iC149 preliminary PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 1/8 FEATURES APPLICATIONS ♦ ♦ ♦ ♦ ♦ ♦ Pulse generator for fast laser diode drivers Pulse width 1 to 64 ns in steps of 0.25 ns Fixed crystal stabilised frequency of 1 MHz Variable frequency of 1 kHz to 2 MHz LVDS und TTL outputs Compatible with HG1D, NZN1D, NZP1D BOARD Copyright © 2013 iC-Haus http://www.ichaus.com preliminary iC149 PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 2/8 DESCRIPTION Pulse generator iC149 produces pulses with a small duty cycle in the range of ca. 1 ns up to 64 ns max. in steps of 0.25 ns at a pulse frequency of 1 MHz. The pulse width is set by means of two hexadecimal coding switches in coarse and fine steps. Alternatively a tunable (P1) oscillator can be used. The pulses are output both as LVDS and TTL signals. This module can easily be used with the evaluation boards HG1D, NZN1D and NZP1D. ELECTRICAL CHARACTERISTICS Operating Conditions: Ta = 25 °C Item No. Symbol Parameter Conditions Unit Min. Typ. Max. 5 5.5 Power Supply 101 102 V5 Power Supply I(V5) Supply Current V5 = 5 V, S1 = ON/OFF, TRIGGER open V5 = 5 V, S1 = ON, TRIGGER 50 Ω vs. Ground 4.5 V 50 75 mA mA Pulse Width 201 Tpmax Maximum Pulsweite V5 = 5 V, Ta = 27 °C, coarse = "F", fine = "F" 63.75 ns 202 Tpmin Minimum Pulsweite V5 = 5 V, Ta = 27 °C, coarse = "0", fine ≤ "F" cf. Figure 6 1 ns preliminary iC149 PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 3/8 PIN CONFIGURATION J1 Figure 1: The populated PCB Figure 2: Pin configuration J1 (PCB bottom view) 16 pole pin header for power supply and signal outputs J2 RJ45 connector for output signals with LVDS or TTL/CMOS levels J3 TRIGGER: SMA connector for trigger output, Rout = 50 Ω JP1 Jumper at position 1-2 selects TTL/CMOS signals for J2 JP2 Jumper at position 1-2: variable frequency from 10 kHz to 2 MHz Jumper at position 2-3: variable frequency from 1 to 100 kHz JP3 Jumper at position 1-2: crystal stabilised fixed frequency of 1 MHz Jumper at position 2-3: variable frequency from 1 kHz to 2 MHz (see JP2) S1 Oscillator ON/OFF S2 Selector switch: programmable pulse or symmetrical 1 MHz signal S3 Coding switch fine S4 Coding switch coarse TP1 LVDS signal at J1 (must be terminated with 100 Ω for measurement purpose) TP2 LVDS signal at J1 TP3 TTL/CMOS signal at J1 TP4 LVDS signal at J2 P1 Trimmer for setting the variable frequency GND GND V5 5 V Power supply 3V3 3.3 V Table 2: Connectors on the PCB iC149 preliminary PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 4/8 BLOCK DIAGRAM Figure 3: Block diagram of the iC149 VARIABLE OSCILLATOR Figure 4: Variable frequency vs. potentiometer setting preliminary iC149 PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 5/8 SETTING THE PULSE WIDTH ∆T = (m ∗ 4 ns + n ∗ 0.25 ns) ± 2 ns 1 ≤ m (coarse) ≤ 15, 0 ≤ n (fine)) ≤ 15 ∆T = (m ∗ 4 ns + 3.75 ns) ± 2 ns 1 ≤ m (coarse) ≤ 15, n (fine)) = 15 Figure 5: Setting the pulse width "coarse" Figure 6: Setting the pulse width "fine", with respect to the supply voltage and device parameter variation iC149 preliminary PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 6/8 SAMPLE PULSES Figure 7: In pulse mode (S2 left hand position) the rising edge of the trigger signal and the LVDS appear simultaneously. The TTL/CMOS has an approx. 1 ns delay. Figure 8: In the symmetrical mode (S2 right hand position) the rising edge of the trigger signal has an approx. 20 ns delay with reference to the output signals. Figure 9: Maximum pulse width at switch setting "FF" Figure 10: Minimum pulse width at switch setting "0B" iC149 preliminary PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 7/8 Figure 11: Minimum variable frequency, JP3 = 2-3, JP2 = 2-3, P1 = CCW Figure 12: Maximum variable frequency, JP3 = 2-3, JP2 = 2-3, P1 = CW Figure 13: Minimum variable frequnecy, JP3 = 2-3, JP2 = 1-2, P1 = CCW Figure 14: Maximum variable frequency, JP3 = 2-3, JP2 = 1-2, P1 = CW Figure 15: Fixed frequency 1 MHz, JP3 = 1-2 iC149 preliminary PROGRAMMABLE ns-PULSE GENERATOR Rev A2, Page 8/8 iC-Haus expressly reserves the right to change its products and/or specifications. 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