收藏本站
MAX8834Y/MAX8834Z
Adaptive Step-Up Converters
with 1.5A Flash Driver
To use this feature, connect the logic signal used to
enable the PA, or equivalent, to the GSMB input.
Assertion of this signal does not change the current sta-
tus of the flash safety timer or the flash current values
stored in the I 2 C registers. Once the signal is deassert-
ed, the current regulators change back to their previ-
ously programmed values. Polarity of this signal is
controlled through bit 6 in the GSMB_CUR register
(Table 11). The default is active-high.
Finger-Burn Protection (NTC)
An NTC input is provided for the (optional) finger-burn
protection feature. To use this feature, connect a 100k ?
NTC with B = 4550 between NTC and AGND. NTC
sources 20μA current and the voltage established by
this current and the NTC resistance is compared inter-
nally to a voltage threshold in the range of 200mV to
550mV, programmed through bits [2:0] of the NTC
Control register (see Table 10).
If the voltage on the NTC pin falls below the programmed
threshold during a flash event, the flash cycle is immedi-
ately terminated, and an indication is latched through bit 3
in the STATUS1 register (see Table 15).
To disable this function, clear bit 3 (enable bit) in the
NTC Control register.
MAXFLASH Function
During high load currents, the battery voltage momen-
tarily drops due to its internal ESR, together with the
serial impedance from the battery to the load. For
equipment requiring a minimum voltage for stable oper-
plus a predefined hysteresis (V LB_HYS ). If it is still
below V LB_TH + V LB_HYS , the FLED1/FLED2 current
regulators reduce their output current again to ensure
that minimum input voltage is available for the system.
If the input voltage is above V LB_TH + V LB_HYS , the cur-
rent regulator increases the output current by one step
(if it is less than the user-defined output current). To
disable the hysteresis, set LB_HYS[1:0] to 11. In this
case, after the FLED1/FLED2 current is reduced, it
stays at the current setting. Figures 12, 13, and 14
show examples of MAXFLASH function operation. See
Tables 12 and 13 for control register details.
The MAXFLASH function continues for the entire dura-
tion of the FLASH/MOVIE event to ensure that the
FLASH/MOVIE output current is always maximized for
the specific operating conditions.
Undervoltage Lockout
The MAX8834Y/MAX8834Z contain undervoltage lock-
out (UVLO) circuitry that disables the IC until V IN is
greater than 2.3V (typ). Once V IN rises above 2.3V
(typ), the UVLO circuitry does not disable the IC until
V IN falls below the UVLO threshold minus the hysteresis
voltage. The MAX8834Y/MAX8834Z also contain a V DD
UVLO circuitry that monitors the V DD voltage. When the
V DD voltage falls below 1.4V (typ), the contents of all
the logic registers are reset to their default states. The
logic registers are only reset in a V DD UVLO condition
and not an IN UVLO condition.
ation, the battery ESR needs to be calculated to esti-
mate the maximum battery current that maintains the
t LB_TMR
I OUT_MAX
battery voltage above the critical threshold. Due to the
complicated measurement of the battery ESR, the
MAX8834Y/MAX8834Z feature the MAXFLASH function
to prevent the battery voltage from dropping below the
threshold voltage. See Figure 11 for details.
The MAX8834Y/MAX8834Z input voltage is monitored
during a FLASH/MOVIE event. If the input voltage
drops below a predefined threshold (V LB_TH ), it indi-
cates that the FLASH/MOVIE event is drawing more
current than the battery can support. As a result, the
FLED1/FLED2 current regulators start decreasing their
output currents by one step. Therefore, the input cur-
rent is reduced and the input voltage starts to rise due
to the internal battery ESR. The input voltage is then
IN
V LB_TH
V LB_HYS
V LB_TH
DOWN
UP
CURRENT
REGULATOR
sampled again after t LB_TMR and compared to V LB_TH
Maxim Integrated
Figure 11. Block Diagram of MAXFLASH Function
17
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MAX8855EVKIT+ KIT EVAL FOR MAX8855
MAX8879ETG+T IC LED DRVR WT/RGB BCKLGT 24TQFN
MAX8901BETA+TCH8 IC LED DRIVER WHITE BCKLGT 8TDFN
MAX8930EWJ+T IC LED DRVR WT/RGB BCKLGT 49WLP
MAXQ2000-KIT EVAL KIT FOR MAXQ2000
MAXQ610-KIT# EVALUATION KIT FOR MAXQ610
MB2146-401-01A KIT STARTER F2MC-8FX 3V
MB2146-401-03A KIT STARTER F2MC-8FX 5V
相关代理商/技术参数
MAX8836ZEREEE+T 功能描述:电流型 PWM 控制器 1.2A PWM Step-Down Converter RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14
MAX8836ZEWEEE+ 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX8836ZEWEEE+T 制造商:Maxim Integrated Products 功能描述:
MAX883C/D 功能描述:低压差稳压器 - LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX883C/D DIE 制造商:Maxim Integrated Products 功能描述:
MAX883CPA 功能描述:低压差稳压器 - LDO 5/3.3/AdjV 200mA Linear Regulator RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX883CPA+ 功能描述:低压差稳压器 - LDO 5/3.3/AdjV 200mA Linear Regulator RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX883CSA 功能描述:低压差稳压器 - LDO 5/3.3/AdjV 200mA Linear Regulator RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20