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Linear Technology
Linear Technology

LTC6990 Datasheet

TimerBlox: Voltage Controlled Silicon Oscillator


LTC6990 Datasheet Preview


Electrical Specifications Subject to Change
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LTC6990
TimerBlox: Voltage
Controlled Silicon Oscillator
FEATURES
n Fixed-Frequency or Voltage-Controlled Operation
Fixed: Single Resistor Programs Frequency
with <2.2% Max Error
VCO: Two Resistors Set VCO Center
Frequency and Tuning Range
n Frequency Range: 488Hz to 2MHz
n 2.25V to 5.5V Single Supply Operation
n 72μA Supply Current at 100kHz
n 500μs Start-Up Time
n VCO Bandwidth >300kHz at 1MHz
n CMOS Logic Output Sources/Sinks 20mA
n 50% Duty Cycle Square Wave Output
n Output Enable (Selectable Low or Hi-Z When Disabled)
n –40°C to 125°C Operating Temperature Range
n Available in Low Profile (1mm) SOT-23 (ThinSOT™)
and 2mm × 3mm DFN Package
APPLICATIONS
n Low Cost Precision Programmable Oscillator
n Voltage-Controlled Oscillator
n High Vibration, High Acceleration Environments
n Replacement for Fixed Crystal and Ceramic Oscillators
n Portable and Battery-Powered Equipment
L, LT, LTC and LTM, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. TimerBlox and ThinSOT are trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners. Protected by U.S.
Patents including 6342817, 6614313.
DESCRIPTION
The LTC®6990 is a precision silicon oscillator with a pro-
grammable frequency range of 488Hz to 2MHz. It can be
used as a fixed-frequency or voltage-controlled oscillator
(VCO). The LTC6990 is part of the TimerBlox™ family of
versatile silicon timing devices.
A single resistor, RSET, programs the LTC6990’s inter-
nal master oscillator frequency. The output frequency
is determined by this master oscillator and an internal
frequency divider, NDIV, programmable to eight settings
from 1 to 128.
fOUT
=
1MHz
NDIV
50kΩ
RSET
,
NDIV
=
1,
2,
4
…128
Optionally, a second resistor at the SET input provides linear
voltage control of the output frequency and can be used
for frequency modulation. A narrow or wide VCO tuning
range can be configured by the appropriate selection of
the two resistors.
The LTC6990 includes an enable function that is synchro-
nized with the master oscillator to ensure clean, glitch-free
output pulses. The disabled output can be configured to
be high impedance or forced low.
The LTC6990 is available in the 6-lead SOT-23 (ThinSOT)
package or a 6-lead 2mm × 3mm DFN.
TYPICAL APPLICATION
Voltage Controlled Oscillator with 16:1 Frequency Range
VCTRL
V+
fOUT
 1MHz VCTRL
0.5
MHz
V
RVCO
100k
OE OUT
LTC6990
GND V+
SET
RSET
100k
DIV
6990 TA01a
V+
C1
0.1μF
VCO Transfer Function
1000
750
500
250
0
0 0.5 1 1.5 2
VCTRL (V)
6990 TA01b
6990p
1
Page 1

LTC6990
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ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (V+) to GND ........................................6V
Maximum Voltage on Any Pin
............................. (GND – 0.3V) ≤ VPIN ≤ (V+ + 0.3V)
Operating Temperature Range (Note 2)
LTC6990C............................................–40°C to 85°C
LTC6990I .............................................–40°C to 85°C
LTC6990H.......................................... –40°C to 125°C
Specified Temperature Range (Note 3)
LTC6990C................................................ 0°C to 70°C
LTC6990I .............................................–40°C to 85°C
LTC6990H.......................................... –40°C to 125°C
Junction Temperature ........................................... 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10sec) ................... 300°C
PIN CONFIGURATION
V+ 1
DIV 2
SET 3
TOP VIEW
7
6 OUT
5 GND
4 OE
DCB PACKAGE
6-LEAD (2mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 64°C/W
EXPOSED PAD (PIN 7) CONNECTED TO GND,
PCB CONNECTION OPTIONAL
TOP VIEW
OE 1
GND 2
SET 3
6 OUT
5 V+
4 DIV
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 230°C/W
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6990CDCB#PBF LTC6990CDCB#TRPBF LDWX
6-Lead (2mm × 3mm) Plastic DFN 0°C to 70°C
LTC6990IDCB#PBF LTC6990IDCB#TRPBF LDWX
6-Lead (2mm × 3mm) Plastic DFN –40°C to 85°C
LTC6990HDCB#PBF LTC6990HDCB#TRPBF LDWX
6-Lead (2mm × 3mm) Plastic DFN –40°C to 125°C
LTC6990CS6#PBF LTC6990CS6#TRPBF
LTDWW
6-Lead Plastic TSOT-23
0°C to 70°C
LTC6990IS6#PBF
LTC6990IS6#TRPBF
LTDWW
6-Lead Plastic TSOT-23
–40°C to 85°C
LTC6990HS6#PBF LTC6990HS6#TRPBF
LTDWW
6-Lead Plastic TSOT-23
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
6990p
2
Page 2

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LTC6990
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 2.25V to 5.5V, OE = V+, DIVCODE = 0 to 15
(NDIV = 1 to 128), RSET = 50k to 800k, RLOAD = 5k, CLOAD = 5pF unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
fOUT
ΔfOUT
ΔfOUT/ΔT
ΔfOUT/ΔV+
Output Frequency
Frequency Accuracy (Note 4)
Frequency Drift Over Temperature
Frequency Drift Over Supply
Recommended Range: RSET = 50k to 800k
Extended Range: RSET = 25k to 800k
Recommended Range
RSET = 50k to 800k
Extended Range
RSET = 25k to 800k
V+ = 4.5V to 5.5V
V+ = 2.25V to 4.5V
0.488
0.488
l
l
l
l
l
±0.8
±0.005
0.23
0.06
1000
2000
±1.5
±2.2
±2.4
±3.2
0.55
0.16
kHz
kHz
%
%
%
%
%/°C
%/V
%/V
Period Jitter (Note 10)
NDIV = 1
NDIV = 2
NDIV = 128
Duty Cycle
NDIV = 1, RSET = 25k to 800k
NDIV > 1, RSET = 25k to 800k
BW Frequency Modulation Bandwidth
tS Frequency Change Settling Time tMASTER = tOUT/NDIV
(Note 9)
0.38
0.22
0.027
0.022
0.004
l 47 50 53
l 48 50 52
0.4•fOUT
6•tMASTER
%P-P
%P-P
%RMS
%P-P
%RMS
%
%
kHz
μs
Analog Inputs
VSET Voltage at SET Pin
ΔVSET/ΔT VSET Drift Over Temperature
ΔVSET/ΔV+ VSET Drift Over Supply
ΔVSET/ΔISET VSET Droop with ISET
RSET Frequency-Setting Resistor
VDIV
ΔVDIV / V+
DIV Pin Voltage
DIV Pin Valid Code Range (Note 5)
DIV Pin Input Current
Recommended Range
Extended Range
Deviation from Ideal VDIV/V+ = (DIVCODE + 0.5)/16
l
l
l
l
l
l
l
0.97
50
25
0
1.00
±75
–150
–7
1.03
800
800
V+
±1.5
±10
V
μV/°C
μV/V
Ω
V
%
nA
Power Supply
V+ Operating Supply Voltage Range
l 2.25
5.5 V
Power-On Reset Voltage
IS Supply Current
RSET = 25k to 800k
RL = ∞, NDIV = 1, RSET = 50k
RL = ∞, NDIV = 1 RSET = 800k
RL = ∞, NDIV = 128, RSET = 50k
RL = ∞, NDIV = 128, RSET = 800k
V+ = 5.5V
V+ = 2.25V
V+ = 5.5V
V+ = 2.25V
V+ = 5.5V
V+ = 2.25V
V+ = 5.5V
V+ = 2.25V
l
l
l
l
l
l
l
l
l
1.95
235 283
145 183
71 105
59 92
137 180
106 145
66 100
56 90
V
μA
μA
μA
μA
μA
μA
μA
μA
6990p
3
Page 3
Part Number LTC6990
Manufactur Linear Technology
Description TimerBlox: Voltage Controlled Silicon Oscillator
Total Page 28 Pages
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