LTC6906HS6#TRPBF Linear Technology, LTC6906HS6#TRPBF Datasheet - Page 11

• Manufacturer Part Number: LTC6906HS6#TRPBF
• Description: IC OSC PREC LP RES SET TSOT23-6
• Manufacturer: Linear Technology
• Type: Oscillator, Siliconr

Specifications of LTC6906HS6#TRPBF

• Frequency: 1MHz
• Voltage - Supply: 2.5 V ~ 5.5 V
• Current - Supply: 78µA
• Operating Temperature: -40°C ~ 125°C
• Package / Case: TSOT-23-6, TSOT-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Count: -

APPLICATIONS INFORMATION
Alternative Methods for Setting the Output Frequency
Any means of sinking current from the SET pin will control
the output frequency of the LTC6906. Equation 2 (repeated
below) gives the fundamental relationship between fre-
quency and the SET pin voltage and current:
This equation shows that the LTC6906 converts conduc-
tance (I
resistance (R
V
it is given approximately by:
where
V
The response of V
Typical Performance graphs. V
–2.3mV/°C. At room temperature V
octave or 60mV/decade of increase in I
SET
SET
V
I
(I
t
V
S
OSC
Figure 16. Using the LTC6906 at Higher Supply Voltages
T
S
SET
is the voltage across an internal diode, and as such
≅ 82 • 10
varies with temperature and the SET pin current.
= kT/q = 25.9mV at T = 300°K (27°C)
is also temperature dependent)
SET
≅ 25.9mV • Log
=
≅ V
ƒ
/V
3.6V TO 5.5V DC
T
OSC
1
SET
SET
• Log
–18
V
) to frequency or, equivalently, converts
+
=
= V
100
Amps
1F
V
e
I
SET
SET
SET
SET
I
SET
I
S
/I
to temperature is shown in the
e
• 10pF
SET



V
GND
DIV
82 • 10
+
LTC6906
) to period.
SET
I
GRD
OUT
SET
SET
changes approximately
–18
SET
A
6906 F16
R
SET
SET
increases 18mV/

 – 2.3mV/ °C

.
(2)
If the SET pin is driven with a current source generating
I
Figure 17 and Figure 18 show a current controlled oscil-
lator and a voltage controlled oscillator. These circuits are
not highly accurate if used alone, but can be very useful
if they are enclosed in an overall feedback circuit such as
a phase-locked loop.
Jitter and Divide Ratio
At a given output frequency, a higher master oscillator
frequency and a higher divide ratio will result in lower
jitter and higher power supply dissipation. Indeterminate
jitter percentage will decrease by a factor of slightly less
than the square root of the divider ratio, while determinate
jitter will not be similarly attenuated. Please consult the
specification tables for typical jitter at various divider ratios.
SET

ƒ
, the oscillator output frequency will be:
OSC
≅
Figure 17. Current Controlled Oscillator
Figure 18. Voltage Controlled Oscillator
25.9mV •
V
V
+
+
V
GND
DIV
V
GND
DIV
+
LTC6906
+
LTC6906

n



6906 F18
GRD
GRD
OUT
SET
OUT
SET
82 • 10
10pF
I
I
SET
SET
R
100k
100kHz TO 1MHz
6906 F17
SET
I
0.65A TO 6.5A
–18
1MHz TO 100kHz
CTRL
V
0V TO 0.585V
A
CTRL

 – 2.3mV/°C

LTC6906
11
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