MAX038.PDF
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19-0266; Rev 2a; 9/96
High-Frequency Waveform Generator
_______________General Description
The MAX038 is a high-frequency, precision function
generator producing accurate, high-frequency triangle,
sawtooth, sine, square, and pulse waveforms with a
minimum of external components. The output frequency
can be controlled over a frequency range of 0.1Hz to
20MHz by an internal 2.5V bandgap voltage
reference and an external resistor and capacitor. The
duty cycle can be varied over a wide range by applying
a ±2.3V control signal, facilitating pulse-width modula-
tion and the generation of sawtooth waveforms.
Frequency modulation and frequency sweeping are
achieved in the same way. The duty cycle and
frequency controls are independent.
Sine, square, or triangle waveforms can be selected at
the output by setting the appropriate code at two
TTL-compatible select pins. The output signal for all
waveforms is a 2V
P-P
signal that is symmetrical around
ground. The low-impedance output can drive up
to ±20mA.
The TTL-compatible SYNC output from the internal
oscillator maintains a 50% duty cycle—regardless of
the duty cycle of the other waveforms—to synchronize
other devices in the system. The internal oscillator can
be synchronized to an external TTL clock connected
to PDI.
____________________________Features
©
0.1Hz to 20MHz Operating Frequency Range
©
Triangle, Sawtooth, Sine, Square, and Pulse
Waveforms
©
Independent Frequency and Duty-Cycle
Adjustments
©
350 to 1 Frequency Sweep Range
©
15% to 85% Variable Duty Cycle
©
Low-Impedance Output Buffer: 0.1
½
©
Low-Distortion Sine Wave: 0.75%
©
Low 200ppm/°C Temperature Drift
______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX038CPP
0°C to +70°C
20 Plastic DIP
MAX038CWP
0°C to +70°C
20 SO
MAX038C/D
0°C to +70°C
Dice*
MAX038EPP
-40°C to +85°C
20 Plastic DIP
MAX038EWP
-40°C to +85°C
20 SO
*Contact factory for dice specifications.
________________________Applications
Precision Function Generators
Voltage-Controlled Oscillators
Frequency Modulators
Pulse-Width Modulators
Phase-Locked Loops
Frequency Synthesizer
FSK Generator—Sine and Square Waves
__________________Pin Configuration
TOP VIEW
REF
1
2
20
V-
GND
19
18
17
OUT
GND
A0
3
4
A1
MAX038
V+
COSC
5
6
16
15
DV+
GND
DGND
SYNC
DADJ
7
8
14
13
12
FADJ
PDI
GND
9
10
PDO
GND
IIN
11
DIP/SO
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
High-Frequency Waveform Generator
ABSOLUTE MAXIMUM RATINGS
V+ to GND ................................................................-0.3V to +6V
DV+ to DGND...........................................................-0.3V to +6V
V- to GND .................................................................+0.3V to -6V
Pin Voltages
IIN, FADJ, DADJ, PDO .....................(V- - 0.3V) to (V+ + 0.3V)
COSC .....................................................................+0.3V to V-
A0, A1, PDI, SYNC, REF.........................................-0.3V to V+
GND to DGND ................................................................±0.3V
Maximum Current into Any Pin .........................................±50mA
OUT, REF Short-Circuit Duration to GND, V+, V- ...............30sec
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 11.11mW/°C above +70°C) ..........889mW
SO (derate 10.00mW/°C above +70°C) .......................800mW
CERDIP (derate 11.11mW/°C above +70°C) ...............889mW
Operating Temperature Ranges
MAX038C_ _ .......................................................0°C to +70°C
MAX038E_ _ ....................................................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, GND = DGND = 0V, V+ = DV+ = 5V, V- = -5V, V
DADJ
= V
FADJ
= V
PDI
= V
PDO
= 0V, C
F
= 100pF,
R
IN
= 25k
, R
L
= 1k
½
, C
L
= 20pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX UNITS
FREQUENCY CHARACTERISTICS
Maximum Operating Frequency
F
o
15pCF
²
15pF, I
IN
= 500µA
V
FADJ
= 0V
20.0
40.0
MHz
Frequency Programming
Current
I
IN
2.50
750
µA
V
FADJ
= -3V
1.25
375
IIN Offset Voltage
V
IN
±1.0
±2.0
mV
Frequency Temperature
Coefficient
Æ
F
o
/°C
V
FADJ
= 0V
600
ppm/°C
F
o
/°C
V
FADJ
= -3V
200
(
Æ
F
o
/F
o
)
Æ
V- = -5V, V+ = 4.75V to 5.25V
±0.4
±2.00
Frequency Power-Supply
Rejection
V+
%/V
(
Æ
F
o
/F
o
)
Æ
V+ = 5V, V- = -4.75V to -5.25V
±0.2
±1.00
V-
OUTPUT AMPLIFIER (applies to all waveforms)
Output Peak-to-Peak Symmetry
V
OUT
±4
mV
Output Resistance
R
OUT
0.1
0.2
½
Output Short-Circuit Current
I
OUT
Short circuit to GND
40
mA
SQUARE-WAVE OUTPUT (R
L
= 100
½
)
Amplitude
V
OUT
1.9
2.0
2.1
V
P-P
Rise Time
t
R
10% to 90%
90% to 10%
V
DADJ
= 0V, dc = t
ON
/t x 100%
12
ns
Fall Time
t
F
12
ns
Duty Cycle
dc
47
50
53
%
TRIANGLE-WAVE OUTPUT (R
L
= 100
½
)
Amplitude
V
OUT
1.9
2.0
2.1
V
P-P
Nonlinearity
F
o
= 100kHz, 5% to 95%
V
DADJ
= 0V (Note 1)
0.5
%
Duty Cycle
dc
47
50
53
%
SINE-WAVE OUTPUT (R
L
= 100
½
)
Amplitude
V
OUT
1.9
2.0
2.1
V
P-P
Total Harmonic Distortion
THD
Duty cycle adjusted to 50%
0.75
%
Duty cycle unadjusted
1.50
2 _______________________________________________________________________________________
½
High-Frequency Waveform Generator
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, GND = DGND = 0V, V+ = DV+ = 5V, V- = -5V, V
DADJ
= V
FADJ
= V
PDI
= V
PDO
= 0V, C
F
= 100pF,
R
IN
= 25k
, R
L
= 1k
½
, C
L
= 20pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SYNC OUTPUT
Output Low Voltage
V
OL
I
SINK
= 3.2mA
0.3
0.4
V
Output High Voltage
V
OH
I
SOURCE
= 400µA
2.8
3.5
V
Rise Time
t
R
10% to 90%, R
L
= 3k
½
, C
L
= 15pF
10
ns
Fall Time
t
F
90% to 10%, R
L
= 3k
½
, C
L
= 15pF
10
ns
Duty Cycle
dc
SYNC
50
%
DUTY-CYCLE ADJUSTMENT (DADJ)
DADJ Input Current
I
DADJ
190
250
320
µA
DADJ Voltage Range
V
DADJ
±2.3
V
Duty-Cycle Adjustment Range
dc
-2.3V
²
V
DADJ
²
2.3V
15
85
%
DADJ Nonlinearity
dc/V
FADJ
-2V
²
V
DADJ
²
2V
2
4
%
Change in Output Frequency
with DADJ
F
o
/V
DADJ
-2V
²
V
DADJ
²
2V
±2.5
±8
%
Maximum DADJ Modulating
Frequency
F
DC
2
MHz
FREQUENCY ADJUSTMENT (FADJ)
FADJ Input Current
I
FADJ
190
250
320
µA
FADJ Voltage Range
V
FADJ
±2.4
V
Frequency Sweep Range
F
o
-2.4V
²
V
FADJ
²
2.4V
±70
%
FM Nonlinearity with FADJ
F
o
/V
FADJ
-2V
²
V
FADJ
²
2V
±0.2
%
Change in Duty Cycle with FADJ dc/V
FADJ
-2V
²
V
FADJ
²
2V
±2
%
Maximum FADJ Modulating
Frequency
F
F
2
MHz
VOLTAGE REFERENCE
Output Voltage
V
REF
I
REF
= 0
2.48
2.50
2.52
V
Temperature Coefficient
V
REF
/°C
20
ppm/°C
Load Regulation
V
REF
/I
REF
0mA
²
I
REF
²
4mA (source)
1
2
mV/mA
-100µA
²
I
REF
²
0µA (sink)
1
4
Line Regulation
V
REF
/V+ 4.75V
²
V+
²
5.25V (Note 2)
1
2
mV/V
LOGIC INPUTS (A0, A1, PDI)
Input Low Voltage
V
IL
0.8
V
Input High Voltage
V
IH
2.4
V
Input Current (A0, A1)
I
IL
, I
IH
V
A0
, V
A1
= V
IL
, V
IH
±5
µA
Input Current (PDI)
I
IL
, I
IH
V
PDI
= V
IL
, V
IH
±25
µA
POWER SUPPLY
Positive Supply Voltage
V+
4.75
5.25
V
SYNC Supply Voltage
DV+
4.75
5.25
V
Negative Supply Voltage
V-
-4.75
-5.25
V
Positive Supply Current
I+
35
45
mA
SYNC Supply Current
I
DV+
1
2
mA
Negative Supply Current
I-
45
55
mA
Note 1:
Guaranteed by duty-cycle test on square wave.
Note 2:
V
REF
is independent of V-.
_______________________________________________________________________________________ 3
½
High-Frequency Waveform Generator
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, V
DADJ
= V
FADJ
= V
PDI
= V
PDO
= 0V, R
L
= 1k
½
, C
L
= 20pF, T
A
= +25°C, unless
otherwise noted.)
OUTPUT FREQUENCY
vs. IIN CURRENT
NORMALIZED OUTPUT FREQUENCY
vs. FADJ VOLTAGE
100M
2.0
1.8
I
IN
= 100
m
A, COSC = 1000pF
33pF
1.6
10M
100pF
1.4
330pF
1.2
1M
1.0
3.3nF
0.8
100k
0.6
33nF
0.4
10k
100nF
0.2
0
-3
-2
-1
0
1
2
3
1k
1
m
F
V
FADJ
(V)
3.3
m
F
100
DUTY CYCLE vs. DADJ VOLTAGE
10
m
F
100
47
m
F
90
10
100
m
F
80
70
1
60
50
0.1
40
1
10
100
1000
30
20
IIN CURRENT (
m
A)
10
I
IN
= 200
m
A
0
-3
-2
-1
0
1
2
3
DADJ (V)
NORMALIZED OUTPUT FREQUENCY
vs. DADJ VOLTAGE
DUTY-CYCLE LINEARITY
vs. DADJ VOLTAGE
1.10
2.0
I
IN
= 500
m
A
I
IN
= 10
m
A
I
IN
= 25
m
A
I
IN
= 50
m
A
1.5
1.05
1.0
0.5
I
IN
= 250
m
A
1.00
0
-0.5
I
IN
= 100
m
A
0.95
I
IN
= 100
m
A
I
IN
= 250
m
A
-1.0
-1.5
0.90
I
IN
= 50
m
A
I
IN
= 500
m
A
-2.0
I
IN
= 25
m
A
0.85
-2.5
I
IN
= 10
m
A
-2.0
-1.0
0
1.0
1.5
2.5
DADJ (V)
DADJ
(V)
4 _______________________________________________________________________________________
High-Frequency Waveform Generator
____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, V
DADJ
= V
FADJ
= V
PDI
= V
PDO
= 0V, R
L
= 1k
½
, C
L
= 20pF, T
A
= +25°C, unless
otherwise noted.)
SINE-WAVE OUTPUT (50Hz)
SINE-WAVE OUTPUT (20MHz)
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50
m
A
C
F
= 1
I
IN
= 400
m
A
C
F
= 20pF
m
F
TRIANGLE-WAVE OUTPUT (50Hz)
TRIANGLE-WAVE OUTPUT (20MHz)
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50
m
A
I
IN
= 400
m
A
C
F
= 20pF
C
F
= 1
m
F
SQUARE-WAVE OUTPUT (50Hz)
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50
m
A
C
F
= 1
m
F
_______________________________________________________________________________________ 5
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