LTC1799HS5#TR Linear Technology, LTC1799HS5#TR Datasheet - Page 9

• Manufacturer Part Number: LTC1799HS5#TR
• Description: IC OSC PREC 1KHZ-33MHZ TSOT23-5
• Manufacturer: Linear Technology
• Type: Oscillator, Siliconr

Specifications of LTC1799HS5#TR

• Frequency: 33MHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Current - Supply: 7mA
• Operating Temperature: -40°C ~ 125°C
• Package / Case: TSOT-23-5, TSOT-5, TSOP-5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Count: -

applicaTions inForMaTion
Jitter
The typical jitter is listed in the Electrical Characteristics
and shown in the Typical Performance Characteristics.
These specifications assume that the capacitance on SET
(Pin 3) is limited to less than 10pF , as suggested in the Pin
Functions description. If this requirement is not met, the
jitter will increase. For more information, contact Linear
Technology Applications group.
A Ground Referenced Voltage Controlled Oscillator
The LTC1799 output frequency can also be programmed by
steering current in or out of the SET pin, as conceptually
shown in Figure 8. This technique can degrade accuracy
as the ratio of (V
dependent of the value of R
Block Diagram. This loss of accuracy will become notice-
able when the magnitude of I
The frequency variation of the LTC1799 is still monotonic.
Figure 9 shows how to implement the concept shown in
Figure 8 by connecting a second resistor, R
the SET pin and a ground referenced voltage source, V
For a given power supply voltage in Figure 9, the output
frequency of the LTC1799 is a function of V
and (V
f
⎡
⎢
⎢
⎢
⎢
⎣
OSC
Figure 8. Concept for Programming via Current Steering
1+
+
(
=
– V
V
V
+
I
R
10MHz
IN
PR
V
SET
SET
RES
− V
N
) = V
0.1µF
+
)
+
•
I
RES
•
R
– V
RES
⎛
⎜
⎜
⎜
⎜
⎝
IN
1+
10k
:
SET
1
2
3
R
R
SET
V
GND
SET
1
R
) / I
LTC1799
+
SET
SET
IN
PROG
•
, as shown in the LTC1799
OUT
RES
DIV
⎞
⎟
⎟
⎟
⎟
⎠
⎤
⎥
⎥
⎥
⎥
⎦
5
4
is comparable to I
is no longer uniquely
÷100
÷1
5V
÷10
IN
IN
OPEN
1799 F08
, R
, between
IN
, R
RES
SET
(1)
IN
.
.
When V
sumes the highest value and it is set by the parallel com-
bination of R
f
the accuracy of f
When V
proaches the ground potential, the oscillator frequency,
f
by the change of V
by ±8%, assuming the variation of V
perature coefficient of V
By manipulating the algebraic relation for f
simple algorithm can be derived to set the values of external
resistors R
1. Choose the desired value of the maximum oscillator
2. Set the desired value of the minimum oscillator fre-
3. Choose V
R
(
OSC
OSC
R
V
SET
frequency, f
voltage V
quency, f
V
from the following:
IN
IN(MAX)
IN(MIN)
, is independent of the value of V
, assumes its lowest value and its accuracy is affected
Figure 9. Implementation of Concept Shown in Figure 8
=
+
–
IN
IN
V
IN
= V
− V
is less than V
SET
V
R
≥ 0.
OSC(MIN)
IN(MAX)
+
IN
RES
V
IN
V
RES
+
RES
+
+
–
, the output frequency of the LTC1799 as-
and R
and R
OSC(MAX)
)
= 1.1 and calculate the ratio of R
OSC
−
R
⎡
⎢
⎢
⎣
0.1µF
RES
SET
⎛
⎜
⎝
(
≤ V
, occurring at minimum input voltage
f
SET
IN
f
f
is within the data sheet limits.
OSC(MAX)
f
OSC(MAX)
OSC(MIN)
OSC(MIN)
= (V
, as shown in Figure 9.
+
. Also note, the output frequency,
, occurring at maximum input
RES
.
+
, and especially when V
1
2
3
+
– V
is 0.02%/°C.
V
GND
SET
LTC1799
+
)
⎞
⎟ V
⎠
SET
− 1
(
OUT
DIV
IN(MIN)
⎤
⎥
⎥
⎦
). At 25°C V
RES
5
4
+
÷100
is ±5%. The tem-
LTC1799
f
÷1
OSC
= (V
− V
5V
OSC
÷10
+
+
– V
RES
)
OPEN
1799 F09
above, a
− 1
IN
SET
IN
varies
/R
1799fc
9
) so
ap-
SET
(2)