iC149
preliminar y
Rev A0.2, Page 1/6
PROGRAMMABLE ns-PULSE GENERATOR
FEATURES
o
o
o
o
Pulse width 1 bis 64 ns in steps of 0.25 ns
Fixed frequency of 1 MHz
LVDS und TTL outputs
Compatible with HG1D, NZN1D, NZP1D
APPLICATIONS
o
Pulse generator for fast laser
diode drivers
BLOCK DIAGRAM
Copyright © 2011 iC-Haus
http://www.ichaus.com
iC149
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Rev A0.2, Page 2/6
PROGRAMMABLE ns-PULSE GENERATOR
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 cod-
ing switches in coarse and fine steps.
The pulses are output both as LVDS and TTL signals.
This module can easily be used with the evaluation
boards HG1D, NZN1D ans NZP1D.
ELECTRICAL CHARACTERISTICS
Test Conditions: Vs = ±15 V, Ta = 25 °C, System Impedace 50
Ω
Item
No.
101
102
Symbol
Parameter
Conditions
Min.
V5
I(V5)
Power Supply
Supply Current
V5 = 5 V, S1 = OFF
V5 = 5 V, S1 = ON, TRIGGER open
V5 = 5 V, S1 = ON, TRIGGER 50
Ω
vs. Ground
V5 = 5 V, Ta = 27 °C,
coarse
= "F",
fine
= "F"
V5 = 5 V, Ta = 27 °C,
coarse
= "0",
fine
= "C"
4.75
Typ.
5
45
50
75
63.75
1
Max.
5.25
V
mA
mA
mA
ns
ns
Unit
Power Supply
Pulse Width
201
202
Tp
max
Tp
min
Maximum Pulsweite
Minimum Pulsweite
iC149
preliminar y
Rev A0.2, Page 3/6
PROGRAMMABLE ns-PULSE GENERATOR
SETTING THE PULSE WIDTH
Typical pulse widths as follows (measured values in
parentheses):
m = 15
m = 14
m = 13
m = 12
m = 11
m = 10
m= 9
m= 8
m= 7
m= 6
m= 5
m= 4
m= 3
m= 2
m= 1
∆T
= 15 * 4 ns = 60 ns
∆T
= 14 * 4 ns = 56 ns
∆T
= 13 * 4 ns = 52 ns
∆T
= 12 * 4 ns = 48 ns
∆T
= 11 * 4 ns = 44 ns
∆T
= 10 * 4 ns = 40 ns
∆T
= 9 * 4 ns = 36 ns
∆T
= 8 * 4 ns = 32 ns
∆T
= 7 * 4 ns = 28 ns
∆T
= 6 * 4 ns = 24 ns
∆T
= 5 * 4 ns = 20 ns
∆T
= 4 * 4 ns = 16 ns
∆T
= 3 * 4 ns = 12 ns
∆T
= 2 * 4 ns = 8 ns
∆T
= 1 * 4 ns = 4 ns
(60.2 ns)
(56.4 ns)
(52.3 ns)
(48.7 ns)
(44.7 ns)
(40.9 ns)
(36.7 ns)
(32.6 ns)
(28.7 ns)
(24.7 ns)
(20.2 ns)
(15.7 ns)
(12.4 ns)
(7.5 ns)
(3.0 ns)
n = 15
n = 14
n = 13
n = 12
n < 12
∆T
= 2.8 ns ±0.4ns
∆T
= 2.5 ns ±0.4ns
∆T
= 2.2 ns ±0.4ns
∆T
= 1.0 ns ±0.4ns
∆T
= 0.0 ns
(2.8 ns)
(2.6 ns)
(2.1 ns)
(1.1 ns)
Table 4: m = 0 (coarse) und n
≥
12 (fine)
Formula to calculate the pulse width:
∆T
= (m
∗
4
ns
+
n
∗
0.25
ns)
±
2
ns
1
≤
m (coarse)
≤
15,
0
≤
n (fine))
≤
15,
m = 0 s. Tab. 4
Table 2: m = 1...15 (coarse), n = 0 (fine)
n = 15
n = 14
n = 13
n = 12
n = 11
n = 10
n= 9
n= 8
n= 7
n= 6
n= 5
n= 4
n= 3
n= 2
n= 1
n= 0
∆T
= 4 ns + 15 * 0.25 ns = 7.75 ns
∆T
= 4 ns + 14 * 0.25 ns = 7.50 ns
∆T
= 4 ns + 13 * 0.25 ns = 7.25 ns
∆T
= 4 ns + 12 * 0.25 ns = 7.00 ns
∆T
= 4 ns + 11 * 0.25 ns = 6.75 ns
∆T
= 4 ns + 10 * 0.25 ns = 6.50 ns
∆T
= 4 ns + 9 * 0.25 ns = 6.25 ns
∆T
= 4 ns + 8 * 0.25 ns = 6.00 ns
∆T
= 4 ns + 7 * 0.25 ns = 5.75 ns
∆T
= 4 ns + 6 * 0.25 ns = 5.50 ns
∆T
= 4 ns + 5 * 0.25 ns = 5.25 ns
∆T
= 4 ns + 4 * 0.25 ns = 5.00 ns
∆T
= 4 ns + 3 * 0.25 ns = 4.75 ns
∆T
= 4 ns + 2 * 0.25 ns = 4.50 ns
∆T
= 4 ns + 1 * 0.25 ns = 4.25 ns
∆T
= 4 ns + 0 * 0.25 ns = 4.00 ns
(7.2 ns)
(6.8 ns)
(6.5 ns)
(6.2 ns)
(6.0 ns)
(5.8 ns)
(5.5 ns)
(4.9 ns)
(4.5 ns)
(4.4 ns)
(4.3 ns)
(4.1 ns)
(3.9 ns)
(3.5 ns)
(3.2 ns)
(3.0 ns)
Table 3: m = 1 (coarse), n = 1...15 (fine)
iC149
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Rev A0.2, Page 4/6
PROGRAMMABLE ns-PULSE GENERATOR
PIN CONFIGURATION
J1
16 pole pin header for power supply and sig-
nal 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
S1
Oscillator ON/OFF
S2
Selector switch: programmable pulse or sym-
metrical 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
GND GND
V5
V5
3V3 3.3 V
Table 5: Connectors on the PCB
Figure 1: The populated PCB
Figure 2: Pin configuration J1
iC149
preliminar y
Rev A0.2, Page 5/6
PROGRAMMABLE ns-PULSE GENERATOR
SAMPLE PULSES
Figure 3: Maximum pulse width
Figure 5: Trigger and LVDS pulse
Figure 4: Minimum pulse width
Figure 6: Trigger and 1 MHz LVDS signal
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