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参数资料
| 型号： | MAX1844EEP+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 20-QSOP |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 600kHz |
| 电源电压： | 4.5 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 20-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
High-Speed Step-Down Controller with
Accurate Current Limit for Notebook Computers
Therefore, V IN must be greater than 3.13V, even with
very large output capacitance, and a practical input volt-
age with reasonable output capacitance would be 3.48V.
PC Board Layout Guidelines
Careful PC board layout is critical to achieving low
switching losses and clean, stable operation. The switch-
ing power stage requires particular attention (Figure 9). If
possible, mount all of the power components on the top
side of the board, with their ground terminals flush
against one another. Follow these guidelines for good
PC board layout:
? Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable,
4) Make the DC-DC controller ground connections as
shown in Figure 9 . This diagram can be viewed as
having two separate ground planes: power ground,
where all the high-power components go; and an ana-
log ground plane for sensitive analog components.
The analog ground plane and power ground plane
must meet only at a single point directly at the IC.
5) Connect the output power planes directly to the out-
put filter capacitor positive and negative terminals
with multiple vias. Place the entire DC-DC converter
circuit as close to the load as is practical.
Pin Configuration
jitter-free operation.
? Keep the power traces and load connections short.
This practice is essential for high efficiency. Using
thick copper PC boards (2oz vs. 1oz) can enhance
full-load efficiency by 1% or more. Correctly routing
TOP VIEW
CS 1
LATCH 2
SHDN 3
20 DH
19 LX
18 BST
PC board traces is a difficult task that must be
approached in terms of fractions of centimeters,
where a single milliohm of excess trace resistance
causes a measurable efficiency penalty.
? Minimize current sensing errors by connecting CS
directly to the R SENSE terminal.
? When trade-offs in trace lengths must be made, it is
preferable to allow the inductor charging path to be
made longer than the discharge path. For example,
it is better to allow some extra distance between the
input capacitors and the high-side MOSFET than to
OVP 4
FB 5
OUT 6
ILIM 7
REF 8
UVP 9
PGOOD 10
MAX1844EEP
20 QSOP
17 SKIP
16 V+
15 TON
14 V CC
13 V DD
12 DL
11 GND
allow distance between the inductor and the low-
side MOSFET or between the inductor and the out-
put filter capacitor.
? Route high-speed switching nodes (BST, LX, DH, and
DL) away from sensitive analog areas (REF, FB, CS).
Layout Procedure
OVP
FB
1
2
20
19
18
17
16
15 BST
14 SKIP
1) Place the power components first, with ground termi-
nals adjacent (Q2 source, C IN- , C OUT- , D1 anode). If
possible, make all these connections on the top layer
with wide, copper-filled areas.
OUT
ILIM
REF
3
4
5
MAX1844EGP
MAX1844ETP
13 V+
12 TON
11 V CC
2) Mount the controller IC adjacent to MOSFET Q2,
preferably on the back side opposite Q2 in order to
6
7
8
9
10
keep LX, GND, and the DL gate-drive lines short and
wide. The DL gate trace must be short and wide,
measuring 10 to 20 squares (50 to 100 mils wide if the
MOSFET is 1 inch from the controller IC GND pin.
3) Group the gate-drive components (BST diode and
capacitor, V DD bypass capacitor) together near the
controller IC.
20 THIN QFN
Chip Information
TRANSISTOR COUNT: 2963
PROCESS: BiCMOS
______________________________________________________________________________________
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1844EGP | 功能描述:电流型 PWM 控制器 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 |
| MAX1844EGP+ | 功能描述:电流型 PWM 控制器 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 |
| MAX1844EGP-T | 功能描述:电流型 PWM 控制器 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 |
| MAX1844ETP | 功能描述:电流型 PWM 控制器 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 |
| MAX1844ETP+ | 功能描述:电流型 PWM 控制器 Step-Down Controller 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 |
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