MAX445 データシートの表示（PDF） - Maxim Integrated
部品番号
コンポーネント説明
メーカー
MAX445 Datasheet PDF : 8 Pages
| |||
Low-Cost, High-Resolution, 200MHz
Video CRT Driver
__________Applications Information
Differential Inputs
VIN+ and VIN- are differential video input pins designed
to allow DC coupling of a 0V to +1V signal into VIN+, with
respect to VIN-. For correct operation, it is recommend-
ed that the signals applied to these inputs be kept within
±1V, with respect to ground. Although large signals and
offsets can be handled safely without damage, exceed-
ing these limits may cause output linearity to suffer.
Contrast Control
The contrast control is the overall DC-gain control that
will vary the voltage gain from 0V/V to -90V/V (with a
200Ω load resistor). An internal reference supply pin,
VREF, provides the nominal 5.5V needed to drive the
contrast input. Normally, a 5kΩ potentiometer between
VREF and ground is used to vary the contrast, but an
external source can be used instead of VREF, with some
degradation of gain stability with temperature.
The contrast control is a linear relationship. Vary the
input from 0V to 5V to achieve a voltage-gain range of
0V/V to -90V/V. This yields the following relationship for
overall voltage gain of this device (for IOUT < 250mA):
VAA - VO = [VIN (Gm) + VOFFSET (0.02)] (RL)
VAA - VO = [VIN (VCONTRAST) (0.09) + VOFFSET (0.02)] (RL)
The MAX445’s overall gain can vary by ±20% due to
normal process variations of internal components. Also,
if multiple devices are used in a system, all devices
must track thermally (i.e., a common heatsink).
Offset Control
The offset control is used to set the output quiescent
current from 5mA to 110mA (typ) when the control input
is adjusted from 0V to 5V. Normally, offset is adjusted
using a 5kΩ potentiometer between VREF and ground.
Blank Control
When asserted (BLANK = TTL high), this input will dis-
able the video signal and allow the output to rise to the
VAA supply independent of offset control.
Bandgap Reference
VREF is a bandgap bias reference for easy adjustment
of the offset and contrast inputs. This reference has a
nominal output voltage of 5.5V ±5% that can source up
to 4mA.
VEE
(-10.5V)
D1
1N4152
50V
+10V
D2
1N4152
50V
BEAD* 24Ω
D3
1N486A
100V
5k
5k
ANALOG
INPUT
BLANK
0.1µF
0.1µF
10
2
VCC
VREF
3 OFFSET
16
VCB
17
VCB
0.1µF
25Ω
4 CONTRAST
6 VIN-
7 VIN+
MAX445
IOUT 19
50Ω 11 BLANK
GNDA GND VEE
5 24*
8
VEE
VEEO
9
21
VAA
(+75V)
10pF
22µF
100V
D4
L3
RL
200Ω
10W
CB
L2
L1
L1, L2, L3, AND CB ARE
ELEMENTS OF THE PEAKING COIL.
LS IS THE TOTAL INDUCTANCE
TO THE CATHODE. RS IS A SERIES
ARC PROTECTION ELEMENT.
CR
RS
100Ω
1
2
W
(CARBON)
LS
CL
NOTES:
CL COMBINES CRT CATHODE, AND PARASITIC C.
D4 (PHILIPS BAV20 OR HITACHI 1SS91) IS ARC PROTECTION DIODE.
SEE APPLICATIONS INFORMATION SECTION.
* STACK POLE 57-0180 OR
INDIANA GENERAL F-1650-H
0.1µF
Figure 1. Typical Connection Diagram
BEAD*
-10.5V
0.1µF
4 _______________________________________________________________________________________
Share Link: 