INTERSIL HFA3724IN

HFA3724
Data Sheet
November 1999
400MHz Quadrature IF
Modulator/Demodulator
• Integrates all IF Transmit and Receive Functions
The Intersil 2.4GHz PRISM™ chip set is a
highly integrated five-chip solution for RF
modems employing Direct Sequence
Spread Spectrum (DSSS) signaling. The
HFA3724 400MHz Quadrature IF
Modulator/Demodulator is one of the five chips in the PRISM™
chip set (see the Typical Application Diagram).
• Broad Frequency Range . . . . . . . . . . . 10MHz to 400MHz
• I/Q Amplitude and Phase Balance . . . . . . . . . . . 0.2dB, 2o
• 5th Order Programmable
Low Pass Filter. . . . . . . . . . . . . . . . . . . 2.2MHz - 17.6MHz
• 400MHz Limiting IF Gain Strip with RSSI. . . . . . . . . .84dB
The HFA3724 is a highly integrated baseband converter for
quadrature modulation applications. It features all the necessary
blocks for baseband modulation and demodulation of I and Q
signals. It has a two stage integrated limiting IF amplifier with 84db
of gain with a built in Receive Signal Strength Indicator (RSSI).
Baseband antialiasing and shaping filters are integrated in the
design. Four filter bandwidths are programmable via a two bit
digital control interface. In addition, these filters are continuously
tunable over a ±20% frequency range via one external resistor. The
modulator channel receives digital I and Q data for processing. To
achieve broadband operation, the Local Oscillator frequency input
is required to be twice the desired frequency of
modulation/demodulation. A selectable buffered divide by 2 LO
output and a stable reference voltage are provided for convenience
of the user. The device is housed in a thin 80 lead TQFP package
well suited for PCMCIA board applications.
• Low LO Drive Level . . . . . . . . . . . . . . . . . . . . . . . -15dBm
• Fast Transmit-Receive Switching . . . . . . . . . . . . . . . . . 1µs
• Power Management/Standby Mode
• Single Supply 2.7V to 5.5V Operation
Applications
• Systems Targeting IEEE 802.11 Standard
• TDD Quadrature-Modulated Communication Systems
• Wireless Local Area Networks
• PCMCIA Wireless Transceivers
• ISM Systems
Ordering Information
TEMP. RANGE
(oC)
4067.7
Features
™
PART NUMBER
File Number
• TDMA Packet Protocol Radios
PACKAGE
HFA3724IN
-40 to 85
80 Ld TQFP
HFA3724IN96
-40 to 85
Tape and Reel
PKG. NO.
• PCS/Wireless PBX
Q80.14x14
• Wireless Local Loop
LIM1_IN
IF
LPF_SEL0
LPF_SEL1
LPF_TUNE_1
LPF_TUNE_0
LPF_RX_Q
LPF_RX_I
MOD_RX_I
MOD_RX_Q
LIM1_OUT
LIM2_IN
LIM2_OUT
MOD_IF_IN
Simplified Block Diagram
IF
LPF_RXI_OUT
RSSI1
RSSI2
LPF_RXQ _OUT
I
MOD_LO_IN
÷2
0o/90o
MOD_LO_OUT
LO_GND
LPF_TXI_IN
Q
∑
MOD_TX_IF_OUT
M
U
X
M
U
X
LPF_TXQ_IN
1
LPF_TX_I
LPF_TX_Q
MOD_TX_Q
MOD_TX_I
2V REF
2V
REF
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Copyright © Intersil Corporation 1999
PRISM® is a registered trademark of Intersil Corporation. PRISM logo is a trademark of Intersil Corporation.
HFA3724
Pinout
LIM1_RSSI
RSSI_RL1
GND
LIM1_OUT+
LIM1_OUTLIM1_VCC
LIM1_PE
GND
GND
GND
GND
GND
GND
GND
GND
GND
LIM2_BYPLIM2_INLIM2_IN+
LIM2_BYP+
80 LEAD TQFP
TOP VIEW
80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61
LIM1_BYP+
LIM1_IN+
LIM1_INLIM1_BYPGND
GND
GND
GND
LPF_VCC
2V REF
LPF_BYP
LPF_TXI_IN
LPF_TXQ_IN
LPF_RXI_OUT
LPF_RXQ_OUT
LPF_SEL1
LPF_SEL0
LPF_TUNE1
LPF_TUNE0
GND
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
2
MOD_TXIMOD_TXQ+
MOD_TXQ-
LPF_RX_PE
LPF_TX_PE
LPF_TXQLPF_TXQ+
LPF_TXILPF_TXI+
LPF_RXQLPF_RXQ+
LPF_RXILPF_RXI+
GND
GND
MOD_RXI+
MOD_RXIMOD_RXQ+
MOD_RXQMOD_TXI+
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
LIM2_RSSI
RSSI_RL2
GND
LIM2_OUT+
LIM2_OUTLIM2_VCC
LIM2_PE
GND
GND
GND
LO_GND
MOD_IF_INMOD IF_IN+
MOD_VCC
MOD_LO_OUT
MOD_VCC
MOD_LO_IN
MOD_RX_PE
MOD_TX_IF_OUT
MOD_TX_PE
HFA3724
LPF_TXQ_IN
LPF_TXI_IN
LPF_RXI_OUT
LPF_RXQ_OUT
Block Diagram
LPF_SEL1
MUX_LPF
LPF_SEL0
LPF_TUNE0
MUX
LPF_TUNE1
LPF_RX PE
LPF_TX_Q LPF_TX_Q +
LPF_TX_I LPF_TX_I +
Q
I
LPF_RX I LPF_RX I +
MUX
LPF_RX Q +
LPF_RX Q MOD_RX Q MOD_RX Q +
MOD TX I +
MOD TX I MOD TX Q +
MOD TX Q -
/
DOWN CONV
90o
MOD_RX I MOD_RX I +
MOD_TX_PE
0o
MOD_RX PE
LPF_TX_PE
∑
÷2
MOD_IF_IN +
MOD_IF_IN LIM2_OUT LIM2_OUT +
IF
LIM2_PE
NOTE: VCC, GND and Bypass capacitors not shown.
3
2V
REF
LPF_BYP
MOD_TX
IF_OUT
50Ω
MOD_LO_OUT
MOD_LO_IN
RSSI
IF
IN
(2XLO)
1.25V
VCC
LO_GND
RSSI_RL2
LIM2_RSSI
SAW
LIM1_INLIM1_RSSI
RSSI_RL1
LIM1_IN+
IF
LIM1_PE
IF LIMITERS
LIM1_OUT LIM1_OUT +
UP CONVERTER
LIM2_IN+
LIM2_IN-
2V REF
HFA3724
Typical Application Diagram
HSP3824
HFA3724
(FILE# 4064)
TUNE/SELECT
HFA3424 (NOTE)
RXI
(FILE# 4131)
A/D
DESPREAD
RXQ
I
÷2
(FILE# 4066)
0o/90o
M
M
U
U
X
X
RSSI
A/D
A/D
CCA
TXI
SPREAD
RFPA
VCO
HFA3925
VCO
TXQ
Q
802.11
MAC-PHY
INTERFACE
CTRL
HFA3624
RF/IF
CONVERTER
DPSK
DEMOD
DATA TO MAC
(FILE# 4067)
DPSK
MOD.
(FILE# 4132)
QUAD IF MODULATOR
DSSS BASEBAND PROCESSOR
DUAL SYNTHESIZER
HFA3524 (FILE# 4062)
TYPICAL TRANSCEIVER APPLICATION USING THE HFA3724
NOTE: Required for systems targeting 802.11 specifications.
For additional information on the PRISM™ chip set, call
(407) 724-7800 to access Intersil’ AnswerFAX system. When
prompted, key in the four-digit document number (File #) of
the datasheets you wish to receive.
The four-digit file numbers are shown in Typical Application
Diagram, and correspond to the appropriate circuit.
4
PRISM™ CHIP SET FILE #4063
HFA3724
Typical Application Diagram
(Targeting IEEE 802.11 Standard)
VCC
80
4
47p
45
PE
54
100p
57 100p
62
63
0.1
48
1K
56
9
47
34
49
61
100p
29
64
47p
100p
79
59
15
36
27
20
18
16 LPF_SEL1
VCC
17 LPF_SEL0
0.01
(NOTE 3)
CONVERTER
HFA3624IA
LO_IN
(NOTE 6)
900
56
19
(NOTE 5)
100p 47
46
37
0.1
IF/RF
TOYOCOM
TQS 432
TX_IF_OUT
VCC
316
42
47nH
10
2V REF
0.1
12
TXI
26
25
4.3K
680
0.1
0.01
39 0.01 24
11
40
680
23
TXQ
50
0.01
41
MOD_TX_PE
43
MOD_RX_PE
NC
560MHz
VCO (AUXILIARY)
0.01
38
100p (NOTE 4)
DUAL SYNTHESIZER
HFA3524IA
RXQ_OUT
0.01
35 0.01 28
47p 220 44
VCO
14
0.01
60 100p
100p
RXI_OUT
0.01
33 0.01 30
13 4.3K
22
21
TYPICAL APPLICATION DIAGRAM (TARGETING IEEE 802.11 STANDARD)
NOTES:
1. Input termination used to match a SAW filter.
2. Typical bandpass filter for 280MHz, BW = 47MHz, Q = 6. Can also be used if desired after the second stage.
3. Network shown for a typical -10dBm input at 50Ω.
4. Output termination used to match a SAW filter.
5. RTUNE value for a 7.7MHz cutoff frequency setting.
6. LO buffer output termination is needed only when the buffer is enabled by pin 50 connected to GND, otherwise tie pin 46 to pin 47.
5
BASEBAND PROCESSOR
HSP3824VI
55
LPF_RX_PE
100p
1
RSSI
VCC
LPF_TX_PE
76
0.1
0.1
560
3
0.1
100p
100p
77
100p
260
2
100p
100p
0.1
VCC
(NOTE 2)
PE
74
(NOTE 1)
56n
RF/IF
TOYOCOM
TQS 432
VCC
75
8 TO 40p
10nH
0.1
HFA3724
Pin Description
PIN
SYMBOL
DESCRIPTION
1
LIM1_BYP+
DC feedback pin for Limiter amplifier 1. Requires good decoupling and minimum wire length to a solid signal
ground.
2
LIM1_In+
Non inverting analog input of Limiter amplifier 1.
3
LIM1_In-
Inverting input of Limiter amplifier 1.
4
LIM1_BYP-
5, 6,
7, 8
GND
9
LPF_VCC
10
2V REF
Stable 2V reference voltage output for external applications. Loading must be higher than 10kΩ. A bypass
capacitor of at least 0.1µF is required.
11
LPF_BYP
Internal reference bypass pin. This is the common voltage (VCM) used for the LPF digital thresholds. Requires
0.1µF decoupling capacitor.
12
LPF_TXI_In
Low pass filter in phase (I) channel transmit input. Conventional or attenuated direct coupling is required for digital
inputs. (Note 7)
13
LPF_TXQ_In
Low pass filter quadrature (Q) channel transmit input. Conventional or attenuated direct coupling is required for
digital inputs. (Note 7)
14
LPF_RXI_Out
Low pass filter in phase (I) channel receive output. Requires AC coupling. (Note 8)
15
LPF_RXQ_Out
Low pass filter quadrature (Q) channel receive output. Requires AC coupling. (Note 8)
16
LPF_Sel1
17
LPF_Sel0
18
LPF_Tune1
19
LPF_Tune0
20
GND
21
LPF_RX_PE
Digital input control pin to enable the LPF receive mode of operation. Enable logic level is High.
22
LPF_TX_PE
Digital input control pin to enable the LPF transmit mode of operation. Enable logic level is High.
23
LPF_TXQ-
Negative output of the transmit Low pass filter, quadrature channel. AC coupling is required. Normally connects to
the inverting input of the quadrature Modulator (Mod_TXQ-), pin 40.
24
LPF_TXQ+
Positive output of the transmit Low pass filter, quadrature channel. AC coupling is required. Normally connects to
the non inverting input of the quadrature Modulator (Mod_TXQ+), pin 39.
25
LPF_TXI-
Negative output of the transmit Low pass filter, in phase channel. AC coupling is required. Normally connects to
the inverting input of the in phase Modulator (Mod_TXI-), pin 38.
26
LPF_TXI+
Positive output of the transmit Low pass filter, in phase channel. AC coupling is required. Normally connects to the
non inverting input of the in phase Modulator (Mod_TXI+), pin 37.
27
LPF_RXQ-
Low pass filter inverting input of the receive quadrature channel. AC coupling is required. This input is normally
coupled to the negative output of the quadrature demodulator (Mod_RXQ-), pin 36.
28
LPF_RXQ+
Low pass filter non inverting input of the receive quadrature channel. AC coupling is required. This input is normally
coupled to the positive output of the quadrature demodulator (Mod_RXQ+), pin 35.
29
LPF_RXI-
Low pass filter inverting input of the receive in phase channel. AC coupling is required. This input is normally
coupled to the negative output of the in phase demodulator (Mod_RXI-), pin 34.
30
LPF_RXI+
Low pass filter non inverting input of the receive in phase channel. AC coupling is required. This input is normally
coupled to the positive output of the in phase demodulator (Mod_RXI-), pin 33.
31, 32
GND
DC feedback pin for Limiter amplifier 1. Requires good decoupling and minimum wire length to a solid signal
ground.
Ground. Connect to a solid ground plane.
Supply pin for the Low pass filter. Use high quality decoupling capacitors right at the pin.
Digital control input pins. Selects four programed cut off frequencies for both receive and transmit channels. Tuning
speed from one cutoff to another is less than 1µs.
SEL1 SEL0 Cutoff Frequency
SEL1 SEL0 Cutoff Frequency
LO
LO
2.2MHz
HI
LO
8.8MHz
LO
HI
4.4MHz
HI
HI
17.6MHz
These two pins are used to fine tune the Low pass filter cutoff frequency. A resistor connected between the two
pins (RTUNE) will fine tune both transmit and receive filters. Refer to the tuning equation in the LPF AC
specifications.
Ground. Connect to a solid ground plane.
Ground. Connect to a solid ground plane.
6
HFA3724
Pin Description
(Continued)
PIN
SYMBOL
DESCRIPTION
33
Mod_RXI+
In phase demodulator positive output. AC coupling is required. Normally connects to the non inverting input of the
Low pass filter (LPF_RXI+), pin 30.
34
Mod_RXI-
In phase demodulator negative output. AC coupling is required. Normally connects to the inverting input of the Low
pass filter (LPF_RXI-), pin 29.
35
Mod_RXQ+
Quadrature demodulator positive output. AC coupling is required. Normally connects to the non inverting input of
the Low pass filter (LPF_RXQ+), pin 28.
36
Mod_RXQ-
Quadrature demodulator negative output. AC coupling is required. Normally connects to the inverting input of the
Low pass filter (LPF_RXQ+), pin 27.
37
Mod_TXI+
In phase modulator non inverting input. AC coupling is required. This input is normally coupled to the Low pass
filter positive output (LPF_TXI+), pin 26.
38
Mod_TXI-
In phase modulator inverting input. AC coupling is required. This input is normally coupled to the Low pass filter
negative output (LPF_TXI-), pin 25.
39
Mod_TXQ+
Quadrature modulator non inverting input. AC coupling is required. This input is normally coupled to the Low pass
filter positive output (LPF_TXQ+), pin 24.
40
Mod_TXQ-
Quadrature modulator inverting input. AC coupling is required. This input is normally coupled to the Low pass filter
negative output (LPF_TXQ-), pin 23.
41
Mod_TX_PE
42
Mod_TX_IF_Out
43
Mod_RX_PE
Digital input control to enable the demodulator section. Enable logic level is High for receive.
44
Mod_LO_In
(2XLO)
Single ended local oscillator current input. Frequency of input signal must be twice the required modulator carrier
and demodulator LO frequency. Input current is optimum at 200µARMS. Input matching networks and filters can
be designed for a wide range of power and impedances at this port. Typical input impedance is 130Ω.This pin
requires AC coupling. (Note 9)
NOTE: High second harmonic content input waveforms may degrade I/Q phase accuracy.
45
Mod_VCC
46
Mod_LO_Out
47
Mod_VCC
48
Mod_IF_In+
Demodulator non inverting input. Requires AC coupling.
49
Mod_IF In-
Demodulator inverting input. Requires AC coupling.
50
LO_GND
51, 52,
53
GND
54
LIM2_PE
55
LIM2_VCC
Limiter amplifier 2 supply pin. Use high quality decoupling capacitors right at the pin.
56
LIM2_Out-
Positive output of limiter amplifier 2. Requires AC coupling.
57
LIM2_Out+
Negative output of limiter amplifier 2. Requires AC coupling.
58
GND
59
RSSI_RL2
Load resistor to ground. Nominal value is 6kΩ. This load is used to terminate the LIM RSSI current output and
maintain temperature and process variation to a minimum.
60
LIM2_RSSI
Current output of RSSI for the limiter amplifier 2. Connect in parallel with the RSSI output of the amplifier limiter 1
for cascaded response.
61
LIM2_BYP+
DC feedback pin for Limiter amplifier 2. Requires good decoupling and minimum wire length to a solid signal
ground.
62
LIM2_In+
Digital input control to enable the Modulator section. Enable logic level is High for transmit.
Modulator open collector output, single ended. Termination resistor to VCC with a typical value of 316Ω.
Modulator/Demodulator supply pin. Use high quality decoupling capacitors right at the pin.
Divide by 2 buffered output reference from “Mod_LO_in” input. Used for external applications where the modulating
and demodulating carrier reference frequency is required. 50Ω single end driving capability.This output can be
disabled by use of pin 50. AC coupling is required, otherwise tie to pin 47 (VCC).
Modulator/Demodulator supply pin. Use high quality decoupling capacitors right at the pin.
When grounded, this pin enables the LO buffer (Mod_LO_Out). When open (NC) it disables the LO buffer.
Ground. Connect to a solid ground plane.
Digital input control to enable the limiter amplifier 2. Enable logic level is High.
Ground. Connect to a solid ground plane.
Non inverting analog input of Limiter amplifier 2.
7
HFA3724
Pin Description
(Continued)
PIN
SYMBOL
DESCRIPTION
63
LIM2_In-
64
LIM2_BYP-
65, 66,
67, 68,
69, 70,
71, 72,
73
GND
74
LIM1_PE
75
LIM1_VCC
Limiter amplifier 1 supply pin. Use high quality decoupling capacitors right at the pin.
76
LIM1_Out-
Negative output of limiter amplifier 1. Requires AC coupling.
77
LIM1_Out+
Positive output of limiter amplifier 1. Requires AC coupling.
78
GND
79
RSSI_RL1
Load resistor to ground. Nominal value is 6kΩ. This load is used to terminate the LIM RSSI current output and
maintain temperature and process variation to a minimum.
80
LIM1_RSSI
Current output of RSSI for the limiter amplifier 1. Connect in parallel with the RSSI output of the amplifier limiter 2
for cascaded response.
Inverting input of Limiter amplifier 2.
DC feedback pin for Limiter amplifier 2. Requires good decoupling and minimum wire length to a solid signal
ground.
Ground. Connect to a solid ground plane.
Digital input control to enable the limiter amplifier 1. Enable logic level is High.
Ground. Connect to a solid ground plane.
NOTES:
7. The HFA3724 generates a lower sideband signal when the “I” input leads the “Q” input by 90 degrees.
8. For a reference LO frequency higher than a CW IF signal input, the “I” channel leads the “Q” channel by 90 degrees.
9. The in-phase reference LO transitions occur at the rising edges of the 2XLO clock signal. Quadrature LO transitions occur at the falling edges.
180 degrees phase ambiguity is expected for carrier locked systems without differential encoding.
TABLE 1. POWER MANAGEMENT
TRANSMIT
RECEIVE
POWER DOWN
LIM1_PE
0
1
0
LIM2_PE
0
1
0
LPF_RX_PE
0
1
0
MOD_RX_PE
0
1
0
MOD_TX_PE
1
0
0
LPF_TX_PE
1
0
0
8
HFA3724
Absolute Maximum Ratings
Thermal Information
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.0V
Voltage on Any Other Pin. . . . . . . . . . . . . . . . . . -0.3V to VCC +0.3V
Thermal Resistance (Typical, Note 10)
θJA (oC/W)
TQFP Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75
Package Power Dissipation at 70oC
TQFP Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1W
Maximum Junction Temperature (Plastic Package . . . . . . . . .150oC
Maximum Storage Temperature Range . . . . . . . -65oC ≤ TA ≤ 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC
(TQFP - Lead Tips Only)
Operating Conditions
Supply Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . +2.7V to +5.5V
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . -40oC ≤ TA ≤ 85oC
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
10. θJA is measured with the component mounted on an low effective thermal conductivity test board in free air. See Technical Brief 379 for details.
DC Electrical Specifications
VCC = 2.7V to 5.5V, Unless Otherwise Specified
PARAMETER
SYMBOL
(NOTE 11)
TEST
LEVEL
TEMP
(oC)
MIN
TYP
MAX
UNITS
Total Supply Current, RX Mode at 5.5V
RXICC
A
Full
-
70
105
mA
Total Supply Current, TX Mode at 5.5V
TXICC
A
Full
-
60
80
mA
Shutdown Current at 5.5V
ICCOFF
A
Full
-
0.8
2.0
mA
All Digital Inputs VIH (TTL Threshold for All VCC)
VIH
A
Full
2.0
-
VCC
V
All Digital Inputs VIL (TTL Threshold for All VCC)
VIL
A
Full
-0.2
-
0.8
V
High Level Input Current at 2.7V VCC, VIN = 2.4V
IIHI
A
25
-
-
80
µA
High Level Input Current at 5.5V VCC, VIN = 4.0V
IIHh
A
25
-
-
400
µA
IIL
A
25
-20
-
+20
µA
Low Level Input Current, VIN = 0.8V
PEt
B
25
-
2
-
µs
Power Down/Up Switching Speed (Figure 23)
PEtpd
B
25
-
10
-
µs
Reference Voltage
VREF
A
Full
1.87
2.0
2.13
V
Reference Voltage Variation Over Temperature
VREFT
B
25
-
800
-
µV/oC
Reference Voltage Variation Over Supply Voltage
VREFV
B
25
-
1.6
-
mV/V
Reference Voltage Minimum Load Resistance
VREFRL
C
25
10
-
-
kΩ
RX to TX/TX to RX Switching Speed (Figure 23)
NOTE:
11. A = Production Tested, B = Based on Characterization, C = By Design
AC Electrical Specifications, Demodulator Performance
Application Targeting IEEE 802.11, VCC = 3V, Figure 23
Unless Otherwise Specified
SYMBOL
(NOTE 12)
TEST
LEVEL
TEMP
(oC)
MIN
TYP
MAX
UNITS
D3db
B
25
-
-84
-
dBm
IF Demodulator I and Q Outputs Voltage Swing
DIQsw
A
Full
300
460
650
mVP-P
IF Demodulator I and Q Channels Output Drive Capability
(ZOUT = 50Ω) CMAX = 10pF
Doutz
C
25
1.2
2
-
kΩ
IF Demodulator I/Q Amplitude Balance, IFin = -70dbm at 50Ω
Dabal
A
Full
-1.0
0
+1.0
dB
IF Demodulator I/Q Phase Balance, IFin = -70dbm at 50Ω
Dphbal
A
Full
-4.0
0
+4.0
Degrees
IF Demodulator Output Variation at -70dbm to 0dbm input
Dovar
A
Full
-0.5
0
+0.5
dB
IF Demodulator RSSI Noise Induced Offset Voltage (Note 14)
Drssio
B
25
-
580
-
mVDC
IF Demodulator RSSI Voltage Output Slope (Note 15)
Drssis
B
25
-
15
-
mV/dB
PARAMETER
IF Demodulator 3dB Limiting Sensitivity (Note 13)
9
HFA3724
AC Electrical Specifications, Demodulator Performance
Application Targeting IEEE 802.11, VCC = 3V, Figure 23
Unless Otherwise Specified (Continued)
SYMBOL
(NOTE 12)
TEST
LEVEL
TEMP
(oC)
MIN
TYP
MAX
UNITS
IF Demodulator RSSI DC Level, Pin = -30dBm (Note 15)
Drssi_30
A
Full
0.90
1.46
1.71
VDC
IF Demodulator RSSI DC Level, Pin = -70dBm (Note 15)
Drssi_70
A
Full
0.456
0.86
0.99
VDC
IF Demodulator RSSI Linear Dynamic Range (Note 16)
Drssidr
B
25
-
60
-
dB
IF Demodulator RSSI Rise and Fall Time from -30dBm to
-50dBm Input at 100pF Load
Drssitr
B
25
-
0.3
-
µs
PARAMETER
NOTES:
12. A = Production Tested, B = Based on Characterization, C = By Design
13. 2XLO input = 572MHz, measure IF input level required to drop the I and Q output at 6MHz by 3dB from a reference output generated at IF input
= -30dBm (hard limiting). LPF selected for 8.8MHz. This is a noise limited case with a BW of 47MHz. Please refer to the Overall Device
Description, IF limiter.
14. The residual DC voltage generated by the RSSI circuit due to a noise limited stage at the end of the chain with no IF input. IF port terminated
into 50Ω. Please referred to the Overall Device Description, IF limiter.
15. Both limiter RSSI current outputs are summed by on chip 6KΩ resistors in parallel.
16. Range is defined where the indicated received input strength by the RSSI is ±3dBm accurate.
AC Electrical Specifications, Modulator Performance
Application Targeting IEEE 802.11, VCC = 3V, Figure 23
Unless Otherwise Specified
SYMBOL
(NOTE 17)
TEST
LEVEL
TEMP
(oC)
MIN
TYP
MAX
UNITS
Mabal
B
25
-1.0
0
+1.0
dB
IF Modulator I/Q Phase Balance (Note 18)
Mphbal
B
25
-4.0
0
+4.0
Degrees
IF modulator SSB Output Power (Note 19)
Mssbpw
A
Full
-12
-7
-4
dBm
IF Modulator Side Band Suppression (Note 19)
Mssbss
A
Full
26
33
-
dBc
IF Mod Carrier Suppression (LO Buffer Enabled) (Note 19)
Mssbcs
A
Full
28
30
-
dBc
IF Mod Carrier Suppression (LO Buffer Disabled) (Note 19)
Mssbcs1
B
25
28
36
-
dBc
IF Modulator Output Noise Floor (Out of Band)
Moutn0
B
25
-
-132
-
dBm/Hz
IF Modulator I/Q 3dB Cutoff SEL0/1 = 2.2MHz (Note 20)
Msel1f
A
Full
1.8
2.2
2.5
MHz
IF Modulator I/Q 3dB Cutoff SEL0/1 = 4.4MHz (Note 20)
Msel2f
A
Full
3.6
4.4
5.0
MHz
IF Modulator I/Q 3dB Cutoff SEL0/1 = 8.8MHz (Note 20)
Msel3f
A
Full
7.3
8.8
9.8
MHz
IF Modulator I/Q 3dB Cutoff SEL0/1 = 17.6MHz (Note 20)
Msel4f
A
Full
14.6
17.6
19.6
MHz
IF Modulator Spread Spectrum Output Power (Note 21)
Mdsspw
B
25
-12
-7
-4
dBm
IF Modulator Side Lobe to Main Lobe Ratio, LPF = 8.8MHz
(Note 21)
Mdsssl
B
25
-
35
-
dB
PARAMETER
IF Modulator I/Q Amplitude Balance (Note 18)
NOTES:
17. A = Production Tested, B = Based on Characterization, C = By Design
18. Data is characterized by DC levels applied to MOD TXI and Q pins for 4 quadrants with LO output as reference or indirectly by the SSB
characteristics.
19. Power at the fundamental SSB frequency of two 6MHz, 90 degrees apart square waves applied at TXI and TXQ inputs. VIH = 3.0V,
VIL = 0.5V. LPF selected to 8.8MHz cutoff.
20. Cutoff frequencies are specified for both modulator and demodulator as the filter bank is shared and multiplexed for Transmit and Receive. Data
is characterized by observing the attenuation of the fundamental of a square wave digital input swept at each channel separately. The IF output
is down converted by an external wideband mixer with a coherent LO input for each of quadrature signals separately.
21. Typical ratio characterization with RTUNE set to 7.7MHz, LPF selected for 8.8MHz. TXI and TXQ Digital Inputs at two independent and aligned
11M chip/s, 223-1 sequence code signals.
10
HFA3724
Typical Performance Curves, Demodulator
(See Figure 23 Test Diagram)
50mV/DIV.
10mA/DIV.
90
25o
-40o
400
OUTPUT SWING (mVP-P)
SUPPLY CURRENT (mA)
85o
100
VCC = 3V
10
4.0
VCC
-100
5.5
FIGURE 1. DEMODULATOR SUPPLY CURRENT vs VCC AND
TEMPERATURE
OUTPUT SWING (mVP-P)
40mV/DIV.
700
500
4.0
VCC
-85
-40o
4.0
VCC
5.5
FIGURE 4. CASCADED LIMITER -3dB INPUT SENSITIVITY
RESPONSE vs VCC AND TEMPERATURE
0.2o/DIV.
+1o
0.1dB/DIV.
AMPLITUDE BALANCE VARIATION
PHASE BALANCE VARIATION
0
85o
25o
-90
2.5
5.5
FIGURE 3. DEMOD I/Q OUTPUT SWING vs VCC AND
TEMPERATURE
0o
-60
-40
-20
INPUT POWER (dBm INTO 50Ω)
1dBm/DIV.
-80
85o
25o
-40o
300
2.5
-80
FIGURE 2. DEMODULATOR I/Q OUTPUT SWING vs INPUT
POWER
-3dB SENSITIVITY (dBm INTO 50Ω)
2.5
EXPECTED VARIATION
WINDOW vs VCC
+0.4dB
0.0dB
EXPECTED VARIATION
WINDOW vs VCC
-0.4dB
-1o
2.5
4.0
VCC
5.5
FIGURE 5. DEMOD I/Q PHASE BALANCE VARIATION vs VCC
11
2.5
4.0
VCC
5.5
FIGURE 6. DEMOD I/Q AMPLITUDE BALANCE VARIATION vs VCC
HFA3724
Typical Performance Curves, Demodulator
(See Figure 23 Test Diagram) (Continued)
0.4dB/DIV.
0.1dB/DIV.
AMPLITUDE BALANCE VARIATION
PHASE BALANCE VARIATION
+2o
EXPECTED VARIATION
WINDOW vs TEMP
0o
+0.4dB
EXPECTED VARIATION
WINDOW vs TEMP
0.0dB
-0.4dB
-2o
-60
-40
-20
0
20
40
TEMPERATURE
80
60
-60
100
FIGURE 7. DEMOD I/Q PHASE BALANCE VARIATION vs
TEMPERATURE
-40
-20
0
20
40
TEMPERATURE
60
100
80
FIGURE 8. DEMOD I/Q AMPLITUDE BALANCE VARIATION vs
TEMPERATURE
100mV/DIV.
100mV/DIV.
1.5V
RSSI DC LEVEL
1.0V
0.5V
-100
-80
-40
-20
-60
INPUT POWER (dBm INTO 50Ω)
85o
25o
-40o
1.0V
IF INPUT = -50dBM
VCC = 3V
0.6V
2.5
0
FIGURE 9. DEMOD RSSI DC LEVEL vs INPUT POWER
4.0
VCC
FIGURE 10. DEMOD RSSI DC LEVEL vs VCC AND
TEMPERATURE
100mV/DIV.
900mV
DC OFFSET
RSSI DC LEVEL
1.4V
85o
25o
-40o
500mV
100mV
2.5
4.0
VCC
5.5
FIGURE 11. DEMODULATOR RSSI DC OFFSET vs VCC AND TEMPERATURE
12
5.5
HFA3724
Typical Performance Curves, Modulator
(See Figure 23 Test Diagram)
10mA/DIV.
10dB/DIV.
-7dBm
SUPPLY CURRENT
90mA
85o
25o
-40o
10mA
2.5
4.0
VCC
5.5
BW = 100kHz
VBW = 30kHz
FIGURE 12. MODULATOR SUPPLY CURRENT vs VCC AND
TEMPERATURE
4.0
VCC
SIDE BAND SUPPRESSION VARIATION
FROM NOMINAL
OUTPUT POWER (dBm AT 50Ω)
-40o
5.5
FIGURE 14. MODULATOR SSB OUTPUT POWER vs VCC AND
TEMPERATURE
0dB
-5dB
2.5
EXPECTED VARIATION
WINDOW
5.5
4.0
VCC
FIGURE 15. MODULATOR SSB SIDE BAND SUPPRESSION
VARIATION vs VCC AND TEMPERATURE
0.5dB/DIV.
-13
LO OUTPUT POWER (dBm AT 50Ω)
1dB/DIV.
+5dB
SIDE BAND SUPPRESSION VARIATION
FROM NOMINAL
286MHz
1dB/DIV.
+5dB
85o
25o
0dB
280MHz
FREQUENCY
FIGURE 13. TYPICAL SSB MODULATOR RESPONSE (NOTE 3
ON AC ELECTRICAL SPECIFICATIONS,
MODULATOR PERFORMANCE TABLE, LO
BUFFER ENABLED)
0.5dB/DIV.
-4
-9
2.5
274MHz
EXPECTED VARIATION
WINDOW
-5dB
2.5
4.0
VCC
5.5
FIGURE 16. MODULATOR LO LEAKAGE VARIATION vs VCC
AND TEMPERATURE
13
85o
25o
-40o
-15.5
-18
2.5
4.0
VCC
5.5
FIGURE 17. MODULATOR LO OUTPUT POWER
(FUNDAMENTAL) vs VCC AND TEMPERATURE
HFA3724
(See Figure 23 Test Diagram) (Continued)
PERCENT OF NOMINAL FREQUENCY
Typical Performance Curves, Modulator
0dB
1dB/DIV.
-3dB
+20%
-20%
10MHz
-30 -25 -20 -15 -10 -5
0 +5 +10 +15 +20 +25 +30
[(787-RTUNE)/RTUNE] * 100%
FIGURE 18. TYPICAL MODULATOR I/Q 3dB CUTOFF
FREQUENCY CURVES
FIGURE 19. LPF CUTOFF FREQUENCY vs RTUNE, VCC = 3V,
TA = 25oC
1MHz
2MHz
-24dBm
10dB/DIV.
PERCENT OF CUTOFF
2%/DIV.
+10%
0%
-10%
-60
-40
-20
0
20
40
TEMPERATURE
60
80
SPAN 50MHz
BW = 300kHz
VBW = 1kHz
100
280MHz
FIGURE 20. LPF CUTOFF FREQUENCY vs TEMPERATURE
AND VCC (NOTE 4 ON AC ELECTRICAL
SPECIFICATIONS, MODULATOR
PERFORMANCE TABLE)
FIGURE 21. TYPICAL MODULATOR SPREAD SPECTRUM
OUTPUT 11M CHIPS/s, QPSK. RTUNE TO 7.7MHz,
8.8MHz SETTING
10dB/DIV.
-24dBm
SPAN 50MHz
BW = 300kHz
VBW = 1kHz
280MHz
FIGURE 22. TYPICAL MODULATOR SPREAD SPECTRUM OUTPUT WITH RTUNE TO +20%
OF 4.4MHz SETTING FOR ILLUSTRATION PURPOSES ONLY
14
HFA3724
Test Diagram (280MHz IF)
VCC
75
2
100p
77
3
76
0.1
57 100p
100p
100p
100p
62
63
56
100p
48
1K
33 0.001 30
34
49
100p 61
100p
14 0.001
29
HI_Z_PROBE
64
35 0.001 28
47p
100p
59
79
36
(NOTE 24)
15 0.001
27
0.001
44
LO_IN
18
56
16
LPF_SEL1
1K
17
LPF_SEL0
19
100p
10
46
2V REF
LO_OUT
0.1
(NOTE 25)
0.1
37 0.001 26
VCC
38
47nH
TX_IF_OUT
316
42
12 4.3K
25
50
39 0.001 24
11
40
680
(NOTE 26)
23
0.001
LIM1_PE
0
1
0
LIM2_PE
0
1
0
LPF_RX_PE
0
1
0
MOD_RX_PE
0
1
0
MOD_TX_PE
1
0
0
LPF_TX_PE
1
0
0
41
NOTES:
22. Input termination used to provide a 50Ω impedance. Limiter Noise Figure ≅ 9dB for this configuration.
23. Bandpass filter for 280MHz, BW = 47MHz, Q = 6.
24. Network shown for a typical -10dBm input at 50Ω.
25. Matching network from 250Ω to 50Ω at 280MHz.
26. Attenuator is optional if TTL driver can drive 50Ω.
FIGURE 23. TEST DIAGRAM (280MHz IF)
22
21
LPF_RX_PE
POWER DOWN
13 4.3K 50
LPF_TX_PE
RECEIVE
MOD_RX_PE
43
TRANSMIT
MOD_TX_PE
TABLE 2. POWER MANAGEMENT
TXI
50
680
(NOTE 26)
0.1
0.001
3 TO 10p
15
RXQ_OUT
HI_Z_PROBE
47p 220
RSSI
RXI_OUT
0.001
60
47p
9
47
100p
0.1
100p
4
45
PE
54
55
80
1
VCC
0.1
560
56
0.1
0.1
VCC
(NOTE 23)
PE
74
(NOTE 22)
IF_IN 100p
VCC
8 TO 40p
10nH
0.1
TXQ
HFA3724
Overall Device Description
The HFA3724 is a highly integrated baseband converter for
half duplex wireless data applications. It features all the
necessary blocks for baseband modulation and
demodulation of “I” and “Q” quadrature multiplexing signals.
It targets applications using all phase shift types of
modulation (PSK) due to its hard limiting receiving front end.
Four fully independent blocks adds flexibility for numerous
applications covering a wide range of IF frequencies. A
differential design architecture, device pin out and layout
have been chosen to improve system RF properties like
common mode signal immunity (noise, crosstalk), reduce
relevant parasitics and settling times and optimize dynamic
range for low power requirements. Single power supply
requirements from 2.7VDC to 5.5VDC makes the HFA3724 a
good choice for portable transceiver designs.
The HFA3724 has a two stage integrated limiting IF amplifier
with frequency response to 400MHz. These amplifiers
exhibit a -84dbm, -3db cascaded limiting sensitivity with a
built in Receive Signal Strength Indicator (RSSI) covering
60db of dynamic range with excellent linearity. An up
conversion and down conversion pair of quadrature doubly
balanced mixers are available for “I” and “Q” baseband IF
processing. These converters are driven by an internal
quadrature LO generator which exhibits a broadband
response with excellent quadrature properties. To achieve
broadband operation, the Local Oscillator frequency input is
required to be twice the desired frequency for
modulation/demodulation. Duty cycle and signal purity
requirements for the 2X LO input using this type of
quadrature architecture are less restrictive for the HFA3724.
Ground reference input signals as low as -15dBm and
frequencies up to 900MHz (2XLO) can be used and tailored
by the user. A buffered, divide by 2, LO single ended 50Ω
selectable output is provided for convenience of PLL
designs. The receive channel mixers “I” and “Q” quadrature
outputs have a frequency response up to 30MHz for
baseband signals and the transmit mixers are summed and
amplified to a single ended open collector output with
frequency response up to 400MHz.
Multiplexed or half duplex baseband 5th order Butterworth
low pass filters are also included in the design. The “I” and
“Q” filters address applications requiring low pass and
antialiasing filtering for external baseband threshold
comparison or simple analog to digital conversion in the
receive channel. During transmission, the filter is used for
pulse shaping or control of spectral mask.
Four filter bandwidths are programmable, (2.2MHz, 4.4MHz,
8.8MHz and 17.6MHz) via a two bit digital or hardwired control
interface. These cut off frequencies are selected for
optimization of spectrum output responses for 2.25M, 5.5M,
11M and 22M chips/sec respectively for spread spectrum
applications (These rates can also be interpreted as symbol
rates for conventional data transmission). External processing
16
correlators in the receive channel as in the Intersil HSP3824
baseband converter, will bring the demodulation to lower
effective data rates. As an example, the use of 11M chips/sec,
11 chip Barker code using the 8.8MHz low pass filter in a QPSK
type of modulation scheme will bring a post processed effective
data rate to 1M symbol/sec or 2M bits/sec. Likewise, the use of
a 2.4M chips/sec, 16 chip spreading code and the use of
2.2MHz filter can process an effective data rate of 150K
symbols/sec or 300K bits/sec. In addition, these filters are
continuously tunable over a ±20% frequency range via one
external resistor. This feature gives the user the ability to
reshape the spectrum of a transmitted signal at the antenna
port which takes into account any spectral regrowth along the
transmitter chain. The modulator “I” and “Q” filter inputs accept
digital signal levels data for modulation and their phase and
gain characteristics, including I / Q matching and group delay
are well suitable for reliable data transmission. In the Receive
mode and over the full input limiting dynamic range, both low
pass filters outputs swing a 500mVP-P baseband signal.
Each block has its own independent power enable control for
power management and half duplex transmit/receive
operation. A stable 2V DC output and a buffered band gap
reference voltage are also provided for an external analog to
digital conversion reference.
Detailed Description
(Refer to Block Diagram)
IF Limiter
Two independent limiting amplifiers are available in the
HFA3724. Each one exhibits a broadband response to
400MHz with 45dB of gain. The low frequency response is
limited by external components because the device has no
internal coupling capacitors. The differential limiting output
swing with a 500Ω load is typically 200mVP-P at the
fundamental frequency and is temperature stable.
Both amplifiers are very stable within their passband and the
cascaded performance also exhibits very good stability for
any input source impedance. Wide bandwidth SAW filters for
spread spectrum applications or any desired source
impedance filter implementation can be used for IF filtering
before the cascaded amplifiers. The stability is remarkable
for such an integrated solution. In fact, in many applications
it is possible to remove the bypass pin capacitors with no
degradation in stability. The cascaded -1dB and -3dB input
limiting sensitivity have been characterized as -79dbm and
84dbm respectively, for a 50Ω single ended input at 280MHz
and with a 47MHz bandwidth interstage bandpass LC filter
(refer to Figure 23, Test Diagram). The input sensitivity is
determined to a large extent by the bandwidth of the
interstage filter and input source impedance.
The noise figure for each stage has been characterized at
6dB for a 250Ω single end input impedance and 9dB for a
50Ω input impedance. These low noise figures combined
HFA3724
with their high gain, eliminate the need for additional IF gain
components. The use of interstage bandpass filtering is
suggested to decrease the noise bandwidth of the signal
driving the second stage. Excessive broadband noise
energy amplified by the first stage will force the last limiting
stage to lose some of its effective gain or “limit on the noise”.
The use of interstage filters with narrower bandwidths will
further improve the sensitivity of the cascaded limiter chain.
The amplifier differential output impedance is 140Ω (70Ω
single ended) which gives the user, the ability to design
simple wide or narrow LC bandwidth interstage filters, or
tailor a desired cascaded gain by using differential
attenuators. The filter can be designed with a desired “Q” by
using the followIng relationship: Q = Rp/X; where Rp is the
parallel combination of 140Ω source resistance and the load
(approximately 500Ω when using 560Ω termination as in
Figure 23, Test Diagram), and X is the reactance of either L
or C at the desired center frequency.
Another independent feature of the limiting amplifier is its
Receive Signal Strength Indicator (RSSI). A Log-Amp
design was developed which resulted in a current output
proportional to the input power. The RSSI output voltage is
set by summing the two stages output currents, which are
full wave rectified signals, to a common resistor to ground.
This full wave rectified voltage can then be converted to DC
by the use of a filter capacitor in parallel with the resistor
(The larger the capacitor value, the less the AC ripple with
the expense of longer RSSI settling times). This
arrangement gives the user the flexibility to set the dynamic
voltage swing to any desired level by an appropriate
resistance choice. Each stage has an available on chip 6KΩ
low temperature coefficient resistor to ground for current
output termination that can be used for convenience. The
RSSI gives a ±3dBm accurate indication of the receive input
power. This accuracy is across a 60dB input dynamic range.
The cascaded HFA3724 RSSI slope is of 5.0µA/dB.
47p
50Ω
I RMS = 200µA
220
44
56
EQUIVALENT
130Ω
FIGURE 24. MOD LO IN (2XLO) EQUIVALENT CIRCUIT
17
Quadrature Down Converter
The quadrature down converter mixers are based in a Gilbert
cell design. The input signal is routed to both mixers in parallel.
With full balanced differential architecture, these mixers are
driven by an accurate internal Local Oscillator (LO) chain as
described later. Phase and gain accuracy of the output
baseband signals are excellent and are a function of the
combination of LO accuracy, balanced device design and
layout characteristics. Mainly used for down conversion, its
input frequency response exceeds 400MHz with a differential
voltage gain of 2.5. With a differential input impedance of 1KΩ,
the input compression point exceeds 2VP-P, which makes it
suitable for use with the hard limiting output from the limiter
amplifier chain or any low power external AGC application. The
output frequency response is limited to 30MHz for “I” and “Q”
baseband signals driving a 4KΩ differential load.
The HFA3724 down conversion mixers can generate two
10MHz, 90o apart signals, with the use of proper low pass
filtering, and exhibits ±4o and ±0.5dB of phase and
amplitude match for a input CW IF signal of 400MHz and a
2XLO input of 780MHz.
LO Quadrature Generator
The In Phase and Quadrature reference signals are
generated by a divide by two chain internal to the device
which drives both the up and down conversion mixers. With
a fully balanced approach, the phase relationship between
the two quadrature signals is within 90o ±4o for a wide 10 to
400MHz frequency range. The reference signal input
frequency needs to be twice the desired internal reference
frequency. The ground referenced 2XLO input is current
driven, which makes the input power requirement a function
of external components that can be calculated assuming the
input impedance of 130Ω. A typical input current value of
200µARMS is the only requirement for reliable LO
generation. Figure 24 shows a typical 2XLO input network.
Divide by two flip flop architectures for LO generation often
require tight control of signal purity or duty cycles. The
HFA3724 has an internal duty cycle compensation scheme
which eases the requirements of tight controlled duty cycles.
In addition, a 50Ω LO buffer is available to the user for PLL’s
design reference. It substitutes a divide by two prescaler
needed to bring the 2X LO frequency reference down. It is
capable to drive 100mVP-P into 50Ω and its frequency
response is from 10MHz to 400MHz corresponding to a
2XLO input frequency response of 20MHz to 800MHz. The
LO buffer can be disabled by removing the ground
connection to the pin LO GND. The quadrature generator is
always enabled for either transmit or receive modes.
HFA3724
Quadrature Up Converter
Programmable Low Pass Filters
The Quadrature up converter mixers are also based on a
doubly balanced Gilbert Cell design. “I” and “Q” Up converter
signals are summed and buffered together through a single end
open collector stage. As with the demodulators, both modulator
mixers are driven from the same quadrature LO generator. It
features a ±4o and 0.5dB of phase and amplitude balance up to
400MHz which are reflected into its SSB characteristics. For “I”
and “Q” differential inputs of 500mVP-P, 90o apart, the carrier
feedthrough or LO leakage is typical -30dBc into 250Ω with a
sideband suppression of minimum 26dBc at 400MHz. Carrier
feedthrough can be further improved by disabling the LO output
port (please refer to pin#50 description) or using a DC bias
network as in Figure 25. Featuring an output compression level
of 1VP-P, the modulator output can generate a CW signal of
typical -10dbm into 250Ω (158mVRMS) when differential DC
inputs of 500mVP-P (equivalent to applying ±125mV ground
referenced levels from the DC bias quiescent point of the
device input) are applied to both “I” and “Q” inputs. Four
quadrant phase shifts of the carrier output, like in Vector
Modulator applications, can be set by proper choice of “I” and
“Q” DC differential inputs, such that the square root of the sum
of the squares of I and Q is constant.
These filters are implemented using a 5th order Butterworth
architecture. They are multiplexed, i.e., the same filter bank
is used for both transmit and receive modes.
37 38
1K
1K
50K
39
1K
MOD_TXQ -
MOD_TXQ +
MOD_TXI -
MOD_TXI +
Although specified to drive a 250Ω load, the HFA3724
modulator open collector output enables user designed
output matching networks to suit any application interface.
The nominal AC current capability of this port is of
1.3mARMS, which is shared between the termination resistor
and the load for I and Q differential DC inputs of 500mVP-P
as explained above. (Use 70.7% of this AC capability for I
and Q quadrature signals in case of SSB generation).
40
1K
50K
43K
43K
FIGURE 25. CARRIER NULL BIASING
18
The filter block, in the transmit mode is set to accept digital
(TTL threshold) input data for “I” and “Q” signals and is
programmable with 4 frequency cutoffs: (2.2MHz, 4.4MHz,
8.8MHz and 17.8MHz). Digital control pins are used to
switch all programmed cutoff modes. The user can design a
multi data rate transceiver or simply hardwire these inputs.
An external resistor is used to fine tune the cut off
frequencies for each setting within ±20% of the nominal
value. This feature is often needed to fulfill requirements of
spectral mask compliance at the antenna output.
The “I” and “Q” filter matching is within 2o for phase and
0.25dB for amplitude at the passband. Group delay
characteristics follow closely a theoretical 5th order
Butterworth design.
When in the receive mode, the filters exhibit a 0dB of gain
with differential inputs and single ended outputs.
In the transmit mode, the digital ground referenced “I” and
“Q” input signals are level shifted, shaped and buffered with
constant driving differential outputs of 550mVP-P.
Baseband Digital Interfacing
Special precautions must be taken when interfacing the
HFA3724 to a digital baseband processor: Large TTL signal
swings, overshoots and current spikes, must be carefully
considered when dealing with the generation of analog
spread spectrum signals which are relatively much smaller in
energy per bandwidth.
In order to avoid distortion or spurious tones on the analog
transmit path, it may be necessary to decrease and/or limit
digital excursions as much as possible without
compromising the specifications. Figure 26 shows a
simplified block diagram of the Transmit digital inputs.
HFA3724
Coupling Capacitors
VIH
TXI
R1 LPF_TXI_IN
4.3K
VIL
0.1
VIH
TXQ
R1
COMPARATOR
12
680
R2
LPF_BYP
1.25V 11
R2
680
13
LEVEL
SHIFTER
TO
I FILTER
COMPARATOR
4.3K LPF TXQ_IN
LEVEL
SHIFTER
TO
Q FILTER
VIL
1.25V
FROM BAND GAP
FIGURE 26. SIMPLIFIED BLOCK DIAGRAM OF THE
TRANSMIT DIGITAL INPUTS
Because of the input comparators high gain, a small
overdrive of about ±150mV from the reference level of 1.25V
is all what is needed to reliably switch and level shift the “I”
and “Q” digital signals. An external attenuator comprising of
R1 and R2 with termination in the available 1.25V reference
voltage pin (LPF BYP) can be calculated based on expected
VIH and VIL inputs from a digital interface. Capacitive
coupling must be avoided which could affect rise and fall
times needed for proper overdrive speed of the comparators.
Limiting the digital excursion on those pins greatly reduce
the possibility of signal corruption at the transmit chain.
19
Capacitor coupling is used to tie all HFA3724 blocks together.
Special bias is used to maintain the DC levels on both ends of
coupling pins (capacitors) when the device is changes from
Transmitter to a Receiver and vice versa. The capacitance
values must be chosen as a compromise to maintain proper
frequency response and settling times (when the device is
brought up from sleep mode or power down).
HFA3724
AC Electrical Specifications, IF Limiter, Single Stage Individual Performance
Full Supply Range, TA = 25oC
SYMBOL
(NOTE 27)
TEST LEVEL
MIN
TYP
MAX
UNITS
IFf
A
-
-
400
MHz
IF Voltage Gain
IFvG
A
39
45
-
dB
IF Amp. Noise Figure at 250Ω Source Input
IFNF
B
-
-
7
dB
IFinmax
B
-
-
500
mVP-P
IF Differential Limiting Output (1st Harmonic at 500Ω Load)
IFVpp
A
160
200
260
mVP-P
IF Voltage Output Variation at -40dBm to -10dBm Input Range,
500Ω Load
IFVppI
A
-0.5
-
+0.5
dB
RSSI Slope, Current Output
IFRSSIsi
B
5.7
-
µA/dB
RSSI Slope, Voltage Output at 6K Load
IFRSSIv
A
25
34
45
mV/dB
RSSI Output Voltage Compliance
IFRSSIvc
B
-
-
VCC-0.7
V
RSSI DC Offset and Noise Induced Voltage at 6K Load
IFRSSIof
A
200
400
600
mV
RSSI Absolute Accuracy, VIN = -40dBm
IFRSSIa
A
-10
-
+10
%
RSSI Rise and Fall Time at 50pF Load (-20dBm to -40dBm
Input)
IFRSSIt
B
-
-
1
µs
PARAMETER
IF Frequency Range (Min Limited by Bypass Capacitors)
Maximum IF Input, Single Ended
NOTE:
27. A = Production Tested, B = Based on Characterization, C = By Design
TABLE 3. IF LIMITER S11, S22 PARAMETER
FREQUENCY
S11 (SINGLE ENDED)
S22 (DIFFERENTIAL)
50MHz
0.96
-4.0o
0.45
0.0o
100MHz
0.95
-8.0o
0.45
3.0o
200MHz
0.91
-17.0o
0.47
7.0o
300MHz
0.84
-26.0o
0.50
9.0o
400MHz
0.80
-33.0o
0.53
10.0o
AC Electrical Specifications, I/Q Down Converter Individual Performance
Full Supply Range, TA = 25oC
SYMBOL
(NOTE 28)
TEST LEVEL
MIN
TYP
MAX
UNITS
QDf
B
10
-
400
MHz
QDIQf
C
-
-
30
MHz
Demodulator Voltage Gain at Frequency Range
QDg
A
6
8
9
dB
Demodulator Differential Input Resistance
Drin
C
-
1
-
kΩ
Demodulator Differential Input Capacitance
Dcin
C
-
0.5
-
pF
Demodulator Differential Output Level at 4K Load,
Input = 200mVP-P
QDdo
A
400
500
560
mVP-P
Demodulator Amplitude Balance
QDab
A
-0.5
-
0.5
dB
Demodulator Phase Balance at 200MHz
QDpb
A
-1.85
-
1.85
Degrees
Demodulator Phase Balance at 400MHz
QDPb1
B
-4
-
4
Degrees
QDoc
B
-
1.25
-
VP-P
PARAMETER
Quadrature Demodulator Input Frequency Range
Demodulator Baseband I/Q Frequency Range
Demodulator Output Compression Voltage at 4K Load
NOTE:
28. A = Production Tested, B = Based on Characterization, C = By Design
20
HFA3724
AC Electrical Specifications, I/Q Up Converter and LO Individual Performance
Full Supply Range, TA = 25oC
SYMBOL
(NOTE 29)
TEST LEVEL
MIN
TYP
MAX
UNITS
2XLO Input Frequency Range (2 X Input Range)
LOinf
B
20
-
800
MHz
2XLO Input Current Range
LOinz
C
50
200
300
µARMS
LOz
C
-
130
-
Ω
BLOout
A
80
100
-
mVP-P
BLOoutZ
C
-
50
-
Ω
Quadrature IF Modulator Output Frequency Range
QMLOf
B
10
-
400
MHz
IF Modulator I/Q Input Frequency Range
QMIQf
C
-
-
30
MHz
IF Modulator Differential I/Q Max Input Voltage
QMdi
C
-
2.25
-
VP-P
QMIQdz
C
-
4
-
kΩ
Mcin
C
-
0.5
-
pF
IF Modulator I/Q Amplitude Balance
QMIQac
A
-0.5
-
0.5
dB
IF Modulator I/Q Phase Balance at 200MHz
QMIQpac
A
-2
-
2
Degrees
IF Modulator I/Q Phase Balance at 400MHz
QMIQp1
B
-4
-
4
Degrees
IF Modulator Output at SSB Into 50Ω, I and Q, 500mVP-P
QMIFo
A
-22
-
-10.0
dBm
IF Modulator Carrier Suppression (LO Buffer Enabled)
QMCs
A
28
30
-
dBc
IF Modulator Carrier Suppression (LO Buffer Disabled)
QMCs1
A
28
36
-
dBc
IF Modulator SSB Sideband Suppression at 200MHz
QMSSBs
A
28
-
-
dBc
IF Modulator SSB Sideband Suppression at 400MHz
QMSSBs
B
26
-
-
dBc
IF Output Level Compression Point
QMIFP1
C
-
1.0
-
VP-P
QMIMsup
B
26
-
-
dBc
PARAMETER
2XLO Input Impedance
Buffered LO Output Voltage, Single Ended
Buffered LO Output Impedance
IF Modulator Differential I/Q Input Impedance
IF Modulator Differential Input Capacitance
IF Modulator Intermodulation Suppression
NOTE:
29. A = Production Tested, B = Based on Characterization, C = By Design
TABLE 4. QUADRATURE MODULATOR S22 PARAMETER
FREQUENCY
S22
50MHz
0.99
-2.8o
100MHz
0.98
-6.5o
200MHz
0.96
-12.3o
300MHz
0.87
-25.1o
400MHz
0.82
-30.8o
AC Electrical Specifications, TX Buffer Individual Performance
Full Supply Range, TA = 25oC
SYMBOL
(NOTE 30)
TEST LEVEL
MIN
TYP
MAX
UNITS
TX LPF Buffer Serial Data Rate
TXBrat
A
-
11
22
MBPS
TX LPF Buffer Digital Input Impedance
LPFDz
C
10
12.5
-
kΩ
PARAMETER
NOTE:
30. A = Production Tested, B = Based on Characterization, C = By Design
21
HFA3724
AC Electrical Specifications, RX/TX 5TH Order LPF Individual Performance
Full Supply Range, TA = 25oC
SYMBOL
(NOTE 31)
TEST LEVEL
MIN
TYP
MAX
UNITS
TX/RX LPF 3dB Bandwidth, Sel0 = 0, Sel1 = 0
LPF3db0
A
1.8
2.20
2.4
MHz
TX/RX LPF 3dB Bandwidth, Sel0 = 1, Sel1 = 0
LPF3db1
A
3.6
4.40
4.8
MHz
TX/RX LPF 3dB Bandwidth, Sel0 = 0, Sel1 = 1
LPF3db2
A
7.4
8.80
9.6
MHz
TX/RX LPF 3dB Bandwidth, Sel0 = 1, Sel1 = 1
LPF3db3
A
14.8
17.60
19.2
MHz
TX/RX LPF Sel0, Sel1 Tuning Speed
LPFsp
B
-
-
1
µs
TX/RX LPF 3dB Bandwidth Tuning
LPFtu
A
-20
-
+20
%
LPF Tune Nominal Resistance
LPFTr
B
-
787
-
Ω
RX LPF Voltage Gain
LPFg
A
-1.0
0
1.0
dB
RX LPF Single Ended Output Voltage Swing at 2kΩ Load
LPFRXar
B
-
500
-
mVP-P
RX LPF Differential Input Impedance
LPFRXzi
A
4
5
-
kΩ
TX LPF Differential Digital Output Voltage Swing at 4kΩ Load
LPFTXo
A
450
550
670
mVP-P
TX/RX I/Q Channel Amplitude Match
LPFIQm
A
-0.5
-
0.5
dB
TX/RX I/Q Channel Phase Match
LPFIQpm
A
-3
-
3
Degrees
TX/RX LPF Total Harmonic Distortion
LPFTHD
B
-
3
-
%
PARAMETER
NOTE:
31. A = Production Tested, B = Based on Characterization, C = By Design
TABLE 5. LOW PASS FILTER PROGRAMMING AND TUNING INFORMATION
MODE
LPF SEL1
LPF SEL0
f3dB
(NOMINAL RTUNE)
BW0
0
0
2.2MHz
BW1
0
1
4.4MHz
BW2
1
0
8.8MHz
BW3
1
1
17.6MHz
f 3dBNOMINAL∗ 787
f TUNED 3dB = ---------------------------------------------------R TUNE
22
HFA3724
PERCENT OF NOMINAL FREQUENCY
TYPICAL f3dB vs RTUNE
+20%
-20%
-30 -25 -20 -15 -10
-5
0
+5
+10 +15 +20 +25 +30
[(787 - RTUNE)/RTUNE] * 100%
FREQUENCY
RTUNE
20% Low
984Ω
Nominal
787Ω
20% High
656Ω
FIGURE 27.
Typical Performance Curves, Individual Blocks
0.25dB/DIV.
7dB
1dB/DIV.
5.5V
85o
45dB
25o
85o
25o
-40o
2.7V
6dB
-40o
40dB
85o
25o
-40o
5dB
2.5V
10M
100M
500MHz
FIGURE 28. SINGLE STAGE LIMITER GAIN vs FREQUENCY
AND TEMPERATURE, VCC = 2.7V, 5.5V
23
4V
VCC
5.5V
FIGURE 29. SINGLE STAGE LIMITER NOISE FIGURE vs VCC
AND TEMPERATURE, RS = 250Ω, FREQUENCY
= 300MHz
HFA3724
Thin Plastic Quad Flatpack Packages (LQFP)
Q80.14x14 (JEDEC MS-026BEC ISSUE C)
D
80 LEAD THIN PLASTIC QUAD FLATPACK PACKAGE
D1
-D-
-B-
-AE E1
e
PIN 1
SEATING
A PLANE
-H-
0.08
0.003
-C-
INCHES
MILLIMETERS
SYMBOL
MIN
MAX
MIN
MAX
NOTES
A
-
0.062
-
1.60
-
A1
0.002
0.005
0.05
0.15
-
A2
0.054
0.057
1.35
1.45
-
b
0.009
0.014
0.22
0.38
6
b1
0.009
0.012
0.22
0.33
-
D
0.626
0.634
15.90
16.10
3
D1
0.547
0.555
13.90
14.10
4, 5
E
0.626
0.634
15.90
16.10
3
E1
0.547
0.555
13.90
14.10
4, 5
L
0.018
0.029
0.45
0.75
N
80
80
e
0.026 BSC
0.65 BSC
7
Rev. 2 4/99
NOTES:
1. Controlling dimension: MILLIMETER. Converted inch
dimensions are not necessarily exact.
2. All dimensions and tolerances per ANSI Y14.5M-1982.
3. Dimensions D and E to be determined at seating plane -C- .
0.13
A-B S
0.005 M C
D S
b
11o-13o
0.020
0.008 MIN
b1
0o MIN
A2 A1
GAGE
PLANE
5. Dimensions D1 and E1 do not include mold protrusion.
Allowable protrusion is 0.25mm (0.010 inch) per side.
6. Dimension b does not include dambar protrusion. Allowable
dambar protrusion shall not cause the lead width to exceed
the maximum b dimension by more than 0.08mm (0.003 inch).
0.09/0.16
0.004/0.006
7. “N” is the number of terminal positions.
BASE METAL
WITH PLATING
L
0o-7o
4. Dimensions D1 and E1 to be determined at datum plane
-H- .
11o-13o
0.25
0.010
0.09/0.20
0.004/0.008
All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification.
Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see web site www.intersil.com
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Intersil Corporation
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TEL: (321) 724-7000
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24
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