provides 2-outputs, shifted by either 180° or 90°. The
oscillator frequency is programmed by a single external
resistor (R
SET
) and spread spectrum frequency modulation
(SSFM) can be activated for improved electromagnetic
compatibility (EMC) performance.
The LTC6908 operates with a single 2.7V to 5.5V supply
and provides rail-to-rail, 50% duty cycle square wave
outputs. A single resistor from 10k to 2M is used to select
an oscillator frequency from 50kHz to 10MHz (5V supply).
The oscillator can be easily programmed using the simple
formula outlined below:
f
OUT
=10MHz • 10k/R
SET
The LTC6908’s SSFM capability modulates the output
frequency by a pseudorandom noise (PRN) signal to
decrease the peak electromagnetic radiation level and
improve EMC performance. The amount of frequency
spreading is fixed at ±10% of the center frequency. When
SSFM is enabled, the rate of modulation is selected by the
user. The three possible modulation rates are f
OUT
/16,
f
OUT
/32 and f
OUT
/64.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
■
■
■
■
Switching Power Supply Clock Reference
Portable and Battery-Powered Equipment
Precision Programmable Oscillator
Charge Pump Driver
TYPICAL APPLICATIO
V
IN
2.8V TO 5.5V
C
BYP
0.1µF
2.25MHz, 2.5V/8A Step-Down Regulator
0
OUTPUT (dBc)
SV
IN
TRACK PV
IN
V
+
OUT1
2.2M
41.2k
R
T
LTC3418
RUN/SS
I
TH
4.99k
820pF
PGOOD
PGND
SGND
SW
C
IN
100µF
0.2µH
–10
–20
–30
–40
0
OUTPUT (dBc)
V
OUT
2.5V
8A
C
OUT
100µF
×2
LTC6908-1
GND
OUT2
44.2k
SET
f
OUT
= 10MHz • 10k/R
SET
MOD
690812 TA01a
1000pF
SYNC/MODE V
FB
4.32k
2k
U
150kHz to 30MHz Output
Frequency Spectrum
(9kHz Res BW)
SSFM DISABLED
SSFM ENABLED
–10
–20
–30
–40
150kHz
FREQUENCY
(FUNDAMENTAL AND HARMONICS SHOWN)
690812 TA01b
U
U
30MHz
690812fa
1
LTC6908-1/LTC6908-2
ABSOLUTE
(Note 1)
AXI U RATI GS
Specified Temperature Range (Note 3)
LTC6908CS6-1/LTC6908CS6-2 ................ 0°C to 70°C
LTC6908IS6-1/LTC6908IS6-2 .............. –40°C to 85°C
LTC6908HS6-1/LTC6908HS6-2 ......... –40°C to 125°C
LTC6908CDCB-1/LTC6908CDCB-2 .......... 0°C to 70°C
LTC6908IDCB-1/LTC6908IDCB-2 ......... –40°C to 85°C
Storage Temperature Range (S6) ........... –65°C to 150°C
Storage Temperature Range (DCB) ........ –65°C to 125°C
Lead Temperature (Soldering, 10sec) ................... 300°C
Total Supply Voltage (V
+
to GND) ...............................6V
Maximum Voltage on any Pin
(GND – 0.3V) ≤ V
PIN
≤ (V
+
+ 0.3V)
Output Short Circuit Duration .......................... Indefinite
Operating Temperature Range (Note 2)
LTC6908CS6-1/LTC6908CS6-2 ............ –40°C to 85°C
LTC6908IS6-1/LTC6908IS6-2 .............. –40°C to 85°C
LTC6908HS6-1/LTC6908HS6-2 ......... –40°C to 125°C
LTC6908CDCB-1/LTC6908CDCB-2 ...... –40°C to 85°C
LTC6908IDCB-1/LTC6908IDCB-2 ......... –40°C to 85°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW
OUT2
OUT1
MOD
6
5
4
TOP VIEW
V
+
1
6 OUT1
5 OUT2
4 MOD
7
1
SET
2
V
+
3
GND
DCB PACKAGE
6-LEAD (2mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 64°C/W
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER
LTC6908CDCB-1
LTC6908IDCB-1
LTC6908CDCB-2
LTC6908IDCB-2
DCB PART MARKING*
LBXZ
LBXZ
LBYB
LBYB
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/
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
2
U
U
W
W W
U
W
GND 2
SET 3
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 150°C,
θ
JA
= 230°C/W
ORDER PART NUMBER
LTC6908CS6-1
LTC6908IS6-1
LTC6908HS6-1
LTC6908CS6-2
LTC6908IS6-2
LTC6908HS6-2
S6 PART MARKING*
LTBYC
LTBYC
LTBYC
LTBYD
LTBYD
LTBYD
690812fa
LTC6908-1/LTC6908-2
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. Test conditions are V
+
= 2.7V to 5.5V, R
L
= 5k, C
L
= 5pF unless otherwise
noted. The modulation is turned off (MOD is connected to OUT2) unless otherwise specified. R
SET
is defined as the resistor connected
from the SET pin to the V
+
pin.
SYMBOL
Δf
OUT
PARAMETER
Frequency Accuracy (Note 4)
CONDITIONS
V
+
= 2.7V
250kHz ≤ f
OUT
≤ 5MHz
250kHz ≤ f
OUT
≤ 5MHz
50kHz ≤ f
OUT
< 250kHz
250kHz ≤ f
OUT
≤ 5MHz
250kHz ≤ f
OUT
≤ 5MHz
50kHz ≤ f
OUT
< 250kHz
5MHz < f
OUT
≤ 10MHz
|
Δf
OUT
| ≤ 1.5%
|
Δf
OUT
| ≤ 2.5%
|
Δf
OUT
| ≤ 3.5%
|
Δf
OUT
| ≤ 2%
|
Δf
OUT
| ≤ 3%
|
Δf
OUT
| ≤ 4%
|
Δf
OUT
| ≤ 4.5%
●
●
●
●
●
●
●
●
●
●
●
●
●
●
ELECTRICAL CHARACTERISTICS
MIN
TYP
±0.5
±2
±2.5
±1
±2.5
±3
±3.5
MAX
±1.5
±2.5
±3.5
±2
±3
±4
±4.5
400
400
2000
400
400
2000
20
UNITS
%
%
%
%
%
%
%
k
k
k
k
k
k
k
%/°C
%/V
%/V
%
ppm/√kHr
V
+
= 5V
R
SET
Frequency Setting Resistor Range
V
+
= 2.7V
20
20
400
20
20
400
10
±0.004
0.04
0.4
±7.5
±10
300
V
+
= 5V
Δf
OUT
/ΔT
Frequency Drift Over Temperature
R
SET
= 100k
Δf
OUT
/ΔV
+
Frequency Drift Over Supply (Note 4) V
+
= 2.7V to 3.6V, R
SET
= 100k
V
+
= 4.5V to 5.5V, R
SET
= 100k
Period Variation
(Frequency Spreading)
Long-Term Stability of Output
Frequency (Note 8)
Duty Cycle (Note 5)
V
+
I
S
Operating Supply Range
Power Supply Current
R
SET
= 2000k, R
L
= ∞, f
OUT
= 50kHz, MOD Pin = V
+
V
+
= 5V
V
+
= 2.7V
R
SET
= 20k, R
L
= ∞, f
OUT
= 5MHz, MOD Pin = GND
V
+
= 5V
V
+
= 2.7V
V
IH_MOD
V
IL_MOD
I
MOD
V
OH
High Level MOD Input Voltage
Low Level MOD Input Voltage
MOD Pin Input Current (Note 6)
High Level Output Voltage (Note 6)
(OUT1, OUT2)
MOD Pin = V
+
, V
+
= 5V
MOD Pin = GND, V
+
= 5V
V
+
= 5V
V
+
= 2.7V
V
OL
Low Level Output Voltage (Note 6)
V
+
= 5V
V
+
= 2.7V
t
r
t
f
Output Rise Time (Note 7)
Output Fall Time (Note 7)
V
+
= 5V
V
+
= 2.7V
V
+
= 5V
V
+
= 2.7V
I
OH
= –0.3mA
I
OH
= –1.2mA
I
OH
= –0.3mA
I
OH
= –0.8mA
I
OL
= 0.3mA
I
OL
= 1.2mA
I
OL
= 0.3mA
I
OL
= 0.8mA
No Modulation, 250kHz ≤ f
OUT
≤ 1MHz
R
SET
= 100k, MOD Pin = V
+
, GND or OPEN
0.25
0.9
±12.5
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
45
2.7
50
55
5.5
%
V
mA
mA
mA
mA
V
V
µA
µA
V
V
V
V
0.4
0.4
1.25
0.9
V
+
– 0.4
0.65
0.6
1.7
1.3
0.4
–4
4.75
4.4
2.35
1.85
2
–2
4.9
4.7
2.6
2.2
0.05
0.2
0.1
0.4
6
11
5
9
4
0.15
0.5
0.3
0.7
V
V
V
V
ns
ns
ns
ns
690812fa
3
LTC6908-1/LTC6908-2
ELECTRICAL CHARACTERISTICS
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
LTC6908C and LTC6908I are guaranteed functional over the
operating temperature range of –40°C to 85°C.
Note 3:
LTC6908C is guaranteed to meet specified performance from
0°C to 70°C. The LTC6908C 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 LTC6908I is guaranteed to meet
the specified performance limits from –40°C to 85°C. The LTC6908H is
guaranteed to meet the specified performance limits from –40°C to 125°C.
Note 4:
Frequency accuracy is defined as the deviation from the f
OUT
equation.
Note 5:
Guaranteed by 5V test
Note 6:
To conform to the Logic IC Standard, current out of a pin is
arbitrarily given a negative value.
Note 7:
Output rise and fall times are measured between the 10% and the
90% power supply levels with no output loading. These specifications are
based on characterization.
Note 8:
Long term drift on silicon oscillators is primarily due to the
movement of ions and impurities within the silicon and is tested at 30°C
under otherwise nominal operating conditions. Long term drift is specified
as ppm/√kHr due to the typically non-linear nature of the drift. To calculate
drift for a set time period, translate that time into thousands of hours, take
the square root and multiply by the typical drift number. For instance, a
year is 8.77kHr and would yield a drift of 888ppm at 300ppm/√kHr. Ten
years is 87.7kHr and would yield a drift of 2,809 ppm at 300 ppm/√kHr.
Drift without power applied to the device may be approximated as 1/10th
of the drift with power, or 30ppm/√kHr for a 300ppm/√kHr device.
[i=s]This post was last edited by paulhyde on 2014-9-15 09:24[/i][size=16pt][font=Times New Roman] [align=center][size=4][b]11 Tips for Taking Part in E-Contests in 2009[/font][/b][/size][/align][size...
This article is quoted from www.witech.com.cn of Feiling Embedded. 1. Bus: As we know, a circuit is always made up of components connected by wires. In analog circuits, connecting wires is not a probl...
[size=7]Detailed explanation of 100 examples of VHDL language.pdf [/size][size=5]My tutor uses VHDL, and I also learned VHDL at the beginning. If you have any questions, please discuss them together. ...
At present, switching power supplies manufactured in China account for 80% of the world market, but we have almost no share in the high-end market. my country is currently short of energy, and the pow...
From being a global leader to losing the market, Korean battery manufacturers have always wanted to regain the lost market and dignity, but facing Chinese battery manufacturers represented by CAT...[Details]
Current Development Status of DVR Market
A DVR, or digital video recorder, uses a hard disk for recording, unlike traditional analog video recorders. It's often called a DVR because it's a com...[Details]
On August 22, the National Energy Administration released the latest data, showing that by the end of July 2025, China's total number of electric vehicle charging infrastructure will reach 16.696 m...[Details]
introduction
Sonar imaging is of great significance in marine resource development and defense. Its long range, intuitive display of the observed area, and target identification make it widely...[Details]
Teletrac Navman has launched the Multi IQ dashcam, a cloud-based solution designed for large commercial vehicle operators. It connects up to five cameras to cover the vehicle's interior, sides, and...[Details]
Common methods for troubleshooting roller press bearing wear include repair welding, thermal spraying, brush plating, and scrapping and replacement. However, these methods are often subject to asse...[Details]
Most cameras on the market use chips manufactured by Japanese companies like Sony, Sharp, Panasonic, and LG. South Korea now has the capability to produce chips, but the quality is somewhat inferio...[Details]
0 Introduction
With a rapidly aging population, a young couple is now required to care for an increasing number of elderly people, leading to a growing difficulty in providing care for them. E...[Details]
We know that the power output by the engine does not directly act on the wheels to drive the car, but needs to pass through a series of power transmission mechanisms. So how is the power transmitte...[Details]
A Beijing chemical project utilizes a distributed control system (DCS). The master control system primarily uses the Modbus protocol, while the remote field devices utilize the PROFIBUS-DP protocol...[Details]
Motor potting compound is a high-performance sealing material widely used for motor encapsulation and insulation. It is essential for motor protection and packaging. Its ideal moisture and water re...[Details]
With the rapid development of the automotive industry, automotive requirements for control, communication, and network management are becoming increasingly stringent. Hardware platforms based on 32...[Details]
The term "remote meter reading" literally emphasizes remoteness. But how far is remote? One kilometer? Two kilometers? Those aren't considered far at all. Currently, the longest distance for ...[Details]
Abstract: This design uses field-effect transistors to create a tube-like audio power amplifier. The preamplifier uses a single Class A transistor, while the power stage utilizes Class AB push-pull...[Details]
Modern automotive electronics have entered a new phase of fundamental change and advancement, evolving from the application of electronic components to in-vehicle electronic systems. Sensors are on...[Details]
Embedded System
京公网安备 11010802033920号
EEWORLD
