- 您现在的位置：买卖IC网 > PDF目录22319 > MAX1999EEI+T (Maxim Integrated)IC REG QD BCK/LINEAR SYNC 28QSOP PDF资料下载
参数资料
| 型号： | MAX1999EEI+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 28/32页 |
| 文件大小： | 0K |
| 描述： | IC REG QD BCK/LINEAR SYNC 28QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 拓扑： | 降压（降压）同步（2），线性（LDO）（2） |
| 功能： | 任何功能 |
| 输出数： | 4 |
| 频率 - 开关： | 200kHz ~ 500kHz |
| 电压/电流 - 输出 1： | 控制器 |
| 电压/电流 - 输出 2： | 控制器 |
| 电压/电流 - 输出 3： | 3.3V，100mA |
| 带 LED 驱动器： | 无 |
| 带监控器： | 无 |
| 带序列发生器： | 是 |
| 电源电压： | 4.5 V ~ 24 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 28-QSOP |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页当前第28页第29页第30页第31页第32页
High-Efficiency, Quad Output, Main Power-
Supply Controllers for Notebook Computers
an MBR0530 (500mA-rated) type for loads up to 1.5A, a
1N5819 type for loads up to 3A, or a 1N5822 type for
loads up to 10A. The rectifier’s rated reverse breakdown
voltage must be at least equal to the maximum input volt-
age, preferably with a 20% derating factor.
Boost Supply Diode
A signal diode, such as a 1N4148, works well in most
applications. Use a small (20mA) Schottky diode for
slightly improved efficiency and dropout characteris-
tics, if the input voltage can go below 6V. Do not use
large power diodes, such as 1N5817 or 1N4001, since
high-junction capacitance can force LDO5 to excessive
voltages.
Applications Information
where V DROP1 and V DROP2 are the parasitic voltage
drops in the discharge and charge paths (see the On-
Time One-Shot section), t OFF(MIN) is from the EC table,
and K is taken from Table 2. The absolute minimum
input voltage is calculated with h = 1.
Operating frequency must be reduced or h must be
increased and output capacitance added to obtain an
acceptable V SAG if calculated V+ (MIN) is greater than
the required minimum input voltage. Calculate V SAG to
be sure of adequate transient response if operation
near dropout is anticipated.
Dropout Design Example
MAX1977: With V OUT5 = 5V, fsw = 400kHz, K = 2.25μs,
t OFF(MIN) = 350ns, V DROP1 = V DROP2 = 100mV, and h = 1.5,
? 0 . 35 μ s × 1 . 5 ?
1 ? ? ?
Dropout Performance
The output voltage-adjust range for continuous-conduc-
tion operation is restricted by the nonadjustable 350ns
(max) minimum off-time one-shot. Use the slower 5V
SMPS for the higher of the two output voltages for best
dropout performance in adjustable feedback mode. The
the minimum V+ is:
V + ( MIN ) = ( 5 V + 0 . 1 V )
? 2 . 25 μ s ?
+ 0 . 1 V ? 0 . 1 V = 6 . 65 V
( ) V 1 . 0
? 0 . 35 μ s × 1 ?
duty-factor limit must be calculated using worst-case val-
ues for on- and off-times, when working with low input
voltages. Manufacturing tolerances and internal propaga-
tion delays introduce an error to the t ON K factor. Also,
keep in mind that transient response performance of
buck regulators operated close to dropout is poor, and
bulk output capacitance must often be added (see the
Calculating with h = 1 yields:
5 V +
V + ( MIN ) =
1 ? ? ?
? 2 . 25 μ s ?
+ 0 . 1 V ? 0 . 1 V = 6 . 04 V
V SAG equation in the Output Capacitor Selection section).
The absolute point of dropout occurs when the inductor
current ramps down during the minimum off-time
( ? I DOWN ) as much as it ramps up during the on-time
( ? I UP ). The ratio h = ? I UP / ? I DOWN indicates the ability to
slew the inductor current higher in response to
increased load, and must always be greater than 1. As
h approaches 1, the absolute minimum dropout point,
Therefore, V+ must be greater than 6.65V. A practical
input voltage with reasonable output capacitance
would be 7.5V.
MAX1658/
the inductor current is less able to increase during each
switching cycle and V SAG greatly increases unless
additional output capacitance is used.
DH_
V+
MAX1659
LDO
12V
POSITIVE
SECONDARY
OUTPUT
A reasonable minimum value for h is 1.5, but this may
be adjusted up or down to allow tradeoffs between
OFF ( MIN ) × h
?
?
?
?
MAX1999
V SAG , output capacitance, and minimum operating
voltage. For a given value of h, the minimum operating
voltage can be calculated as:
V + ( MIN ) = ( V OUT _ + V DROP 1 ) + V DROP 2 ? V DROP 1
? t ?
1 ? ? ?
K
MAX1777
MAX1977
T1
10 μ H
1:2.2
DL_
T1 = TRANSPOWER TECHNOLOGIES TTI-5870
Figure 12. Transformer-Coupled Secondary Output
5V
MAIN
OUTPUT
28
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| ECS-F1HE335K | CAP TANT 3.3UF 50V 20% RADIAL |
| V300C3V3H50BG2 | CONVERTER MOD DC/DC 3.3V 50W |
| AMM18DTMS | CONN EDGECARD 36POS R/A .156 SLD |
| TH3D475M050D0900 | CAP TANT 4.7UF 50V 20% 2917 |
| ADP199ACBZ-R7 | IC HIGH-SIDE LOAD SWITCH 8WLCSP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1999EVKIT | 功能描述:DC/DC 开关控制器 Evaluation Kit for the MAX1777 MAX1977 MAX1999 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX199ACAI | 功能描述:模数转换器 - 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 |
| MAX199ACAI+ | 功能描述:模数转换器 - ADC 12Bit 8Ch 100ksps 4.18V 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 |
| MAX199ACAI+T | 功能描述:模数转换器 - ADC 12Bit 8Ch 100ksps 4.18V 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 |
| MAX199ACAI-T | 功能描述:模数转换器 - 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 |
发布紧急采购，3分钟左右您将得到回复。