MAX849:1节至3节电池、大功率、低噪声、升压型DC-DC转换器

集成2路ADC,提供精确的电池电压监测

The MAX848/MAX849 boost converters set a new standard of high efficiency and high integration for noise-sensitive power-supply applications, such as portable phones and small systems with RF data links. The heart of the these devices is a synchronous boost-topology regulator that generates a fixed 3.3V output (or 2.7V to 5.5V adjustable output) from one to three NiCd/NiMH cells or one Li-Ion cell. Synchronous rectification provides a 5% efficiency improvement over similar nonsynchronous boost regulators. In standby mode, pulse-skipping PFM operation keeps the output voltage alive with only 150µW quiescent power consumption. Fixed-frequency PWM operation ensures that the switching noise spectrum is limited to the 300kHz fundamental and its harmonics, allowing easy post-filtering noise reduction. For even tighter noise spectrum control, synchronize to a 200kHz to 400kHz external clock. Battery monitoring is provided by a two-channel, voltage-to-frequency analog-to-digital converter (ADC). One channel is intended for a single-cell battery input (0.625V to 1.875V range), while the other channel is for monitoring higher voltages (0V to 2.5V range). Two control inputs are provided for push-on, push-off control via a momentary pushbutton switch. Upon power-up, an internal comparator monitors the output voltage to generate a power-good output (POK). The devices differ only in the current limit of the N-channel MOSFET power switch: 0.8A for the MAX848, and 1.4A for the MAX849.

关键特性
  • Up to 95% Efficiency
  • 3.3V Dual Mode™ or 2.7V to 5.5V Adj. Output
  • 0.7V to 5.5V Input Range
  • 0.15mW Standby Mode
  • 300kHz PWM Mode or Synchronizable
  • Two-Channel ADC with Serial Output
  • Power-Good Function
MAX848、MAX849:典型工作电路
MAX848、MAX849:典型工作电路
应用
  • 蜂窝电话
  • 数字无绳电话
  • 手持式仪表(PDA、掌上电脑)
  • 本地3.3V至5V转换电源
  • 掌上电脑
  • PCS电话
  • 个人通信装置
数据手册DataSheet
语言下载文件备注
英文MAX848-MAX849.pdfRev 2; 12/1997
关键参数
Part NumberVIN
(V)
VIN
(V)
VOUT1
(V)
VOUT1
(V)
Preset VOUT
(V)
IOUT1
(A)
Output Adjust. MethodSwitch TypeSynchronous SwitchingICC
(mA)
Shutdown Mode Supply Current
(µA)
Shutdown Mode Supply Current
(µA)
DC-DC OutputsOper. Freq.
(kHz)
Package/PinsBudgetary
Price
minmaxminmaxmaxtyptypmaxSee Notes
MAX8480.75.52.75.53.30.3
  • Preset
  • Resistor
InternalYes0.0354201400SOIC(N)/16$2.38 @1k
MAX8491SOIC(N)/16$2.50 @1k
开发工具
技术资料
相关产品
  • MAX847:1节电池、升压型、双向寻呼机系统电源IC
  • MAX717:3.3V掌上电脑及闪存存储器电源稳压器
  • MAX722:3.3V/5V掌上电脑及LCD电源稳压器
订购型号
型号状况推荐替代产品封装温度RoHS/无铅
MAX849ESE停止供货MAX849ESE+SOIC(N),;16引脚;61.9mm²-40°C至+85°CRoHS/无铅:否
MAX849ESE+生产中SOIC(N),;16引脚;61.9mm²-40°C至+85°CRoHS/无铅:无铅
MAX849ESE+T生产中SOIC(N),;16引脚;61.9mm²-40°C至+85°CRoHS/无铅:无铅
MAX849ESE-T停止供货MAX849ESE+TN.SO;16引脚-40°C至+85°C参考数据资料
MAX848-MAX849.pdf MAX849
Linear Regulators in Portable Applications MAX883
典型工作电路 MAX849