T4260-IL Atmel, T4260-IL Datasheet - Page 26

• Manufacturer Part Number: T4260-IL
• Description: IC RECEIVER AM/FM FRONT 44-SSOP
• Manufacturer: Atmel

Specifications of T4260-IL

• Frequency: AM, FM
• Modulation Or Protocol: AM, FM
• Applications: AM/FM Radio Receiver
• Current - Receiving: 85mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 8 V ~ 10 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Sensitivity: -
• Memory Size: -
• Data Rate - Maximum: -

External Voltage at AMLF
(Pin 17)
26
T4260
The N- and R- divider can be calculated as following:
Example of AM settings:
If the receiving frequency is 0.84 MHz (AM) and the following conditions are:
f
11540 and a R-Divider of 400 is necessary.
R = f
N = AM Prescaler
By using two ICs, for example, it is possible to operate the AMLF (pin 17) of the second
IC either with the tuning voltage (VTUNE [pin 18]), the DAC 1 voltage [pin 1] or the
DAC 2 voltage [pin 2] from the first T4260. For voltage reduction at the AMLF [pin 17], a
voltage factor ratio of 100/16 (R
This means that an applied voltage from 0.5 V at pin 17 (AMLF) corresponds to a tuning
voltage of 3.625 V. It is recommended to use R
allowed range of R
Figure 12. External Voltage at AMLF (Pin 17)
The maximum input voltage at the AMLF input (pin 17) depends on the applied supply
voltage as well as on the gain and offset settings. To avoid any damages during the
product’s lifetime, the following formulas regarding SWAMLF voltage, gain and offset
settings have to be observed (see chapter “Permitted DAC Conditions” on page 21).
V
(R
This means when having a gain factor of 2 and an offset value of 1 V, the applied
SWAMLF voltage should be limited to a voltage lower than 0.83 V.
SWAMLF voltage < (V
e.g.: maximum SWAMLF voltage = (10 V + 3 V - 1 V)/(2
It is also possible to reduce the gain or offset instead (or along with) the SWAMLF
voltage.
N = AM Prescaler
N = (f
R = f
f
f
ref
VCO
ref
SWAMLF
1
= 4 MHz; f
= reference oscillator frequency (pin 27)
+ R
ref
= N
ref
rec
/f
/f
2
step
step
)/R
x ([R
+ f
2
IF
= 4 MHz/10 KHz = 400
f
step
)/f
= 7.25
1
step
step
+ R
= 10 kHz; f
2
1
]/R
is 10 k to 1 M and 1.6 k to 160 k for R
(f
(f
rec
S
2
rec
) x DAC gain factor + DAC offset < V
+ 3 V - DAC offset)/(DAC gain factor
+ f
+ f
IF
IF
)/f
IF
)/f
step
= 10.7 MHz and an AM-Prescaler of 10 a N-Divider of
step
VTUNE or DAC
1
R
R
/R
1
2
T4260
= 10
2
) is required.
Gain
(0.84 MHz + 10.7 MHz)/10 KHz = 11540
(AM mode)
(FM mode)
(For all modes)
T4260
AMLF
1
with 100 k and R
7.25) = 0.83 V
S
+ 3 V
7.25)
2
.
2
with 16 k . The
4528J–AUDR–11/04