Applications Information
Use in a Typical Wireless
Phone Application
The MAX1765 is ideal for use in digital cordless and
PCS phones. The PA is connected directly to the step-
up converter output for maximum voltage swing and
power efficiency (Figure 10). The internal linear regula-
tor is used for postregulation to generate low-noise
power for DSP, control, and RF circuitry. The following
equations may be used to estimate the typical available
output current under conditions other than those listed
here:
where I
LIM
is the peak inductor current limit, f
SW
is the
operating frequency (typically 1.2MHz), L is the induc-
tance of the chosen inductor, L
RESR
is the resistance of
the chosen inductor, R
NCH
and R
PCH
are the resis-
tances of the internal N-channel and P-channel,
respectively.
I
I
I
I D
I
f
D
L
V I R L
D
V V I R L
V I R R
OUTMAX LIM
RIPPLE
RIPPLE
SW
IN LIM NCH ESR
OUT IN LIM NCH ESR
OUT LIM PCH NCH
,
=
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
( )
= ?nbsp ?nbsp ?nbsp +
(
)
[
]
=
+ ?nbsp +
(
)
+
(
)
2
1
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
______________________________________________________________________________________ 17
Figure 9. Soft-Start, Maximum Current Limit
C
SS
R
SS
I
LIM
= 1.25A
t
SS
= R
SS
C
SS
500k?/SPAN> < R
SS
< 1M?/DIV>
MAX1765
REF
ISET
0.22糉
Figure 8. Soft-Start, Reduced Current Limit
C
SS
MAX1765
REF
ISET
0.22糉
R
SS1
R
SS2
I
LIM
= 1.25A
t
SS
= (R
SS1
|| R
SS2
) C
SS
( )
R
SS2
R
SS1
+
R
SS2
Table 3. Component Selection Guide
PRODUCTION
3.3?/SPAN>H INDUCTORS
CAPACITORS
SCHOTTKY DIODES
Surface Mount
Coilcraft DS3316P
Coilcraft LPT3305
AVX TPS series
Kemet T510 series
Sanyo POSCAP series
Motorola MBR0520L
Nihon EP10QY03
Table 4. Component Suppliers
SUPPLIER COUNTRY
PHONE
AVX
USA
843-448-9411
Coilcraft
USA
847-639-6400
Kemet
USA
810-287-2536
USA
408-629-4789
Motorola
Japan
81-45-474-7030
USA
847-956-0666
Sumida
Japan
81-3-3607-3302
Note:Please indicate that you are using the MAX1765 when
contacting these component suppliers.
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
MAX1989MUE+
IC TEMP SENSOR REMOTE 16TSSOP
MAX31723MUA+
IC THERMOMETER/STAT SPI-3W 8UMAX
MAX31826MUA+T
IC TEMP SENSOR DIGITAL 8UMAX
MAX4006EUT+T
IC CURRENT MONITOR 1% SOT23-6
MAX4008EUT+T
IC CURRENT MONITOR 1% SOT23-6
MAX4370ESA+T
IC CNTRLR HOT-SWAP 8-SOIC
MAX4995AFAVB+
IC CURRENT SWITCH 10% 10UTQFN
MAX5900AAEUT+T
IC HOT-SWAP CONTROLLER SOT23-6
相关代理商/技术参数
MAX1765EUE+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-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
MAX1765EVKIT
功能描述:直流/直流开关转换器 Evaluation Kit for the MAX1765 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
MAX176ACPA
功能描述:模数转换器 - ADC Integrated Circuits (ICs) RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
MAX176ACPA+
功能描述:模数转换器 - ADC 12Bit 250ksps 5V- Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
MAX176ACWE
功能描述:模数转换器 - ADC Integrated Circuits (ICs) RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
MAX176ACWE+
功能描述:模数转换器 - ADC 12Bit 250ksps 5V- Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
MAX176ACWE+T
功能描述:模数转换器 - ADC 12Bit 250ksps 5V- Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32