U2761B
Preliminary Information
Rev. A6, 17-Aug-00
1 (11)
DECT RF / IF IC
Description
The U2761B is an integrated circuit manufactured in
Atmel Wireless & Microcontrollers' UHF5S technology,
designed for DECT application. It contains rejection
mixer, IF amplifier, FM demodulator working at f = f
IF
/2,
baseband filter, RSSI, TX preamplifier and power-ramp-
ing generator for power amplifier.
Features
D Supply-voltage range 2.7 V to 4.7 V
D Low current consumption
D Few external components
D On-chip baseband filter
D LO switch and TX preamplifier
D Ramp-signal generator for power amplifier
Block Diagram
MIXER_IN1
MIXER_IN2
IF amp 1
IF amp 2
IF_TANK1
IF_IN1
IF_IN2
IR mixer
IF_TANK2
Demodulator
T/R switch
Bandgap
QUAD_TANK1
QUAD_TANK2
DEMOD_OUT
VS1
VS2
TX driver
MIXER_OUT1
MIXER_OUT2
Ramp
generator
RAMP_SET
RAMP_OUT
LO_IN1
LO_IN2
Control
logic
TX_ON
RX_ON
OpAmp
+
OP_N
OP_P
TX_RF_OUT
OP_OUT
14657
Figure 1. Block diagram
Ordering Information
Extended Type Number
Package
Remarks
U2761BMFS
SSO28
Tube
U2761B-MFSG3
SSO28
Taped and reeled
U2761B
Rev. A6, 17-Aug-00
Preliminary Information
2 (11)
Pin Description
Pin
Symbol
Function
1
RSSI
Received signal strength indi-
cator output
2
PU
Hardware power-up input
3
IF_TANK1
IF tank circuit Pin 1
4
IF_TANK2
IF tank circuit Pin 2
5
GND1
Ground
6
MIXER_IN1
Mixer RF differential input 1
7
MIXER_IN2
Mixer RF differential input 2
8
GND2
Ground
9
TX_RF_OUT
Output of TX driver amplifier
10
VS1
Supply voltage input 1
11
IF_IN1
IF amplifier differential input 1
12
IF_IN2
IF amplifier differential input 2
13
RAMP_OUT
Ramp-signal output for PA
14
RAMP_SET
Slew-rate setting of ramp
signal
15
RX_ON
RX control input
16
TX_ON
TX control input
17
MIXER_OUT1
Mixer IF differential output 1
18
MIXER_OUT2
Mixer IF differential output 2
19
VS2
Supply voltage input 2
20
LO_IN1
Local oscillator input 1
21
LO_IN2
Local oscillator input 2
22
GND3
Ground
23
QUAD_TANK1
Quadrature tank circuit 1
24
QUAD_TANK2
Quadrature tank circuit 2
25
DEMOD_OUT
Output of demodulator
26
OP_N
OP Input inverting
27
OP_P
OP Input non-inverting
28
OP_OUT
OP Output
1
2
3
4
5
6
7
8
10
9
27
22
21
20
18
19
17
12
11
28
25
26
23
24
16
15
14
13
MIXER_OUT1
TX_ON
VS2
OP_OUT
OP_P
OP_N
RX_ON
DEMOD_OUT
MIXER_OUT2
QUAD_TANK2
LO_IN1
LO_IN2
GND3
QUAD_TANK1
GND2
MIXER_IN1
VS1
IF_TANK1
TX_RF_OUT
IF_TANK2
IF_IN2
IF_IN1
PU
RSSI
GND1
MIXER_IN2
RAMP_OUT
RAMP_SET
U2761B
Figure 2. Pinning
U2761B
Preliminary Information
Rev. A6, 17-Aug-00
3 (11)
Absolute Maximum Ratings
All voltages refer to GND (Pins 5, 8 and 22)
Parameter
Symbol
Value
Unit
Supply voltage
Pins 10 and 19
V
S
5.0
V
Junction temperature
T
j
150
C
Storage temperature
T
stg
40 to +125
C
Thermal Resistance
Parameter
Symbol
Value
Unit
Junction ambient
R
thJA
130
K/W
Operating Range
All voltages refer to GND (Pins 5, 8 and 22)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Supply voltage
Pins 10 and 19
V
S
2.7
3.0
4.7
V
Ambient temperature
T
amb
25
+25
+85
C
Electrical Characteristics
Test conditions: V
S
= 3.0 V, T
amb
= 25
C, unless otherwise specified
Parameter
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
Power supply
Total supply current
TX
30
mA
pp y
RX
I
50
mA
RX (RSSI only)
I
S
47
mA
Standby, PU = GND
1
10
mA
IR mixer
Pins 6, 7, 17 and 18
Image-rejection ratio
Pins 17 and 18
IRR
20
dB
DSB noise figure
Pins 17 and 18
NFDSB=
NFSSB
10
dB
Conversion gain
R
load
= 200
W
G
conv
12
dB
Output interception point
Pins 17 and 18
OIP3
10
dBm
Input impedance
Pins 6 and 7
Z
in
50
W
Input matching
Pins 6 and 7
VSWR
in
<2:1
LO switch and TX driver
Pin 9, 20 and 21
Power gain (high)
@ P
in
= 40 dBm
G
p
30
dB
Input impedance
Pin 20 or Pin 21 to GND
Z
in
50
W
Input matching
Pins 20 and 21
VSWR
in
<2:1
Isolation LO-TX
RX mode: LO Pin 20 or Pin 21 to
Pin 9
Isol
37
dB
U2761B
Rev. A6, 17-Aug-00
Preliminary Information
4 (11)
Electrical Characteristics (continued)
Test conditions: V
S
= 3.0 V, T
amb
= 25
C, unless otherwise specified
Unit
Max.
Typ.
Min.
Symbol
Test Conditions / Pins
Parameter
Output impedance
Pin 9
Z
out
100
W
Maximum output power
Pin 9
P
max
3
dBm
Gain compression
@ TX_RF_OUT
Pin 9
P
1dB
1
dBm
Output interception point
Pin 9
OIP3
10
dBm
IF amplifier
Pins 3, 4, 11 and 12
Input impedance
Pins 11 and 12
Z
in
200
400
W
Lower cut-off frequency
fl
3dB
90
MHz
Upper cut-off frequency
fu
3dB
130
MHz
Power gain
G
p
85
dB
Bandwidth of external tank
circuit
Pins 3 and 4
BW
3dB
10
MHz
Noise figure
NF
9
dB
RSSI
Pins 1, 6 and 7
RSSI sensitivity
At IF_IN1, IF_IN2, Pins 6 and 7
P
min
20
dB
mV
RSSI compression
At IF_IN1, IF_IN2, Pins 6 and 7
P
max
100
dB
mV
RSSI dynamic range
DR
80
dB
RSSI resolution
Slope of the RSSI has to be steady
Acc
2
dB
RSSI rise time
P
in
= 30 dB
mV to 100 dBmV, Pin 1
t
r
1
ms
RSSI fall time
P
in
= 100 dB
mV to 30 dBmV, Pin 1
t
f
1
ms
Quiescent output current
@ P
in
< 20 dB
mV at
IF_IN1, IF_IN2
Pin 1
I
out
30
mA
Max. output current
@ P
in
= 100 dB
mV at
IF_IN1, IF_IN2
Pin 1
I
out
150
mA
FM demodulator
Pins 23, 24 and 25
Co-channel rejection ratio
@ P
in
= 75 dBm at
IR-mixer input
CCRR
10
dB
Sensitivity
Quality factor of external tank cir-
cuit approx. 20, f
res
= f
IF
/2
S
0.5
V/MHz
Amplitude of recovered
signal
Nominal deviation of signal
288 kHz
A
288
mVss
Output-voltage DC range
Pin 25
FMout
DC
0.4
V
S
0.4
V
Output impedance
Pin 25
Z
out
13
k
W
AM rejection ratio
Pin 25
AMRR
tbd
dB
OpAmp
Pins 26, 27 and 28
Power gain bandwidth
PGBW
10
MHz
Excess phase
R
load
= 1 k
W, C
load
= 15 pF
d
80
Input offset voltage
Pins 26 and 27
V
offs
1
mV
Open-loop gain
g
70
dB
U2761B
Preliminary Information
Rev. A6, 17-Aug-00
5 (11)
Electrical Characteristics (continued)
Test conditions: V
S
= 3.0 V, T
amb
= 25
C, unless otherwise specified
Unit
Max.
Typ.
Min.
Symbol
Test Conditions / Pins
Parameter
Output-voltage range
Pin 28
V
out
0.3
V
S
0.3
V
Common mode input
voltage
Pins 26 and 27
V
in
0.3
V
S
0.3
V
Common mode rejection
ratio
Pin 28
CMRR
t.b.d.
dB
Total harmonic distortion
Pin 28
THD
t.b.d.
%
Ramp generator
Pins 13 and 14
Min. output voltage
Accord. to PA RAMP input
V
min
0.2
V
Max. output voltage
Accord. to PA RAMP input
V
max
1.95
V
Rise time
C
RAMP
= 270 pF at Pin 14
t
r
5
s
Fall time
C
RAMP
= 270 pF at Pin 14
t
f
5
s
Logic input levels (RX_ON, TX_ON)
Pins 15 and 16
High input level
= `1'
V
iH
1.5
V
Low input level
= `0'
V
iL
0.5
V
High input current
= `1'
I
iH
5
5
A
Low input current
= `0'
IiL
5
5
A
Power / standby
Pin 2
Power-up high input level
PU = `1'
V
PU
2.0
V
Standby low input level
PU = `0'
V
PU,OFF
0.7
V
Power-up high input cur-
rent
PU = `1'
V
PU
= 3
V,
V
PU
= 4.6 V
I
PU
20
40
30
60
40
80
A
Standby low input current
PU = `0'
V
PU
= 0 V,
V
PU
= 0.5 V
I
PU,OFF
0.1
1
A
Settling time
VS = 0 > active operation
Switched
VS = 0 to VS = 3 V
t
soa
< 10
s
Settling time
standby > active operation
Switched
PU = 0 to PU = 1
t
ssa
< 10
s
Settling time
active operation > standby
Switched
VS = 3 V to VS = 0
t
sas
< 2
s
Active Blocks Corresponding to RX / TX
Logic
Active Parts
PU
RX_ON
TX_ON
OP
Demo-
dulator
IF amplifiers
IR mixer
RSSI
RX switch
TX switch
TX driver
Ramp
generator
TX mode
1
0
1
off
off
off
off
off
off
on
on
on
RX mode
1
1
0
on
on
on
on
on
on
off
off
off
RSSI
1
1
1
off
off
on
on
on
on
off
off
off
Standby
0
X
X
off
off
off
off
off
off
off
off
off
1
0
0
off
off
off
off
off
off
on
off
off
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