CONEX CX74037 Datasheet
CX74037
Transmit RF IC for TDMA or AMPS Applications
Conexant’s CX74037 Transmit RF Application-Specific Integrated Circuit (ASIC) is
a triple-mode, dual-band transmitter intended for use in IS-136 compliant cellular
phones. As a dual mode IC, it can be used in Time Division Multiple Access
(TDMA) mode or Advanced Mobile Phone System (AMPS) mode. The device is
available in a 48-pin 7x7 Land Grid Array (LGA) package with downset paddle.
The CX74037 RF IC device includes the following functional components:
•
In-Phase and Quadrature (I/Q) modulator
•
Two Intermediate Frequency (IF) Voltage Controlled Oscillator (VCO) inputs
•
IF Variable Gain Amplifier (VGA)
•
Two upconverters
•
Two drivers for external Power Amplifiers (PAs).
The CX74037 48-pin, 7x7 LGA package pin configuration is shown in Figure 1. A
CX74037 block diagram is shown in Figure 2.
VGA_EN
LO_CELL
VCC_MIX
MIX_IN+
MIX_INVCC_IF
VGA_GC
VGA_OUT-
VGA_OUT+
VCC_LD_PCS
POT_CELL
DRV_ENA
RF_PCS_OUT
VCC_BIAS
RF_CELL_OUT
BAND
1
2
3
4
5
6
7
8
9
10
11
12
13
LO_PCS_INNCNC
45464748 44 43 42 41 40 39 38
17161514 18 19 20 21 22 23 24
IF_SELECT
IF_VCO_IN2-
IF_VCO_IN2+
Features
• Sectional enable lines for independent control of
circuits within the chip
• 90 dB IF VGA range
• Separate IF frequencies can be used for the 800
MHz (AMPS) and 1900 MHz Bands (PCS)
• Dual drivers for 800 MHz and 1900 MHz
• PA driver is deactivated by using the Driver Enable
signal when there is no transmission
• Available in a 48-pin, 7x7 LGA package with
downset paddle
Applications
• Cellular and/or PCS-band phones
• TDMA and/or AMPS-mode phones
• Portable battery powered equipment
MODE
NC
37
36
35
34
33
32
31
30
29
28
27
26
25
NC
IF_VCO_IN1IF_VCO_IN1+
NC
NC
NC
VCC_DIV
MIX_CELL_OUT
PULL_ENA
VCC_DIFF_DRV
MIX_PCS_OUT
NC
NC
Data Sheet
NC
I_DATA-
POT_PCS
VCC_MID_PCS
VCC_DRV_CEL
I_DATA+
DRV_PCS_IN
DRV_CELL_IN
Q_DATA+
VCC_MOD
Q_DATA-
101103A-1_080400
Figure 1. CX74037 48-Pin, 7x7 LGA Package Pin Configuration
Conexant Proprietary
Data Subject to Change September 27, 2000
Doc. No. 101103A
CX74037 Transmit RF IC for TDMA or AMPS Applications
PCS RF SAW
PCS LO
PCS-TDMA
RF Out
Cell RF Out
Cell RF SAW
Figure 2. CX74037 Functional Block Diagram
Cell LO
Technical Description
The CX74037 is a TDMA transmitter for the 800 MHz and 1900
MHz bands. It also can be used as an FM transmitter in AMPS
mode at the 800 MHz band. A band select command chooses
between the 800 MHz band and the 1900 MHz band. A mode
select command chooses between TDMA and AMPS mode.
The chip consist of an I/Q modulator, IF LO input buffer, IF VGA,
two upconverters for the 800 MHz and 1900 MHz bands, and
two PA drivers for the 800 MHz and the 1900 MHz bands.
I/Q Modulator
signal to an IF signal using one of the two local oscillator inputs.
This signal is fed directly to the VGA amplifier.
Variable Gain Amplifier
receives its signal from the I/Q modulator, amplifies it, and then
is taken off-chip to be filtered before routing it to the
upconverter. A dynamic range of 90 dB is available on the
amplifier. A DC voltage of 0.2 to 2.5 V is needed to control the
gain of the amplifier.
Upconverters
receive the IF signal from the VGA amplifier. Each upconverter
requires an external LO controlled by an external Phase Locked
Loop (PLL). The band select command switches between the
800 MHz and the 1900 MHz bands.
. The I/Q modulator converts the incoming I/Q
. The VGA is a differential amplifier that
. The 800 MHz and 1900 MHz upconverters
CX74037
TX RFIC
2 2
LPF or BPF
IF LO IN
VCC
I Data
IF Select
Band Select
PULL En
PA Driver En
Interface
VGA En
Q Data
Vvga
101103A-2_080900
PA Drivers
÷ 2
. Two PA drivers are included, the 800 MHz driver
and the 1900 MHz driver. Each driver takes its input from the
upconverter after passing through an image rejection filter. The
driver amplifies the signal and sends it to an external PA.
Electrical and Mechanical Specifications ________________
The signal pin assignments and functional pin descriptions are
found in Table 1. The absolute maximum ratings of the
CX74037 are provided in Table 2, the recommended operating
conditions are specified in Table 3. Electrical characteristics for
the CX74037 are shown in Table 4. Table 5 defines the control
signal logic.
Figure 3 provides the package dimensions for the 48-pin, 7x7
LGA package.
ESD Sensitivity
The CX74037 is a static-sensitive electronic device. Do not
operate or store near strong electrostatic fields. Take proper
ESD precautions.
Data Sheet
Conexant Proprietary
Data Subject to Change September 27, 2000
Doc. No. 101103A
Transmit RF IC for TDMA or AMPS Applications CX74037
Table 1. CX74037 Signal Definition (1 of 2)
Pin NO. Name Description
1 Mix_IN+ Input to RF Upconverters. Internally AC c oupled, high impedance.
2 Mix_IN- Input to RF Upconverters. Internally AC c oupled, high impedance.
3 VCC_IF Supply volta ge for the AGC amplifier.
4 VGA_GC The input pin f or AGC gain control. A DC contr ol voltage should be applied to this pin to vary the gain of the IF amplifier.
5 VGA_OUT- VGA Output, open collector. External resistive (300 ohms ) pull up to Vcc required.
6 VGA_OUT+ VGA Output, open c ollector. External resisti ve (300 ohms) pull up to Vcc required.
7 VCC_LD_PC S Supply voltage for the PCS l ast stage driver amplifier.
8 POT_CELL This pin is connected to an external resistor. The value of the resistor will vary the bias current of the cellular driver.
9 DRV_ENA
10 RF_PCS_OUT Output pin for t he PCS driver amplifier. Impedance matching is required.
11 VCC_BIAS Supply voltage of bias cells.
12 RF_CELL_OUT Output pin for the cellular driver amplif ier. Impedance matching is required.
13 BAND This is a control signal input pin. It selects between cell ular band and PCS band. When the input is low, the cellular band is chosen.
14 VCC_DRV_CEL Supply voltage for the driver of the c ellular band.
15 POT_PCS This pin is connected to an external resistor. The value of the resistor will vary the bias current of the PCS driver.
16 VCC_MID_PCS Supply voltage for the f irst amplifier in the PCS driv er block.
17 DRV_CELL_IN The Cellular driver amplifier input pin. Impedance matching is required.
18 DRV_PCS_IN The PCS driver amplifier input pin. Impedance matching i s required.
19 I_DATA+ The baseband input for I channel. This is a balanced input. A DC bias has to be supplied t o the pin.
20 I_DATA- Same as pin 20, except complement ary input. This pin should be pul l low (0 V) in FM mode.
21 VCC_MOD Supply voltage for the I/Q modulator.
22 Q_DATA+ The baseband input for Q channel. This i s a balanced input. A DC bias has to be supplied to the pin.
23 Q_DATA- Same as pin 23, except complementary input.
24 NC There is no connection on thi s pin. Should be tied to ground.
25 NC There is no connection on thi s pin. Should be tied to ground.
26 NC There is no connection on thi s pin. Should be tied to ground.
27 MIX_PCS_OUT Output of the P CS upconverter. Impedance matching required.
28 VCC_DIFF_DRV Supply volta ge for a differential amplifier in the upconverter block.
29 PULL_ENA This is a control signal input pin. When the input is low, the IF VCOs, RF Mixer and buffers, and div ide by 2 sections will be
30 MIX_CELL_OUT Output of the Cellular upconverter. Impedance matching requi red.
31 VCC_DIV Supply volta ge for the dividers and VCO buffer.
32 NC There is no connection on thi s pin. Should be tied to ground.
33 NC There is no connection on thi s pin. Should be tied to ground.
34 NC There is no connection on thi s pin. Should be tied to ground.
35 IF VCO IN1+ Input pin for the modulator LO signal. The frequency is 2xIF. Can be used single-ended. AC ground the unused pin.
36 IF VCO IN1- Input pin for the modulator LO signal. The frequency is 2xIF. Can be used single-ended. AC ground the unused pin.
37 NC There is no connection on thi s pin. Should be tied to ground.
38 NC There is no connection on thi s pin. Should be tied to ground.
39 MODE This is a control signal input pin. When the i nput is low, the AMPS mode is selected. If the input is high, T DMA mode is selected. FM
40 IF VCO IN2+ Input pin for the modulator LO signal. The frequency is 2xIF. Can be used single-ended. AC ground the unused pin.
41 IF VCO IN2- Input pin for the modulator LO signal. The frequency is 2xIF. Can be used single-ended. AC ground the unused pin.
42 IF_SELECT Control signal to select IF VCO INPUT1 or INPUT2. “1” will select IF VCO INPUT1 and “0” will select IF VCO INPUT2.
This is the input pin for the upconverter a nd the driver control signal. When the pin is low the driver and the upconverter are
deactivated.
When the input is high, the PCS band is chosen.
disabled. When the input is high, the mentioned sections will be enabled.
output is 9 dB hi gher at the modulator output .
101103A
Conexant – Proprietary
September 27, 2000 Data Subject to Change
3
CX74037 Transmit RF IC for TDMA or AMPS Applications
Table 1. CX74037 Signal Definition (2 of 2)
Pin No. Name Description
43 NC Connect to gro und.
44 NC Connect to gro und.
45 LO_PCS_IN This is the input pin for the local oscillator for the PCS band. It is internally matched.
46 VCC_MIX Supply volta ge for the mixer in the upconverter block and for the LO buffer .
47 LO_CELL This is the input pin for the local oscillator for the cellular band. It is internally matched.
48 VGA_EN This is a control signal input pin. When the input is low, the VGA and I/Q Modulator sections will be disabled. When the input is high,
the mentioned sections will be enabled.
Table 2. Absolute Maximum Ratings
Parameter Symbol Minimum Typical Maximum Units
Supply voltage VCC –0.3 +5.0 V
Input voltag e range –0.3 VCC V
Power dissipation 600 mW
Ambient operat ing temperature –30 +80 °C
Storage temperature –40 +125 °C
Table 3. CX74037 Recommended Operating Conditions
Parameter Symbol Minimum Typical Maximum Units
Supply volta ge 2.7 3. 0 3.6 V
Logic level high 1.9 V
Logic level low 0.8 V
Supply current in 800 MHz TDM A @ 7 dBm 75 mA
Supply current in 800 MHz AMP S @ 7 dBm 75 mA
Supply current in 800 MHz (DRV_ENA off) 45 mA
Supply current in 1900 MHz TD MA @ 8.0 dBm 84 mA
Supply current in 1900 MHz TDMA (DRV_ENA off ) 48 mA
Supply current in sleep mod e 20
µ
A
4
Conexant – Proprietary
101103A
Data Subject to Change September 27, 2000
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