LTC6905CS5-100#TRM [ADI]
CMOS Output Clock Oscillator, 100MHz Nom;
| 型号： | LTC6905CS5-100#TRM |
| 厂家： | 
ADI |
| 描述： | CMOS Output Clock Oscillator, 100MHz Nom 机械 振荡器 |
| 文件： | 总8页 (文件大小：153K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC6905-XXX Series
Fixed Frequency
SOT-23 Oscillator
U
DESCRIPTIO
FEATURES
The LTC®6905-XXX series are precision, fixed frequency
siliconoscillatorsdesignedtominimizeboardspacewhile
maximizing accuracy and ease of use.
■
No External Components to Set Frequency
■
Frequency Error: ±0.5% Typical
■
Fast Start-Up Time: 100µs Typical
■
±20ppm/°C Temperature Stability
Programmed at the factory to a fixed frequency, the
LTC6905-XXX series of parts need no external trim com-
ponents. Aninternalthree-statedividerallowsfordivision
of the master clock by 1, 2 or 4, providing 3 frequencies
(for each device).
■
Includes Output Enable
■
Includes Frequency Divide by 1, 2 or 4
■
Rise Time: 0.5ns, CL = 5pF
■
Timing Jitter: <0.8% Typical
■
Duty Cycle: 50% ±2.5%
The LTC6905-XXX series operate with a single 2.7V to
5.5V power supply and provide a rail-to-rail, 50% duty
cycle, square wave output. The OE pin will disable the
output when brought low and synchronously enable the
output when brought high, avoiding pulse slivers.
■
IS = 8mA Typical (fOSC = 100MHz, CL = 5pF)
■
CMOS Output Drives 600Ω Load
■
Single Supply 2.7V to 5.5V
Low Profile (1mm) ThinSOTTM Package
■
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The four products of the LTC6905-XXX family are:
APPLICATIO S
LTC6905-133: fOSC = 133MHz, 66.7MHz, 33.3MHz
LTC6905-100: fOSC = 100MHz, 50MHz, 25MHz
LTC6905-96: fOSC = 96MHz, 48MHz, 24MHz
LTC6905-80: fOSC = 80MHz, 40MHz, 20MHz
■
Data Clocks for High Reliability Applications
■
High Vibration, High Acceleration Environments
■
Replacement for Fixed Crystal and Ceramic
Oscillators
The LTC6905-XXX series of parts provides a factory trim
option to modify the divider ratios from 1, 2, 4 to 8, 16, 32.
A second trim option allows for additional master clock
frequencies. For the alternate divider ratios and unlisted
frequencies, contact LTC marketing.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6614313, 6342817.
U
TYPICAL APPLICATIO
Typical Distribution of Frequency Error, T = 25°C
A
40
V
S
= 3V
Basic Connection
30
20
10
0
f
= 133MHz
3V
OSC
1
2
3
5
4
+
3V
0.1µF
V
OUT
LTC6905-133
GND
÷1
÷2
OE
DIV
OPEN
÷4
6905x TA01
–1
–0.5
0.0
0.5
1
6905x TA02
% FREQUENCY ERROR
6905xfa
1
LTC6905-XXX Series
W W
U W
U W
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ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
+
Supply Voltage (V+) to GND ........................–0.3V to 6V
DIV to GND .................................... –0.3V to (V+ + 0.3V)
OE to GND ..................................... –0.3V to (V+ + 0.3V)
Output Short-Circuit Duration (Note 6)........... Indefinite
Operating Temperature Range (Note 8)
V
GND
OE
1
2
3
5
4
OUT
DIV
S5 PACKAGE
5-LEAD PLASTIC SOT-23
LTC6905C .......................................... –40°C to 85°C
LTC6905I............................................ –40°C to 85°C
LTC6905H ........................................ –40°C to 125°C
Specified Temperature Range (Note 8)
LTC6905C ............................................... 0°C to 70°C
LTC6905I............................................ –40°C to 85°C
LTC6905H ........................................ –40°C to 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
TJMAX = 125°C, θJA = 150°C/W
ORDER PART NUMBER
S5 PART MARKING*
LTC6905CS5-133
LTC6905IS5-133
LTC6905HS5-133
LTC6905CS5-100
LTC6905IS5-100
LTC6905HS5-100
LTBPM
LTBPM
LTBPM
LTBPK
LTBPK
LTBPK
LTC6905CS5-96
LTC6905IS5-96
LTC6905HS5-96
LTC6905CS5-80
LTC6905IS5-80
LTC6905HS5-80
LTBPJ
LTBPJ
LTBPJ
LTBPH
LTBPH
LTBPH
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
*The temperature grade is identified by a label on the shipping container.
The
●
denotes the specifications which apply over the full specified
ELECTRICAL CHARACTERISTICS
otherwise noted. All voltages are with respect to GND.
+
+
temperature range, otherwise specifications are at T = 25°C or as noted. OE = DIV = V , V = 2.7V to 3.6V, R = 15k, C = 5pF, unless
A
L
L
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
∆f
Frequency Accuracy (Notes 2, 7)
LTC6905C-XXX
+
T = 25°C, V = 3V
±0.5
±1.0
±1.5
%
%
A
0°C < T < 70°C
●
●
A
LTC6905I-XXX
25°C < T < 85°C
±1.8
±2.9
%
%
A
–40°C < T < 85°C
A
LTC6905H-XXX
25°C < T < 125°C
±2.3
±2.9
%
%
A
–40°C < T < 125°C
●
●
A
+
V = 5V
±1.5
±20
0.5
%
ppm/°C
%/V
∆f/∆T
∆f/∆V
Freq Drift Over Temp (Note 2)
Freq Drift Over Supply (Notes 2, 7)
Timing Jitter (Note 3)
+
V = 2.7V to 3.6V
0.8
%
Long-Term Stability of Output Frequency
300
ppm/√kHr
6905xfa
2
LTC6905-XXX Series
The
●
denotes the specifications which apply over the full specified
ELECTRICAL CHARACTERISTICS
otherwise noted. All voltages are with respect to GND.
+
+
temperature range, otherwise specifications are at T = 25°C or as noted. OE = DIV = V , V = 2.7V to 3.6V, R = 15k, C = 5pF, unless
A
L
L
SYMBOL PARAMETER
CONDITIONS
MIN
47.5
2.7
TYP
MAX
52.5
5.5
UNITS
Duty Cycle
DIV = 0V
●
●
50
%
V
+
V
Operating Supply Range
+
+
I
Power Supply Current
DIV = V (÷ 1), V = 3.6V
LTC6905-133
S
●
●
●
●
10
8
8
15
12
12
11
mA
mA
mA
mA
LTC6905-100
LTC6905-96
LTC6905-80
7
+
DIV = 0 (÷ 4), V = 3.6V
LTC6905-133
LTC6905-100
LTC6905-96
LTC6905-80
●
●
●
●
5
4
4
8
7
7
6
mA
mA
mA
mA
3.5
+
V
V
High Level DIV or OE Pins Input Voltage
Low Level DIV or OE Pins Input Voltage
DIV Input Current (Note 4)
●
●
V – 0.15
V
V
IH
0.2
40
IL
+
+
I
DIV = V
V = 5.5V
●
●
15
–11
µA
µA
DIV
+
DIV = 0V
V = 5.5V
–40
+
+
I
OE Input Current (Note 4)
OE = V
V = 5.5V
15
–11
µA
µA
OE
+
OE = 0V
V = 5.5V
+
V
High Level Output Voltage (Note 4)
V = 5.5V
I
I
= –1mA
= –4mA
●
●
5.25
5.20
5.45
5.30
V
V
OH
OL
OH
OH
+
V = 2.7V
I
I
= –1mA
= –4mA
●
●
2.5
2.3
2.6
2.5
V
V
OH
OH
+
V
Low Level Output Voltage (Note 4)
OUT Rise/Fall Time (Note 5)
V = 5.5V
I
I
= 1mA
= 4mA
●
●
0.05
0.2
0.25
0.3
V
V
OL
OL
+
V = 2.7V
I
I
= 1mA
= 4mA
●
●
0.1
0.4
0.3
0.5
V
V
OL
OL
t , t
r
0.5
ns
f
Note 1: Absolute Maximum Ratings are those values beyond which the life
Note 6: A heat sink may be required to keep the junction temperature
below the absolute maximum when the output is shorted indefinitely.
Note 7: The LTC6905 is optimized for the performance with a 3V power
supply voltage. Refer to Typical Performance Characteristics curves in this
data sheet for additional information regarding the LTC6905 voltage
coefficient, especially between 4.5V and 5.5V. Please consult LTC
Marketing for parts optimized for 5V operation.
of the device may be impaired.
Note 2: Frequency accuracy is tested with DIV = V (÷1). Other divide
ratios are guaranteed by design.
+
Note 3: Jitter is the ratio of the peak-to-peak distribution of the period to
the mean of the period. This specification is based on characterization and
is not 100% tested.
Note 8: The LTC6905C-XXX is guaranteed functional over the operating
temperature range and is guaranteed to meet specified performance from
0°C to 70°C. The LTC6905C-XXX is designed, characterized and expected
to meet specified performance from –40°C to 85°C but is not tested or QA
sampled at these temperatures. The LTC6905I-XXX is guaranteed to meet
specified performance from –40°C to 85°C.
Note 4: To conform with the Logic IC Standard convention, current out of
a pin is arbitrarily given as a negative value.
Note 5: Output rise and fall times are measured between the 10% and
90% power supply levels.
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3
LTC6905-XXX Series
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TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Frequency
Frequency Error vs Supply Voltage
2.50
18
16
14
12
10
8
5.5V
2.7V
2.00
1.50
1.00
0.50
O
LTC6905-133
÷1
÷2
÷2
÷1
÷4
6
4
÷4
LTC6905-100
LTC6905-96
LTC6905-80
2
–0.50
0
2.5
3.5
4
4.5
5
5.5
100
FREQUENCY (MHz)
3
0
50
150
200
SUPPLY VOLTAGE (V)
6905x G09
6905x G01
+
R
OUT
vs V
Jitter vs Frequency
Frequency vs Temperature
1.0
0.8
45
40
35
30
25
20
15
10
5
1.20
1.00
0.6
÷4
÷2
÷1
0.4
0.80
0.2
0
0.60
0.40
–0.2
–0.4
–0.6
–0.8
–1.0
0.20
0
0
–40 –20
0
20 40 60 80 100 120
2.5
3
3.5
4
5.5
140
4.5
5
0
20 40 60 80 100 120
FREQUENCY (MHz)
160 180
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
6905x G08
6905x G04
6905x G05
LTC6905-80 Output Operating at
20MHz, V = 3V
LTC6905-133 Output Operating at
133MHz, V = 3V
S
S
0.75V/DIV
0.75V/DIV
6905x G06
6905x G07
10ns/DIV
2.5ns/DIV
6905xfa
4
LTC6905-XXX Series
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PI FU CTIO S
V+ (Pin 1): Voltage Supply (2.7V ≤ V+ ≤ 5.5V). This supply
must be kept free from noise and ripple. It should be
bypasseddirectlytotheGND(Pin2)witha0.1µFcapacitor
or higher.
toV+ forthe÷1setting, thehighestfrequencyrange. Float-
ing Pin 4 divides the master oscillator by 2. Pin 4 should
betiedtoGNDforthe÷4setting,thelowestfrequencyrange.
To detect a floating DIV pin, the LTC6905 attempts to pull
thepintowardmidsupply.Thisisrealizedwithtwointernal
current sources, one tied toV+ and Pin 4 and the other one
tiedtogroundandPin4.Therefore,drivingtheDIVpinhigh
requires sourcing approximately 15µA. Likewise, driving
DIV low requires sinking 15µA. When Pin 4 is floated, it
shouldbebypassedbya1nFcapacitortogroundoritshould
besurroundedbyagroundshieldtopreventexcessivecou-
pling from other PCB traces.
GND (Pin 2): Ground. Should be tied to a ground plane for
best performance.
OE (Pin 3): Output Enable. Pull to V+ or leave floating to
enable the output driver (Pin 5). Pull low to disable the
output. The output is disabled asynchronously. Pulling OE
pin low will immediately disable the output. Pulling the OE
pin high will bring the output high on the next low to high
transition of the clock. This eliminates pulse slivers.
OUT (Pin 5): Oscillator Output. This pin can drive 5kΩ
and/or 5pF loads. For heavier loads, refer to the Applica-
tions Information section.
DIV (Pin 4): Divider-Setting Input. This three-state input
selects among three divider settings. Pin 4 should be tied
W
BLOCK DIAGRA
3
OE
f
V
= 1V ±5%
MO
N
RES
f
=
+
+
OSC
PROGRAMMABLE
DIVIDER
(N = 1, 2 OR 4)
(V – V
)
V
OUT
SET
1
5
+
GAIN = 1
MASTER OSCILLATOR
R
SET
I
RES
+
DIVIDER
SELECT
V
–
f
MO
15µA
–
+
DIV
THREE-STATE
INPUT DETECT
4
+
V
BIAS
–
I
RES
15µA
GND
2
GND
6905x BD
Table 1. LTC6905-XXX Frequency Settings
DIV SETTING
V+
LTC6905-133
133.33MHz
66.66MHz
LTC6905-100
100MHz
50MHz
LTC6905-96
96MHz
LTC6905-80
80MHz
OPEN
48MHz
40MHz
GND
33.33MHz
25MHz
24MHz
20MHz
6905xfa
5
LTC6905-XXX Series
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APPLICATIO S I FOR ATIO
then the oscillator frequency may show an additional
error if the switching frequency is 1.4MHz (80MHz/64).
The magnitude of this effect is heavily dependent on
supply bypass and routing.
START-UP TIME
The start-up and settling time to within 1% of the final
frequency is typically 100µs.
MAXIMUM OUTPUT LOAD
JITTER AND POWER SUPPLY NOISE
The LTC6905 output (Pin 5) can drive a capacitive load
(CLOAD) of 5pF or more. Performance driving a CLOAD
greater than 5pF depends on the oscillator’s frequency
(fOSC) and output resistance (ROUT). The output rise time
If the LTC6905 is powered by a supply that has frequency
contentequaltotheoutputfrequencythentheoutputjitter
mayincrease. Inaddition, powersupplyrippleinexcessof
20mV at any frequency may increase jitter.
or fall time due to ROUT and CLOAD is equal to 2.2 • ROUT
•
Higher divide ratios will result in lower percentage jitter.
For example, jitter percentage of the LTC6905-80 operat-
ing at 20MHz is lower than for the same part operating at
80MHz. Please consult the Jitter vs Frequency graph
showing jitter at various divider ratios.
C
LOAD(from10%to90%oftheriseorfalltransition).Ifthe
total output rise time plus fall time is arbitrarily specified
tobeequaltoorlessthan20%oftheoscillator’speriod(1/
fOSC), then the maximum output CLOAD in picofarads (pF)
should be equal to or less than [45454/(ROUT • fOSC)]
(ROUT in ohms and fOSC in MHz).
LTC6905 SUGGESTED CRITICAL COMPONENT
LAYOUT
Example: An LTC6905-100 is operating with a 3V power
supply and is set for a fOSC = 50MHz.
ROUT with V+ = 3V is 27Ω (using the ROUT vs V+ graph in
In order to provide the specified performance, it is re-
quired that the supply bypass capacitor be placed as close
as possible to the LTC6905. The following additional rules
should be followed for best performance:
the Typical Performance Characteristics).
The maximum output CLOAD should be equal to or less
than [45454/(27 • 50)] = 33.6pF.
1) The bypass capacitor must be placed as close as
possible to the LTC6905, and no vias should be placed
between the capacitor and the LTC6905. The bypass
capacitor must be on the same side of the circuit board
as the LTC6905.
The lowest resistive load Pin 5 can drive can be calculated
using the minimum high level output voltage in the Elec-
trical Characteristics. With a V+ equal to 5.5V and 4mA
output current, the minimum high level output voltage is
5.2V and the lowest resistive load Pin 5 can drive is 1.30k
(5.2V/4mA). With a V+ equal to 2.7V and 4mA output
current,theminimumhighleveloutputvoltageis2.4Vand
thelowestresistiveloadPin5candriveis600Ω(2.4V/4mA).
2) Ifagroundplaneisused,theconnectionoftheLTC6905
tothegroundplaneshouldbeascloseaspossibletothe
LTC6905GNDpinandshouldbecomposedofmultiple,
high current capacity vias.
FREQUENCY ACCURACY AND POWER SUPPLY NOISE
The frequency accuracy of the LTC6905 may be affected
when its power supply generates noise with frequency
contents equal to fMO/64 or its multiples. fMO is the
highest frequency for an LTC6905-XXX which is with
DIV = V+ (÷1). This is also the frequency indicated in the
part number (i.e., LTC6905-100, fMO = 100MHz). fMO/64
is the master oscillator control loop frequency. For ex-
ample, if the LTC6905-80 with a master oscillator fre-
quency of 80MHz is powered by a switching regulator,
C
LTC6905
6905x F02
Figure 2. LTC6905 Suggested Critical Component Layout
6905xfa
6
LTC6905-XXX Series
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PACKAGE DESCRIPTIO
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
0.62
MAX
0.95
REF
2.90 BSC
(NOTE 4)
1.22 REF
1.50 – 1.75
(NOTE 4)
2.80 BSC
1.4 MIN
3.85 MAX 2.62 REF
PIN ONE
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.90 BSC
0.09 – 0.20
(NOTE 3)
NOTE:
S5 TSOT-23 0302
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
6905xfa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
7
LTC6905-XXX Series
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TYPICAL APPLICATIO S
Driving a 50Ω Cable with the LTC6905
50Ω
CABLE
950Ω
1
2
3
5
4
V
20
OUT
+
3V
0.1µF
V
OUT
LTC6905-XXX
50Ω
GND
6905x TA02
3V
OE
DIV
Driving the DIV Pin Without Three-State Buffers
A
B
DIV
0
0
1
1
0
1
0
1
÷ 1
÷ 2
÷ 2
÷ 4
1
2
3
5
4
+
3V
0.1µF
V
OUT
LTC6905-XXX
3V
GND
A
B
3V
OE
DIV
10k
10k
6905x TA04
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2
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6905xfa
LT/LT 1005 REV A • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005
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