SANYO LA8608

Ordering number: EN 4077A
Monolithic Linear IC
LA8608V
1.8 V Low-Voltage Narrowband
FM-IF System
Overview
Package Dimensions
The LA8608V is a narrowband FM-IF system intended for
communications equipment, operates at just 1.8 V, and is
contained in an ultrasmall package with a 0.65 mm pitch. In
addition to the various functions needed for reception, the
LA8608V also offers other functions such as noise detection
and electric field intensity detection, and is optimum for
compact designs, such as for cordless phones.
unit : mm
3175A-SSOP24
[LA8608V]
Functions
. 2nd mixer, 2nd local oscillator, IF amplifier, limiter,
detector, signal meter
. quadrature
Noise detector, noise amplifier, noise detector, Schmitt
trigger, comparator
Features
. Because this IC has three independent noise detection and
.
.
.
amplification amplifiers, it can be used to form a secondary
biquad bandpass filter; furthermore, because it is equipped
with detector and Schmitt trigger functions, it can be easily
used for carrier sense applications.
Broad signal meter linearity (70 dB typ.)
Low operating voltage: 1.8 V to 6 V
Small package: SSOP-24 (0.65 mm pitch)
SANYO : SSOP24
Specifications
Maximum Ratings at Ta = 25 °C
Parameter
Symbol
Maximum supply voltage
VCCmax
Allowable power dissipation
Pd max
Conditions
Ratings
Unit
8.0
V
300
mW
Operating temperature
Topr
–20 to +75
°C
Storage temperature
Tstg
–40 to +125
°C
Ratings
Unit
Operating Conditions at Ta = 25 °C
Parameter
Symbol
Recommended supply voltage
VCC
Operating supply voltage range
VCC op
Conditions
3.0
V
1.8 to 6.0
V
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53095HA (II) - No.4077 1/14
LA8608V
Operating Characteristics at Ta = 25 °C, VCC = 3 V, fC = 21.7 MHz, fmod = 1 kHz, dev = ±3 kHz
Parameter
Quiescent current
–3 dB limiting sensitivity
Demodulation output
S/N ratio
AM rejection ratio
Total harmonic distortion
Noise detection output
Schmitt trigger level
Schmitt hysteresis
Schmitt output level
Signal meter output
Comparator output
Mixer conversion gain
Mixer input frequency
Mixer input resistance
Mixer output resistance
IF input resistance
FM detection output impedance
Symbol
Icco
–3dBL.S.
VO
S/N(1)
S/N(2)
AMR
THD
VND(1)
VND(2)
VND(3)
VND(4)
SH
SHhy
VSH(1)
VSH(2)
VSM(1)
VSM(2)
VSM(3)
VCOMP(1)
VCOMP(2)
GM
Output
No input
–3 dB
Vin = 80 dBµ
Vin = 80 dBµ, Non-modulation
Vin = 20 dBµ, Non-modulation
Vin = 80 dBµ, AM 30% modulation
Vin = 80 dBµ
Vin = 10 dBµ, VCC = 2.1 V
Vin = 10 dBµ, VCC = 3.0 V
Vin = 10 dBµ, VCC = 5.0 V
Vin = 30 dBµ
min
115
54
20
30
1.6
12
Vin = 13 dBµ
Vin = 26 dBµ
Vin = 5 dBµ
Vin = 50 dBµ
Vin = 80 dBµ
V9 = 1.5 V
V9 = 0.9 V
typ
2.8
5
170
60
25
40
0.7
1.9
2.2
2.3
0
20
1
max
3.8
11
230
2.0
2.8
0.1
27
0.5
2.8
0.8
1.3
2.8
0.1
1.1
1.6
0.3
1.4
2.0
0.5
20
90
3.6
1.8
1.8
2.4
Unit
mA
dBµ
mVrms
dB
dB
dB
%
V
V
V
V
dBµ
dB
V
V
V
V
V
V
V
dB
MHz
kΩ
kΩ
kΩ
kΩ
No.4077 - 2/14
LA8608V
Block Diagram and Pin Assignment
Unit (resistance:Ω, capacitance:F)
Pins
1. CRYSTAL
2. OSC
3. MIX-OUT
4. VREF
5. VCC
6. IF-IN
7. D.C1
8. D.C2
9. COMP(+)
10. COMP-OUT
11. LIMT.OUT
12. QUAD-COIL
13. SCHMITT-OUT
14. S.DET.
15. DET-OUT
16. IN(–)1
17.
18.
19.
20.
21.
22.
23.
24.
OUT1
IN(–)2
OUT2
IN(–)3
OUT3
NOISE-DET.
GND
MIX-IN
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LA8608V
AC Test Circuit
Unit (resistance:Ω, capacitance:F)
Sample Application Circuit (1)
Unit (resistance:Ω, capacitance:F)
No.4077 - 4/14
LA8608V
Sample Application Circuit (2)
Allowable power dissipation, Pd max - mW
Unit (resistance:Ω, capacitance:F)
Ambient temperature, Ta - °C
No.4077 - 5/14
LA8608V
Pin Description
Unit (resistance:Ω)
Pin No.
Pin Name
Pin Voltage
[V]
VCC
Internal equivalent circuit
Remarks
1
CRYSTAL
2
OSC
VCC–0.7
3
MIX-OUT
VCC–0.3
4
VREF
1.2V
5
6
VCC
IF-IN
VCC
VCC–0.9
Power supply
IF amp input
7
D.C1
VCC–0.9
IF amp DC feedback
8
D.C2
VCC–0.9
9
COMP (+)
Comparator threshold setting pin;
set by external resistance
10
COMP-OUT
Comparator output;
open collector
11
LIM.OUT
0.2
Limiter amp output
12
QUAD-COIL
VCC
Discriminator connection
13
SCHMITT-OUT
Forms a Colpitts oscillator.
MIX buffer output
Regulated voltage output
Noise Schmitt output;
open collector
Continued on next page.
No.4077 - 6/14
LA8608V
Continued from preceding page.
Unit (resistance:Ω)
Pin No.
Pin Name
Pin Voltage
[V]
0.1 to 1.5
Internal equivalent circuit
Remarks
14
S.DET
15
DET-OUT
1.2
FM detection output
16
IN (–)1
1.0
Operational amplifier negative
input
17
OUT1
1.0
Operational amplifier output
18
IN (–)2
1.0
Operational amplifier negative
input
19
OUT2
1.0
Operational amplifier output
20
IN (–)3
1.0
Operational amplifier negative
input
21
OUT3
1.0
Operational amplifier output
22
NOISE-DET
0 to 1.4
Noise wave detection output
23
24
GND
MIX-IN
0
1.2
Electric field intensity signal
output
GND
Mixer input
No.4077 - 7/14
LA8608V
IC Usage Notes
1. About the local oscillator
Fig. 1
Fig. 1 shows the equivalent circuit for the local oscillator.
In this circuit, when C1 = 22 pF, the change in the negative resistance versus C2 is shown in Fig. 2, the change in the operational
load capacitance is shown in Fig. 3, and the frequency deviation is shown in Fig. 4. In the application circuit,
C2 = 120 pF, and in this case the negative resistance according to Fig. 2 is –58 Ω. In order to increase the negative resistance, it is
necessary to decrease the value of C2. To increase the oscillation level, it is possible to add external resistor R1 and raise the local
oscillator current. However, the oscillation level on pin 1 must be set to 110 dB or less. If set to a greater level, distortion will
occur in the oscillation waveform.
Fig. 3
Negative resistance, R — Ω
Operating load capacitance, CL — pF
Fig. 2
Frequency deviation, ∆ f — ppm
Fig. 4
(Note)
Fig 2 to 4: C1 = 22 pF
Figs. 3, 4: Reference to operating load
capacitance 16 pF
No.4077 - 8/14
LA8608V
2. About the built-in operational amplifiers
The LA8608V has three independent operational amplifiers on chip that can be used as needed. If they are not to be used, short
the I/O pins.
Sample application 1:
Noise amplifier
Using the three operational amplifiers, it is possible to form a secondary biquad bandpass filter. (For details on the filter
response characteristics, refer to the data provided later.)
Fig. 5
The calculation of the transfer function for the above diagram is as shown below.
ω02 =
R5
C1C2R3R4R6
1
ω0
=
C
Q
1R2
H=
R2R5
R1R4
In normal use, R3 = R4 = R5 = R6 = Rf, and C1 = C2 = Cf:
Therefore,
ω0 =
1
CfRf
fO =
1
2πCfRf
Q = CfR2 x ω0
=
R2
Rf
H=
=
R2Rf
R1Rf
R2
R1
fo = center frequency, H = pass band gain, Q = selectivity
No.4077 - 9/14
LA8608V
Noise amplified by this amp passes through the noise detector, and is detected by R and C connected to pin 22. The Schmitt
circuit operates on the basis of this DC, and the Shmitt output appears on pin 13. Because the pass band gain is determined by
R2/R1, changing these resistances makes it possible to vary the Schmitt circuit level to some extent. By varying the level, it is
possible to continue operating Schmitt circuit up to a signal-to-noise ratio of approximately 30 dB on the No. 2 mixer input. To
continue operating Schmitt circuit at a higher S/N ratio, add a resistor between pin 17 and GND. This makes it possible to
increase the signal-to-noise ratio of the input level at which the Schmitt circuit continue operating by approximately 10 dB. (Refer
to Fig. 6.)
S/N for noise Schmitt trigger — dB
S/N for noise amp gain and Schmitt trigger
Misoperation when
Ri < 1 kΩ
With RB
Misoperation when
Ri < 12 kΩ
No RB
Unit (resistance: Ω, capacitance: F)
Fig. 6
Sample application 2:
(1) When an operational amplifier is used in a signal system amplifier, etc., connect a capacitor of about 1000 pF between the
output (pins 17, 19, 21) and GND. This capacitor prevents local oscillation when the signal is clipped on the negative side.
Fig. 7
(2) When used in the signal system amplifier, etc. and the dynamic range of the output must be expanded, use the scheme
described below.
1) Use RB1 to set the output DC voltage to
approximately 1/2VCC .
Output DC voltage
VODC = VB (1 +
R2
R3
)
VB = 1 V
2) Add 10 kΩ between the output pin and
GND.
Fig. 8
No.4077 - 10/14
LA8608V
Quiescent, Icco — mA
Reference voltage (Pin 3), Vref — V
Demodulation output,
noise output, AM output — dBm
Icco, Vref — VCC
Vo, Noise, AM-OUT — VIN
Demodutation output
(Mitsumi)
Noise output
Unit (resistance: Ω, capacitance: F)
(Murata)
Demodutation output
Unit (resistance: Ω, capacitance: F)
Noise output
Total harmonic
distortion
Input voltage, VIN — dBµ
Detuning characteristics
Input voltage, VIN — dBµ
Demodutation output, VO — dBm –3 dBL.S.20dB
SIN AD — dBµ
THD — dB Demodutation output,
Noise output, AM output — dBm
Supply voltage, VCC — V
Vo, Noise, AM-OUT, THD — VIN
Vo, –3dB L.S. 20dB SIN AD — VCC
Referenced to VIN = 80 dBµ
Supply voltage,VCC — V
S curve output
When
using
coil
Unit
(resistance: Ω, capacitance: F)
Ceramic
discriminator
Detuning frequency,
∆f — kHz
When using
a ceramic
discriminator
Coil
Detection
coil
YD0051
(Mitsumi)
Discriminator
CDBM455C7 (Murata)
Unit
(resistance: Ω, capacitance: F)
Input voltage, VIN — dBµ
VND — VIN
Noise detection output voltage, VND — V
Signal meter output voltage, VSM — V
Detuning frequency ∆ f — kHz (21.70MHz)
VSM — VIN
Unit (resistance: Ω,
capacitance: F)
Input voltage, VIN — dBµ
No.4077 - 11/14
LA8608V
f Response
Schmitt off
Schmitt on
–3dB L.S. 20dB SIN AD — VOSC
Third intercept point
Mixer
conversion
gain
Output level — dBm
Supply voltage, VCC — V
Mixer conversion gain — dB
Frequency, f — Hz
Input level — dBm
Vref, Icco — VCC
Noise, Vo — VIN
Signal meter output Voltage VSM
—V
VSM — Ta
Ambient temperature, Ta — °C
Pin 22 supply voltage, Pin 22 output voltage — V
Quiescent current Icco — mA
Supply voltage, VCC — V
Demodutation, Noise output, Noise, Vo — dBm
VOSC — dBµ
Reference voltage (Pin 3), Vref — V
–3dBL.S.20 dB SIN AD — dBµ
Response — dB
Input voltage, VIN — dBµ
Schmitt trigger level
Input voltage, VIN — dBµ
VIN — Ta
Saturation level
at no input
Schmitt on
Unit (resistance: Ω,
capacitance: F)
Schmitt off
Ambient temperature, Ta — °C
No.4077 - 12/14
LA8608V
S curve output temperature characteristics (1)
S curve output temperature characteristics (2)
Non-modulation
Non-modulation
Using CDBM455C7
(Murata)
Using YD0051 (Mitsumi)
Detuning frequency,
∆f – kHz
Detuning frequency
∆ f — kHz
Iosc — VCC
(Mitsumi)
Supply voltage, VCC — V
Vo, THD — Ta
Demodutation output, VO — V
Local oscillation current, Iosc — µA
Input voltage, VIN — dBµ
IOSC — Ta
Ambient temperature, Ta — °C
Schmitt on
S/N at Vin = 20 dBµ
Ambient temperature, Ta — °C
S/N ratio (S/N),
AM rejection ratio (AMR) — dB
Schmitt trigger level — dBµ
Schmitt off
used
THD: 400 to 30 kHz
BPF used
Total harmonic distortion, THD — %
When using coil
Local oscillation current, Iosc — µA
Pin 15 DC output, Dct-OUT — V
Dct-OUT — VIN
Ambient temperature, Ta — °C
No.4077 - 13/14
LA8608V
No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment,
nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or
indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1 Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors
and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and
expenses associated with such use:
2 Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO
ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume
production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use
or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of May, 1995. Specifications and information herein are subject to change without notice.
No.4077 - 14/14