DEMO MANUAL DC2073B
LTC1799, LTC6900, LTC6905,
LTC6905-XXX, LTC6906, LTC6907
LTC6908 SOT23 Silicon Oscillators
DESCRIPTION
DC2073B demo board features Linear Technology's SOT23
packaged silicon oscillators. The DC2073B demo board is
available in eleven different options; DC2073B-A through
DC2073B-K. These eleven options provide for the evalu-
ation of resistor-set oscillator ICs and fixed frequency
ICs (Table1).
Design files for this circuit board are available at
http://www.linear.com/demo/DC2073B
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Table 1. Resistor-Set Oscillator ICs and Maximum Frequency Error at T
A
= 25°C
PART NUMBER, BOARD ASSEMBLY
LTC
®
6905,
DC2073B-A
LTC1799,
DC2073B-B
LTC6900,
DC2073B-C
LTC6905-133,
DC2073B-D
LTC6905-100,
DC2073B-E
LTC6905-96,
DC2073B-F
LTC6905-80,
DC2073B-G
LTC6906,
DC2073B-H
LTC6907,
DC2073B-I
LTC6908-1,
DC2073B-J
LTC6908-2,
DC2073B-K
FREQUENCY PROGRAM METHOD
Resistor Programmable
Resistor Programmable
Resistor Programmable
DESCRIPTION
17.225MHz ≤ f
OSC
≤ 170MHz, ±1.4% at V
+
= 2.7V
and ±2.2% at V
+
= 5V
5kHz ≤ f
OSC
≤ 10MHz, ±1.5% at V
+
= 3V and
±1.5% at V
+
= 5V (Up to 20MHz)
5kHz ≤ f
OSC
≤ 10MHz, ±1.5% at V
+
= 3V and
±1.5% at V
+
= 5V (Up to 20MHz)
Three Fixed Frequencies Set by Three-State Input f
OSC
= 133MHz, 66.7MHz and 33.5MHz,
±1.0% at V
+
= 3V and ±1.5% Typical at V
+
= 5V
Three Fixed Frequencies Set by Three-State Input f
OSC
= 100MHz, 50MHz and 25MHz,
±1.0% at V
+
= 3V and ±1.5% Typical at V
+
= 5V
Three Fixed Frequencies Set by Three-State Input f
OSC
= 96MHz, 48MHz and 24MHz,
±1.0% at V
+
= 3V and ±1.5% Typical at V
+
= 5V
Three Fixed Frequencies Set by Three-State Input f
OSC
= 80MHz, 40MHz and 20MHz,
±1.0% at V
+
= 3V and ±1.5% typical at V
+
= 5V
Resistor Programmable
Resistor Programmable
Spread Spectrum Modulation, Complementary
Outputs (0°/180°) Resistor Programmable
Spread Spectrum Modulation, Quadrature
Outputs (0°/90°) Resistor Programmable
10kHz ≤ f
OSC
≤ 1MHz, ±0.5% at V
+
= 2.7V to 3.6V
and ±0.7% at V
+
= 2.25V
400kHz ≤ f
OSC
≤ 4MHz, ±0.65% at V
+
= 3V to 3.6V
250kHz ≤ f
OSC
≤ 5MHz, ±1.5% at V
+
= 2.7V and
±2.0% at V
+
= 5V
250kHz ≤ f
OSC
≤ 5MHz, ±1.5% at V
+
= 2.7V and
±2.0% at V
+
= 5V
dc2073bfa
1
DEMO MANUAL DC2073B
QUICK START PROCEDURE
Test Equipment:
1. A single 3V power supply.
2. An oscilloscope with a bandwidth of at least 5x f
OSC
.
(For example, if f
OSC
= 100MHz then use a 500MHz
oscilloscope).
3. A screwdriver to adjust the potentiometer.
Note:
The DC2073B potentiometer is shorted with a
zero ohm resistor for factory testing. The zero ohm
(RJ10) resistor must be removed to allow setting the
frequency with a screwdriver. If the potentiometer is
set to a high value (>100k), then touching the DC2073B
can produce output jitter.
Basic Test Procedure:
1. Connect power supply to V
+
and GND, turrets E4 and E5.
2. Connect oscilloscope probe to OUT1 and GND.
Note: The ground lead of an oscilloscope probe has a
series inductance that can generate a resonant circuit
with the probe's capacitance. Probe resonance adds
transient peaks and ringing on a high speed wave-
form. Reliable probing of the high frequency LTC6905
and LTC6905-XXX (with corresponding demo boards
DC2073B-A, -D, -E, -F or -G), must use a very short
connection of the oscilloscope probe ground to the board
GND (see probe tip picture in Figure 1 Test Setup).
3. Set the JP1 jumper to the N divider position for the
desired frequency shown on Table2.
4. Turn on supply.
5. The oscilloscope display shows a 3V squarewave
(0V to 3V).
6. For the resistor-set ICs (DC2073B-A, -B, -C, -H, -I, -J
or -K) turn the RPOT potentiometer for the desired fre-
quency. (The frequency adjustment is very coarse when
the potentiometer is turned near the fully clockwise or
counter-clockwise position).
Verify Oscillator Accuracy
The f
OSC
accuracy of the resistor-set ICs (DC2073B-A, -B,
-C, -H, -I, -J or -K), can be verified by setting RSET to the
exact value from the f
OSC
equation shown in Table 2. For
the DC2073B-A, -B, -C, -J, -K, RSET = RPOT + RSET2.
RSET1 and RSET2 are never installed on the same board.
Connecting an ohmmeter across RPOT and RSET1 or
RSET2 forces current into the IC set pin (Pin 3 or 4) and
causes an error in the ohmmeter reading. The RS resistor
is in series with RPOT and equal to RSET1 or RSET2 and
the equivalent RSET = RPOT + RS.
Procedure to Verify Oscillator Accuracy
a. Calculate RSET for the desired frequency (RSET in Table 2).
b. Remove the power supply leads from DC2073B and con-
nect an ohmmeter from POT (E6) to V
+
(DC2073B-A,
-B, -C, -J or -K) or GND (DC2073B-H or-I).
C. Adjust RPOT for the exact value of RSET needed.
Note: If the potentiometer is turned near the fully clock-
wise or counter-clockwise position the RPOT adjustment
may be too coarse for setting an exact RSET value. In
addition, for a frequency adjustment near the upper or
lower f
OSC
range, RSET may be greater or less than the
default DC2073B RPOT + RSET1 or RSET2 value, in this
case the RSET1 or RSET2 resistor must be removed
and replaced with a lower or higher value.
2
dc2073bfa
DEMO MANUAL DC2073B
QUICK START PROCEDURE
Table 2. f
OSC
Frequency and N Divider Setting
LTC6905, DC2073B-A
168.5MHz •10kΩ
1
168.5MHz •10kΩ
f
OSC
=
+1.5MHZ
• , R
SET
=
R
SET
N• f
OSC
– 1.5MHz
N
N = 1 (JP1 to V
+
), 68.9MHz ≤ f
OSC
≤ 170MHz
N = 2 (JP1 to OPEN), 34.45MHz ≤ f
OSC
≤ 85MHz
N = 4 (JP1 to GND), 7.225MHz ≤ f
OSC
≤ 42.5MHz
LTC6900, DC1073A-C
f
OSC
=
10MHz 20kΩ
10MHz 20kΩ
•
, R
SET
=
•
N
R
SET
f
OSC
N
LTC1799, DC2073B-B
f
OSC
=
10MHz 10kΩ
10MHz 10kΩ
•
, R
SET
=
•
N
R
SET
f
OSC
N
N = 1 (JP1 to GND), 500kHz ≤ f
OSC
≤ 20MHz
N = 10 (JP1 to OPEN), 50kHz ≤ f
OSC
≤ 2MHz
N = 100 (JP1 to V
+
), 5kHz ≤ f
OSC
≤ 200kHz
LTC6905-133, DC2073B-D
f
OSC
=
133MHz
N
N = 1 (JP1 to GND), 500kHz ≤ f
OSC
≤ 20MHz
N = 10 (JP1 to OPEN), 50kHz ≤ f
OSC
≤ 2MHz
N = 100 (JP1 to V
+
), 5kHz ≤ f
OSC
≤ 200kHz
LTC6905-10, DC2073B-E
100MHz
f
OSC
=
N
N = 1 (JP1 to V
+
), f
OSC
= 100MHz
N = 2 (JP1 to OPEN), f
OSC
= 50MHz
N = 4 (JP1 to GND), f
OSC
= 25MHz
LTC6905-80, DC2073B-G
80MHz
f
OSC
=
N
N = 1 (JP1 to V
+
), f
OSC
= 80MHz
N = 2 (JP1 to OPEN), f
OSC
= 40MHz
N = 4 (JP1 to GND), f
OSC
= 20MHz
LTC6907, DC2073B-I
4MHz 50kΩ
4MHz 50kΩ
f
OSC
=
•
, R
SET
=
•
N
R
SET
f
OSC
N
N = 1 (JP1 to GND), 0.4MHz ≤ f
OSC
≤ 4MHz
N = 3 (JP1 to OPEN), 133kHz ≤ f
OSC
≤ 1.33MHz
N = 10 (JP1 to V
+
), 40kHz ≤ f
OSC
≤ 400kHz
N = 1 (JP1 to V+), f
OSC
= 133MHz
N = 2 (JP1 to OPEN), f
OSC
= 66.7MHz
N = 4 (JP1 to GND), f
OSC
= 33.5MHz
LTC6905-96, DC2073B-F
96MHz
f
OSC
=
N
N = 1 (JP1 to V
+
), f
OSC
= 96MHz
N = 2 (JP1 to OPEN), f
OSC
= 48MHz
N = 4 (JP1 to GND), f
OSC
= 24MHz
LTC6906, DC2073B-H
1MHz 100kΩ
1MHz 100kΩ
f
OSC
=
•
, R
SET
=
•
N
R
SET
f
OSC
N
N = 1 (JP1 to GND), 0.1MHz ≤ f
OSC
≤ 1MHz
N = 3 (JP1 to OPEN), 33kHz ≤ f
OSC
≤ 333kHz
N = 10 (JP1 to V
+
), 10kHz ≤ f
OSC
≤ 100kHz
LTC6908-1, DC2073B-J
Complementary Outputs (0°/180°) without Modulation:
250kHz ≤ f
OSC
≤ 5MHz, (JP1 to DIV/MOD)
10MHz 10kΩ
10MHz 10kΩ
f
OSC
=
•
, R
SET
=
•
N
R
SET
f
OSC
N
Spread Spectrum Modulation Rate:
(JP1 to GND), f
OSC
/16
(JP1 to OPEN), f
OSC
/32
(JP1 to V
+
), f
OSC
/64
LTC6908-1, DC2073B-K
Quadrature Outputs (0˚/90˚) without Modulation:
250kHz ≤ f
OSC
≤ 5MHz, (JP1 to DIV/MOD)
10MHz 10kΩ
10MHz 10kΩ
f
OSC
=
•
, R
SET
=
•
N
R
SET
f
OSC
N
Spread Spectrum Modulation Rate:
(JP1 to GND), f
OSC
/16
(JP1 to OPEN), f
OSC
/32
(JP1 to V
+
), f
OSC
/64
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dc2073bfa
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