参数资料
型号: MAX6921AQI+T
厂商: Maxim Integrated
文件页数: 7/13页
文件大小: 0K
描述: IC DRVR VFD TUBE SRL 28-PLCC
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 500
显示器类型: 真空荧光 (VF)
接口: 4 线串行
电流 - 电源: 1.65mA
电源电压: 8 V ~ 76 V
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 28-LCC(J 形引线)
供应商设备封装: 28-PLCC(11.51x11.51)
包装: 带卷 (TR)
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
V BB
40 ?
TYPICAL
V BB
40 ?
TYPICAL
SLEW-RATE
CONTROL
750 ?
TYPICAL
OUT_
SLEW-RATE
CONTROL
750 ?
TYPICAL
OUT_
V SS
Figure 2. MAX6921 CMOS Output Driver Structure
Detailed Description
The MAX6921/MAX6931 are VFD tube drivers compris-
ing a 4-wire serial interface driving 20 high-voltage rail-
to-rail output ports. The driver is suitable for both static
and multiplexed displays.
The output ports feature high current-sourcing capabili-
ty to drive current into grids and anodes of static or
multiplex VFDs. The ports also have active current sink-
ing for fast discharge of capacitive display electrodes
in multiplexing applications.
The 4-wire serial interface comprises a 20-bit shift reg-
ister and a 20-bit transparent latch. The shift register is
written through a clock input CLK and a data input DIN.
For the MAX6921, the data propagates to a data output
DOUT. The data output allows multiple drivers to be
cascaded and operated together. The output latch is
transparent to the shift register outputs when LOAD is
high, and latches the current state on the falling edge
of LOAD.
Each driver output is a slew-rated controlled CMOS
push-pull switch driving between V BB and GND
(MAX6921) or V SS (MAX6931). The output rise time is
always slower than the output fall time to avoid shoot-
through currents during output transitions. The output
slew rates are slow enough to minimize EMI, yet are
fast enough so as not to impact the typical 100μs digit
multiplex period and affect the display intensity.
Initial Power-Up and Operation
An internal reset circuit clears the internal registers of
the MAX6921/MAX6931 on power-up. All outputs OUT0
to OUT19 and the interface output DOUT (MAX6921
only) initialize low regardless of the initial logic levels of
the CLK, DIN, BLANK, and LOAD inputs.
Figure 3. MAX6931 CMOS Output Driver Structure
4-Wire Serial Interface
The MAX6921/MAX6931 use 4-wire serial interface with
three inputs (DIN, CLK, LOAD) and a data output
(DOUT, MAX6921 only). This interface is used to write
output data to the MAX6921/MAX6931 (Figure 4) (Table
1). The serial interface data word length is 20 bits,
D0–D19.
The functions of the four serial interface pins are:
? CLK input is the interface clock, which shifts data
into the MAX6921/MAX6931s’ 20-bit shift register on
its rising edge.
? LOAD input passes data from the MAX6921/
MAX6931s’ 20-bit shift register to the 20-bit output
latch when LOAD is high (transparent latch), and
latches the data on LOAD’s falling edge
? DIN is the interface data input, and must be stable
when it is sampled on the rising edge of CLK.
? DOUT is the interface data output, which shifts data
out from the MAX6921’s 20-bit shift register on the
rising edge of CLK. Data at DIN is propagated
through the shift register and appears at DOUT (20
CLK cycles + t DO ) later.
A fifth input, BLANK, can be taken high to force outputs
OUT0 to OUT19 low, without altering the contents of the
output latches. When the BLANK input is low, outputs
OUT0 to OUT19 follow the state of the output latches. A
common use of the BLANK input is PWM intensity control.
The BLANK input’s function is independent of the oper-
ation of the serial interface. Data can be shifted into the
serial interface shift register and latched regardless of
the state of BLANK.
_______________________________________________________________________________________
7
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MAX6921AUI 功能描述:VFD驱动器 12-Output 76V Serial VFD Tube Driver RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube
MAX6921AUI+ 功能描述:VFD驱动器 12-Output 76V Serial VFD Tube Driver RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube
MAX6921AUI+T 功能描述:VFD驱动器 12-Output 76V Serial VFD Tube Driver RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube
MAX6921AUI-T 功能描述:VFD驱动器 12-Output 76V Serial VFD Tube Driver RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube
MAX6921AWI 功能描述:VFD驱动器 12-Output 76V Serial VFD Tube Driver RoHS:否 制造商:Maxim Integrated 工作电源电压:8 V to 76 V, 3 V to 5.5 V 电源电流:0.9 mA, 700 uA 最大工作温度:+ 125 C 封装 / 箱体:SOIC-20 封装:Tube