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参数资料
| 型号： | MAX8568AETE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/17页 |
| 文件大小： | 0K |
| 描述： | IC BATT MANAGE LITH 16-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 功能： | 备份管理 |
| 电池化学： | 锂离子（Li-Ion）；镍金属氢化物（NiMH） |
| 电源电压： | 2.8 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（3x3） |
| 包装： | 管件 |
Complete Backup-Management ICs
for Lithium and NiMH Batteries
Note that both V BK(NILO) and V BK(NIHI) can be set with a
2-resistor voltage-divider as shown in the typical applica-
tion circuit (see Figure 7) if the factory-set ratio between
the two thresholds is acceptable. In that case:
REF
16
R17
R 6 = R 8 ?
1 ?
?
?
V REF
V BK ( NILO )
?
?
?
TERMV
15
V BK(NIHI) = 1.163 x V BK(NILO)
R18
V BK(NIMAX) = 1.283 x V BK(NIHI)
One 3-resistor-divider can be used to set both
V BK(NILO) and V BK(NIHI) independently. Figure 4 shows
the connections of R17, R18, and R19. Select R19 in
the 100k ? to 1M ? range. The equations for the two
upper divider-resistors are:
STRTV
14
R19
?
R 18 = R 19 ?
1 ?
V REF
? V BK ( NILO )
?
?
?
Figure 4. 3-Resistor Divider Used to Set V BK(NILO) and V BK(NIHI)
Step-Up Capacitor Selection
? 1 . 163 × V REF
R 17 = ( R 18 + R 19 ) × ?
1 ?
? V BK ( NIHI )
?
?
?
Choose output capacitors to supply output peak cur-
rents with acceptable voltage ripple. Low equivalent-
series-resistance (ESR) capacitors are recommended.
Ceramic capacitors have the lowest ESR, but low-ESR
R 9 = R 10 ?
1 ?
2 ? ( V BKSU
) C
V BK BKSU ?
Setting the Switchover Voltage
V INOK sets the IN voltage at which backup mode starts.
INOK connects to a resistor-divider between IN and
GND. The MAX8568 requires V IN greater than 2.8V for
proper operation when not backing up, so the backup
threshold, V IN(BACKUP) , must be set for no less than
2.8V. Once V INOK drops below 2.43V (typ), V IN may be
less than 2.8V. The resistor-divider for INOK is shown in
Figure 7 (R9 and R10). Select resistor R10 to be in the
100k ? to 1M ? range. Calculate R9 as follows:
? V IN(BACKUP) ?
?
? V INOK ?
where V INOK = 2.43V, and V IN(BACKUP) must be set
greater than 2.8V.
Step-Up Converter
The step up DC-DC converter is most likely used with
NiMH backup batteries, but can also be used with
rechargeable lithium backup batteries. If the backup
battery voltage is greater than the set output voltage at
BKSU, the output voltage follows the backup battery
voltage. The voltage difference between the backup
battery and BKSU never exceeds a diode forward-volt-
age drop. If I/O OUT (Figure 7) is less than BK during
charge mode, no current flows from BK to I/O OUT.
tantalum or polymer capacitors offer a good balance
between cost and performance.
Output voltage ripple has two components: variations in
the charge stored in the output capacitor with each LX
pulse and the voltage drop across the capacitor’s ESR
caused by the current into and out of the capacitor. The
equations for calculating output ripple are:
V RIPPLE = V RIPPLE(C) + V RIPPLE(ESR)
V RIPPLE(ESR) = I PEAK x R ESR(CBKSU)
1 ? L ? 2
V RIPPLE ( C ) = ? ? I PEAK
?
where I PEAK is the peak inductor current (see the
Inductor Selection section). For ceramic capacitors, the
output voltage ripple is typically dominated by
V RIPPLE(C) .
Input capacitors connected to IN and BK should be
X5R or X7R ceramic capacitors. C IN should be 4.7μF or
greater. C BK should be 10μF or greater when using the
step-up converter. If the step-up converter is not used,
then C BK can be reduced to 1μF.
Capacitance and ESR variation with temperature should
be considered for best performance in applications with
wide operating temperature ranges.
12
______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8568AETE+ | 功能描述:电池管理 Backup-Mgt IC for Li & NiMH Bat RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8568AETE+T | 功能描述:电池管理 Backup-Mgt IC for Li & NiMH Bat RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8568AETE-T | 功能描述:电池管理 Backup-Mgt IC for Li & NiMH Bat RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8568BETE | 功能描述:电池管理 Backup-Mgt IC for Li & NiMH Bat RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8568BETE-T | 功能描述:电池管理 Backup-Mgt IC for Li & NiMH Bat RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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