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| 型号： | MAX1967EUB+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/15页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 127kHz |
| 占空比： | 95% |
| 电源电压： | 2.7 V ~ 28 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： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
Low-Cost Voltage-Mode PWM
Step-Down Controllers
Detailed Description
The MAX1966/MAX1967 are BiCMOS switch-mode
power-supply controllers designed to implement sim-
ple, buck-topology regulators in cost-sensitive applica-
tions. The main power-switching circuit consists of two
N-channel MOSFETs (or a dual MOSFET), an inductor,
and input and output filter capacitors. An all N-channel
synchronous-rectified design provides high efficiency
at reduced cost. Gate drive for the N-channel high-side
switch is provided by a flying capacitor boost circuit
that uses a 0.1μF capacitor connected to BST.
Major circuit blocks of the MAX1966/MAX1967 are
shown in Figures 1 and 2:
fully off. There must be a low-resistance, low-inductance
connection from the DL driver to the MOSFET gate for
the adaptive dead-time circuit to work properly.
Otherwise, the sense circuitry in the MAX1966/
MAX1967 detects the MOSFET gate as off while there
is charge left on the gate. Use very short, wide traces
measuring no less than 50mils to 100mils wide if the
MOSFET is 1in away from the MAX1966/MAX1967. The
same type of adaptive dead-time circuit monitors the
DH off edge. The same recommendations apply for the
gate connection of the high-side MOSFET.
The internal pulldown transistor that drives DL low is
robust, with a 1.1 ? typical on-resistance. This helps
prevent DL from being pulled up due to capacitive cou-
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Control Logic
Gate Driver Outputs
Current-Limit Comparator
Clock Generator
Ramp Generator
Error Amplifier
Error Comparator
Soft-Start
5V Linear Regulator (MAX1967)
800mV Reference
Thermal Shutdown
pling from the drain to the gate of the low-side synchro-
nous-rectifier MOSFET during the fast rise time of the
inductor node. The gate drivers are capable of driving
up to 1A. Use MOSFETs with combined total gate
charge of less than 200nC and a maximum V TH of 3.5V.
Internal Soft-Start
The MAX1966/MAX1967 feature an internally set soft-
start function that limits inrush current. It accomplishes
this by ramping the internal reference input to the con-
troller transconductance amplifier from 0 to the 0.8V
reference voltage. The ramp time is 1024 oscillator
cycles that begins when initial power is applied. At the
nominal 100kHz switching rate, the soft-start ramp is
approximately 10ms. The soft-start does not function if
In the MAX1996, most blocks are powered from V IN . In
the MAX1967, an internal 5V linear regulator steps
down the input voltage to supply both the IC and the
gate drivers. The synchronous-rectified gate driver is
directly powered from 5V V L , while the high-side-switch
gate driver is indirectly powered from V L plus an exter-
nal diode-capacitor boost circuit.
Resistorless Current Limit
The MAX1966/MAX1967 use the R DS(ON) of the low-
side N-channel MOSFET to sense the current. This
eliminates the need for an external sense resistor usual-
ly placed in series with the output. The voltage mea-
sured across the low-side R DS(ON) is compared to a
fixed -305mV reference (Figures 1 and 2) . The peak
inductor current limit is given by the equation below:
I PEAK = 305 mV / R DS ( ON )
MOSFET Gate Drivers
The DH and DL drivers are optimized for driving
MOSFETs with low gate charge. An adaptive dead-time
circuit monitors the DL output and prevents the high-
side FET from turning on until the low-side MOSFET is
the MAX1966/MAX1967 are shut down by pulling
COMP/EN low.
High-Side Gate-Drive Supply (BST)
Gate-drive voltage for the high-side N-channel switch is
generated by a flying-capacitor boost circuit (Figures 3
and 4). The flying capacitor is connected between BST
and LX.
On startup, the synchronous rectifier (low-side MOS-
FET) forces LX to ground and charges the boost
capacitor to 5V. On the second half-cycle, the
MAX1966/MAX1967 turn on the high-side MOSFET by
closing an internal switch between BST and DH. This
provides the necessary gate-to-source voltage to drive
the high-side FET gate above its source at the input
voltage.
Internal 5V Linear Regulator
(MAX1967)
All MAX1967 functions are internally powered from an
on-chip, low-dropout 5V regulator. The MAX1967 has a
maximum regulator input voltage (V VIN ) of 28V. The
VCC pin must be connected to VL through a 10 ? resis-
tor and VL must be bypassed with a 2.2μF capacitor to
GND. For operation at V VIN < 5V, connect VL to VIN
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| MAX19681EXW+D | 制造商:Maxim Integrated Products 功能描述:12-BIT, 1.5GSPS HIGH-DYNAMIC PERFORMANCE DAC - Rail/Tube |
| MAX1968EUI | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
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| MAX1968EUI+T | 功能描述:功率驱动器IC Power Driver for Peltier TEC Modules RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX1968EUI-T | 功能描述:功率驱动器IC RoHS:否 制造商:Micrel 产品:MOSFET Gate Drivers 类型:Low Cost High or Low Side MOSFET Driver 上升时间: 下降时间: 电源电压-最大:30 V 电源电压-最小:2.75 V 电源电流: 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
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