参数资料
型号: MAX1763EEE+T
厂商: Maxim Integrated Products
文件页数: 10/18页
文件大小: 0K
描述: IC REG BST SYNC 3.3V/ADJ 16QSOP
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: 两者兼有
输出数: 1
输出电压: 3.3V,2.5 V ~ 5.5 V
输入电压: 0.7 V ~ 5.5 V
PWM 型: 混合物
频率 - 开关: 1MHz
电流 - 输出: 1.5A
同步整流器:
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
1.5A, Low-Noise, 1MHz, Step-Up
DC-DC Converter
Table 2. Selecting the Operating Mode
choose an operating frequency (from 500kHz to
1.2MHz) to avoid interference in sensitive applications.
CLK/SEL
0
1
External clock
500kHz to 1.2MHz
MODE
Normal
operation
Forced PWM
Synchronized
PWM
FEATURES
High efficiency at all
loads. Fixed
frequency at all but
light loads.
Low noise, fixed
frequency at all loads.
Low noise, fixed
frequency at all loads.
For the most noise-sensitive applications, limit the
external synchronization signal duty cycle to less than
10% or greater than 90%. This eliminates the possibility
that noise from the power switching will coincide with
the synchronization signal. If the synchronization signal
edge falls on the power switching edge, a slight fre-
quency jitter may occur.
Synchronous Rectifier
The MAX1763 features an internal 130m Ω P-channel syn-
chronous rectifier to enhance efficiency. Synchronous
rectification provides a 5% efficiency improvement over
Step-Up Converter
During DC-DC converter operation, the internal N-chan-
nel MOSFET switch turns on for the first part of each
cycle, allowing current to ramp up in the inductor and
store energy in a magnetic field. During the second
part of each cycle, the MOSFET turns off and inductor
current flows through the synchronous rectifier to the
output filter capacitor and the load. As the energy
stored in the inductor is depleted, the current ramps
down and the synchronous rectifier turns off, the N-
channel FET turns on, and the cycle repeats. At light
loads, depending on the CLK/SEL pin setting, output
voltage is regulated using either PWM or by switching
only as needed to service the load (Table 2).
Normal Operation
Pulling CLK/SEL low selects the MAX1763 ’s normal
operating mode. In this mode, the device operates in
PWM when driving medium to heavy loads, and at light
loads only, switches as needed. This optimizes efficien-
cy over the widest range of load conditions. In normal
operation mode, the output voltage regulates 1% higher
than in forced-PWM mode. See Efficiency vs. Load
Current in the Typical Operating Characteristics section.
Forced-PWM Operation
When CLK/SEL is high, the MAX1763 operates in a low-
noise forced-PWM mode. During forced-PWM opera-
tion, the MAX1763 switches at a constant frequency
(1MHz) and modulates the MOSFET switch pulse width
to control the power transferred per cycle and regulate
the output voltage. Switching harmonics generated by
fixed-frequency operation are consistent and easily fil-
tered. See the Noise Spectrum plot in the Typical
Operating Characteristics .
Synchronized-PWM Operation
In a variation of forced-PWM mode, the MAX1763 can
be synchronized to an external frequency by applying
a clock signal to CLK/SEL. This allows the user to
similar boost regulators that rely on diode rectifiers. In
PWM mode, the synchronous rectifier is turned on during
the second half of each switching cycle. In low-power
mode, an internal comparator turns on the synchronous
rectifier when the voltage at LX exceeds the boost regula-
tor output and turns it off when the inductor current drops
below 120mA. When setting output voltages greater than
4V, an external 0.5A Schottky diode must be connected
in parallel with the on-chip synchronous rectifier.
Low-Voltage Startup Oscillator
The MAX1763 uses a CMOS low-voltage startup oscil-
lator for a 1.1V guaranteed minimum startup input volt-
age. At startup, the low-voltage oscillator switches the
N-channel MOSFET until the output voltage reaches
2.15V. Above this level, the normal feedback and con-
trol circuitry take over. Once the device is in regulation,
it can operate down to 0.7V input because internal
power for the IC is derived from the output through the
OUT pin. Do not apply full system load until the output
exceeds 2.3V.
Shutdown, ONA, ONB
ONA and ONB turn the MAX1763 on or off. When ONA =
1 or ONB = 0, the device is on. When ONA = 0 and
ONB = 1, the device is off (Table 3). Logic high ON
control can be implemented by connecting ONB high
and using ONA for the control input. Momentary one-
pushbutton ON/OFF control is described in the
Applications Information section. Both ONA and ONB
have approximately (0.15 ? V OUT )V of hysteresis.
Reference
The MAX1763 has an internal 1.250V reference.
Connect a 0.22μF ceramic bypass capacitor to GND
within 0.2in (5mm) of the REF pin. REF can source up
to 50μA of external load current.
Gain Block
The MAX1763 gain block can function as a power-OK
comparator or can be used to build a linear regulator
10
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MAX1763EUE+TG069 制造商:Maxim Integrated Products 功能描述:
MAX1763EUE-T 功能描述:直流/直流开关转换器 1.5A Low-Noise 1MHz Step-Up 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