LM13700/LM13700A
Dual Operational Transconductance Amplifiers with
Linearizing Diodes and Buffers
General Description
The LM13700 series consists of two current controlled
transconductance amplifiers, each with differential inputs
and a push-pull output. The two amplifiers share common
supplies but otherwise operate independently. Linearizing di-
odes are provided at the inputs to reduce distortion and allow
higher input levels. The result is a 10 dB signal-to-noise im-
provement referenced to 0.5 percent THD. High impedance
buffers are provided which are especially designed to
complement the dynamic range of the amplifiers. The output
buffers of the LM13700 differ from those of the LM13600 in
that their input bias currents (and hence their output DC lev-
els) are independent of I
ABC
. This may result in performance
superior to that of the LM13600 in audio applications.
Features
n
g
m
adjustable over 6 decades
n
Excellent g
m
linearity
n
Excellent matching between amplifiers
n
Linearizing diodes
n
High impedance buffers
n
High output signal-to-noise ratio
Applications
n
Current-controlled amplifiers
n
Current-controlled impedances
n
Current-controlled filters
n
Current-controlled oscillators
n
Multiplexers
n
Timers
n
Sample-and-hold circuits
Connection Diagram
Dual-In-Line and Small Outline Packages
DS007981-2
Top View
Order Number LM13700M, LM13700N or LM13700AN
See NS Package Number M16A or N16A
May 1998
LM13700/LM13700A
Dual
Operational
T
ransconductance
Amplifiers
with
Linearizing
Diodes
and
Buffers
1999 National Semiconductor Corporation
DS007981
www.national.com
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (Note 2)
LM13700
36 V
DC
or
18V
LM13700A
44 V
DC
or
22V
Power Dissipation (Note 3) T
A
= 25C
LM13700N, LM13700AN
570 mW
Differential Input Voltage
5V
Diode Bias Current (I
D
)
2 mA
Amplifier Bias Current (I
ABC
)
2 mA
Output Short Circuit Duration
Continuous
Buffer Output Current (Note 4)
20 mA
Operating Temperature Range
LM13700N, LM13700AN
0C to +70C
DC Input Voltage
+V
S
to -V
S
Storage Temperature Range
-65C to +150C
Soldering Information
Dual-In-Line Package
Soldering (10 sec.)
260C
Small Outline Package
Vapor Phase (60 sec.)
215C
Infrared (15 sec.)
220C
See AN-450 "Surface Mounting Methods and Their Effect
on Product Reliability" for other methods of soldering
surface mount devices.
Electrical Characteristics
(Note 5)
Parameter
Conditions
LM13700
LM13700A
Units
Min
Typ
Max
Min
Typ
Max
Input Offset Voltage (V
OS
)
0.4
4
0.4
1
Over Specified Temperature Range
2
mV
I
ABC
= 5 A
0.3
4
0.3
1
V
OS
Including Diodes
Diode Bias Current (I
D
) = 500 A
0.5
5
0.5
2
mV
Input Offset Change
5 A
I
ABC
500 A
0.1
3
0.1
1
mV
Input Offset Current
0.1
0.6
0.1
0.6
A
Input Bias Current
Over Specified Temperature Range
0.4
5
0.4
5
A
1
8
1
7
Forward
6700
9600
13000
7700
9600
12000
mho
Transconductance (g
m
)
Over Specified Temperature Range
5400
4000
g
m
Tracking
0.3
0.3
dB
Peak Output Current
R
L
= 0, I
ABC
= 5 A
5
3
5
7
R
L
= 0, I
ABC
= 500 A
350
500
650
350
500
650
A
R
L
= 0, Over Specified Temp Range
300
300
Peak Output Voltage
Positive
R
L
=
, 5 A
I
ABC
500 A
+12
+14.2
+12
+14.2
V
Negative
R
L
=
, 5 A
I
ABC
500 A
-12
-14.4
-12
-14.4
V
Supply Current
I
ABC
= 500 A, Both Channels
2.6
2.6
mA
V
OS
Sensitivity
Positive
V
OS
/
V
+
20
150
20
150
V/V
Negative
V
OS
/
V
-
20
150
20
150
V/V
CMRR
80
110
80
110
dB
Common Mode Range
12
13.5
12
13.5
V
Crosstalk
Referred to Input (Note 6)
100
100
dB
20 Hz
<
f
<
20 kHz
Differential Input Current
I
ABC
= 0, Input =
4V
0.02
100
0.02
10
nA
Leakage Current
I
ABC
= 0 (Refer to Test Circuit)
0.2
100
0.2
5
nA
Input Resistance
10
26
10
26
k
Open Loop Bandwidth
2
2
MHz
Slew Rate
Unity Gain Compensated
50
50
V/s
Buffer Input Current
(Note 6)
0.5
2
0.5
2
A
Peak Buffer Output Voltage
(Note 6)
10
10
V
Note 1: "Absolute Maximum Ratings" indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits.
Note 2: For selections to a supply voltage above
22V, contact factory.
www.national.com
2
Electrical Characteristics
(Note 5) (Continued)
Note 3: For operation at ambient temperatures above 25C, the device must be derated based on a 150C maximum junction temperature and a thermal resistance,
junction to ambient, as follows: LM13700N, 90C/W; LM13700M, 110C/W.
Note 4: Buffer output current should be limited so as to not exceed package dissipation.
Note 5: These specifications apply for V
S
=
15V, T
A
= 25C, amplifier bias current (I
ABC
) = 500 A, pins 2 and 15 open unless otherwise specified. The inputs to
the buffers are grounded and outputs are open.
Note 6: These specifications apply for V
S
=
15V, I
ABC
= 500 A, R
OUT
= 5 k
connected from the buffer output to -V
S
and the input of the buffer is connected
to the transconductance amplifier output.
Schematic Diagram
Typical Performance Characteristics
One Operational Transconductance Amplifier
DS007981-1
Input Offset Voltage
DS007981-38
Input Offset Current
DS007981-39
Input Bias Current
DS007981-40
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3
Typical Performance Characteristics
(Continued)
Peak Output Current
DS007981-41
Peak Output Voltage and
Common Mode Range
DS007981-42
Leakage Current
DS007981-43
Input Leakage
DS007981-44
Transconductance
DS007981-45
Input Resistance
DS007981-46
Amplifier Bias Voltage vs
Amplifier Bias Current
DS007981-47
Input and Output Capacitance
DS007981-48
Output Resistance
DS007981-49
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4
Typical Performance Characteristics
(Continued)
Circuit Description
The differential transistor pair Q
4
and Q
5
form a transcon-
ductance stage in that the ratio of their collector currents is
defined by the differential input voltage according to the
transfer function:
(1)
where V
IN
is the differential input voltage, kT/q is approxi-
mately 26 mV at 25C and I
5
and I
4
are the collector currents
of transistors Q
5
and Q
4
respectively. With the exception of
Distortion vs Differential
Input Voltage
DS007981-50
Voltage vs Amplifier
Bias Current
DS007981-51
Output Noise vs Frequency
DS007981-52
Unity Gain Follower
DS007981-5
Leakage Current Test Circuit
DS007981-6
Differential Input Current Test Circuit
DS007981-7
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5
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