U2510B
All-Band AM/FM Receiver and Audio Amplifier
Description
The U2510B is an integrated bipolar one-chip AM/FM
radio circuit. It contains an FM front end with
preamplifier, FM IF and demodulator, a complete AM
receiver, an AF amplifier and a mode switch for AM, FM
and tape. This circuit is designed for clock radios and
portable radio-cassette recorders.
Features
D
Superior FM strong signal behavior by using RF AGC
D
Soft mute and HCC for decreasing interstation noise
in FM mode
D
Excellent AFC performance (level controlled, both
polarities available)
D
Level indicator (LED drive) for AM and FM
D
DC mode control: AM, FM and tape
D
Wide supply-voltage range and low quiescent current
D
High AF output power: 1 W
D
Electronic volume control
D
Electronic AF bandwidth control (treble and high cut)
D
Output stage for headphone and speaker drive
Block Diagram
FM RF
tank
FM ant.
V
S
9
8
7
AFC
FM RF
BPE
AGC
12
FM
front end
FM
AGC
AM
front end
RF AGC
Voltage stab.
and
mode control
15
AM/FM
IF
AGC
AM
AGC
AFC
control
AM IF
amp. and
detect.
IF
Level
indic.
AF preamp.
Volume
Mute
HCC
21
13
20
19
1 22
18
FM IF
amp.
FM
discr.
Power
amp.
25
23
24
4
6
14
16
2
26
28
27
3
FM osc.
tank
IF BPE
(Replaceable)
11
AM
ant.
AM osc.
tank
10
5
V
Ref
AM
S
2
V
S
AFC mode
LED
V
S
Treble
Vol
13912
FM Tape
Figure 1. Block diagram
Rev. A3, 23-Feb-01
1 (15)
U2510B
Order Information
Extended Type Number
U2510B-M
U2510B-M__T
Package
SDIP28
SDIP28
Pin
5
28
AF-GND
6
Remarks
V
S
< 6 V supply voltage
Symbol
AMOsc
FM–AFC
Function
AM oscillator tank circuit input, recommended
load impedance approximately 2.5 kW
AFC diode connection, coupling capacitor
(C
19
) determines the AFC characteristic
(holding range and slope)
FM oscillator tank circuit input, recommended
load impedance approximately 3 kW
Regulated voltage output (2.4 V)
FM RF tank circuit connection, recommended
load impedance approximately 3 kW
AM RF tank circuit connection, recommended
load impedance approximately 20 kW
FM AGC voltage output, time constant (C
20
).
Loading this pin by a resistor (to GND) will
increase the FM AGC threshold, grounding
this pin will switch off the FM AGC function
FM RF input (common-base preamplifier
transistor), recommended (RF) source
impedance approximately 100
W
FM front-end ground
AM/FM IF output
(collector output of the IF preamplifier)
Mode control input:
Pin
| Function
open
| FM
Ground
| AM
V
S
(R
4
= 10 kW) | Tape
AM IF input, input impedance = 3.1 kW
FM IF input, input impedance = 330
W
Treble control voltage input
Level indicator output
(open-collector output, LED drive)
IF ground
AFC function control input:
Pin
| Function
open
| AFC off
Ground
| f
OSC
> f
in
V
S
| f
OSC
< f
in
AGC/AFC voltage, time constant adjust (C
10
),
input impedance approximately 42 kW
AM/FM detector output, the load capacitor
(C
11
) in conjunction with the detector output
resistance (7.5 kW) determines the (FM)
deemphasis as well as the (modulation)
frequency response of the AM detector
Audio amplifier input, input resistance
approximately 100 kW, coupling capacitor
(C
9
) determines the low frequency response
Ripple filter connection. Load capacitance
(C
12
) determines the frequency response of the
supply-voltage ripple rejection
Supply voltage input
Audio amplifier output
Ground of the audio power stage
Pin Description
Mute
FM-discr
1
2
27
AFout
7
8
9
10
11
FMOsc
V
Ref
FMtank
AMtank
FM-AGC
CF
3
26
V
S
Ripple in
Vol ctrl in
4
25
AMOsc
5
24
AFin
12
FMin
FM-AFC
FMOsc
6
23
AM/FM detect
7
22
V
AGC/AFC
13
14
15
V
Ref
FMtank
8
21
AFC switch
IF-GND
FE-GND
AM/FM
IFout
Mode ctrl
switch
9
20
AMtank
10
19
LED drive
FM-AGC
FMin
11
18
V
Treble in
FM-IFin
16
17
18
19
20
21
AM-IFin
FM-IFin
V
Treble in
LED drive
IF-GND
AFC switch
12
17
FE-GND
AM/FM
IFout
13
16
AM-IFin
Mode ctrl
switch
22
23
V
AGC/AFC
AM/FM
detect
14
14812
15
Figure 2. Pinning
Pin
1
Symbol
Mute
Function
Mute voltage output, time constant (C
23
),
mute depth and threshold adjustable by load
resistance (R
3
)
FM discriminator filter connection, ceramic
resonator or equivalent LC-circuit
Audio negative feedback input. Blocking
capacitor (C
8
) determines the audio amplifiers
low-end cut-off frequency
Input for volume control voltage
24
AFin
2
3
FM-discr
CF
25
Ripple in
4
Vol ctrl in
26
27
28
V
S
AFout
AF-GND
2 (15)
Rev. A3, 23-Feb-01
U2510B
Absolute Maximum Ratings
Parameters
Supply voltage
Power dissipation
Ambient temperature range
Symbol
V
S
P
tot
T
amb
Value
13
900
–20 to +75
Unit
V
mW
°C
Electrical Characteristics
V
S
= 6 V, T
amb
= 25°C, test circuit (figure 16), unless otherwise specified
Parameters
Supply voltage range
Oscillator stop voltage
Operating temperature range
Supply quiescent current
Test Conditions / Pins
Symbol
V
S
V
S
T
Min.
2.5
2.2
–20
Typ.
Max.
9*
+75
Unit
V
V
°C
mA
mA
mA
V
V
i1
= V
i2
= V
4
= 0;
AM (S
2
= AM)
I
S
4.0
FM (S
2
= FM)
I
S
6.5
TAPE (S
2
= Tape)
I
S
2.2
Regulated voltage
Pin 8
V
Ref
2.4
Audio amplifier
V
i3
(Pin 24), test point: V
o
(Pin 27) f = 1 kHz
AF measuring range: 30 Hz to 20 kHz, S
2
= Tape, S
4
= A, S
5
= A
Input resistance
Pin 24
R
j
100
Closed loop voltage gain
GV
af1
= 20 log (V
o
/V
i3
)
V
i3
= 10 mV
GV
af1
40
Output voltage
V
i3
= 100 mV, S
4
= B
V
o
0.7
High–end cut-off frequency
f
c
(–3 dB)
f
c
13
S
5
= B
f
c
0.8
Supply-voltage rejection ratio SVRR = 20 log (V
hum
/V
o
)
V
hum
= 200 mV,
f
hum
= 200 Hz, S
4
= B
SVRR
32
Noise voltage
S
4
= B, V
i3
= 0
V
n
300
AF output power
THD = 10 %, R
L
= 8
W
V
S
= 4.5 V
P
o
225
V
S
= 6.0 V
420
P
o
400
V
S
= 9.0 V
P
o
1000
Distortion
P
o
= 50 mW, R
L
= 8
W
d
0.6
FM section,
V
i2
= 60 dBmV, f
i2
= 98 MHz, f
m
= 1 kHz, dev. =
"
22.5 kHz, f
iIF
= 10.7 MHz,
AF measuring range: 300 Hz to 20 kHz, S
2
= FM, S
1
= A, S
6
= B, test point: V
D
(Pin 23)
FM front-end voltage gain
GV
FM
= 20 log (V
iIF
/ V
i2
)
S
1
= B, V
i2
= 40 dbmV
GV
FM
30
Recovered audio voltage
Pin 23
VD
af
85
Detector output resistance
Pin 23
R
Do
7.5
Detector output distortion
dev. =
"
75 kHz
V
i2
= 60 dBmV
THD
0.5
V
i2
= 105 dBmV
THD
0.8
*
U2510B-M__T: max. 6 V
kW
dB
mV
kHz
kHz
3
1000
dB
mV
mW
mW
mW
%
dB
mV
kW
%
%
4 (15)
Rev. A3, 23-Feb-01
U2510B
Electrical Characteristics (continued)
V
S
= 6 V, T
amb
= 25°C, test circuit (figure 16), unless otherwise specified
Parameters
AM rejection ratio
RF sensitivity
Limiting threshold (-3 dB)
Mute voltage
Test Conditions / Pins
m = 30%
(S+N)/N = 26 dB
(S+N)/N = 46 dB
Test point: Mute
V
i2
= 0
V
i2
= 60 dBmV
Referred to V
0
at V
i2
= 0
S
6
= A
S
6
= C
f
OSC
> f
in
, S
3
= A, S
6
= A
V
i2
x
10 dBmV
V
i2
= 20 dBmV
V
i2
= 80 dBmV
Symbol
AM
RR
V
i2
V
i2
V
i2
V
mute
V
mute
MD
MD
Min.
Typ.
25
9
22
3
1.8
0.4
26
20
no AFC
"
180
"
220
5.5
180
Max.
Unit
dB
dBmV
dBmV
dBmV
V
V
dB
dB
Mute depth
AFC holding range
FHR
FHR
FHR
LED current
I
LED
Oscillator voltage
eZ
load
= 2.5 kW
Pin 7
V
OSC
AM section
V
i1
= 60 dBmV, f
i1
= 1.6 MHz, f
m
= 1 kHz, m = 30%, f
iIF
= 455 kHz,
AF measuring range: 300 Hz to 20 kHz, (S
2
= AM, S
1
= B, test point: V
D
)
AM front end voltage gain
GV
AM
= 20 log (V
iIF
/V
i1
)
GV
AM
V
i1
= 20 dBmV, S
1
= A
Recovered audio voltage
V
D af1
Detector output resistance
Pin 23
R
Do
Detector output distortion
V
i1
= 60 dBmV
THD
V
i1
= 105 dBmV
THD
RF sensitivity
(S+N)/N= 10 dB
V
i1
(S+N)/N= 26 dB
V
i1
V
i1
(S+N)/N= 46 dB
AGC figure of merit referred
V
i1
= 105 dBmV, voltage
to V
D af
drop (V
D af
) = –10 dB
FOM
IF input resistance
Pin 16
Z
i
LED current
I
LED
Oscillator voltage
Pin 5
V
OSC
kHz
kHz
mA
mV
25
70
7.5
1
3
0
16
35
100
3.1
5.5
160
dB
mV
kW
%
%
dBmV
dBmV
dBmV
dB
kW
mA
mV
Rev. A3, 23-Feb-01
5 (15)
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