MODEL 25D MANUAL PRODUCT OVERVIEW:

Transcription

1 MODEL 25D MANUAL PRODUCT OVERVIEW: The Model 25D drive electronics is a high voltage push-pull power amplifier capable of output voltage swings in the order of 175v P-P, push-pull. The Model 25D provides output rep rates from DC-30MHz and typical rise and fall times of 8ns. 1

2 Specifications: Rise and Fall Time: Output Voltage Swing: Output Impedance: Bias Voltage: Input Signal: Input Impedance: Input AC Power: Cooling: <8ns (Typical with most Electro-Optic Modulators) >175v P-P push-pull. (Output Voltage is adjustable from approximately, 140v to 175v by front panel control) 100 Ohm Balanced Line Continuously adjustable between +/- 550v DC by front panel control Either TTL Compatible or Unipolar 0-1V, selectable by internal switch on driver assembly 50 ohms, either mode 100VAC to 240VAC 50/60Hz. Set by internal push-pin selectable and is set at time of shipment. Serial Number 5253 and above use wide range power supplies. Forced air-cooling. (Total dissipation approx. 350W). Dimensions: The dimensions are 45cm W x 44cm L x 17.5cm H. The weight is 32lbs Environmental Conditions: Typical lab use. Technical Overview: The Model 25D has a maximum output of 175v p-p. The output stage is the only saturating part of the amplifier. Although the amplifier accepts standard TTL drive levels as its input, the entire 2

3 amplifier, with the exception of the output stage, is linear. At the very input of the amplifier, a switch allows the user to select either TTL or Low-Level Analog as its required input format. TTL Input: (Logic high >+2v, <+4.5v, Logic low <+.8v) This input mode employs a S140 line driver as a buffer between the input signal entering the system and the power amplifier. This allows the user some latitude on logic highs and lows at the input. As the input section of the amplifier is linear, it is important to not drive this section of the amplifier into saturation and cutoff. Because of the on-board line driver, the input signals may be rather poor and still the internal line driving gate delivers the required signal to the amplifier. Analog Input: This input mode is included to allow operation of the Model 25D with the Model 305 Synchronous Countdown. The Model 305 outputs a 0 to +1v, high-speed analog pulse which is used to operate the Model 25D in the Pulse-Picking mode. The Analog input should only be selected when driven by the Model 305 Note: For most applications, the TTL input mode is selected. The only exception is when the Model 25D is configured with the Model 305 Synchronous Countdown for use as a Pulse Picker. In either configuration, the input impedance is 50 ohms. All signal levels should be checked with an oscilloscope with the signal terminated in 50 ohms before applying to the driver input. Care should be taken when using a function generator or pulse generator, as output levels from these instruments can easily exceed the max Vih allowed for the S140 buffer in the driver. Pulse Selection: The Analog Mode is selected and configured at the factory when mated to the Model 305. The pulse width from the Analog out of the M305 and the M25D is fixed at approximately 18ns. If the driver is to be used for wider pulse widths, an external pulse generator may be used with adjustable pulse widths and rep rates. The driver is completely DC coupled and will accept any pulse format from DC to 30MHz. The minimum and maximum pulse width is determined by the setting of the pulse generator. 3

4 Controls and Indicators: Drive Voltage control allows the end user to set the P-P output of the amplifier to the proper level for the modulator and the wavelength of operation. Limits are 175v max and 138v min. This is typically set by the user while monitoring the detected output of the system with an oscilloscope. Bias Voltage Adjustment control allows the end user to set the static DC bias on the modulator which sets the quiescent optical operating point. For example, when the system is being used as a high-speed shutter, the user might set the throughput intensity of the system to minimum at logic low input level. Then, when the input signal goes to logic high, maximum throughput intensity is obtained. The inverse may be obtained by setting the Bias at maximum transmission with logic low input. Then when the input goes high, minimum transmission is obtained. Bias Voltage Meter is an analog volt meter that indicates the actual differential bias voltage applied to the modulator. This voltage is not referenced to ground but is to the internal electrodes of the modulator. Bias voltage range is approximately, +/- 400vDC. 4

5 Equipment Installation: The Model 25D amplifier is designed for typical surface mounting. The rear panel s main connector provides a ground to earth the chassis. A power cord is included with the system. When installing, ensure that the top cover and rear panel are not blocked. A minimum of 6 behind the rear panel should be available for proper air flow. Proper cable routing is a best practice for Power Cord, Input Signal Cable and J1, J2, and J3 Modulator Connector Cables. The integrity of the unit may be impaired if used in a manner not intended or specified by Conoptics. Equipment Maintenance and Service: The Model 25D includes a 1-year Warranty on all parts and labor. The unit is not field serviceable. If an issue does arise, it is important to shut the system down and immediately contact Conoptics service department at support@conoptics.com. It is important to use a properly rated main power supply cord. Improperly rated power cords may cause overheating of the power cord. Fuse Info: The Model 25D incorporates a Series 326 Little Fuse Ceramic 3AB Slow Blow. 5

6 MODEL 25D INPUT SIGNAL FORMAT SELECTION SWITCH (S1) Up Position sets the input of the driver to accept a 0 to +1V input signal. Input impedance 50 ohms. The UP position is used for Pulse Selection Systems where the system is configured to include a Model 305 Synchronous Countdown. Down Position sets the input of the driver to accept a TTL logic level at the input connector on the rear panel. Input impedance is 50 ohms. Note: To change the input format switch, remove the top cover on the Model 25D driver electronics while the system is powered off. 6

7 MODEL 25D CONNECTION DIAGRAM FOR PULSE SELECTION SYSTEM (ANALOG SETTING) 7

8 MODEL 25D CONNECTION DIAGRAM TO PULSE GENERATOR (TTL SETTING) 8

9 MODEL 25D AMPLIFIER ELECTRONICS D D RED CR3 1N4007 CR2 1N4007 C3 30UF 500V + R8 100K 1/2W Q1 MJE350 R7 100K Q2 MJE350 R9 200 J1-550VDC C LP C2 30UF 500V + R4 100K 5W /2W D1 9 1N4742 V+ Vc Vz 7 V- U1 COMP UA VREF C1 100PF BLK C R6 R5 6.8K 6.8K B R3 R2 R1 B 470K 1W 50K 3.3K A A CONOPTICS INC. DANBURY, CT Size Document Number Rev A -550VDC BIAS SUPPLY Thursday, April 06, 2006 Date: Sheet of