Gennum Corporation GK509 Datasheet
Class A Amplifier with 2 DC Coupled
Gain Blocks & Schottky Diodes
GK509 DATA SHEET
FEATURES
µA typical current drain
• 100
• low noise and distortion
• 1.0 to 5 VDC operating range
• DC coupled stages
• Class A output stage
• Schottky diodes for MPO control
• variable transducer current
• 4 k
Ω microphone decoupling resistor
STANDARD PACKAGING
• 8 pin PLID
®
• Chip ( 61 x 55 mils)
DESCRIPTION
The GK509 is a Class A amplifier utilizing Gennum’s
proprietary low voltage JFET technology. It consists of a
single-ended, low noise inverting gain block, a Class
A output stage, an on-chip microphone decoupling
resistor, and a pair of Schottky diodes for symmetrical
peak clipping.
Block A typically has an open loop voltage gain of 56 dB,
with the closed loop gain set by the ratio of the feedback
resistor to the source impedance. It is recommended that
the maximum closed loop gain be 20 dB lower than the
open loop gain. All blocks of the device are internally bias
compensated, preventing any DC current flow via external
feedback resistors. Without this compensation audible
scratchiness would be present during changes in volume
control settings.
The output stage of the GK509 is a Class A current drive.
It has a fixed reference voltage of typically 30 mV at pin 2
of the device. The current that flows in the transducer is the
ratio of the 30 mV reference voltage and the on-chip
emitter resistor (R
transducer, simply place an external R
to ground, thereby decreasing the equivalent emitter resistance
). To increase the bias current in the
E
resistor from pin 2
E
and increasing the current.
V
MIC
A IN
Revision Date: January 2001
The GK509 also contains a pair of Schottky diodes in the
feedback configuration of the output stage, which provides
approximately 12 dB of MPO control.
V
B
6
R
MIC
5
4
All resistors in ohms, all capacitors in farads unless otherwise stated
- A
A OUT
- B
R
E
3
1
GND
BLOCK DIAGRAM
21K
7
8
2
MPO
B OUT
R
E
Document No. 510 - 69 -06
GENNUM CORPORATION P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3 tel. +1 (905) 632-2996
Web Site: www.gennum.com E-mail: hipinfo@gennum.com
ABSOLUTE MAXIMUM RATINGS
PIN CONNECTION
PARAMETER VALUE/UNITS
Supply Voltage 5 V DC
Operating Temperature Range -10°C to 40° C
Storage Temperature Range -20°C to 70° C
A IN
A OUT
R
GND
4
E
1
5
V
MIC
V
B
MPO
B OUT
8
CAUTION
CLASS 1 ESD SENSITIVITY
ELECTRICAL CHARACTERISTICS
VP - Pin voltage measured with conditions as shown in Test Circuit.
Positive current corresponds to current INTO the pin.
Negative current corresponds with current OUT of the pin.
Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Amplifier Current I
Transducer Current I
Maximum Transducer Current I
A Input Bias Voltage (pin 4) V
A Input Bias Current (pin 4) I
A O/P Voltage Swing-Hi (pin 3) V
AMP
TRANS
TRANS (MAX)VP2
BIAS A
BIAS A
OH A
RFA = 1 M, (Note 1) -50 0 50 nA
VIN = 0.4 V DC, R
= 0 V 2 - - mA
IP3 =
A Output Swing-Lo (pin 3) V
A Open Loop Voltage Gain A
B Output Sat. Voltage (pin 8) V
A Output Current Capability I
Diode Voltage Drop V
Emitter Bias Voltage (pin 2) V
On-chip Microphone Resistor R
On-chip Emitter Resistor R
OL A
OL
SAT B
OUT
D
RE
MIC
E
I
= +1 µA, RFA = ∞, 200 280 - mV
IN
I
P3 =
RL = 1 kΩ, VP2 = 0 V - 100 180 mV
(S2 = b), RL = ∞, (Note 4) 140 265 325 mV
Input Referred Noise IRN NFB 0.2 to 10kHz at 12 dB/Oct - 1 - µVRMS
Harmonic Distortion THD 500 mVRMS Output - 1 - %
= 1.3 V
B
FA
-10 µA (Note 2)
+10 µA (Note 3)
55 100 145 µA
170 230 290 µA
500 570 650 mV
= ∞, 200 580 - mV
46 56 - dB
-30 - µA
21.5 30 35.5 mV
34 5kΩ
90 125 160 Ω
All parameters and switches remain as shown in Test Circuit unless otherwise stated in CONDITIONS column.
NOTES: 1. I
2. V
3. V
4. V
510 - 69 - 06
= (VP4 -V
BIAS A
OH A
OL A
=
D
=
=
(V
P4[RFA = 1M]
(VP3 -V
P3 [VIN = 0.4VDC, RFA = ∞, IP3 = -10 µA]
(VP3 -V
P8 [Id = +(1.5 x ITRANS)]
P3 [IIN = +1µA, RFA = ∞, IP3 =+10 µA]
)/1M
-V
P8 [Id = +(0.5 x ITRANS)]
)
)
)/2
2
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