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| 型号： | MC33997DW |
| 厂商： | Freescale Semiconductor |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | IC SWITCH 3.3/5V SUPPLY 24-SOIC |
| 标准包装： | 30 |
| 应用： | 切换电源，微处理器 |
| 输入电压： | 6 V ~ 26.5 V |
| 输出数： | 5 |
| 输出电压： | 3.3V，5V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 24-SOIC W |
| 包装： | 管件 |
FUNCTIONAL DESCRIPTION
INTRODUCTION
FUNCTIONAL DESCRIPTION
INTRODUCTION
The 33997 multi-output power supply integrated circuit is
capable of operating from 6.0 V up to 26.5 V with 40 V
transient capability. It incorporates a step-down switching
controller regulating directly to 5.0 V. The 3.3 V linear
regulator uses an external pass transistor, thus reducing the
power dissipation of the integrated circuit. The 33997 also
provides a 3.3 V linear standby regulator and two 5.0 V
sensor supply outputs protected by internal low-resistance
LDMOS transistors against short-to-battery and short-to-
ground.
FUNCTIONAL PIN DESCRIPTION
SWITCHING REGULATOR (VDDH)
The switching regulator is a high-frequency (750 kHz),
conventional buck converter with integrated high-side p-
channel power MOSFET. Its output voltage is regulated to
provide 5.0 V with ±2% accuracy and it is intended to directly
power the digital and analog circuits of the Electronic Control
Module (ECM). The switching regulator output is rated for
1400 mA total output current. This current can be used by the
linear regulator V DDL and sensor supplies V REF1 and
V REF2 . The 33997 switching controller utilizes "Sensorless
Current Mode Control" to achieve good line rejection and
stabilize the feedback loop. A soft-start feature is
incorporated into the 33997. When the device is enabled, the
switching regulator output voltage V DDH ramps up to about
half of full scale and then takes 16 steps up to the nominal
regulation voltage level (5.0 V nominal).
3.3 V LINEAR REGULATOR (VDDL)
The 3.3 V linear post-regulator is powered from the 5.0 V
switching regulator output (V DDH ). A discrete pass transistor
is used to the power path for the V DDL regulator. This
arrangement minimizes the power dissipation off the
controller IC. The FBL pin is the feedback input of the
regulator control loop and the DRVL pin the external NPN
pass transistor base drive. Power up, power down, and fault
management are coordinated with the 5.0 V switching
regulator.
SENSOR SUPPLIES (VREF1) AND (VREF2)
The sensor supplies are implemented using a protected
switch to the main 5.0 V (switching regulator) output. The
33997 integrated circuit provides two low-resistance LDMOS
power MOSFETs connected to the switching regulator output
(V DDH ). These switches have short-to-battery and short-to-
ground protection integrated into the IC. When a severe fault
conditions is detected, the affected sensor output is turned off
and the sensor Retry Timer starts to time out. After the Retry
Timer expires, the sensor supply tries to power up again.
Sensor supplies V REF can be disabled by pulling the Sensor
Enable SNSEN pin low (see Figure 9 for the V REF Retry
Timer operation).
Notes: Severe fault conditions on the V REF1 and V REF2
outputs, like hard shorts to either ground or battery, may
battery above 17 V are considered “double faults” and neither
one of the V REF outputs is protected against such conditions.
Depending on the V DDH capacitor value and its ESR
value, the severity of the short may disrupt the V DDH
operation.
KEEP-ALIVE REGULATOR, STANDBY (VKAM)
The Keep-Alive Regulator V KAM (keep-alive memory) is
intended to provide power for “key off” functions such as
nonvolatile SRAM, “KeyOff" timers and controls, KeySwitch
monitor circuits, and perhaps a CAN/SCP monitor and wake-
up function. It may also power other low-current circuits
required during a “KeyOff” condition. The regulated voltage is
nominally 3.3 V. A severe fault condition on the V KAM output
is signaled by pulling the VKAMOK signal low.
KEEP-ALIVE OPERATION STANDBY, POWER-
DOWN MODE (VKAM)
When the EN pin is pulled low, the power supply is forced
into a low-current standby mode. In order to reduce current
drawn by the V PWR and KA_V PWR pins, all power supply
functions are disabled except for the V KAM and Enable (EN)
pins. The latter pin is monitored for the "wake-up" signal. The
switching transistor gate is actively disabled and the V DDL
and V DDH pins are actively pulled low.
POWER-UP DELAY TIMERS
Two Power-Up Delay timers are integrated into the control
section of the integrated circuit. One timer monitors the input
voltage at the V PWR input pin (see Figure 5 ), and the other
monitors the input voltage at the KA_V PWR input pin . In both
cases, sufficient supply voltage must be present long enough
for the timers to “time out” before the switching regulator can
be enabled.
FAULT-OFF TIMER
If the V DDL output voltage does not reach its valid range
at the end of soft-start period, or if the V DDH or V DDL output
voltage gets below its PWROK threshold level, the Fault-Off
Timer shuts the switching regulator off until the timer “times
out” and the switching regulator retries to power up again
(see Figure 9 for Fault-Off Timer operation details).
disrupt the operation of the main regulator V DDH . Shorts to
33997
Analog Integrated Circuit Device Data
14
Freescale Semiconductor
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| MC33997DWR2 | 制造商:Rochester Electronics LLC 功能描述:MLPS 3.3 IC - Bulk |
| MC33999EK | 功能描述:多路器开关 IC 16 LOW SIDE PWM&SPI RoHS:否 制造商:Texas Instruments 通道数量:1 开关数量:4 开启电阻（最大值）:7 Ohms 开启时间（最大值）: 关闭时间（最大值）: 传播延迟时间:0.25 ns 工作电源电压:2.3 V to 3.6 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UQFN-16 |
| MC33999EK | 制造商:Freescale Semiconductor 功能描述:IC SWITCH 16 OUT SPI/PWM 54SOIC |
| MC33999EKR2 | 功能描述:多路器开关 IC 16 LOW SIDE PWM&SPI RoHS:否 制造商:Texas Instruments 通道数量:1 开关数量:4 开启电阻（最大值）:7 Ohms 开启时间（最大值）: 关闭时间（最大值）: 传播延迟时间:0.25 ns 工作电源电压:2.3 V to 3.6 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UQFN-16 |
| MC3399DW | 制造商: 功能描述: 制造商:undefined 功能描述: |
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