LH2440 NSC | Alldatasheet
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| CRT Preamplifier and Driver | General Description Features The LH2440 is a wide band amplifier for high resolution CRT 90 MHz bandwidth at 40 Vpp swing | monitors. The device includes a low level amplifier with DCm Rise/fall times of 4 ns contrast/brighiness contro! and circuitry for black level # OC contrast and brightness controls clamping to accomplish DC restoration. Also included is a ™ Externally gated comparator for DC restoration of video high voltage output stage to directly drive a CRT’s cathode. signal The LH2440 provides almost the entire circuitry needed ing Ease of use the video channel between the monitor input connection and the CRT cathode. Applications The LH2440 can swing 40 Vpp into an 8.5 pF load with 4S Video preamplifier and CRT driver for high resolution rise and fall times. The device requires minimum external monitors. components, thus, facilitating video amplifier design. More- " ‘over, high frequency bypassing for the high voltage amplifier is internally provided for ease of use. _[s internally provided Tor e890 ote Block and Connection Diagrams Voor Vocz d fin so Ke input ° > “> {2G Vout Veer High Voltage CAT: Video Amplifier Camp contrast Comparator T | 5] B 4 7 3 8] 9 10] Gnd Contrast Feedback Brightness care Galn Comp! Comp2_ sumrr0460-1 [3 12 Output (Bet Bite ee =e [} 7 Brightness Control TB oie a = 4 Feedback {J 3 Clamp Cate [——p 2 Contrast Control Fy 1 inpet | Order Number LH2440S or LH2440AS. See NS Package Number HY12A | ©1990 Nabona! Semiconductor Corpormton = TL/K/10460
| Absolute Maximum Ratings | If Milltary/Aerospace specified devices are required, Power Dissipation, Pp 7w | please contact the National Semiconductor Sales Storage Temperature Range, Tsy¢ =40°C to +125°C | Office/Distributors for availability and specifications. Operating Temperature Range, Tse 20°C to + 80°C Supply Voltage, Voc 413.50 Lead Temperature (Soldering, < 10 Sec.) 300°C | Supply Voltage, Voce + 70V ESD Tolerance 2kv | Electrical Characteristics Voc1 = 12V, Veoz = 80V. CLoap = 8.5 pF, Vout = 40 Vep Swing with 30 Voc Offset Unless Otherwise Specified | Tease = 25°C Unless Otherwise Noted (Note 1). Unite ax Symbo! Parameter Conditions Tested Design Othenee (Note 2) | (Notes) | Noted) loot Supply Current | No Output Load feo | o | ‘| mA loca a [28 [vans Vou | Clamp Gate High Input V | Gimp Comparator OFF |_| 20 | | Wain lou Clamp Gate Low V4 = OV | [reweoree™ Toe | we Ts Voutioc) | Output Offset Voltage [ 3% | x4 | | Vv [_ [8] Vivi Oi | OutputVotage Range | r= Ovwoiey | ste | vowse | |v | ReeTine sd Sg = sn vewsd | 4] 6 | Ss 'e [ FaTime |e = 50M, tH2ag0A TT ns Avan VUMin) Avsv 10 FA Avev | Atenuaton'@ av van avd as | id ra Tei) [Ganon =i as Tgseoo | os | *+dS*dtCO er ie | Settingtine iw tee dC 18 Bw | Bandwani-oe5y | Yt] Os | Owesroot iP SSSSC—~ | i Wote 12 Boleface imis are guaranteed over full temperature range, Note 2: Tested mits are guaranteed and 100% production tested. Note 3: Design mts are guranteed (but not production tested) over he indicated temperature range. These limits ae notused to calculate outgoing gualty level ©1980 Navonal Semeonductor Corpomton
Applications Hints | OUTPUT INFORMATION SHORT CIRCUIT PROTECTION Precautions must be taken to prevent excessive overshoot ‘The LH2440 is designed to drive the capacitive load at the | and ringing caused by the inductance of the wire used to CRT's cathode and does not include short circuit protection. connect the LH2440's output to the CRT;s cathode. Since With no series current limiting resistor at the output, the the wire’s inductance and the capacitance at the cathode LH2440 will be destroyed if the output is inadvertantly short- | form an LC tank circuit when driven by the amplifier, at the ed to ground or V+. When driving a resistive load, it is reo- | resonant frequency the circuit may introduce overshoot and ommended that the load be greater than 6002. | ringing. A damping resistor in series with the output of the LH2440 can critically damp the output ringing. The resistor THERMAL CONSIDERATIONS | value may be calculated from the following equation: The LH2440 requires | that the package be heat sunk for . proper operation under any condition. The worst case pow- Damping Resistor, R > 24C7E er dissipation occurs during full scale transitions i.e., when where , L = Inductance of output wire verticie fines of black and white stripes are displayed on the C = Capacitance at CRT cathode screen. The amplifier's power dissipation depends on the Usually, a 602-1002 damping resistor is adequate. As an power supply voltage as well as operating frequency. For added advantage, the damping resistor also protects the instance at Voc) = 12V, Vogg = 60V, and 60 MHz (10ns | ampiifier’s output against arcing by providing current fimit- pixel), the power dissipation is 5 watts. Such high power | ing. Keep in mind that the damping resistor should not be dissipation demands that proper care be exercised to en- | too large; otherwise, the output signal's rise/fall time may sure sufficient heat sinking. be significantly affected due to the AC time constant formed LH2440's maximum ratings require that the device case by the damping resistor and the cathode’s capacitance. temperature be limited to 80°C. Thus at 50°C ambient tem- GROUND CONNECTION perature and § watts power dissipation, the thermal resist- . , ance of the heat sink should be less than (80°C — 50°C) = LH2440's ground connection is internally connected to the SOW. Several approaches to heat sinking may be taken, Package’s metal tab. Thus, for proper operation, the tab The simplest ig a slug of aluminum with a volume of 3 cu should be connected to the power supply ground. inches or a sheet of aluminum with an area of 30 sq. inches | and a thickness of 0.1 inches. Alternatively, commercially | available heat sinks may be used. | j ©1990 Natonel Semiconductor Corporation
Physical Dimensions inches (milimeters) | 250 9.240 0.125 ast 0.181 6.006 | xg tts 45? STO p08 s:73) os) “| Fr aosa 0.110 fy N Tio Y 0.25020.020 (635020.508) 0.70 2.104% ode j me | 1203 4 5 6 7 8 8 1 2 | ——t Uy t SEATING PLANE PIN NO.1 een | 4.050 £0.020 ar) a 14 x2-t0080.001 9.018-0022 0.008 - 0.015 (254020025) (0487-0558) (0203-0381) 12-Lead Single-In-Line Package (J) Order Number LH2440S LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT | DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or 2. A critical component is any component of a life systems which, (a) are intended for surgical implant support device or system whose failure to perform can into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life failure to perform, when properly used in accordance support device or system, or to affect its safety or with instructions for use provided in the labeling, can effectiveness. be reasonably expected to result in a significant injury to the user. a Watonel Semeondacior Nationa Semiconductor WS Japan LW. aional Semiconductor ‘ations! Semicondutores National Semiconductor ys Em = sac” Ss scape $3008 Samecomucter Ore lusnestase 19 nS New Straw — Sula $13, 5 Foor eg Fane Une, 1989 {et Fer #41 6c Mie A P.O. Bow 50000 Cave Fureanfeciruck Shinju Ghmscnsin Gotten Paz, 1b anorcon, 82 metewire, 008 Sans Cura, CA 05082-2000 Wes! Germany Toe 160, lacen 77 Mody Road, Tasha Enat, 01451 Seo Pauls SP, Bread clo, Auavale Tat (48) 721.8000 Tet (08-4) 1090 Tar3-2087001, Keven, rong Kom Tat Balm) 2124086 Ter 85) 267-6000 TWK: (G10) 30-0200 Toler 827-449 FacaaeTo | Terg7a3t Fax (5/11) 200-1909 NSBR BR Fax: BF-2-2677459 Fax: ©8144) 503854 Telee $2006 NSSEA HX Far 33112538 ‘asorel doe ol samme ry rexponati yor ve of wy Grainy cesonbed, re crout nlatcenaas ae imped and Metonalreeres the ght at any me wiht robe © change si ret and spect, © 1980 Netonal Semeonducier Corporation 21