Linear Technology LTC1799CS5, LTC1799IS5 Datasheet
FEATURES
UNITS (%)
25
20
15
10
5
0
–1.25 –0.75 –0.25 0 0.25 0.75 1.25
FREQUENCY ERROR (%)
1799 TA02
■
One External Resistor Sets the Frequency
■
Fast Start-Up Time: <1ms
■
1kHz to 33MHz Frequency Range
■
Low Profile (1mm) ThinSOTTM Package
■
Frequency Error ≤1.5% 5kHz to 20MHz
(TA = 25°C)
■
Frequency Error ≤2% 5kHz to 20MHz
(TA = 0°C to 70°C)
■
±40ppm/°C Temperature Stability
■
0.05%/V Supply Stability
■
50% ±1% Duty Cycle 1kHz to 2MHz
■
50% ±5% Duty Cycle 2MHz to 20MHz
■
1mA Typical Supply Current
■
100Ω CMOS Output Driver
■
Operates from a Single 2.7V to 5.5V Supply
U
APPLICATIO S
■
Low Cost Precision Oscillator
■
Charge Pump Driver
■
Switching Power Supply Clock Reference
■
Clocking Switched Capacitor Filters
■
Fixed Crystal Oscillator Replacement
■
Ceramic Oscillator Replacement
■
Small Footprint Replacement for Econ Oscillators
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
LTC1799
1kHz to 33MHz
Resistor Set SOT-23 Oscillator
U
DESCRIPTIO
The LTC®1799 is a precision oscillator that is easy to use
and occupies very little PC board space. The oscillator
frequency is programmed by a single external resistor
(R
). The LTC1799 has been designed for high accuracy
SET
operation (≤1.5% frequency error) without the need for
external trim components.
The LTC1799 operates with a single 2.7V to 5.5V power
supply and provides a rail-to-rail, 50% duty cycle square
wave output. The CMOS output driver ensures fast rise/fall
times and rail-to-rail switching. The frequency-setting
resistor can vary from 3k to 1M to select a master
oscillator frequency between 100kHz and 33MHz (5V
supply). The three-state DIV input determines whether the
master clock is divided by 1, 10 or 100 before driving the
output, providing three frequency ranges spanning 1kHz
to 33MHz (5V supply). The LTC1799 features a proprietary
feedback loop that linearizes the relationship between
R
and frequency, eliminating the need for tables to
SET
calculate frequency. The oscillator can be easily programmed using the simple formula outlined below:
=
=
=
fMHz
=•
10
OSC
NR
•
10
100
,
DIV Pin V
N Open
=
,
10
,
DIV Pin
1
,
DIV Pin GND
k
SET
+
TYPICAL APPLICATIO
5V
3k ≤ R
SET
≤ 1M
0.1µF
SOT-23 Actual Size
Basic Connection
1
+
V
OUT
LTC1799
2
GND
3
SET
DIV
1799 TA01
U
5
4
1kHz ≤ f
÷100
OSC
÷1
≤ 33MHz
5V
÷10
OPEN
Typical Distribution of Frequency Error,
TA = 25°C (5kHz ≤ f
≤ 20MHz, V+ = 5V)
OSC
1
LTC1799
TOP VIEW
S5 PACKAGE
5-LEAD PLASTIC SOT-23
1
2
3
V
+
GND
SET
54OUT
DIV
PACKAGE/ORDER I FOR ATIO
UU
W
WWWU
ABSOLUTE AXI U RATI GS
(Note 1)
Supply Voltage (V+) to GND ........................–0.3V to 6V
DIV to GND ....................................–0.3V to (V+ + 0.3V)
SET to GND ...................................–0.3V to (V+ + 0.3V)
Operating Temperature Range
LTC1799C ............................................... 0°C to 70°C
LTC1799I............................................ – 40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ORDER PART NUMBER
LTC1799CS5
LTC1799IS5
S5 PART MARKING
T
= 125°C, θJA = 256°C/W
JMAX
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
LTND
LTNE
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C. V+ = 2.7V to 5.5V, RL=5k, CL = 5pF, unless otherwise noted.
All voltages are with respect to GND.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
∆f Frequency Accuracy V+ = 5V 5kHz ≤ f ≤ 20MHz ±0.5 ±1.5 %
(Notes 2, 3) 1kHz ≤ f ≤ 5kHz ±2.5 %
R
SET
f
MAX
f
MIN
∆f/∆T Freq Drift Over Temp (Note 3) R
∆f/∆V Freq Drift Over Supply (Note 3) V+ = 3V to 5V, R
+
V
I
S
V
IH
V
IL
I
DIV
2
Frequency-Setting Resistor Range ∆f < 1.5% V+ = 5V 5 200 kΩ
Maximum Frequency ∆f < 2.5%, Pin 4= 0V V+ = 5V 33 MHz
Minimum Frequency ∆f < 2.5%, Pin 4= V
Timing Jitter Pin 4 = V
(Note 4) Pin 4 = Open 0.13 %
Long-Term Stability of Output Frequency 300 ppm/√kHr
Duty Cycle (Note 7) Pin 4 = V+ or Open (DIV Either by 100 or 10) ● 49 50 51 %
Operating Supply Range ● 2.7 5.5 V
Power Supply Current R
High Level DIV Input Voltage ● V+ – 0.4 V
Low Level DIV Input Voltage ● 0.5 V
DIV Input Current (Note 5) Pin 4 = V
The ● denotes the specifications which apply over the full operating
5kHz ≤ f ≤ 20MHz, LTC1799C
5kHz ≤ f ≤ 20MHz, LTC1799I
20MHz ≤ f ≤ 33MHz ±2.5 %
V+ = 3V 5kHz ≤ f ≤ 10MHz ±0.5 ±1.5 %
5kHz ≤ f ≤ 10MHz, LTC1799C
5kHz ≤ f ≤ 10MHz, LTC1799I
1kHz ≤ f ≤ 5kHz ±2.5 %
10MHz ≤ f ≤ 20MHz ±2.5 %
+
= 3V 10 200 kΩ
V
+
= 3V 20 MHz
V
+
= 31.6k ● ±0.004 %/°C
SET
= 31.6k ● 0.05 0.1 %/V
SET
+
Pin 4 = 0V 0.4 %
Pin 4 = 0V (DIV by 1), R
= 200k, Pin 4 = V+, RL = ∞ V+ = 5V ● 0.7 1.1 mA
SET
R
= 10k, Pin 4 = 0V, RL = ∞ V+ = 5V ● 2.4 mA
SET
+
Pin 4 = 0V V
= 5k to 200k ● 45 50 55 %
SET
+
= 3V ● 2mA
V
V+ = 5V ● 5 8 µA
+
= 5V ● –8 –5 µA
● ±2%
● ±2.5 %
● ±2%
● ±2.5 %
1 kHz
0.06 %
LTC1799
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V+ = 2.7V to 5.5V, RL=5k, CL = 5pF, Pin 4 = V+ unless otherwise noted.
All voltages are with respect to GND.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OH
V
OL
t
r
t
f
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Frequencies near 100kHz and 1MHz may be generated using two
different values of R
section). For these frequencies, the error is specified under the following
assumption: 10k < R
is guaranteed by design and test correlation.
Note 3: Frequency accuracy is defined as the deviation from the
f
OSC
High Level Output Voltage (Note 5) V+ = 5V IOH = –1mA ● 4.8 4.95 V
= –4mA ● 4.5 4.8 V
I
OH
V+ = 3V IOH = –1mA ● 2.7 2.9 V
I
= –4mA ● 2.2 2.6 V
OH
Low Level Output Voltage (Note 5) V+ = 5V IOL = 1mA ● 0.05 0.15 V
= 4mA ● 0.2 0.4 V
I
OL
V+ = 3V IOL = 1mA ● 0.1 0.3 V
= 4mA ● 0.4 0.7 V
I
OL
OUT Rise Time V+ = 5V Pin 4 = V+ or Floating, RL = ∞ 14 ns
(Note 6) Pin 4 = 0V, R
V+ = 3V Pin 4 = V+ or Floating, RL = ∞ 19 ns
Pin 4 = 0V, R
OUT Fall Time V+ = 5V Pin 4 = V+ or Floating, RL = ∞ 13 ns
(Note 6) Pin 4 = 0V, R
V+ = 3V Pin 4 = V+ or Floating, RL = ∞ 19 ns
Pin 4 = 0V, R
(see the Table 1 in the Applications Information
SET
equation.
≤ 100k. The frequency accuracy for f
SET
= 20MHz
OSC
= ∞ 7ns
L
= ∞ 11 ns
L
= ∞ 6ns
L
= ∞ 10 ns
L
Note 4: 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 5: To conform with the Logic IC Standard convention, current out of
a pin is arbitrarily given as a negative value.
Note 6: Output rise and fall times are measured between the 10% and
90% power supply levels. These specifications are based on
characterization.
Note 7: Guaranteed by 5V test.
3
LTC1799
UW
TYPICAL PERFOR A CE CHARACTERISTICS
Frequency Variation
vs R
SET
4
TA = 25°C
GUARANTEED LIMITS APPLY
3
OVER 5k TO 200k RANGE
2
1
0
–1
VARIATION (%)
–2
–3
–4
1 10 100 1000
TYPICAL
HIGH
TYPICAL
LOW
R
(kΩ)
SET
Peak-to-Peak Jitter vs Frequency
0.7
0.6
0.5
0.4
0.3
JITTER (%)
0.2
0.1
0
1k 100k 1M 10M
÷10
÷100
10k
OUTPUT FREQUENCY, f
÷1
OUT
(Hz)
1799 G01
100M
1799 G03
Frequency Variation
Over Temperature
1.00
R
= 31.6k
SET
÷1 OR ÷10 OR ÷100
0.75
0.50
0.25
0
–0.25
VARIATION (%)
–0.50
–0.75
–1.00
–40
TYPICAL
HIGH
TYPICAL
LOW
–20 0
TEMPERATURE (°C)
40 80
20 60
Supply Current
vs Output Frequency
4.5
TA = 25°C
= 5pF
C
4.0
L
= 1M
R
L
3.5
3.0
2.5
2.0
1.5
SUPPLY CURRENT (mA)
1.0
0.5
0
÷100 (5V)
÷100 (3V)
1k 100k 1M 100M
÷10 (3V)
10k
OUTPUT FREQUENCY, f
÷1 (5V)
÷10 (5V)
÷1 (3V)
OUT
1799 G02
10M
(Hz)
1799 G04
Output Resistance
vs Supply Voltage
140
120
100
80
OUTPUT RESISTANCE (Ω)
60
OUTPUT SINKING CURRENT
40
2.5 3.0
4
= 25°C
T
A
OUTPUT SOURCING CURRENT
4.5
4.0
3.5
SUPPLY VOLTAGE (V)
5.0
5.5
1799 G05
6.0
LTC1799 Output Operating at
20MHz, VS = 5V
V+ = 5V, R
1V/DIV
= 5k, CL = 10pF V+ = 3V, R
SET
12.5ns/DIV
1799 G06
LTC1799 Output Operating at
10MHz, VS = 3V
= 10k, CL = 10pF
SET
1V/DIV
25ns/DIV
1799 G07
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