MAX038.pdf

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19-0266; Rev 5; 2/04
IT
TION K
VALUA
E
BLE
AVAILA
High-Frequency Waveform Generator
____________________________Features
o
0.1Hz to 20MHz Operating Frequency Range
o
Triangle, Sawtooth, Sine, Square, and Pulse
Waveforms
o
Independent Frequency and Duty-Cycle
Adjustments
o
350 to 1 Frequency Sweep Range
o
15% to 85% Variable Duty Cycle
o
Low-Impedance Output Buffer: 0.1Ω
o
Low 200ppm/°C Temperature Drift
________________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.
MAX038
_______________Ordering Information
PART
MAX038CPP
MAX038CWP
MAX038C/D*
MAX038EPP*
MAX038EWP*
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 Plastic DIP
20 SO
Dice
20 Plastic DIP
20 SO
*Contact
factory prior to design.
________________________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
GND
2
A0
3
A1
4
COSC
5
GND
6
DADJ
7
FADJ
8
GND
9
IIN
10
20
V-
19
OUT
18
GND
MAX038
17
V+
16
DV+
15
DGND
14
SYNC
13
PDI
12
PDO
11
GND
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
High-Frequency Waveform Generator
MAX038
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- ...................30s
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, 10s) .................................+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
= 25kΩ, R
L
= 1kΩ, C
L
= 20pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
FREQUENCY CHARACTERISTICS
Maximum Operating Frequency
Frequency Programming
Current
IIN Offset Voltage
Frequency Temperature
Coefficient
F
o
I
IN
V
IN
∆F
o
/°C
V
FADJ
= 0V
V
FADJ
= 0V
V
FADJ
= -3V
CONDITIONS
C
F
≤
15pF, I
IN
= 500µA
MIN
20.0
2.50
1.25
±1.0
600
200
±0.4
±0.2
±2.00
%/V
±1.00
TYP
40.0
750
375
±2.0
MAX
UNITS
MHz
µA
mV
ppm/°C
F
o
/°C
V
FADJ
= -3V
(∆F
o
/F
o
)
V- = -5V, V+ = 4.75V to 5.25V
∆V+
Frequency Power-Supply
Rejection
(∆F
o
/F
o
)
V+ = 5V, V- = -4.75V to -5.25V
∆V-
OUTPUT AMPLIFIER (applies to all waveforms)
Output Peak-to-Peak Symmetry
Output Resistance
Output Short-Circuit Current
Amplitude
Rise Time
Fall Time
Duty Cycle
Amplitude
Nonlinearity
Duty Cycle
SINE-WAVE OUTPUT (R
L
= 100Ω)
Amplitude
Total Harmonic Distortion
V
OUT
R
OUT
I
OUT
V
OUT
t
R
t
F
dc
V
OUT
F
O
= 100kHz, 5% to 95%
dc
V
OUT
THD
CF = 1000pF, F
O
= 100kHz
V
DADJ
= 0V (Note 1)
47
1.9
10% to 90%
90% to 10%
V
DADJ
= 0V, dc = t
ON
/t x 100%
47
1.9
Short circuit to GND
1.9
±4
0.1
40
2.0
12
12
50
2.0
0.5
50
2.0
2.0
mV
0.2
Ω
mA
2.1
V
P-P
ns
ns
53
2.1
53
2.1
%
V
P-P
%
%
V
P-P
%
SQUARE-WAVE OUTPUT (R
L
= 100Ω)
TRIANGLE-WAVE OUTPUT (R
L
= 100Ω)
2
_______________________________________________________________________________________
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
= 25kΩ, R
L
= 1kΩ, C
L
= 20pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
SYNC OUTPUT
Output Low Voltage
V
OL
Output High Voltage
V
OH
Rise Time
t
R
Fall Time
t
F
Duty Cycle
dc
SYNC
DUTY-CYCLE ADJUSTMENT (DADJ)
DADJ Input Current
I
DADJ
DADJ Voltage Range
V
DADJ
Duty-Cycle Adjustment Range
dc
DADJ Nonlinearity
dc/V
FADJ
Change in Output Frequency
F
o
/V
DADJ
with DADJ
Maximum DADJ Modulating
F
DC
Frequency
FREQUENCY ADJUSTMENT (FADJ)
FADJ Input Current
I
FADJ
FADJ Voltage Range
V
FADJ
Frequency Sweep Range
F
o
FM Nonlinearity with FADJ
F
o
/V
FADJ
Change in Duty Cycle with FADJ dc/V
FADJ
Maximum FADJ Modulating
F
F
Frequency
VOLTAGE REFERENCE
Output Voltage
Temperature Coefficient
Load Regulation
Line Regulation
LOGIC INPUTS (A0, A1, PDI)
Input Low Voltage
Input High Voltage
Input Current (A0, A1)
Input Current (PDI)
POWER SUPPLY
Positive Supply Voltage
SYNC Supply Voltage
Negative Supply Voltage
Positive Supply Current
SYNC Supply Current
Negative Supply Current
V+
DV+
V-
I+
I
DV+
I-
4.75
4.75
-4.75
35
1
45
5.25
5.25
-5.25
45
2
55
V
V
V
mA
mA
mA
V
IL
V
IH
I
IL
, I
IH
I
IL
, I
IH
V
A0
, V
A1
= V
IL
, V
IH
V
PDI
= V
IL
, V
IH
2.4
±5
±25
0.8
V
V
µA
µA
V
REF
V
REF
/°C
V
REF
/I
REF
V
REF
/V+
0mA
≤
I
REF
≤
4mA (source)
-100µA
≤
I
REF
≤
0µA (sink)
4.75V
≤
V+
≤
5.25V (Note 2)
CONDITIONS
I
SINK
= 3.2mA
I
SOURCE
= 400µA
10% to 90%, R
L
= 3kΩ, C
L
= 15pF
90% to 10%, R
L
= 3kΩ, C
L
= 15pF
MIN
TYP
0.3
3.5
10
10
50
250
±2.3
2
±2.5
2
MAX
0.4
UNITS
V
V
ns
ns
%
µA
V
%
%
%
MHz
MAX038
2.8
190
-2.3V
≤
V
DADJ
≤
+2.3V
-2V
≤
V
DADJ
≤
+2V
-2V
≤
V
DADJ
≤
+2V
15
320
85
4
±8
190
-2.4V
≤
V
FADJ
≤
+2.4V
-2V
≤
V
FADJ
≤
+2V
-2V
≤
V
FADJ
≤
+2V
250
±2.4
±70
±0.2
±2
2
320
µA
V
%
%
%
MHz
I
REF
= 0
2.48
2.50
20
1
1
1
2.52
2
4
2
V
ppm/°C
mV/mA
mV/V
Note 1:
Guaranteed by duty-cycle test on square wave.
Note 2:
V
REF
is independent of V-.
_______________________________________________________________________________________
3
High-Frequency Waveform Generator
MAX038
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, V
DADJ
= V
FADJ
= V
PDI
= V
PDO
= 0V, R
L
= 1kΩ, C
L
= 20pF, T
A
= +25°C, unless
otherwise noted.)
OUTPUT FREQUENCY
vs. IIN CURRENT
MAX038-08
NORMALIZED OUTPUT FREQUENCY
vs. FADJ VOLTAGE
1.8
33pF
F
OUT
NORMALIZED
100pF
330pF
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
-3
-2
-1
0
V
FADJ
(V)
1
2
3
I
IN
= 100µA, COSC = 1000pF
MAX038-09
100M
2.0
10M
1M
OUTPUT FREQUENCY (Hz)
3.3nF
100k
33nF
10k
100nF
1k
1µF
3.3µF
100
10µF
47µF
100µF
DUTY CYCLE (%)
DUTY CYCLE vs. DADJ VOLTAGE
90
80
70
60
50
40
30
20
10
0
-3
-2
-1
0
DADJ (V)
1
2
3
I
IN
= 200µA
MAX038-16B
100
10
1
0.1
1
10
100
1000
IIN CURRENT (µA)
NORMALIZED OUTPUT FREQUENCY
vs. DADJ VOLTAGE
MAX038-17
DUTY-CYCLE LINEARITY
vs. DADJ VOLTAGE
DUTY-CYCLE LINEARITY ERROR (%)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
-2.5
-2.0
I
IN
= 50µA
I
IN
= 25µA
I
IN
= 10µA
-1.0
0
1.0
1.5
2.5
DADJ (V)
I
IN
= 100µA
I
IN
= 250µA
I
IN
= 500µA
MAX038-18
1.10
NORMALIZED OUTPUT FREQUENCY
I
IN
= 10µA
1.05
I
IN
= 25µA
I
IN
= 50µA
1.00
2.0
0.95
I
IN
= 100µA
I
IN
= 250µA
0.90
I
IN
= 500µA
0.85
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
= 1kΩ, C
L
= 20pF, T
A
= +25°C, unless
otherwise noted.)
SINE WAVE THD vs. FREQUENCY
6
5
THD (%)
4
3
2
1
0
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
MAX038 toc01
MAX038
SINE-WAVE OUTPUT (50Hz)
7
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50µA
C
F
= 1µF
SINE-WAVE OUTPUT (20MHz)
TRIANGLE-WAVE OUTPUT (50Hz)
I
IN
= 400µA
C
F
= 20pF
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50µA
C
F
= 1µF
TRIANGLE-WAVE OUTPUT (20MHz)
SQUARE-WAVE OUTPUT (50Hz)
I
IN
= 400µA
C
F
= 20pF
TOP: OUTPUT 50Hz = F
o
BOTTOM: SYNC
I
IN
= 50µA
C
F
= 1µF
_______________________________________________________________________________________
5

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