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参数资料
| 型号： | MAX1858EEG+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/21页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 660kHz |
| 占空比： | 90% |
| 电源电压： | 4.75 V ~ 23 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： | 24-SSOP（0.154"，3.90mm 宽） |
| 包装： | 管件 |
Dual 180° Out-of-Phase PWM Step-Down
Controller with Power Sequencing and POR
Pin Description (continued)
PIN
14
15
16
17
18
19
20
21
22
23
24
NAME
DH1
LX1
BST1
DL1
PGND
V L
DL2
BST2
LX2
DH2
EN
FUNCTION
High-Side Gate Driver Output for Regulator 1 (REG1). DH1 swings from LX1 to BST1.
External Inductor Connection for Regulator 1 (REG1). Connect LX1 to the switched side of the
inductor. LX1 serves as the lower supply rail for the DH1 high-side gate driver.
Boost Flying-Capacitor Connection for Regulator 1 (REG1). Connect BST1 to an external ceramic
capacitor and diode according to Figure 1.
Low-Side Gate-Driver Output for Regulator 1 (REG1). DL1 swings from PGND to V L .
Power Ground
Internal 5V Linear-Regulator Output. Supplies the regulators and powers the low-side gate drivers
and external boost circuitry for the high-side gate drivers.
Low-Side Gate-Driver Output for Regulator 2 (REG2). DL2 swings from PGND to V L .
Boost Flying-Capacitor Connection for Regulator 2 (REG2). Connect BST2 to an external ceramic
capacitor and diode according to Figure 1.
External Inductor Connection for Regulator 2 (REG2). Connect LX2 to the switched side of the
inductor. LX2 serves as the lower supply rail for the DH2 high-side gate driver.
High-Side Gate-Driver Output for Regulator 2 (REG2). DH2 swings from LX2 to BST2.
Active-High Enable Input. A logic low shuts down both controllers. Connect to V L for always-on
operation.
Detailed Description
DC-DC PWM Controller
The MAX1858 step-down converters use a PWM volt-
age-mode control scheme (Figure 2) for each out-of-
phase controller. The controller generates the clock
signal by dividing down the internal oscillator or SYNC
input when driven by an external clock, so each con-
troller ’ s switching frequency equals half the oscillator
frequency (f SW = f OSC /2). An internal transconductance
error amplifier produces an integrated error voltage at
the COMP pin, providing high DC accuracy. The volt-
age at COMP sets the duty cycle using a PWM com-
parator and a ramp generator. At each rising edge of
the clock, REG1 ’ s high-side N-channel MOSFET turns
on and remains on until either the appropriate duty
cycle or until the maximum duty cycle is reached.
REG2 operates out-of-phase, so the second high-side
MOSFET turns on at each falling edge of the clock.
During each high-side MOSFET ’ s on-time, the associat-
ed inductor current ramps up.
During the second-half of the switching cycle, the high-
side MOSFET turns off and the low-side N-channel
MOSFET turns on. Now the inductor releases the stored
energy as its current ramps down, providing current to
the output. Under overload conditions, when the induc-
tor current exceeds the selected valley current-limit
(see the Current-Limit Circuit (ILIM_) section), the high-
side MOSFET does not turn on at the appropriate clock
edge and the low-side MOSFET remains on to let the
inductor current ramp down.
Synchronized Out-of-Phase Operation
The two independent regulators in the MAX1858 oper-
ate 180 ° out-of-phase to reduce input filtering require-
ments, reduce electromagnetic interference (EMI), and
improve efficiency. This effectively lowers component
cost and saves board space, making the MAX1858
ideal for cost-sensitive applications.
Dual-switching regulators typically operate both con-
trollers in-phase, and turn on both high-side MOSFETs
at the same time. The input capacitor must then sup-
port the instantaneous current requirements of both
controllers simultaneously, resulting in increased ripple
voltage and current when compared to a single switch-
ing regulator. The higher RMS ripple current lowers effi-
ciency due to power loss associated with the input
capacitor ’ s effective series resistance (ESR). This typi-
cally requires more low-ESR input capacitors in parallel
to minimize input voltage ripple and ESR-related loss-
es, or to meet the necessary ripple-current rating.
_______________________________________________________________________________________
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相关代理商/技术参数 |
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|---|---|
| MAX1858EEG+ | 功能描述:电压模式 PWM 控制器 Dual 180 Out Buck Controllers RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1858EEG+T | 功能描述:电压模式 PWM 控制器 Dual 180 Out Buck Controllers RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1858EEG-T | 功能描述:DC/DC 开关控制器 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 |
| MAX1858EVKIT | 功能描述:DC/DC 开关控制器 Evaluation Kit for the MAX1858 MAX1875 MAX1876 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 |
| MAX185ACNG | 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 |
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