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FM IF RECEIVER S1T8513A
INTRODUCTION
The S1T8513A is designed for FM IF Detection on the pager set. It
includes a voltage regulator, low battery detection circuit, Mixer,
Oscillator, FSK comparator and limiting IF Amplifier.
FEATURES
• Operating voltage range: 1.0 ~ 4.0V
• Typical supply current: 1.1mA at 1.4V
• Low battery detection circuit (alarm function): 1.05V
• Voltage regulator : Vreg = 1.0V (Typ.)
• Mixer operating frequency: 10 ~ 50MHz
• High transmitting rate: 1200 / 2400bps
• FSK Data reception
• Package type: 20-SSOP (0.65mm)
ORDERING INFORMATION
20−SSOP−225
Device Package Operating Temperature
S1T8513A02-V0B0 20-SSOP-225 −20°C to +70°C
BLOCK DIAGRAM
MI GND REGO
20 19 18 17 16 15 14 13 12 11
2’nd
MIX
X-tal
Osc
1 2 3 4 5 6 7 8 9 10
OSCI OSCO MO Vcc LI LD FSKI IFO QD RAO
REGC
1.0V Reg
AO FSKO QC BSC LPFO LPFI
FSK
COMP.
Alarm
Limiting IF
Amplifier
Quick
Charge
filter AMP
audio AMP
Quad
Detector
1
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S1T8513A FM IF RECEIVER
PIN CONFIGURATION
OSCI
OSCO
MO
Vcc
LI
LD
FSKI
IFO
QD
RAO
1
2
3
4
KA8513B
5
6
7
8
9
10
S1T8513A
20
19
`18
17
16
15
14
13
12
11
MI
GND
REGO
REGC
AO
FSKO
QC
BSC
LPFO
LPFI
2
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FM IF RECEIVER S1T8513A
PIN DESCRIPTION
Pin No Symbol Description
1 OSCI Oscillator input. The oscillator is an internally-biased colpitts type.
2 OSCO Oscillator output.
3 MO Mixer output pin. Output impedance ≈ 2kΩ.
Connect a 455kHz filter between this pin and the LI.
4 V
CC
VCC pin.
5 LI IF limiter amplifier input. Input impedance 2kΩ.
6 LD Bypass capacitor connect pin for the IF limiter amplifier.
7 FSK1 Differential Amp. reference input on the FSK comparator.
8 IFO IF Amp output.
9 QD Quadrature detection, phase shiftier pin.
10 RAO Recovered audio signal output.
11 LPFI Low pass filter amplifier input. Bias is supplied from pin 10.
12 LPFO Low pass filter amplifier output.
13 BSC Battery saving control pin.
High: Battery saving off. Low: Battery saving on
14 QC Quick charge control pin.
High: Quick charge-discharge on. Low: Quick charge-discharge off.
15 FSKO FSK signal output pin.
16 AO Alarm output. This pin becomes High when VCC drops below 1.05V.
17 REGC S1T8513A has an internal PNP transistor.
But, it also can support an external PNP transistor to control the power.
18 REGO Regulated voltage output.
19 GND Ground.
20 MI Mixer input impedance ≈ 5kΩ.
ABSOLUTE MAXIMUM RATINGS
Characteristic Symbol Value Unit
Max. Supply Voltage V
Power Dissipation P
Operating Temperature T
Storage Temperature T
CC (MAX)
D
OPR
STG
4 V
800 mW
−20 — +70 °C
−55 — +125 °C
3
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S1T8513A FM IF RECEIVER
ELECTRICAL CHARACTERISTICS
(VCC = 1.4V ±5%, fIN
= 21.4MHz, f
(2MIX)
= ±4.8kHz, f
DEV
= 600Hz, Ta = 25°C, unless otherwise specified)
MOD
Characteristic Symbol Test Conditions Min. Typ. Max. Unit
Operating current I
Alarm Detection Voltage V
Alarm Low Level Output Voltage V
Alarm High Level Leakage Current I
FSK Low Level Output Voltage V
FSK High Level Leakage Current I
Regulator Output Voltage V
Quick Charge Current I
Input for −3dB Sensitivity V
Input for −12dB SINAD Sensitivity V
Recovered Audio Output Voltage V
Mixer Conversion Voltage Gain ∆G
CCN
I
CCS
AD
O (AL)
LKG (AL)
L (FSK)
LKG (FSK)
O (REG)
C
LIM
I (SEN)
O (RAO)
V (M)
Signal to Noise Ratio S/N V
Total Harmonic Distortion THD V
No Input Signal − 1.1 1.6 mA
Battery Saving − 0 10 µA
− 1.0 1.05 1.1 V
I = 100µA − − 0.4 V
− − − 2 µA
I = 100µA − − 0.4 V
− − − 2 µA
− 0.95 1.0 1.05 V
− 50 70 − µA
Mixer Input − 2.5 7.5 µVrms
IF Input − 6.0 18.0 µVrms
V
IN (2MIX)
= 500µVrms 37 55 73 mVrms
Ceramic Filter loss = −1dB 8 12 16 dB
IN (2MIX)
IN (2MIX)
= 500µVrms 38 55 − dB
= 500µVrms − 2.0 3.5 %
Mixer 3rd Order Intercept Point 3RD − − −10 − dBm
Mixer Input Resistance R
Limiting Amplifier Input Resistance R
I (MIX)
I (LA)
AM Rejection Ratio AMR V
Data Shaping Output Duty Ratio DR V
IN (2MIX)
= 5µVrms
(AM = 300%)
IN (2MIX)
= 500µVrms 40 50 60 %
− 3.5 5 6.5 kΩ
− 1.4 2 2.6 kΩ
25 40 − dB
4
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FM IF RECEIVER S1T8513A
APPLICATION CIRCUIT
Alarm out FSK out
Reg.out
VCC
R9
51
20.945MHz
+
2.2µ
100P
100K 100K
H
L LH
0.01µ
MI GND REGO REGC AO FSKO QC BSC LPFO LPFI
20 19 18 17 16 15 14 13 12 11
2’nd
2’nd
MIX
MAX
1.0V Regulator
Alarm
FSK
COMP
Quick
Charge
AMP
Filter
AMP
Audio
X-tal
Osc
1 2 3 4 5 6 7 8 9 10
OSCI OSCO MO Vcc IFI IF
C3
56P
33P
Limiting IF
Amplifier
FSKI IFO QD RAO
0.1µ
DEC
+
10µ
C4 C9
CDBM455
CFMW455E
Vcc
Quad
Detector
22P
+
10µ
68K
68K
3.3n
560P
68K
R2
3.3K
5
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S1T8513A FM IF RECEIVER
NOTES
6
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