MAXIM MAX2902EGI

19-2145; Rev 2; 12/07
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Features
The MAX2900–MAX2904 complete single-chip 200mW
transmitters are designed for use in the 868MHz/
915MHz frequency bands. The MAX2900/MAX2901/
MAX2902 are compliant with the FCC CFR47 part 15.247
902MHz to 928MHz ISM-band specifications. MAX2903/
MAX2904 are compliant with the ETSI EN330-220 specification for the European 868MHz ISM band.
♦ Versions for U.S. 902MHz to 928MHz Band and
European 868MHz Band
♦ -7dBm to +23dBm Adjustable Differential RF
Output Power
♦ +23dBm Output Power at 4.5V, +20dBm Output
Power at 3.0V
♦ Support BPSK, OOK, ASK, and FM Modulations
♦ Modulation Filter for Direct Sequence BPSK up to
8Mchips/s
♦ Fully Integrated VCO with On-Chip Tank
♦ Extremely Low Frequency Pulling for OOK
Modulation (typ 60kHz peak, 5kHz RMS)
♦ Integrated Frequency Synthesizer for up to
8 Channels (MAX2900)
♦ +2.7V to +4.5V Supply Operation
♦ Small 28-Pin QFN Package with Exposed Pad
(5mm ✕ 5mm)
These transmitter ICs offer a high level of integration
while minimizing the number of external components.
This is achieved by full integration of the transmit modulator, power amplifier, RF VCO, 8-channel frequency synthesizer, and baseband PN sequence lowpass filter. By
filtering the BPSK modulation, the spurious emissions are
reduced, enabling up to eight independent transmit
channels in the U.S. ISM band. Inputs are provided for
spread-spectrum BPSK, ASK, and OOK. FM can be
achieved by directly modulating the VCO. The devices
are intended primarily for use with an external differential
antenna.
Ordering Information
Applications
Automatic Meter Reading
Wireless Security Systems/Alarms
Wireless Sensors
Wireless Data Networks
Wireless Building Control
PART
MAX2900EGI
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
28 QFN-EP*
MAX2901EGI
-40°C to +85°C
28 QFN-EP*
MAX2902EGI
-40°C to +85°C
28 QFN-EP*
MAX2903EGI
MAX2904EGI
-40°C to +85°C
-40°C to +85°C
28 QFN-EP*
28 QFN-EP*
*Exposed pad
Functional Diagrams/Pin Configurations
VTUNE
CPOUT
VCC5
D2
28
27
26
REFOUT VCC4
25
REFIN
OSC
CPOUT
VCC5
23
22
28
27
24
1
21 D0
VTUNE
1
2
20 D1
GND
2
VREG
25
REFIN
OSC
23
22
24
21 VCO+
20 VCO-
÷4
CP
26
MAX2901/
MAX2903
MAX2900
GND
DIV63 REFOUT VCC4
CP
19 N.C.
3
8-CHANNEL
SYNTHESIZER
REG
VREG
19 DIVOUT
3
DUALCHANNEL
(/62 OR /63)
SYNTHESIZER
REG
18 GND
18 N.C.
VCC1
4
5
17 RF+
RLPF
5
17 RF+
EN
6
16 RF-
EN
6
16 RF-
REFEN
7
REFEN
7
VCC1
4
RLPF
GATE
8
9
MODIN OOKIN
15 GND
10
VCC2
11
12
VASK
LD
13
14
PWRSET VCC3
GATE
8
9
MODIN OOKIN
15 GND
10
11
12
VCC2
VASK
LD
13
14
PWRSET VCC3
Functional Diagrams/Pin Configurations are continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX2900–MAX2904
General Description
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +5.0V
Analog/Digital Input Voltage to GND..........-0.3V to (VCC + 0.3V)
Analog/Digital Input Current ..............................................±10µA
Continuous Power Dissipation (TA = +70°C)
28-Pin QFN-EP (derate 28.5mW/°C above +70°C)............2W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
CAUTION! ESD SENSITIVE DEVICE
Part Selection Information
Five different versions are available. The versions differ
by their frequency band of operation, and by the synthesizer’s mode of operation. The MAX2900 has an internal
8-channel synthesizer.
The MAX2901 and MAX2903 are dual-channel versions
with a selectable internal synthesizer division ratio of 62
or 63. The MAX2901 operates in the 902MHz to
928MHz ISM band and the MAX2903 operates in the
867MHz to 870MHz European ISM band.
The MAX2902 and MAX2904 require an off-chip frequency synthesizer. The MAX2902 operates in the
902MHz– 928MHz ISM band and MAX2904 operates in
the 867MHz–870MHz European ISM band.
The MAX2901–MAX2904 provide LO outputs to drive a
receiver and/or an external synthesizer.
PART
FREQUENCY RANGE (MHz)
SYNTHESIZER
LO OUTPUTS
MAX2900EGI
902 to 928
Internal 8 selectable channels
No
MAX2901EGI
902 to 928
Internal 2 selectable channels
Yes
MAX2902EGI
902 to 928
Off-chip
Yes
MAX2903EGI
867 to 870
Internal 2 selectable channels
Yes
MAX2904EGI
867 to 870
Off-chip
Yes
DC ELECTRICAL CHARACTERISTICS
(VCC = +2.7V to +4.5V, EN = OOKIN = REFEN = high, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless
otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
MAX
UNITS
4.5
4.5
V
VCC = +4.0V
0.7
10
VCC = +4.5V
60
200
Synth mode: OOKIN = low
(MAX2900/MAX2901/MAX2903 only)
32
40
Transmit mode with output
matching optimized for
+23dBm at +4.5V: PWRSET
loaded with 22kΩ resistor
TA = -40°C
to +85°C
150
Transmit mode with output
matching optimized for
+20dBm at +3.0V: PWRSET
loaded with 22kΩ resistor
TA = -40°C
to +85°C
110
Supply Voltage
2.7
Shutdown mode: EN =
REFEN = low
Supply Current
2
-3σ
TYP
+3σ
µA
200
mA
135
_______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
(VCC = +2.7V to +4.5V, EN = OOKIN = REFEN = high, TA = -40°C to +85°C. Typical values are at VCC = +4.5V, TA = +25°C, unless
otherwise noted.) (Note 1)
PARAMETER
Supply Current (continued)
VCO Input Tuning Pin Current
CONDITIONS
MIN
-3σ
TYP
Transmit mode with output
matching optimized for
+17dBm at +3.0V: PWRSET
loaded with 36kΩ resistor
TA = +25°C
75
Transmit mode with output
matching optimized for
+14dBm at +3.0V: PWRSET
loaded with 51kΩ resistor
TA = +25°C
57
+3σ
MAX
mA
Reference-only mode: EN = low
2
3
PA standby mode: OOKIN = low
(MAX2902/MAX2904 only)
29
33
0.02
2
VTUNE = +4.5V, TA = +25°C
VREG VCO Regulator Voltage
UNITS
2.0
µA
V
DIGITAL INPUT/OUTPUTS (PINS EN, REFEN, D0, D1, D2, MODIN, OOKIN, LD)
VCC
- 0.5V
Input Level High
V
Input Level Low
Input Bias Current
-10
Output Level High
VCC
- 0.4
V
10
µA
V
Output Level Low
Output Current
0.5
-100
0.4
V
100
µA
ANALOG CONTROL INPUTS (PINS PWRSET, RLPF, VASK)
PWRSET Voltage
1.2
V
RLPF Voltage
1.2
V
VASK Input Impedance
100
220
400
kΩ
_______________________________________________________________________________________
3
MAX2900–MAX2904
DC ELECTRICAL CHARACTERISTICS (continued)
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
AC ELECTRICAL CHARACTERISTICS
(MAX290_ EV kits. VCC = +2.7V to +4.5V, RRLPF = 68kΩ, RPWRSET = 22kΩ, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF
= 868MHz (MAX2903/MAX2904), VASK = VREG, f REF = 14.56MHz (MAX2900/MAX2901/MAX2902) or f REF = 13.62MHz
(MAX2903/MAX2904), chip rate on MODIN = 1.22Mbps, POUT = +23dBm, TA = -40°C to +85°C. Typical values are at VCC = +4.5V,
TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
-3σ
TYP
+3σ
MAX
UNITS
ANALOG INPUT PINS
VTUNE Input Capacitance
VTUNE = +1.35V
15
pF
3
pF
DIGITAL INPUT PINS
Digital Input Pin Capacitance
VCO AND SYNTHESIZERS SECTION
RFOUT Frequency Range
REFIN Reference Frequency
Range
REFDIV Fixed Reference Divider
Ratio
Main Divider Ratios
PLL Comparison Frequency
(MAX2900/MAX2901/MAX2902)
902
917.28
928
(MAX2903/MAX2904)
867
868
870
(MAX2900/MAX2901/MAX2902)
14
14.56
15
(MAX2903/MAX2904)
13
13.78
14.5
(MAX2900)
4
4
4
Table 4 (MAX2900)
249
256
(MAX2901/MAX2903)
62
63
(MAX2900)
3.5
(MAX2901/MAX2903)
13
VCO Buffer Output Power
300Ω differential load (MAX2901–MAX2904)
REFDIV Fixed Reference
Divider Ratio
(MAX2901/MAX2903)
VCO Phase Noise
At 100kHz offset, measured at RFOUT,
PLL loop BW = 5kHz
VCO Tuning Gain
(MAX2900/MAX2901/MAX2902)
OOKIN clocked at 19kHz, internal (crystal)
or external reference frequency
PLL Phase Noise
Measured at RFOUT, 5kHz offset,
PLL loop BW = 50kHz
REFOUT Voltage Swing
3.75
15
-12
1
1
44
65
MHz
MHz
dBm
1
-101
(MAX2903/MAX2904)
VCO Frequency Pulling with
OOK Modulation
3.64
MHz
dBc/Hz
86
MHz/V
85
5
60
kHz RMS
kHz peak
-96
dBc/Hz
100
mVp-p
CPOUT Charge Pump Current
500
µA
Reference Spurs
-62
dBc
300
mV
Reference Input Voltage for
Nominal Operation
Using an external frequency reference
200
BPSK, OOK MODULATOR, AND PA
MODIN Frequency Range
1.2
Modulation Filter Nominal 3dB
Bandwidth
1
Modulation Filter Final Attenuation Measured at 30MHz
Carrier Suppression
Noise Power Density
4
At 960MHz (measured at RFOUT at
+23dBm output power)
28
8
Mb/s
MHz
41
dB
28
dB
-150
dBc/Hz
_______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
(MAX290_ EV kits. VCC = +2.7V to +4.5V, RRLPF = 68kΩ, RPWRSET = 22kΩ, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF
= 868MHz (MAX2903/MAX2904), VASK = VREG, f REF = 14.56MHz (MAX2900/MAX2901/MAX2902) or f REF = 13.62MHz
(MAX2903/MAX2904), chip rate on MODIN = 1.22Mbps, POUT = +23dBm, TA = -40°C to +85°C. Typical values are at VCC = +4.5V,
TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
RF Output Power
CONDITIONS
MIN
-3σ
TYP
+3σ
PWRSET = 22kΩ, VCC = +4.5V,
TA = +25°C
21
23.5
25
PWRSET = 22kΩ, VCC = +4.5V,
TA = -40°C to +85°C
20.5
PWRSET = 22kΩ, VCC = +3.0V, TA = +25°C
18
MAX
dBm
25
20
UNITS
21
RF Output Power Flatness
fRF = 900MHz to 930MHz
(MAX2900/MAX2901/MAX2902)
fRF = 867MHz to 870MHz
0.1
Adjacent Channel Power Ratio
PN sequence at 1.22MHz
-17
dBc
Alternate Channel Power Ratio
PN sequence at 1.22MHz
-26
dBc
80
dB
OOK Control Range
ASK Output Power Adjustment
Range
RFOUT Rise and Fall Time
Spurious Emissions
Unlocked, Out-of-Band Spurious
Output Level
0.3
40
ASK output power backoff relative to max power
OOKIN = high,
VASK = 0
dB
41
dB
OOKIN = high,
VASK = 1V
Square-wave signal applied on OOK
16
1
At 2nd harmonic of RF output frequency
with external matching network
-50
At 3rd harmonic of RF output frequency
with external matching network
-51
At 4th harmonic of RF output frequency
with external matching network
-63
µs
dBc
Out of 902MHz to 928MHz band other than
harmonics with external matching network
(MAX2900/MAX2901/MAX2902)
< -70
Out of 867MHz to 870MHz band other than
harmonics with external matching network
(MAX2903/MAX2904)
< -70
Any condition when synthesizer unlocked
(pin LD low)
< -50
Modulation off, measured at 960MHz, any
gain setting (MAX2900/MAX2901/MAX2902)
-126
-120
Modulation off, measured at 900MHz, any
gain setting (MAX2903/MAX2904)
-126
-120
dBm
Noise Level Out of Band
dBm/Hz
Output VSWR for Guaranteed
Stability
2:1
Maximum Allowable Output VSWR
2:1
Note 1: Devices are production tested at TA = +25°C and +85°C. Min/Max values are guaranteed by design and characterization
over temperature and supply voltage.
_______________________________________________________________________________________
5
MAX2900–MAX2904
AC ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(MAX290_ EV kits. VCC = +4.5V, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), RRLPF =
68kΩ, RPWRSET = 22kΩ, VASK = VREG, fREF = 14.56MHz (MAX2900/MAX2901/MAX2902) or fREF = 13.78MHz (MAX2903/MAX2904),
chip rate on MODIN = 1.22 Mbps, RF output matching network optimized for +23dBm, V CC = 4.5V, T A = +25°C, unless
otherwise noted.)
SHUTDOWN CURRENT vs. VCC
120
TA = -40°C
110
100
24
OUTPUT POWER (dBm)
130
26
MAX2900 toc02
TA = +25°C
140
SHUTDOWN CURRENT (μA)
10
TA = +85°C
1
TA = +85°C
TA = +25°C
22
TA = -40°C
20
18
90
TA = -40°C
TA = +25°C
0.1
80
2.5
3.0
3.5
16
2.5
4.5
4.0
3.0
3.5
4.0
4.5
2.5
3.0
3.5
VCC (V)
VCC (V)
VCO PHASE NOISE AT 917.28MHz
PLL LOCK TIME
VCO SUPPLY PUSHING vs. VCC
MAX2900 toc05
918.0
MAX2900 toc04
-40dBc/Hz
917.5
OUTPUT FREQUENCY (MHz)
4.5
4.0
VCC (V)
100kHz
MAX2900 toc06
SUPPLY CURRENT (mA)
MAX2900 toc01
TA = +85°C
150
OUTPUT POWER vs. VCC
100
MAX2900 toc03
SUPPLY CURRENT vs. VCC
160
917.0
20kHz/div
916.5
916.0
915.5
915.0
-140dBc/Hz
FREQUENCY OFFSET (MHz)
-100kHz
2.5
3.0
3.5
4.0
4.5
STOP 30μs
START 0s
VCC (V)
3000
25
C
RF POWER (dBm)
2000
45deg/div
1500
22
21
20
500
19
-225deg
20
30
40
RRLPF (kΩ)
50
60
70
START 0s
STOP 40μs
A: VCC = 4.5V, TA = -40°C
B: VCC = 4.5V, TA = +25°C
C: VCC = 4.5V, TA = +85°C
D: VCC = 2.7V, TA = -40°C
E: VCC = 2.7V, TA = +25°C
F: VCC = 2.7V, TA = +85°C
23
1000
10
A
B
24
2500
0
6
225deg
MAX2900 toc08
MAX2900 toc07
3500
RF POWER vs. FREQUENCY
(MAX2900/MAX2901/MAX2902)
BPSK MODULATION OUTPUT vs. TIME
MAX2900 toc09
LOWPASS FILTER 3-dB RESPONSE
vs. RRLPF
LOWPASS FILTER 3-dB BANDWIDTH (kHz)
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
E
D
F
18
900
905
910
915
920
FREQUENCY (MHz)
_______________________________________________________________________________________
925
930
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
RF POWER (dBm)
30dBm
MKR
917.31MHz
-16.33dBm
30dBm
MAX2900 toc12
RF OUTPUT MATCHING
OPTIMIZED FOR +14dBm
OUTPUT AT VCC = +3.0V
MAX2900 toc11
16
MAX2900 toc10
17
MKR
917.35MHz
8.17dBm
VCC = +3.6V
15
10dB/div
10dB/div
VCC = +3.0V
14
VCC = +2.7V
13
12
-70dBm
860
864
868
876
872
CENTER 917.28MHz
-70dBm
SPAN 20MHz
SPAN 20MHz
CENTER 917.28MHz
FREQUENCY (MHz)
30dBm
MKR
910MHz
23.17dBm
MAX2900 toc15
22dBVp-p
MAX2900 toc14
Tf
Tr
MAX2900 toc13
0dBVp-p
SPURIOUS LEVEL FROM
DC TO 7TH HARMONIC
RF OUT RISE AND FALL TIME TRANSIENT
WITH SQUARE ASK
RF OUT RISE AND FALL TIME TRANSIENT
WITH SQUARE OOK
Tf
Tr
10dB/div
10dB/div
-100dBVp-p
STOP 86μs
START 46μs
-78dBVp-p
-70dBm
SPURIOUS LEVEL BETWEEN ±50MHz
FROM CARRIER FREQUENCY
TRANSMITTER EFFICIENCY vs. RPWRSET
10dB/div
45
TRANSMITTER EFFICIENCY (%)
MAX2900 toc16
30dBm
40
35
A
B
C
D
E
F
30
25
A: VCC = 4.5V, TA = -40°C
B: VCC = 4.5V, TA = +25°C
C: VCC = 4.5V, TA = +85°C
D: VCC = 2.7V, TA = -40°C
E: VCC = 2.7V, TA = +25°C
F: VCC = 2.7V, TA = +85°C
20
15
10
-70dBm
CENTER 917.28MHz
SPAN 100MHz
STOP 7GHz
START 0Hz
STOP 85μs
START 45μs
MAX2900 toc17
10dB/div
14
18
22
26
30
34
38
RPWRSET (kΩ)
_______________________________________________________________________________________
7
MAX2900–MAX2904
Typical Operating Characteristics (continued)
(MAX290_ EV kits. VCC = +4.5V, fRF = 917.28MHz (MAX2900/MAX2901/MAX2902) or fRF = 868MHz (MAX2903/MAX2904), RRLPF =
68kΩ, RPWRSET = 22kΩ, VASK = VREG, fREF = 14.56MHz (MAX2900/MAX2901/MAX2902) or fREF = 13.78MHz (MAX2903/MAX2904),
chip rate on MODIN = 1.22 Mbps, RF output matching network optimized for +23dBm, V CC = 4.5V, T A = +25°C, unless
otherwise noted.)
OUTPUT SPECTRUM WITH PN SEQUENCE
RF POWER vs. FREQUENCY
OUTPUT SPECTRUM WITH 600kHz
AT 1.22MHz AT MODIN
(MAX2903/MAX2904)
SQUARE WAVE INPUT AT MODIN
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
MAX2900–MAX2904
Pin Description
MAX2902
MAX2904
1
NAME
PIN TYPE
1
PIN
MAX2901
MAX2903
1
VTUNE
Analog Input
2
2
2
GND
Supply Pin
3
3
3
VREG
Analog
Input/Output
Regulated voltage output to supply the VCO.
Bypass with a 0.01µF capacitor to GND as
close to the part as possible.
4
4
4
VCC1
Supply Pin
Power supply pin for VCO circuits. Bypass
with a 1000pF and a 10µF capacitor to GND
as close to the part as possible.
5
5
5
RLPF
6
6
6
EN
Digital Input
Chip-enable digital input pin. Set EN low
maintain the chip in power-down mode.
7
7
7
REFEN
Digital Input
Enable for crystal oscillator and frequency
reference buffer.
8
8
8
MODIN
Digital Input
BPSK modulation input
9
9
9
OOKIN
Digital Input
On-off keying modulation. On state = high.
Power supply pin for internal RF buffer
circuits. Bypass with a 100pF and a 0.01µF
capacitor to GND as close to the part as
possible.
MAX2900
8
FUNCTION
VCO tuning voltage input
Ground
Resistor to ground on this pin sets the
Analog Input
Resistor to Ground modulation filter bandwidth.
10
10
10
VCC2
Supply
11
11
11
VASK
Analog Voltage
Input
12
12
—
LD
Digital Output
—
—
12
D.C.
13
13
13
PWRSET
14
14
14
VCC3
ASK voltage input pin
Lock detector output digital pin. Level is
high when PLL is inside lock range.
Do NOT Connect —
Analog Input
Current input set to adjust output power.
Resistor to Ground
Supply
Power supply pin for RF power amplifier
circuits. Bypass with a 100pF capacitor to GND
as close to the part as possible.
_______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
PIN
MAX2900
MAX2901
MAX2903
MAX2902
MAX2904
NAME
PIN TYPE
FUNCTION
15
15
15
GND
Supply Pin
Ground
16, 17
16, 17
16, 17
RF-, RF+
RF Output
RF differential output, open-collector type
18
—
—
N.C.
Not Connected
—
18
—
GND
Supply Pin
—
—
18
D.C.
Do Not Connect
—
19
—
19
N.C.
Not Connected
—
—
19
—
DIVOUT
ECL Output
—
Ground
Divider output
—
20, 21
20, 21
VCO-, VCO+
Open Collector
RF
20
—
—
D1
Digital Input
Channel selection bit 1
21
—
—
D0
Digital Input
Channel selection bit 0
22
22
22
OSC
Analog Input
Crystal oscillator connection. See Typical
Operating Circuit.
23
23
23
REFIN
Analog Voltage
Input
Reference input pin analog (can be used as
input or as crystal oscillator driver). See
Typical Operating Circuit.
24
24
—
VCC4
Supply Pin
Power-supply pin for the synthesizer circuits.
Bypass with a 1000pF capacitor to GND as
close to the part as possible.
—
—
24
VCC4
Supply Pin
Power-supply pin for the digital circuits.
Bypass with a 100pF capacitor to GND as
close to the part as possible.
25
25
25
REFOUT
Analog Output
26
—
—
D2
Digital Input
Channel selection bit 2
—
26
—
DIV63
Digital Input
Division ratio selections (division ratio = 62
when DIV63 = high; division
ratio = 63 when DIV63 = low).
—
—
26
N.C.
Not Connected
27
27
—
VCC5
Supply Pin
Power-supply pin for charge pump circuits.
Bypass with a 100pF capacitor to GND as
close to the part as possible.
—
—
27
VCC5
Supply Pin
Power-supply pin. Bypass with a 100pF
capacitor to GND as close to the part as
possible.
28
28
—
CPOUT
Analog Output
—
—
28
D.C.
Do Not Connect
GROUND
Electrical
Ground
GROUND
GROUND
GROUND
VCO output (differential)
Buffered clock analog output pin
—
Charge pump output pin
—
Back side of package is connected to
ground.
_______________________________________________________________________________________
9
MAX2900–MAX2904
Pin Description (continued)
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Detailed Description
Principles of Operation
When EN goes high, the reference and the VCO start
while the PA stays in the off mode. For MAX2900/
MAX2901/MAX2903, the PLL also starts when EN goes
high. After the lock-detect pin LD goes high, the PA is set
to stand-by mode. For the MAX2902/MAX2904, the VCO
loop has to be closed by using an external synthesizer.
After this, pulling OOKIN high turns on the PA. The internal modulation filter smoothes the power ramp-up of the
PA.
The modulation filter BW is typically 0.8MHz, used for a
1.22Mbps chip rate, and can be adjusted by varying
RLPF. A high value can be used for RLPF to get a slow
PA ramping up when BPSK is not used.
The reference blocks can be turned on separately (and
earlier) by pulling REFEN high, to allow the crystal frequency to settle.
The device supports various modulation modes:
• BPSK, filtered by the internal modulation filter, is
obtained through the MODIN pin. This is the preferred mode of operation for MAX2900.
• OOK is obtained digitally with the OOKIN pin.
• ASK is obtained through the ASK pin.
•
•
FM is imposed on the VCO or the reference.
FM is the preferred mode of operation for the
MAX2903/MAX2904 due to the narrowband operation common in Europe.
The maximum output power is set by the output matching network and the external biasing resistor on the
PWRSET pin.
For the MAX2901–MAX2904, differential LO outputs are
provided to drive a companion receiver and/or an
external synthesizer.
Power-Up Modes
The circuit has four modes of operations, defined as
follows:
1) Shutdown mode: Pin EN and REFEN are low, all
functions are off, and the current consumption is
leakage only.
2) Synth mode: Pin EN and REFEN are high, pin
OOKIN is low. The reference circuits, VCO, and
synthesizer are turned on. The power amplifier is in
stand-by mode. Total current is less than 50mA.
Note that as long as the LD pin is not going high,
indicating that the PLL is unlocked, OOKIN high is
ignored.
10
3) Transmit mode: Pin EN and REFEN are high. If output
pin LD is high, the device is ready to transmit. When
OOKIN is high, the power amplifier is turned on. The
current consumption varies between 50mA and
120mA, depending on the output power requested by
the combination of the OOK duty cycle, the PWRSET
value, and output matching circuit.
4) Reference Only mode: This mode enables the use
of the crystal reference from the IC to drive the
external logic ICs. To obtain this mode, set the
REFEN pin high and EN low. In this mode, only the
reference circuit turns on, the crystal oscillator starts,
and the clock is present at the REFOUT pin. The current consumption remains much lower than that in the
SYNTH mode because the VCO, synthesizer, and PA
standby circuits are off. When EN goes high, the IC
goes into the SYNTH mode.
Synthesizer Programming
The three pins D0–D2 (MAX2900) and DIV63 (MAX2901/
MAX2903) are used as digital entries to program the synthesizer division ratios. Tables 4 and 5 show the division
ratios obtained for the various pin logic levels.
TO INTERNAL
CONTROL
CIRCUIT
PIN PWRSET
100Ω
1.2V
INTERNAL
CIRCUITS
EXTERNAL
RESISTOR
Figure 1. PIN PWRSET Equivalent Circuit
Analog Input Control Pins
The two pins PWRSET and VASK are analog inputs
used to control the power of the transmitter. The equivalent input schematics are defined in Figures 1, 2, and
3. The PWRSET pin sets the biasing of the amplification
chain. Because the last stage of the amplifier operates
in saturation, the output power mostly depends on the
load and supply voltage. The purpose of the PWRSET
resistor is to achieve optimum biasing (and therefore
efficiency) for various maximum output power configurations. For a given application with a known operating
voltage and peak power, a fixed value of resistor is
determined. The output power range of -7dBm to
+23dBm at 4.5V is obtained by choosing a combination
of output load line and the resistor on PWRSET; 22kΩ is
______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
TO VREG
(2.1V)
TO INTERNAL
CONTROL
CIRCUIT
PIN
VASK
>200kΩ
1.5V
EXTERNAL
RESISTOR
BRIDGE
INTERNAL
CIRCUITS
Figure 2. PIN VASK Equivalent Circuit
The VASK pin is an input to the internal gain control circuitry. The gain control is greater than 30dB over the
full range of input voltages from 0 to VREG = 2.1V. This
input is used for ASK modulation. At 1V, a typical 15dB
attenuation is obtained from the peak power. When this
input is not used, connect VASK to VREG.
The RLPF input controls the modulation filter center frequency.
TO INTERNAL
CONTROL
CIRCUIT
Data Filter Characteristics
The data filter approximates a 3rd-order Butterworth filter. The 3dB cut-off frequency is adjusted through the
resistor on pin RLPF, which controls the first two poles
of the filter (the last high-frequency pole is fixed and set
around 10MHz). The filter is adjustable in a range from
approximately 700kHz to 7MHz.
With the nominal setting (3dB cut off at 0.8MHz), the filter attenuation is 10dB at 3.6MHz. If used with a BPSK
at 1.22MHz, this provides about 30dB of modulation
rolloff at 3.6MHz. Hence, a significant channelization
effect is obtained.
In the wideband setting (3dB cut off at 5MHz), the
attenuation at 30MHz is still 30dB, helping to pass the
FCC spurious emissions at 960MHz.
PIN RLPF
100Ω
1.2V
The RLPF pin sets the bandwidth of the modulation filter. The default filter bandwidth, obtained with a 68kΩ
resistor, is for 1.2Mchips/s. The bandwidth is increased
to accommodate 5Mchips/s by decreasing the resistor
value to about 26kΩ. The minimum value for the resistor
is 12kΩ, which generates the maximum filter bandwidth. A higher value can be used in FM mode to set
up a slow ramp-up time for the PA.
INTERNAL
CIRCUITS
EXTERNAL
RESISTOR
Figure 3. PIN RLPF Equivalent Circuit
______________________________________________________________________________________
11
MAX2900–MAX2904
used on the EV kit board for +23dBm output power at
4.5V, and 22kΩ is also recommended for +20dBm output power at +3.0V. For +17dBm at 3.0V, 36kΩ is recommended. The current consumption, efficiency, and
distortion in the amplification chain are affected by the
choice of the resistor RPWRSET, offering a lot of design
flexibility.
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Table 1. MAX2900 Power-Up Modes
LOGIC LEVEL
INTERNAL BLOCK STATUS
REFEN
EN
OOKIN
REFERENCE
VCO MOD FILTER
SYNTHESIZER
PA
0
0
X
Off
Off
Off
Off
1
0
X
On
Off
Off
Off
1
1
0
On
On
On
Off
1
1
1
On
On
On
On only after LD
goes high
Table 2. MAX2901/MAX2903 Power-Up Modes
REFEN
EN
OOKIN
REFERENCE
VCO MOD FILTER
SYNTHESIZER
PA
0
0
X
Off
Off
Off
Off
1
0
X
On
Off
Off
Off
1
1
0
On
On
On
Off
1
1
1
On
On
On
On only after LD
goes high
Table 3. MAX2902/MAX2904 Power-Up Modes
REFEN
EN
OOKIN
REFERENCE
VCO MOD FILTER
PA
0
0
X
Off
Off
Off
1
0
0
On
Off
Off
0
1
0
Off
On
Off
1
1
0
On
On
Off
0
1
1
Off
On
On
1
1
1
On
On
On
Table 4. MAX2900 Synthesizer
Programming
12
Table 5. MAX2901/MAX2903 Synthesizer
Programming
D0
D1
D2
DIVISION RATIO
DIV 63
DIVISION RATIO
0
1
1
249
0
62
0
1
0
250
1
63
0
0
1
251
0
0
0
252
1
1
1
253
1
1
0
254
1
0
1
255
1
0
0
256
______________________________________________________________________________________
C2
WBFM
(OPT)
C3
R4
R3
R5
C13
C35
OOK
MODIN (PN)
C4
C1
R1
REFEN
EN
RLPF
VCC1
VREG
GND
VTUNE
7
6
5
4
3
2
1
MODIN
8
28
CPOUT
C28
9
C8
VCC2
10
÷4
REFOUT
VASK
VCC4
24
R7
R8
ASK
(OPT)
VREG
LD
12
8-CHANNEL
SYNTHESIZER
R6
11
25
C26
13
23
REFIN
C18
D1
D0
15
16
17
GND
RF-
RF+
18 N.C.
19 N.C.
20
21
VCC_DRV
VCC3
OSC
14
22
C24
C23
MAX2900 TYPICAL OPERATING CIRCUIT
OOKIN
26
D2
MAX2900
GATE
REG
CP
VCC5
27
REFOUT
L2
L1
D1
D0
C12
C32
C31
Y1 (OPT)
VCC_PA
C16
L4
L3
C15
C34
C33
EXT REFERENCE (OPT)
L5
LOOP
ANTENNA
Typical Operating Circuits
______________________________________________________________________________________
13
MAX2900–MAX2904
PWRSET
C25
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
C2
WBFM
(OPT)
C3
R4
R3
C1
C13
C35
OOK
MODIN (PN)
R5
C4
R1
REFEN
EN
RLPF
VCC1
VREG
GND
VTUNE
7
6
5
4
3
2
1
______________________________________________________________________________________
9
OOKIN
26
DIV63
C8
VCC2
10
MAX2901/
MAX2903
GATE
REG
CP
VCC5
27
R7
R6
11
VASK
C26
24
VCC4
LD
R8
ASK
(OPT)
VREG
12
DUALCHANNEL
(/62 OR /63)
SYNTHESIZER
25
REFOUT
13
23
C18
14
22
15
16
17
18
19
20
21
VCC_DRV
VCC3
OSC
C24
C23
GND
RF-
RF+
GND
L2
DIVOUT
VCO-
VCO+
MAX2901/MAX2903 TYPICAL OPERATING CIRCUIT
MODIN
8
28
CPOUT
C28
REFOUT
REFIN
14
PWRSET
L1
C12
C32
C31
R11
Y1
C25
VCC_PA
C16
L4
L3
C15
VCOOUT
C37
R10
VCC
EXT REFERENCE
/FM INPUT
C34
C33
L5
LOOP
ANTENNA
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Typical Operating Circuits (continued)
C2
C3
R4
R3
R5
C13
C35
OOK
MODIN (PN)
C4
C1
R1
REFEN
EN
RLPF
VCC1
VREG
GND
VTUNE
7
6
5
4
3
2
1
OOKIN
9
GATE
REG
27
C8
VCC2
10
26
VCC5 N.C.
VASK
R7
R6
11
25
REFOUT
C26
R8
ASK
(OPT)
VREG
D.C.
12
MAX2902/
MAX2904
24
13
23
C18
14
22
R11
VCO-
VCO+
15
16
17
GND
RF-
RF+
18 D.C.
19 N.C.
20
21
VCC_DRV
VCC3
VCC4 REFIN OSC
L2
MAX2902/MAX2904 TYPICAL OPERATING CIRCUIT
MODIN
8
28
D.C.
C28
L1
C12
C32
C31
VCOOUT
C37
R10
VCC
L4
L3
C15
VCC_PA
C16
RFIN
1GHz
FREQUENCY
SYNTH
C34
C33
REFFREQ
/FM
L5
LOOP
ANTENNA
Typical Operating Circuits (continued)
______________________________________________________________________________________
15
MAX2900–MAX2904
WBFM
(OPT)
PWRSET
CPOUT REFIN
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Functional Diagrams/
Pin Configurations (continued)
Chip Information
TRANSISTOR COUNT: 898
D.C.
VCC5
N.C.
28
27
26
REFOUT VCC4
25
REFIN
OSC
23
22
24
VTUNE
1
21 VCO+
GND
2
20 VCO-
VREG
3
19 N.C.
VCC1
4
RLPF
5
17 RF+
EN
6
16 RF-
REFEN
7
REG
GATE
8
9
MODIN OOKIN
16
18 D.C.
MAX2902/
MAX2904
15 GND
10
11
12
VCC2
VASK
D.C.
13
14
PWRSET VCC3
______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
32L QFN.EPS
______________________________________________________________________________________
17
MAX2900–MAX2904
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
MAX2900–MAX2904
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
18
______________________________________________________________________________________
200mW Single-Chip Transmitter ICs for
868MHz/915MHz ISM Bands
Revision History
REVISION
NUMBER
REVISION
DATE
1
8/03
—
—
2
12/07
Separate VCO Tuning Gain specification into two rows
4
DESCRIPTION
PAGES
CHANGED
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 19
© 2007 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.