U2762B Datasheet, PDF (2/9 Pages) TEMIC Semiconductors – 900-MHz ISM Band Receiver

U2762B
Pin Description
NC 1
RSSI 2
28 _VCC1
27 LO REF
A1 REF 3
26 _{LO in}
A1 in 4
25 GND1
GND2 5
24 A2 out
Mix out 6
V_CC3 7
A2 in ₈
23 _VCC2
22 _{Lim1 in}
21 Lim1 REF
A2 REF 9
20 ^{Lim1 out}
Data out 10
19 ^GND3
Com Nin 11
18 ^{Lim2 in}
Com in 12
SL in 13
17 Lim2 REF
16 DEM NTank
DEM out 14
15 ^{DEM Tank}
13960
Figure 2. Pinning
Pin Symbol
Function
1
NC Not connected
2
RSSI Signal-strength indicator
3 A1 REF RF reference
4
A1 in RF input
5
GND2 IF ground
6 Mix out Mixer output
7
V_CC3 IF and AF power supply
8
A2 in IF amplifier A2 input
9 A2 REF IF amplifier A2 reference
10 Data out Data output
11 Com Nin Comparator reference
12 Com in Comparator input / slicer output
13
SL in Slicer input
14 DEM out Demodulator output
15 DEM Tank Quadrature filter
16
DEM Quadrature filter
NTank
17 Lim2 REF Limiter2 reference
18 Lim2 in Limiter2 input
19 GND3 IF and AF Ground
20 Lim1 out Limiter1 output
21 Lim1 REF Limiter1 reference
22 Lim1 in Limiter1 input
23
V_CC2 IF power supply 1
24 A2 out IF amplifier A2 output
25 GND1 RF ground
26 LO in Local oscillator input
27 LO REF Local oscillator reference
28
V_CC1 RF power supply
Functional Description
RF Amplifier / Mixer
The RF amplifier / mixer down-converts the antenna
signal to the IF frequency. It has asymmetrical RF and IF
ports. The LO input includes an amplifier for good sensi-
tivity and can be used in a symmetrical- as well as an
asymmetrical configuration.
IF Amplifier A2
An additional gain stage enables an application-specific
insertion point for IF filtering.
Limiter 1 / 2
The two-stage limiting amplifier is designed to be
directly coupled to low-cost 10.7-MHz ceramic IF filters
in front of each stage. The total dynamic range is 65 dB.
Demodulator
The quadrature demodulator in the receiving path
contains an internal 7-pF quadrature capacitor to couple
the IF signal to the external tank providing the 90-degree
phase shift. The tank may be either an LC-tank circuit or
an alignment-free discrete ceramic resonator.
Bit-Slicer Amplifier and Comparator
The bit-slicer limits the baseband signal. Furthermore it
eliminates the DC-offset by an AC-coupled lowpass filter
to the demodulator output. A second lowpass filter
recovers the exact comparator threshold value of the
bit-slicer’s output. The time constants of both lowpass
filters can be selected independently from each other to
optimize power-up timing.
2 (9)
Rev. A3, 10-Jun-98
Preliminary Information