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| 型号： | MAX1997ETJ+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/31页 |
| 文件大小： | 0K |
| 描述： | IC PWR SUPPLY TFT LCD 32TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 控制器，TFT LCD |
| 输入电压： | 2.7 V ~ 5.5 V |
| 输出数： | 5 |
| 输出电压： | 2.7 V ~ 13 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
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Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
Shutdown ( SHDN )
A logic-low signal on the SHDN pin disables all device
functions including the reference. During shutdown, the
supply current drops to 0.1μA (typ) to maximize battery
life. The output capacitance, feedback resistors, and load
current determine the rate at which each output voltage
decays. A logic-high signal on the SHDN pin activates the
MAX1997/MAX1998. (See the Power-Up Sequencing
section.) Do not leave the SHDN pin floating. Toggling
SHDN (below 0.4V) or cycling IN (below 2.2V) clears the
fault latch.
Power-Up Sequencing and
Inrush Current Control
Once SHDN is pulled high and the input voltage on IN
exceeds the rising input UVLO threshold (2.7V typ), the
reference turns on. With a 0.22μF REF bypass capacitor,
the reference reaches its regulation voltage of 1.25V in
approximately 1ms. When the reference voltage is ready,
the MAX1997/MAX1998 enable the oscillator and fault
detector. After the oscillator is enabled, the controller
(N1, Figure 1), which connects the main step-up regu-
lator output to the source driver ’ s supply pins.
Soft-Start
Each positive regulator (MAIN, REG P, REG 1, and REG
2) includes a 5-bit soft-start DAC whose input is the ref-
erence, and whose output is stepped in 32 steps from
zero up to the reference voltage. The soft-start DAC of the
negative regulator (REG N) steps from the reference
down to 125mV in 32 steps. The soft-start duration scales
with the switching frequency selected and is 2.73ms for
1.5MHz operation, 5.46ms for 750kHz operation, and
10.92ms for 375kHz operation.
SHUTDOWN
turns on the external P-channel MOSFET P1 (Figure 1) by
pulling GATE low. The GATE is pulled down with a 10μA
current source. Add a capacitor from the gate of P1 to its
SHDN = 0 OR
V IN NOT
PRESENT
SHDN = 1 AND
V IN PRESENT
drain to slow down the turn-on rate of the MOSFET,
which reduces inrush current.
To guarantee slow turn-on at lower V IN , add a series
ENABLE REF,
BIAS, AND UVLO
V IN < 2.7V
resistor between the GATE pin and the gate of the exter-
V IN < 2.7V
V IN > 2.7V
nal P-channel MOSFET. The typical value of the resistor
ranges between 100k ? and 200k ? . Once GATE reaches
approximately 0.6V, an internal N-channel MOSFET turns
on and pulls GATE to ground in order to maximize the
GATE NOT READY
ENABLE OSC,
OC COMP, GATE
CLEAR FAULT
enhancement of the external P-channel MOSFET. After P1
fully turns on, REG 1 and the fault counter are enabled.
GATE NOT READY
GATE READY
A logic-high signal on ONDC enables the main step-up
regulator and the sequence control block. The
sequence control state diagram is shown in Figure 7.
The unique sequence control block allows the positive
ONDC = 0
ENABLE REG 1
AND FAULT
COUNTER
ONDC = 0
ONDC = 1
ONDC = 0
gate-driver voltage (V G_ON ), negative gate-driver volt-
age (V G_OFF ), and the source-driver supply voltage
(V SOURCE ) to be turned on in any order. The capacitor
at the CT pin is kept discharged until the main step-up
BOOST SOFT-START
DONE AND V CT > ONP
V CT < ONP
ENABLE
BOOST, VCOM,
SEQUENCE
BLOCK
V CT < ON2
V CT > ON2
regulator is enabled. An internal 5μA current source
starts charging the CT capacitor and the CT voltage
ramps linearly up to approximately V IN . REG P, REG N,
and REG 2 are enabled when the CT voltage exceeds
their associated ON_ control inputs. In addition, the
ENABLE REG P
V CT > ONN V CT < ONN
ENABLE REG N
ENABLE REG 2,
DRVA HIGH
IMPEDANCE
positive linear regulator waits for the completion of the
main step-up regulator soft-start. The positive linear
regulator is controlled by ONP . The negative linear reg-
ulator is controlled by ONN . REG2 and the open-drain
output DRVA are controlled by ON2 . The DRVA signal
can be used to turn on an external N-channel MOSFET
Figure 7. Power-Up Sequence State Diagram
______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1997EVKIT | 制造商:Maxim Integrated Products 功能描述:QUINTUPLE/TRIPLE OUTPUT TFT LCD POWER SUPPLIE - Bulk |
| MAX19983A | 功能描述:上下转换器 RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985AETX+ | 功能描述:上下转换器 High-Gain 700MHz to 1GHz Downconv RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985AETX+T | 功能描述:上下转换器 High-Gain 700MHz to 1GHz Downconv RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985ETX+ | 功能描述:上下转换器 Dual, SiGe, .7-1GHz Downconversion Mixer RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
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