EXAR XR-2207 Service Manual

查询XR2207供应商

FEA TURES

...the analog plus company

TM

APPLICATIONS

XR-2207

Voltage-Controlled

Oscillator

June 1997–3

 Excellent Temperature Stability (20ppm/°C)
 Linear Frequency Sweep
 Adjustable Duty Cycle (0.1% to 99.9%)
 Two or Four Level FSK Capability
 Wide Sweep Range (1000:1 Minimum)
 Logic Compatible Input and Output Levels
 Wide Supply Voltage Range (4V to 13V)
 Low Supply Sensitivity (0.1% /V)
 Wide Frequency Range (0.01Hz to 1MHz)
 Simultaneous Triangle and Squarewave Outputs

GENERAL DESCRIPTION

The XR-2207 is a monolithic voltage-controlled oscillator
(VCO) integrated circuit featuring excellent frequency
stability and a wide tuning range. The circuit provides
simultaneous triangle and squarewave outputs over a
frequency range of 0.01Hz to 1MHz. It is ideally suited for
FM, FSK, and sweep or tone generation, as well as for
phase-locked loop applications.

 FSK Generation
 Voltage and Current-to-Frequency Conversion
 Stable Phase-Locked Loop
 Waveform Generation

– Triangle, Sawtooth, Pulse, Squarewave

 FM and Sweep Generation

The XR-2207 has a typical drift specification of 20ppm/°C.
The oscillator frequency can be linearly swept over a
1000:1 range with an external control voltage; and the
duty cycle of both the triangle and the squarewave
outputs can be varied from 0.1% to 99.9% to generate
stable pulse and sawtooth waveforms.

ORDERING INFORMA TION

Part No. Package

XR-2207M 14 Lead 300 Mil CDIP -55°C to +125°C

XR-2207CP 14 Lead 300 Mil PDIP 0°C to +70°C

XR-2207D 16 Lead 300 Mil JEDEC SOIC 0°C to +70°C

XR-2207ID 16 Lead 300 Mil JEDEC SOIC -40°C to +85°C

BLOCK DIAGRAM

Timing

Capacitor

Timing

Resistors

Rev. 2.02

1975

EXAR Corporation, 48720 Kato Road, Fremont, CA 94538  [phone]  FAX [phone]

C1
C1

R1
R2
R3
R4

Operating

T emperature Range

VCCGND BIAS

1

10 11

2

3

4
5
6
7

VCO

Current

Switches

A1

A2

14
13

SWO

12

V

9

BKI2

8

BKI1

Triangle Wave OutTWO
Square Wave Out

EE

Binary
Keying
Inputs

Figure 1. Block Diagram

1

XR-2207

PIN CONFIGURATION

161

V

1

V

CC

2

C1

3

C2

4

R1

5

R2

6

R3

7

R4

14

TWO

13

SWO

12

V

EE

11

BIAS

10

GND

9

BKI2

8

BKI1

CC

C1
C2

R1
R2
R3
R4

BKI1

2
3
4
5
6
7

NC

15

NC

14

TWO

13

SWO

12

V

11
10

98

EE

BIAS
GND
BKI2

14 Lead PDIP, CDIP (0.300”)

PIN DESCRIPTION

Pin # Symbol Type Description

1 V

CC

2 C1 I Timing Capacitor Input.
3 C2 I Timing Capacitor Input.
4 R1 I Timing Resistor 1 Input.
5 R2 I Timing Resistor 2 Input.
6 R3 I Timing Resistor 3 Input.
7 R4 I Timing Resistor 4 Input.
8 BKI1 I Binary Keying 1 Timing Resistor Select Input.

9 BKI2 I Binary Keying 2 Timing Resistor Select Input.
10 GND Ground Pin.
11 BIAS I Bias Input for Single Supply Operation.
12 V

EE

13 SWO O Square Wave Output Signal.
14 TWO O Triangle Wave Output Signal.

15, 16 NC Only SOIC-16 Package.

Positive Power Supply.

Negative Power Supply .

16 Lead SOIC (Jedec, 0.300”)

Rev. 2.02

2

XR-2207

P

Unit

Conditi

ELECTRICAL CHARACTERISTICS

Test Conditions: Test Circuit of

= R4 = 20kΩ, RL = 4.7kΩ, Binary Inputs Grounded, S1 and S2 Closed Unless Otherwise Specified

R

3

arameters

General Characteristics

Supply Voltage
Single Supply
Split Supplies

Supply Current See
Single Supply 5 7 5 8 mA Measure at Pin 1, S1, S

Split Supply See
Positive 5 7 5 8 mA Measure at Pin 1, S1, S

Negative 4 6 4 7 mA Measured at Pin 12, S1, S

Oscillator Section - Frequency Characteristics

Upper Frequency Limit 0.5 1.0 0.5 1.0 MHz C =500pF, R
Lowest Practical Frequency 0.01 0.01 Hz C =50µF, R3 = 2MΩ
Frequency Accuracy 1 3 1 5 % of f
Frequency Matching 0.5 0.5 % of f
Frequency Stability

Temperature
Power Supply

Sweep Range 1000:1 3000:1 1000:1 fH/f

Sweep Linearity % C =5000pF
10:1 Sweep
1000:1 Sweep

FM Distortion 0.1 0.1 % 10% FM Deviation
Recommended Range of

Timing Resistors
Impedance at Timing Pins 75 75 Ω Measured at Pins 4, 5, 6, or 7
DC Level at Timing Terminals 10 10 mV

Binary Keying Inputs

Switching Threshold 1.4 2.2 2.8 1.4 2.2 2.8 V Measured at Pins 8 and 9,

Input Impedance 5 5 kΩ

Figure 3

XR-2207ID/XR-2207M XR-2207CP/D
Min. T yp. Max. Min. Typ. Max.

8 26 8 26 V See

4 13 4 13 V See

and

Figure 4

, VCC = VEE = 6V, TA = +25°C, C = 5000pF, R1 = R2 =

s

ons

Figure 3
Figure 4
Figure 3

Open

Figure 4

Open

Open

= 2kΩ

3

O
O

20 50 30 ppm/°C 0°C < TA< 70°C

0.15 0.15 %V
R3 = 1.5kΩ for f

L

R3 = 2MΩ for f

1 2 1.5 fH=10kHz, fL= 1kHz

5 5 fH=100kHz, fL= 100Hz

1.5 2000 1.5 2000 kΩ See Characteristic Curves

Referenced to Pin 10

H1

L

2

2

2

Notes
Bold face parameters are covered by production test and guaranteed over operating temperature range.

Rev. 2.02

3

XR-2207

P

Unit

Conditi

l

Linearity

ELECTRICAL CHARACTERISTICS (CONT’D)

XR-2207ID/XR-2207M XR-2207CP/D

arameters

Output Characteristics

Triangle Output Measured at Pin 13
Amplitude
Impedance
DC Leve

Squarewave Output Measured at Pin 13, S

Amplitude 11 12 11 12 Vpp
Saturation Voltage 0.2 0.4 0.2 0.4 V Referenced to Pin 12
Rise Time 200 200 nsec
Fall Time 20 20 nsec

Min. Typ. Max. Min. Typ. Max.

4 6 4 6 V

10 10 Ω

+100 +100 mV Referenced to Pin 10

0.1 0.1 % From 10% to 90% to Swing

s

PP

ons

Closed

CL  10pF
CL  10pF

2

Notes
Bold face parameters are covered by production test and guaranteed over operating temperature range.

Specifications are subject to change without notice

ABSOLUTE MAXIMUM RATINGS

Power Supply 26V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage Temperature Range -65°C to +150°C. . . . .

Power Dissipation (package limitation)

Ceramic package 750mW. . . . . . . . . . . . . . . . . . . . . . .

Plastic package 625mW. . . . . . . . . . . . . . . . . . . . . . . . .

Derate above +25°C 5mW/°C. . . . . . . . . . . . . . . . . .

SOIC package 500mW. . . . . . . . . . . . . . . . . . . . . . . . .

Derate above +25°C 4mW/°C. . . . . . . . . . . . . . . . .

Derate above +25°C 6mW/°C. . . . . . . . . . . . . . . . . .

Rev. 2.02

4

Q1 Q2 Q3 Q4

XR-2207

V

CC

1

Binary
Keying
Inputs

Q5

R1

Q6 Q7

R2

Timing Resistors

9

BB

8

AA

R

Q19

Capacitor

Q8 Q9

Q16

Q17

Timing

2

3

4567

Ground

BIAS

10

11

Q18

Q12

Q23

Q13

R

Q10 Q11

4R

Q22

Q14 Q15

R3

R4

Q20

R
R

R6R5 R7

Q21

Q24

–

+

2R

2R

14

Square Wave

Output

Q25 Q26

Triangle Wave

Output

13

Q27

V

EE

12

Rev. 2.02

Figure 2. Equivalent Schematic Diagram

5

XR-2207

PRECAUTIONS

The following precautions should be observed when
operating the XR-2207 family of integrated circuits:

1. Pulling excessive current from the timing terminals
will adversely affect the temperature stability of the
circuit. To minimize this disturbance, it is
recommended that the total current drawn from pins
4, 5, 6, and 7 be limited to  6mA. In addition,
permanent damage to the device may occur if the
total timing current exceeds 10mA.

2. T erminals 2, 3, 4, 5, 6 , and 7 have very low internal
impedance and should, therefore, be protected from
accidental shorting to ground or the supply voltage.

3. The keying logic pulse amplitude should not exceed
the supply voltage.

SYSTEM DESCRIPTION

The XR-2207 functional blocks are shown in the block
diagram given in

Figure 1

. They are a voltage controlled
oscillator (VCO), four current switches which are
controlled by binary keying inputs, and two buffer
amplifiers for triangle and squarewave outputs.

Figure 2

is a simplified XR-2207 schematic diagram that shows the
circuit in greater detail.

The VCO is a modified emitter-coupled current controlled
multivibrator. Its oscillation is inversely proportional to the
value of the timing capacitor connected to pins 2 and 3,
and directly proportional to the total timing current IT. This
current is determined by the resistors that are connected
from the four timing terminals (pins 4, 5, 6 and 7) to
ground, and by the logic levels that are applied to the two
binary keying input terminals (pins 8 and 9). Four different
oscillation frequencies are possible since I

can have four

T

different values.
The triangle output buffer has a low impedance output

(10Ω TYP) while the squarewave is an open-collector
type. An external bias input allows the XR-2207 to be
used in either single or split supply applications.

V

CC

I+

C

0.1µF

C2

3

SWO
TWO
BIAS

12

Binary

Keying Inputs

0.1µF

8
9

10

S1

A
B

GND

2

1

C1

V+

XR-2207

R14R25R36R47V-

R2R1 R3 R4

Figure 3. Test Circuit for Single Supply Operation

13
14

11

RL

5.1K

3.9K

V

S2

Square Wave

Triangle Wave

CC

Output

Output

V

CC

Rev. 2.02

6

V

CC

C

I+

0.1µF

C2

3

SWO
TWO
BIAS

12

0.1µF

S1

13
14

11

Binary

Keying Inputs

8
9

10

21

C1

V+

A
B
GND

XR-2207

R14R25R36R47V-

R2R1 R3 R4

Figure 4. Test Circuit for Split Supply Operation

RL

Triangle Wave

I-

V

CC

S2

Square Wave

Output

Output

V

EE

XR-2207

OPERA TING CONSIDERATIONS

Supply Voltage (Pins 1 and 12)

The XR-2207 is designed to operate over a power supply
range of 4V to 13V for split supplies, or 8V to 26V for
single supplies.

Figure 5

shows the permissible supply

voltage for operation with unequal split supply voltages.

Figure 6

and

Figure 7

show supply current versus supply
voltage Performance is optimum for 6V split supply , or
12V single supply operation. At higher supply voltages,
the frequency sweep range is reduced.

Ground (Pin 10)

For split supply operation, this pin serves as circuit
ground. For single supply operation, pin 10 should be AC
grounded through a 1µF bypass capacitor. During split
supply operation, a ground current of 2I
terminal, where I

is the total timing current.

T

flows out of this

T

Bias for Single Supply (Pin 11)

For single supply operation, pin 11 should be externally

+

biased to a potential between V

Figure 3

). The bias current at pin 1 1 is nominally 5% of the

total oscillation timing current, I

/3 and V+/2V (see

.

T

Bypass Capacitors

The recommended value for bypass capacitors is 1µF
although larger values are required for very low frequency
operation.

Timing Resistors (Pins 4, 5, 6, and 7)

The timing resistors determine the total timing current, I
available to charge the timing capacitor. Values for timing
resistors can range from 2kΩ to 2MΩ; however, for
optimum temperature and power supply stability,
recommended values are 4kΩ to 200kΩ (see

Figure 9, Figure 10

and

Figure 11

). T o avoid parasitic pick

Figure 8

up, timing resistor leads should be kept as short as
possible. For noisy environments, unused or deactivated
timing terminals should be bypassed to ground through

0.1µF capacitors.

Timing Capacitor (Pins 2 and 3)

The oscillator frequency is inversely proportional to the
timing capacitor, C. The minimum capacitance value is
limited by stray capacitances and the maximum value by
physical size and leakage current considerations.
Recommended values range from 100pF to 100µF. The
capacitor should be non-polarized.

,

T

,

Rev. 2.02

7

XR-2207

25

20

15

10

Positive Supply

5

0

Typical

Operating

Range

-5 -10 -15 -20

Negative Supply (V)

Figure 5. Operating Range for Unequal Split

Supply Voltages

15

TA=25°C

35

RT=Parallel Combination

30
25

20
15

10

Positive Supply (mA)

of Activated Timing

Resistors

=25°C

T

A

=5kΩ

R

R

T

T

R

T

=2MkΩ

RT=2kΩ RT=3kΩ

R

=20kΩ

5
0

4 6 8 10 12 14

810121416182022242628

T

Single Supply Voltage (V)

Figure 6. Positive Supply Current, 1

at Pin 1) vs. Supply Voltage

T

=200kΩ

+

(Measured

=25°C

A

10

5

Negative Supply Current (mA)

0

0 6 8 10 12 14

Split Supply Voltage (V)

Figure 7. Negative Supply Current, I

(Measured at Pin 12) vs. Supply Voltage

1MΩ

100kΩ

Timing

Resistor

10kΩ

Total T iming Resistor RT

1kΩ

0 8 16 24

-

Figure 8. Recommended Timing Resistor

Range

4V 8V 12V0

Single Supply Voltage (V)

Value vs. Power Supply Voltage

Rev. 2.02

8