Page 1
10-45
10
IF AMPLIERS
Product Description
Ordering Information
Typical Applications
Features
Functional Block Diagram
RF Micro Devices, Inc.
7625 Thorndike Road
Greensboro,NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Optimum Technology Matching® Applied
Si BJT GaAs MESFETGaAs HBT
Si Bi-CMOS
ü
SiGe HBT
Si CMOS
0-25dB 0-20dB -12-+12 17dB 6dB
PD
BW SEL2
BW SEL1
RSSI Q
RSSI I
VREF
IN I+
IN I-
DCFB I
VCC2
DCFB Q
IF OUTQ
Q DATA
VCC3
VCC1
IN Q+
IN Q-
IF OUTI
I DATA
1
2
11
14
13
24
23
20
19
5 8
15
18
21
10
17
16
9
7
4
VGC
DC
Bias
RF2670
8MHZ DUAL BASEBAND AGC WITH
PROGRAMMABLE LOW PASS FILTERING
• Digital Cordless Telephones
• Secure Communication Links
•WirelessLANs
• Inventor y Tracking
• Wireless Security
• Battery Powered Applications
The RF2670 is a monolithic integrated circuit specifically
designed for direct conversion to baseband Q PSK receivers. The part provides dual baseband amplifiers with a
70 dB gain range (single pin analog input) and separate I
and Q RSSI. On-chip programmable baseband filters are
incorporated into each amplifier providing 1MHz, 2MHz,
4MHz, or 8MHz bandwidth with a 5-pole Bessel
response. I and Q output are availablein digital or analog
form. The data comparators use a self generated DC reference to track DC offsets in the received signal. The
analog outputs have a 500mVpp swing with approximately 1.7V DC offset. A 2.0V reference voltage is also
available for A/D converters changing DC bias.
• I/Q Baseband Receivers
•10dBto80dBGainRange
• Digital and Analog Outputs
• On-Chip Selectable IF Bandwidths
• Reference Voltage for A/D Converter
• 2.7V to 3.6V Operation
RF2670 8MHz Dual Baseband AGC with Programmable Low
Pass Filtering
RF2670PCBA Fully Assembled Eval Board.
10
Rev A4 010820
.069
.053
.050
.016
8°MAX
0°MIN
.010
.008
.157
.150
.244
.228
1
.344
.337
.012
.008
.025
.010
.004
.033
Package Style: SSOP-24
Page 2
10-46
RF2670
Rev A4 010820
10
IF AMPLIERS
Absolute M aximum Ratings
Parameter Ratings Unit
Supply Voltage -0.5 to +3.6 V
DC
Control Voltages -0.5 to +3.6 V
DC
Input RF Level +20 dBm
Operating Ambient Temperature -40 to +85 °C
Storage Temperature -40 to +150 °C
Parameter
Specification
Unit Condition
Min. Typ. Max.
Baseband Amplifiers
T=25°C, VCC=3.0V
Frequency Range 0.01 8 MHz Minimum frequency is dependent upon input
blocking cap, DC feedback cap, and gain
setting. Recommendedc omponents yields a
minimum frequency of less than 10kHz.
Voltage Gain 77 80 83 dB
Noise Figure 5 dB At maximum gain setting
35 dB At minimum gain setting
Input IP3 -65 dBm At maximum gain setting
+2 dBm At minimum gain setting
Output DC offset 0 25 mV
Gain Control Range 65 70 dB
Gain Control Voltage Range 1.2 2.0 V
Gain Control Sensitivity -0.08 dB/mV
VGA Output Voltage 500 mV
PP
VGA DC Output Voltage 1.7 V
Output P1dB 1 1.64 V
PP
Driving a 5kΩ load
RSSI Range 55 60 dB At maximum gain setting
RSSI Output Voltage Compli-
ance
0.5 to 2.4 V Maximum RSSI is 2.5V or V
CC
-0.3, which-
ever is less.
Input Impedance 1.5 2 2.5 kΩ Differential
Integrated Filters
Characteristics Five pole Bessel Five pole Bessel internal LPF.
Three pole external LPF.
Bandwidth 1, 2, 4, 8 MHz Selectable from 1MHz, 2MHz, 4MHz, and
8MHz.
Passband Ripple 1 dB
Group Delay 100 ns At 8MHz, increa sing as bandwidth
decreases.
UltimateRejection 50 80 dB
Data Amplifiers
Voltage Gain 100 dB
Bandwidth 8 MHz
Rise and Fall Time 2 5 ns 5pF Load
Logic High Output V
CC
-0.3V V Can sink/source 1mA and maintain these
logic levels.
Logic Low Out put 0.3 V Can sink/source 1mA and maintain these
logic levels.
Hysteresis 40 mV
Power Down Control
Logical Controls “ON” VCC-0.3V V Voltage supplied to the input
Logical Controls “OFF” 0.3 V Voltage supplied to the input
Control Input Impedance >1 MΩ
Turn on Time 10 13 ms With recommended DC feedback cap
(270nF)
Caution! ESD sensi t ive device.
RF Micro Devices believes the furnishedinformation is correct and accurate
at the time of this printing. However, RF Micro Devices reservesthe right to
make changes to its products without notice.RF Micro Devices does not
assume responsibility for the use of the described product(s).
Page 3
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RF2670
Rev A4 010820
10
IF AMPLIERS
Parameter
Specification
Unit Condition
Min. Typ. Max.
Power Supply
Voltage 2.7 3.0 3.6 V
Current Consumption 13 17 mA V
CC
=3.0V; PD=High
1 µAVCC=3.0V; Sleep Mode, PD=Low
Page 4
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RF2670
Rev A4 010820
10
IF AMPLIERS
Pin Function Description Interface Schematic
1INI-
Complementary input for the in-phase IF channel.
2INI+
Input for the in-phase IF channel.
3 GND2
Ground for VCC2.
4 DCFB I
DC feedback capacitor for in-phase channel.
5 VCC2
Powersupply for VGA amplifier 3, differentialto single-ended converter,
and post filter.
6 GND3
Ground for VCC3.
7IFOUTI
Analog signal IF output for in-phase channel.
8 VCC3
Power supply for data amplifier.
9IDATA
Logic-level data output for the in-phase channel. This is a digita l output
signal obtained from the output of a Schmitt trigger.
10 RSSI I
Received signal strength indicator for the in-phase channel.
11 PD
Enable pin for the receiver circuits. PD>2.0V powers up all of the functions. PD<1.0V turns off all of the functions.
12 GND1
Ground for VCC1 for both the in-phase and quadrature c hannels.
13 BW SEL1
Bandwidth select logic input. Pin 13 and pin 14 provide a two bit control
word for the setting of the IF band width. See Table1. Additional filtering
should be used at the amplifiers to precisely control the 3dB bandwidth
of the system. See design information details about differential input filters.
14 BW SEL2
See pin 13.
15 Q DATA
Logic-level data output for the quadrature channel. This is a digital output signal obtained from the output of a Schmitt trigger.
16 RSSI Q
Received s ignal strength indicator for the quadrature channel.
17 VREF
Gain control reference voltage.
18 IF OUT Q
Analog signal IF output for quadrature channel.
19 VGC
Gain control voltage.
20 VCC1
Power supply for bias circuits and VGA amplifiers for both the in-phase
and quadrature channels.
21 DCFB Q
DC feedback capacitor for quadrature channel.
22 GND1
Ground for VCC1 for both the in-phase and quadrature c hannels.
23 IN Q+
Plus input for quadrature channel
24 IN Q-
Minus in put for quadrature channel
Table 1: Bandwidth Selection Controls
BWSEL1 BWSEL2
IF
-3dB
Frequency
001MHz
012MHz
104MHz
118MHz
Page 5
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RF2670
Rev A4 010820
10
IF AMPLIERS
Differential Filter Design Information
Butterworth Response
RS
RS
C1
L
L
RL
RL
C2
C1
C1bw
1
2
-- -
10
12
⋅⋅
2 π fc RL⋅⋅ ⋅
------------------------------------- -
C2
C2bw
1
2
-- -
10
12
⋅⋅
2 π fc RL⋅⋅ ⋅
------------------------------------- -
L
Lbw RL 10
6
⋅⋅
2 π fc⋅⋅
-----------------------------------
=;=;=
C1bw 5.1672 C2bw; 15.4554 Lbw; 0.1377===
RS 125 RL; 1000
RS
RL
------ -
; 0.125== =
Differential LC Filter Component Values
(Butterworth Response)
1
10
100
1000
10000
100000
1.E+05 1 .E+06 1.E+07
Frequency
Component Value
C2 (pF)
C1 (pF)
L(µH)
Page 6
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RF2670
Rev A4 010820
10
IF AMPLIERS
Differential Filter Design Information (Cont.)
Bessel Response
RS
RS
C1
L
L
RL
RL
C2
C1
C1bw
1
2
-- -
10
12
⋅⋅
2 π fc RL⋅⋅ ⋅
------------------------------------- -
C2
C2bw
1
2
-- -
10
12
⋅⋅
2 π fc RL⋅⋅ ⋅
------------------------------------- -
L
Lbw RL 10
6
⋅⋅
2 π fc⋅⋅
-----------------------------------
=;=;=
C1bw 2.9825 C2bw; 15.4697 Lbw; 0.0860===
RS 125 RL; 1000
RS
RL
------ -
; 0.125== =
Differential LC Filter Component Values
(Bessel Response)
1
10
100
1000
10000
100000
1.E+05 1 .E+06 1.E+07
Frequency
Component Value
C2 (pF)
C1 (pF)
L(µH)
Page 7
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RF2670
Rev A4 010820
10
IF AMPLIERS
Pin Out
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
IN-I
IN+I
GND2
DCFBI
VCC2
GND3
IF OUT I
VCC3
I DATA
RSSI I
PD
GND1
IN-Q
IN+Q
GND1
DCFBQ
VCC1
VGC
IF OUT Q
V REF
RSSI Q
Q DATA
BW SEL2
BWSEL1
Page 8
10-52
RF2670
Rev A4 010820
10
IF AMPLIERS
Evaluation Board Schema t ic
(Download Bill of Materials from www.rfmd.com.)
C26
10 nF
C25
100 pF
C24
10 nF
C23
100 pF
C22
10 nF
C21
100 pF
P3-1
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
IN I-
IN I+
GND2
DCFB I
VCC2
GND3
IF OUT I
VCC3
I DATA
RSSI I
VIFEN
GND1
IN Q-
IN Q+
GND1
DCFB Q
VCC1
VGC
IF OUT Q
VREF
RSSI Q
Q DATA
BW SEL2
BW SEL1
C6
100 nF
C5
100 nF
C2
1nF
L1
10
µ
H
C1
220 pF
T1
50
Ω µ
strip
J1
IIN
L2
10
µ
H
DCFB I
C9
220 nF
VCC
50
Ω µ
strip
J2
IF OUT I
50
Ω µ
strip
J3
I DATA
RSSI I
C13
68 pF
VIFEN
C8
100 nF
C7
100 nF
C3
1nF
L3
10
µ
H
C4
220 pF
T2
50
Ω µ
strip
J4
QIN
L4
10
µ
H
DCFB Q
C10
220 nF
VCC
VGC
50
Ω µ
strip
J5
IF OUT Q
VREF
C11
47 nF
RSSI Q
C12
68 pF
50
Ω µ
strip
J6
Q DATA
BW SEL2
BW SEL1
C27
10
µ
F
2670400-
P5
1
2
3
P5-1 BW SEL2
GND
P5-3 BW SEL1
P4
1
2
3
P4-1 DCFB Q
GND
P4-3 VREF
P3
1
2
3
VCC
GND
P3-3 VGC
P2
1
2
3
P2-1 RSSI Q
GND
P2-3 RSSI I
P1
1
2
3
P1-1 VIFEN
GND
P1-3 DCFB I
L1-L4 and C1-C4 make two LPFs. The fc of the RF2670 is variable;
therefore the L and C components must be variable. The following
table gives recommended component values ("std" indicates standard
eval board value).
Desired BW BW1, BW2 C1, C4 (pF) C2, C3 (pF) L1-L4(µH)
700 kHz
1.4 MHz
2.8 MHz
7.0 MHz
00
01
10
11
330
220 (std)
100
33
1800
1000 (std)
470
180
22
10
4.7
2.2
Page 9
10-53
RF2670
Rev A4 010820
10
IF AMPLIERS
Evaluation Board Layout
Board Size 3.0” x 2.0”
Page 10
10-54
RF2670
Rev A4 010820
10
IF AMPLIERS
RF2670 IF Bandwidth Response
-35.0
-25.0
-15.0
-5.0
5.0
15.0
25.0
35.0
45.0
55.0
65.0
0.1 1.0 10.0 100.0
IF Frequency (MHz)
Gain (dB)
BW_SEL (0-0)
BW_SEL (0-1)
BW_SEL (1-0)
BW_SEL (1-1)
Page 11
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RF2670
Rev A4 010820
10
IF AMPLIERS
IIP3 versus Voltage Gain
-80.0
-70.0
-60.0
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0
Voltage Gain (dB)
IP3 (dB)
-40°C
+25°C
+100°C
Noise Figure versus Voltage Gain
(Non-Matched Input Z)
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0
Voltage Gain (dB)
Noise Figure (dB)
-40°C
+25°C
+100°C
Voltage Gain versus Gain Control Voltage
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
1.21.31.41.51.61.71.81.9 2
Gain Control Voltage (V)
Voltage Gain (dB)
-40°C
+25°C
+100°C
Page 12
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RF2670
Rev A4 010820
10
IF AMPLIERS
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