Zarlink ACE9020KG Receiver and transmitter interface Datasheet

ACE9020
Receiver and Transmitter Interface
DS4287
Features
• Low Power Low Voltage (3.6 to 5.0 V) Operation
• Power Down Modes
• Differential Signals to Minimise Cross-talk
• Auxiliary Oscillator with Transmit Up-converter
• Prescaler for Main Synthesiser
• Part of the ACE Integrated Cellular Phone Chipset
• Small Outline 28 pin Package
ISSUE 5.0
December 1997
Ordering Information
SSOP 28 lead package, code NP28
ACE9020B/KG/NP1S - anti-static sticks
ACE9020B/KG/NP1T - tape mounted
PD1
PD2
GND
BIAS_REF
VCC_TX
TXPA+
TXPARSET_TXPA
GND_TXOSC
TANK+
TANKVCC_DIV
GND_OSC
MOD_CNTRL
1
28
ACE9020
ACE9020 is a VHF oscillator, up-converter and prescaler.
It is used in an offset modulated transmit architecture where a
UHF synthesiser makes the channel selection and a second
synthesiser generates a fixed transmit offset.
A VCO signal drives a buffer in ACE9020 to feed an onchip prescaler and transmit up-converter. The prescaler is a
dual two-modulus divider and drives the main synthesiser
input of the ACE9030. The SSB up-converter suppresses the
unwanted transmit sideband.
The VHF oscillator is buffered to drive the auxiliary
synthesiser input of the ACE9030 and is locked to the offset
frequency. This frequency is modulated by varying the
resonant frequency of the external tank circuit. Both this
oscillator and the UHF VCO drive the up-converting mixer to
generate the transmit signal.
Various power saving modes for battery economy are
included. These allow the transmit sections to be shut down
during stand-by and the whole chip can be shut down during
sleep mode. The circuit techniques used have been chosen to
minimise external components and at the same time give very
high performance.
14
15
VCC
n.c.
n.c.
VCC_RX
n.c.
RXVCOIN
GND_RX
VCC_TXOSC
TXOSCTXOSC+
GND_DIV
RATIO_SEL
DIV_OUTDIV_OUT+
Note: Pin 1 is identified by moulded spot
and by coding orientation.
NP28
Figure 1 - Pin connections - top view
TXOSC+
Applications
• AMPS and TACS Cellular Telephone
• Two-Way Radio Systems
TXOSCRSET_TXPA
TANK+
TANK-
Related Products
ACE9020 is part of the following chipset:
• ACE9030 Radio Interface and Twin Synthesiser
• ACE9040 Audio Processor
• ACE9050 System Controller and Data Modem
BIAS_REF
PD1
PD2
TXPA+
VHF
OSC
TXPA-
BIAS &
POWER
DOWN
CONTROL
RXVCOIN
ABSOLUTE MAXIMUM RATINGS
Supply voltage
Storage temperature
Operating temperature
Voltage at any pin
Static Sensitivity (HBM) min
6V
- 65°C to + 150°C
- 30°C to + 85°C
-0.3V to VCC +0.3V
500V
RATIO_SEL
MOD_CNTRL
DIVIDE BY
64/65 OR 128/129
DIV_OUT+
DIV_OUT-
Figure 2 - ACE9020 simplified block digram
ACE9020
PIN Connections
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Name
PD1
PD2
GND
BIAS_REF
VCC_TX
TXPA+
TXPARSET_TXPA
GND_TXOSC
TANK+
TANKVCC_DIV
GND_OSC
MOD_CNTRL
DIV_OUT+
DIV_OUTRATIO_SEL
GND_DIV
TXOSC+
TXOSCVCC_TXOSC
GND_RX
RXVCOIN
n.c.
VCC_RX
n.c.
n.c.
VCC
Type
I
I
Supply
I
Supply
O
O
I
Supply
I
I
Supply
Supply
I
O
O
I
Supply
O
O
Supply
Supply
I
Supply
Supply
Description
Power down control input 1
Power down control input 2
Ground
Reference current for bias control
Transmit section supply voltage
Transmit up-converter open collector output
Transmit up-converter open collector output
Reference current for transmit oscillator
Ground
Transmit oscillator tank circuit
Transmit oscillator tank circuit
Divider section supply voltage
Ground
Modulus control input
Divider output positive
Divider output negative
Ratio select
Ground divider section
Transmit oscillator monitor output positive
Transmit oscillator monitor output negative
Transmit oscillator supply voltage
Ground
Input buffer for 1GHz VCO signal from ACE9010
No connection
Receiver section supply voltage
No connection
No connection
ON/OFF logic supply voltage
Electrical Characteristics
These characteristics apply over these ranges of conditions (unless otherwise stated):
TAMB = – 30°C to + 85°C, VCC = 3.75 ± 0.15V or 4.85 ± 0.15V (see fig. 3 for test circuit).
DC Characteristics
Characteristic
Supply Currents
Sleep PD1 = 0, PD2 = 0
Standby PD1 = 1, PD2 = 0
Transmit Set Up PD1 = 0, PD2 = 1
Duplex PD1 = 1, PD2 = 1
Input Levels
PD1, PD2 High
PD1, PD2 Low
Mod Cntrl High
Mod Cntrl Low
Ratio Sel High
Ratio Sel Low
Input Currents
PD1, PD2 High
PD1, PD2 Low
2
Min
Typ
Max
Unit
6
36
48
0.11
8
51
63
mA
mA
mA
mA
1.9
0
Vcc/2 + 0.3
0
0.6Vcc
0
3.1
0.5
Vcc
Vcc/2 - 0.3
Vcc
0.4Vcc
V
V
V
V
V
V
-0.1
40
0.1
µA
µA
ACE9020
Electrical Characteristics
These characteristics apply over these ranges of conditions (unless otherwise stated):
TAMB = -30°C to + 85°C, VCC = 3.75 ± 0.15V or VCC 4.85 ± 0.15V (see fig. 3 for test circuit).
AC Characteristics
Characteristic
TXOSC Output
Differential Output
TxOsc Frequency
Frequency / Supply Sensitivity
Spurii > 700MHz
Differential Output Capacitance
External Tank Inductance f = 90MHz
External Tank Inductance f = 122.5MHz
Power up time (from standby)
TXPA Output Signal
Output Power (RL = 50Ω)
Noise at ∆f = +/- 45 MHz
Noise at ∆f = +/- 25 kHz
Harmonic Content
Spurious - Image
Spurious (fVCO ± 2faux)
Spurious (fVCO ± 3faux)
Spurious (∆f = 45MHz ± 15 kHz) except 2fVCO - 9faux
Spurious 2fVCO - 9faux
Spurii within 800 to 940 MHz (note1)
Other Spurii except image
Isolation TXPA off (PD2 = PD1 = 1)
Power up time
Isolation TXPA to RVCOIN
Residual Modulation (note 2)
RVCOIN Input Signal
Signal Level
Input Impedance
Divider input frequency
Upconverter input frequency
Phase Noise ∆f = 45MHz
Phase Noise ∆f = 25kHz
Spurious - harmonic
Spurious - non-harmonic
Divider
Differential Output Level
Output Rise / Fall time
Mod Control Set up time
Mod Control Hold time
Min
Typ
500
70
82
56
0
Max
65
mV p-p
MHz
kHz
dBc
pF
nH
nH
µs
6
-145
-100
-20
-10
-30
-25
-105
-60
-70
-30
dBm
dBc/Hz
dBc/Hz
dBc
dBc
dBc
dBc
dBc
dBc
dBc
dBc
140
75
-40
2
100
68
3
55
-40
dB
µs
dB
dB
1100
1040
-155
-117
-20
-80
dBm
Ω
MHz
MHz
dBc/Hz
dBc/Hz
dBc
dBc
25
45
-10
50
800
910
500
Unit
600
15
20
1
mV p-p
ns
ns
ns
Notes:
1. Exceptions.
Harmonics of divider output -37dBc max applicable when fVCO = 975.1354 MHz Ratio = 65
10th Harmonic of faux -47dBc applicable when faux = 90MHz, fVCO = 989.9375MHz
2. Residual modulation referenced to a 1kHz signal giving 3kHz deviation. Measured with 750µs de-emphasis and CCITT
filter.
2
ACE9020
Vcc
100p
6k8
5,12,21,25,28
10
19
100n
VCO Control
18p
20
TXOsc
+
Vcc
-
BB545
27n
11
1p
6k8
100p
6
ACE9020
Rxvcoin
23
7
14
15
27p
+
TXPA
-
18n
27n
Tx
Output
1p
Mod Cntrl
Div Out
16
Ratio Sel
17
1 2
4
8
+
-
3,9,13,
18,22
PD1
PD2
22k
faux = 90 MHz
18k
Figure 3 - ACE9020 Test circuit
Description
The ACE9020 is designed for use in a transceiver such as
an analog cellular phone, which uses an offset modulation
transmit architecture. The circuit consists of a VHF voltage
controlled oscillator to generate the offset frequency, an
upconverter to transmit frequency and also a prescaler for the
main UHF phase locked loop. The Rxvcoin signal to the
ACE9020 is normally the UHF local oscillator used for
downconversion.
A basic block diagram is shown in fig. 2, further
information on external connections is provided in the test
circuit (fig. 3) and the applications diagram (fig. 4).
VHF Oscillator
This oscillator is a differential design which uses an
external tank circuit as shown in fig. 3 and fig. 4. The
components shown in fig. 3 give a VCO frequency of 90MHz.
A varactor diode is coupled capacitively to the tank circuit; the
anode is referenced to ground via a resistor. The VCO control
from a synthesiser (eg ACE9030) charge pump output is
applied to the cathode of the varactor also through a resistor.
These resistors should be the same value to keep the
differential circuit balanced. The VCO gain with the
components shown will be typically 2 MHz/V. Modulation is
applied to the anode via a resistive divider as shown in fig. 4;
the actual signal applied to the varactor will be small as the
frequency deviation will typically be a maximum of 12kHz in
many applications. Differential buffered outputs from the
oscillator (TXOSC) interface directly to the ACE9030 auxiliary
synthesier inputs.
Upconverter
An image reject mixer is used for the upconversion. This
provides typically 20dB rejection of the unwanted upper
sideband. The quadrature networks for the mixer are all
provided on chip; this is optimised for UHF local oscillator and
VHF offset oscillator frequencies typically used for analog
cellular phones on the AMPS and TACS systems. Further
4
filtering of the TXPA output will be required to provide further
suppression of the unwanted upper sideband, local oscillator
signal and harmonics to meet cellular telephone
specifications. SAW filters are available for the various
transmit frequency bands.
The upconverter outputs (TXPA + and -) are differential
current outputs. The use of differential outputs minimises
current switching within the device and thus minimise crosstalk to other circuit blocks. The TXPA outputs must be
matched to the external filter, normally 50Ω and single-ended.
The network shown in fig. 3 provides a transformation from
400Ω differential to 50Ω single-ended and also provides dc
bias from the Vcc supply to the open collector TXPA outputs.
This network provides plus and minus 90° phase shift in each
output which are then summed. Alternatively a Balun
transformer could be used, it will again be necessary to
provide dc bias to the TXPA outputs. The load to the current
outputs should be maximised to obtain the maximum power
output; 400Ω is an optimum figure as higher values require
impractical component values for matching.
Prescaler
The two modulus prescaler is part of the UHF phase
locked loop. It will typically be operating with ACE9030 radio
interface and synthesiser. There is also a choice of divider
ratio, set by the ratio select input as shown in table. 1, below.
Mod_Cntrl = LOW
Mod_Cntrl = HIGH
Ratio Sel
= LOW
÷129
÷128
Ratio Sel
= HIGH
÷65
÷64
Table 1
The differential divider outputs can be directly coupled to
the ACE9030 main synthesiser inputs.
ACE9020
Power Control Circuits
The inputs PD1 and PD2 are used to select the operating
modes as shown below:
PD1
0
1
1
PD2
0
0
1
Mode
Sleep
Standby
Transmit Set Up
0
1
Duplex
All circuits off
Prescaler On
Prescaler, VHF
oscillator on. Upconverter off
All circuits on
The power down inputs (PD1, PD2) are compatible with
ACE9030 digital outputs (DO5, 6, 7). These modes allow
circuit operation and power consumption to be optimised. The
ACE9020 can be put in sleep mode (0, 0) when the power
consumption is minimal. The standby mode (1, 0) is used
when the phone is in standby (receive only). The prescaler is
operational to maintain the main UHF PLL; all circuitry
associated with transmit functions is turned off.
There is an intermediate transmit set up state (1, 1). This
allows the VHF oscillator and phase locked loop to stabilise
before enabling the upconverter, preventing spurious
transmissions. The time required for this state will be
determined primarily by the VHF PLL settling time. The power
down inputs can then be set to (0, 1) the full duplex condition.
The intermediate state should also be used during a ‘handoff’
during conversation on an analogue cellular phone, the VHF
PLL continuing to operate while the main UHF PLL changes
channel, the transmit output being disabled. It is also
recommended that the intermediate state is used when going
from duplex (0, 1) to standby (1, 0) modes.
Operating Notes
Good RF layout techniques should be used for this device
to obtain optimum performance and also minimise crosstalk
between circuit blocks. RF supply decoupling should be
provided adjacent to Vcc pins; a value of 27pF is
recommended.
Two external bias resistors are required. A 22kΩ resistor
is connected from BIAS REF (Pin 4) to ground. This sets an
accurate reference current for the chip. An 18k resistor is
connected from RSET TXPA (Pin 8) to ground which controls
the output level of the VHF oscillator and hence the TXPA
output level.
Figure 4 - Application Diagram
4
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