if a slight reduction in efficiency is
acceptable. Lower current-rated inductors may be
used if ISET is employed to reduce the peak inductor
current (see Setting the Switch Current Limit and Soft-
Start). For high efficiency, choose an inductor with a
high-frequency core material to reduce core losses. To
minimize radiated noise, use a toroid or shielded induc-
tor. See Table 3 for suggested components and Table
4 for a list of component suppliers.
Output Diode
To assist startup with input voltages below 1.1V or
when V
OUT
is set for >4V, use a Schottky diodesuch
as a 1N5817, MBR0520L or equivalentbetween LX
and POUT (Figure 2). The Schottky diode carries cur-
rent after the synchronous rectifier turns off. Thus, its
current rating only needs to be 500mA. Connect the
diode as close to the IC as possible. Do not use ordi-
nary rectifier diodes; their slow switching speeds and
long reverse-recovery times render them unacceptable.
For input voltages over 1.8V, the Schottky diode may
improve light-load efficiency.
Input and Output Filter Capacitors
Choose input and output filter capacitors that will ser-
vice the input and output peak currents with accept-
able voltage ripple. Choose input capacitors with
working voltage ratings over the maximum input volt-
age and output capacitors with working voltage ratings
higher than the output. A 100礔, 100m? low equiva-
lent-series-resistance (ESR) tantalum output capacitor
is recommended for most applications. At the output of
the linear regulator (OUTL), use a 4.7礔 ceramic
capacitor for stability at loads up to 500mA.
The input filter capacitor reduces peak currents drawn
from the input source and also reduces input switching
noise. The input voltage source impedance determines
the required size of the input capacitor. When operat-
ing directly from one or two NiMH cells placed close to
the MAX1765, use a single 33礔 low-ESR input filter
capacitor.
The Sanyo POSCAP, Panasonic SP/CB, and Kemet
T510 are good low-ESR capacitors. Low-ESR tantalum
capacitors offer a good trade-off between price and
performance. Do not exceed the ripple current ratings
of tantalum capacitors. Avoid aluminum electrolytic
capacitors; their high ESR typically results in higher
output ripple voltage.
Bypass Capacitors
Bypass REF to GND with 0.22礔. Also, bypass OUT to
GND with a 0.68礔 ceramic capacitor, and connect
OUT to POUT with a 4.7﹔esistor. Each of these com-
ponents should be placed as close to its respective IC
pins as possible, within 0.2in (5mm).
Layout Considerations
High switching frequencies and large peak currents
make PC board layout a critical part of design. Poor
design will cause excessive EMI and ground bounce,
both of which can cause instability or regulation errors
by corrupting the voltage and current feedback signals.
Power componentssuch as the inductor, converter
IC, filter capacitors, and output diodeshould be
placed as close together as possible, and their traces
should be kept short, direct, and wide. Connect the
inductor from the battery to the LX pins as close to the
IC as possible.
Keep the voltage feedback network very close to the
IC, within 0.2in (5mm) of the FB pins. Keep noisy
traces, such as those from the LX pin, away from the
voltage feedback networks and guarded from them
using grounded copper. Refer to the MAX1765 EV kit
for a full PC board example.
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
16 ______________________________________________________________________________________
Figure 7. Feedback Connections
MAX1765
INL
OUTL
POUT
OUT
FBL
FB
GND
PGND
R3
R4
R2
R1
STEP-UP
OUTPUT
LINEAR-
REGULATOR
OUTPUT
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相关代理商/技术参数
参数描述
MAX1765EEE+ 功能描述:直流/直流开关转换器 800mA Step-Up w/500mA Linear Reg 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
MAX1765EEE+T 功能描述:直流/直流开关转换器 800mA Step-Up w/500mA Linear Reg 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
MAX1765EEE-T 功能描述:直流/直流开关转换器 800mA Step-Up w/500mA Linear Reg 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
MAX1765EUE 功能描述:直流/直流开关转换器 800mA Step-Up w/500mA Linear Reg 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
MAX1765EUE+ 功能描述:直流/直流开关转换器 800mA Step-Up w/500mA Linear Reg 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