参数资料
型号: MAX1703
厂商: Maxim Integrated Products, Inc.
元件分类: DC/DC变换器
英文描述: 1-Cell to 3-Cell, High-Power 1.5A, Low-Noise, Step-Up DC-DC Converter
中文描述: 1节至3节电池、大功率(1.5A)、低噪声、升压型DC-DC转换器
文件页数: 12/16页
文件大小: 273K
代理商: MAX1703
M
__________________Design Procedure
Setting the Output Voltages
Set the output voltage between 2.5V and 5.5V by con-
necting a resistor voltage-divider to FB from OUT to
GND, as shown in Figure 2. The resistor values are then
as follows:
R1 = R2(V
OUT
/ V
FB
- 1)
where V
FB
, the boost-regulator feedback setpoint, is
1.24V. Since the input bias current into FB is less than
20nA, R2 can have a large value (such as 270k
or
less) without sacrificing accuracy. Connect the resistor
voltage-divider as close to the IC as possible, within
0.2in. (5mm) of the FB pin.
Inductor Selection
The MAX1703’s high switching frequency allows the
use of a small surface-mount inductor. A 4.7μH induc-
tor should have a saturation-current rating that exceeds
the N-channel switch current limit. However, it is gener-
ally acceptable to bias the inductor current into satura-
tion by as much as 20%, although this will slightly
reduce efficiency. For high efficiency, choose an induc-
tor with a high-frequency core material, such as ferrite,
to reduce core losses. To minimize radiated noise, use
a toroid, pot core, or shielded bobbin inductor. See
Table 3 for suggested components and Table 4 for a
list of component suppliers. Connect the inductor from
the battery to the LX pins as close to the IC as possible.
Output Diode
Use a Schottky diode such as a 1N5817, MBR0520L, or
equivalent. The Schottky diode carries current during
both start-up and PFM mode after the synchronous recti-
fier turns off. Thus, its current rating only needs to be
500mA. Connect the diode between LXN/LXP and
POUT, as close to the IC as possible. Do not use ordi-
nary rectifier diodes, since slow switching speeds and
long reverse recovery times will compromise efficiency
and load regulation.
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 330μF, 100m
, low-ESR tantalum capacitor is recom-
mended for a 5V output. For full output load current,
one 470μF or two 220μF, 100m
low-ESR tantalum
capacitors are recommended for a 3.3V output. The
input filter capacitor (C
IN
) also reduces peak currents
drawn from the input source and reduces input switch-
ing noise. The input voltage source impedance deter-
mines the required size of the input capacitor.
When operating directly from one or two NiCd cells
placed close to the MAX1703, use a 100μF, low-ESR
input filter capacitor.
Sanyo OS-CON and Panasonic SP/CB-series ceramic
capacitors offer the lowest ESR. Low-ESR tantalum
capacitors are a good choice and generally offer a
good tradeoff between price and performance. Do not
exceed the ripple current ratings of tantalum capaci-
tors. Avoid most aluminum-electrolytic capacitors,
because their ESR is often too high.
1-Cell to 3-Cell, High-Power (1.5A),
Low-Noise, Step-Up DC-DC Converter
12
______________________________________________________________________________________
Sanyo OS-CON series
Nichicon PL series
Sumida RCH654 series
Through Hole
Matsuo 267 series
Sprague 595D series
AVX TPS series
CAPACITORS
1N5817
DIODES
PRODUCTION
INDUCTORS
Table 3. Component Selection Guide
Table 4. Component Suppliers
(714) 960-6492
USA: (714) 969-2491
Matsuo
(847) 639-1469
USA: (847) 639-6400
Coilcraft
(803) 626-3123
FAX
SUPPLIER
USA: (803) 946-0690
(800) 282-4975
AVX
PHONE
(602) 994-6430
USA: (602) 303-5454
Motorola
(619) 661-1055
81-7-2070-1174
USA: (619) 661-6835
Japan: 81-7-2070-6306
Sanyo
(847) 956-0702
81-3-3607-5144
USA: (847) 956-0666
Japan: 81-3-3607-5111
Sumida
Sumida CDR125
Surface Mount
Motorola MBR0520L
Coilcraft DO3316
相关PDF资料
PDF描述
MAX1703ESE 1-Cell to 3-Cell, High-Power 1.5A, Low-Noise, Step-Up DC-DC Converter
MAX1705 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator
MAX1706C 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator
MAX1706D BALUN HYBRID 750-950MHZ 1:4
MAX1705C 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator
相关代理商/技术参数
参数描述
MAX17030EVKIT+ 功能描述:电源管理IC开发工具 MAX17030 Eval Kit 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
MAX17030GTL+ 功能描述:电压模式 PWM 控制器 1/2/3-Phase PWM IMVP-6.5 VID Ctlr RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
MAX17030GTL+T 功能描述:电压模式 PWM 控制器 1/2/3-Phase PWM IMVP-6.5 VID Ctlr RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
MAX17031ETG+ 功能描述:电压模式 PWM 控制器 Dual PWM Step-Down Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel
MAX17031ETG+T 功能描述:电压模式 PWM 控制器 Dual PWM Step-Down Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel