Maxim MAX445CPG, MAX445C-D Datasheet

19-0302; Rev 0; 9/94

Low-Cost, High-Resolution, 200MHz

Video CRT Driver

_______________General Description

The MAX445 is a high-performance, monolithic, variable­gain transconductance amplifier with a high-voltage
open-collector output capable of directly driving a video
display (CRT cathode). A 2.5ns rise time is achieved
using a peaking network with a 200Ω load resistor and
an 8pF total load (CRT and parasitic capacitance).

Differential inputs and a linear adjustable gain stage
with an output offset adjustment make the versatile
MAX445 well suited for many video display applica­tions. A buffered bandgap reference voltage is avail­able for the gain (contrast) and offset adjustments
along with a TTL BLANK input to turn off the output cur­rent, independent of signal input.

The MAX445 is available in a 24-pin power-tab DIP
package. A suitable heatsink must be attached to
maintain the junction temperature within the recom­mended operating range.

________________________Applications

CRT Driver for High-Resolution Monochrome and
Color Displays

High-Voltage, Variable-Gain Transconductance
Amplifier

________________Functional Diagram

V

AA

____________________________Features

♦ 2.5ns Rise/Fall Time into an 8pF Load
♦ 200MHz Small-Signal Bandwidth
♦ 50Vp-p Output
♦ Ground Referenced Differential Inputs
♦ Linear Variable Gain for Contrast Control
♦ Offset Adjustment for Black Level
♦ 5.5V Bandgap Reference
♦ Drives 1280 x 1024 and 1530 x 1280 Displays

______________Ordering Information

PART

MAX445CPG
MAX445C/D 0°C to +70°C**

* Case temperature range, T

Maximum Ratings and Applications Information for thermal/heat
sink considerations.

**Dice are specified at TJ= +25°C, DC parameters only.

TEMP. RANGE PIN-PACKAGE

0°C to +70°C*

CASE

24 Power-Tab DIP
Dice

= 0°C to +90°C. See Absolute

__________________Pin Configuration

TOP VIEW

MAX445

R

VIN+

VIN-

GNDA

L

V

CONTRAST

BLANK

IOUT

MAX445

BAND

GAP

VREF

CURRENT

AMP

GND

PRE-AMP

OFFSET

________________________________________________________________

OUT

VCB

GND

VREF

OFFSET

CONTRAST

GNDA

VIN­VIN+

V

BLANK

GND

1
2
3
4

MAX445

5
6
7

V

EE

8

V

EE

9

CC

10
11
12

Power-Tab DIP

Maxim Integrated Products

Call toll free 1-800-998-8800 for free samples or literature.

GND

24

GND

23

GND

22

V

EEO

21

N.C.

20

IOUT

19

N.C.

18

VCB

17

VCB

16

GND

15

GND

14

GND

13

1

Low-Cost, High-Resolution, 200MHz
Video CRT Driver

ABSOLUTE MAXIMUM RATINGS

VAAOutput Supply.................................................................80V

Output Supply with Respect to VCB...............................70V

V

AA

VCB Common-Base Supply...................................................20V

Positive Supply............................................................12.5V

V

CC

Negative Supply..........................................................-12.5V

V

EE

Differential Input Voltage..........................................................2V

Common-Mode Input Voltage................................................±2V

MAX445

Contrast Input Voltage.................................................-1V to +6V

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

ELECTRICAL CHARACTERISTICS

(VAA= 20V, VCB = 10V ±0.5V, VCC= 10V ±0.5V, VEE= -10.5V ±0.5V, VIN = (VIN+) - (VIN-) = 0V, CONTRAST = 1.0V,
OFFSET = 1.0V, R

Output-Common-Base Supply Current
Positive Supply Current
Negative Supply Current

Low Blank Input Bias Current
High Blank Input Bias Current
Contrast Input Bias Current
Offset Input Bias Current
VIN+ or VIN- Signal Input Current

VIN+ or VIN- DC Input Impedance
VIN+ or VIN- Input Capacitance
Reference Output Voltage

Output Current (Blanked)

Output Current
Output Current Change vs. Temperature

Output Current Change vs. Contrast ADJ
Output Current Change vs. VIN, Blanked

Amplifier Linearity Error (∆Gm/∆VIN)
Contrast Linearity Error (∆Gm/∆Contrast)

= 0Ω, BLANK = 0.4V, T

L

to VIN

OUT

= +25°C, unless otherwise noted.)

CASE

CB

CC

I

VEE

VCC, VEE= ±5%, VIN = +250mV,
CONTRAST = 5.0V, referred to input

BLANK = 0.4V

IL

BLANK = 2.4V
CONTRAST = 5.0V
OFFSET = 1.0V

VCM= ±0.5V, CONTRAST = 5.0V

IN

I

LOAD

BLANK = 2.4V, OFFSET = 1V, VAA= 75V
BLANK = 2.4V, OFFSET = 3V
OFFSET = 0V, CONTRAST = 4.0V
OFFSET = 5.0V, CONTRAST = 1V
TC= +25°C to +90°C
CONTRAST = 0V to 5V

BLANK = 2.4V, CONTRAST = 5.0V,
∆VIN- = 0.3V

CONTRAST = 5.0V
CONTRAST = 1.0V
CONTRAST = 0V
CONTRAST = 4.0V, OFFSET = 1.0V
VIN = 0.2V, OFFSET = 0V
OFFSET = 0V, R

∆I

∆I

∆I

I

OUT

I

OUT

GmTransconductance, I

EE

IH
IC

IB
IS

VIN

REF

OUT
OUT

OUT

Offset Input Voltage.....................................................-1V to +6V

Blank Input Voltage.....................................................-1V to +6V

Bandgap-Reference Output Current...................................-5mA

Continuous Power Dissipation

derate at 170mW/°C above T

Operating Junction Temperature ......................-55°C to +150°C

Storage Temperature.........................................-55°C to +150°C

Lead Temperature (soldering, 10sec).............................+300°C

CONDITIONS

+ I

VEEO

= 2mA

= 100Ω

LOAD

= +90°C.......................10W

CASE

-0.1 25
80 140

400 600

70 120

-25 25

±1
±1

UNITSMIN TYP MAXSYMBOLPARAMETER

mA40I
mA70I
mA-100I

dB25PSRRPower-Supply Rejection Ratio

mA-0.6 0I
mA-0.4 0I

µA010I
µA010I
µA-50 50I
dB36CMRRInput Common-Mode Rejection Ratio
kΩ10R
pF2C

V5.25 5.75V

mA

mA
mA±3

mA±10
mA±1

mA/V

%±2
%±3

MHz200BWBandwidth, 3dB

2 _______________________________________________________________________________________

Low-Cost, High-Resolution, 200MHz

Video CRT Driver

ELECTRICAL CHARACTERISTICS (continued)

(VAA= 20V, VCB = 10V ±0.5V, VCC= 10V ±0.5V, VEE= -10.5V ±0.5V, VIN = (VIN+) - (VIN-) = 0V, CONTRAST = 1.0V,
OFFSET = 1.0V, R

Rise/Fall Time (10% to 90%)

Settling Time (90% to 100% ±2%)

= 0Ω, BLANK = 0.4V, T

L

= +25°C, unless otherwise noted.)

CASE

CONDITIONS

RL= 200Ω,

tr, t

CL= 8pF,

f

VAA= 75V,
tr(VIN) < 1ns,

CL= 8pF, no peaking

s

No peaking,
OUTp-p = 50V

With peaking,
OUTp-p = 45V

UNITSMIN TYP MAXSYMBOLPARAMETER

3.6
ns

2.5

ns8t

%±2Thermal Distortion

______________________________________________________________Pin Description

PIN

1, 12, 13, 14,

15, 22, 23, 24

2 VREF Reference Output (+5.5V)
3 OFFSET Output Voltage Offset-Adjustment Input
4 CONTRAST Output Gain-Adjustment Input
5 GNDA Pre-Amp Ground
6 VIN- Inverting Signal Input
7 VIN+ Noninverting Signal Input

8, 9 V

10 V

11 BLANK Blanking Input, TTL
16, 17 VCB Output Common-Base Supply (+10V)
18, 20 N.C. No Connection—leave open

19 IOUT Open-Collector Current Output

21 V

NAME FUNCTION

GND High-Current Ground. Connect all pins to ground plane.

EE

CC

EEO

Negative Supply (-10.5V)
Positive Supply (+10V)

Negative Supply for Output Stage (-10.5V)

MAX445

_______________________________________________________________________________________ 3