MAXIM MAX2370 Technical data

General Description

The MAX2370 integrated quadrature transmitter is
designed for 450MHz applications. The device takes a
differential I/Q baseband input and converts it up to
intermediate frequency (IF) through a quadrature modu­lator and IF variable-gain amplifier (VGA). The signal is
then routed to an external IF filter and upconverted to RF
through an image-reject mixer and RF VGA. The signal
is further amplified with an on-chip power amplifier (PA)
driver. An IF synthesizer, an RF synthesizer, a local
oscillator buffer, and an SPI™/QSPI™/MICROWIRE™­compatible, 3-wire programmable bus complete the
basic functional blocks of this IC.

The MAX2370 is available in a 48-pin TQFN package
with exposed paddle and is specified for the extended
temperature range (-40°C to +85°C).

Applications

450MHz CDMA/WCDMA Phones

OFDM, cdma2000®, WCDMA, NMT

Wireless Data Links

Features

♦ 450MHz Operating Frequency

♦ +8dBm Output Power

-64dBc Typical ACPR at ±885kHz Offset

-66dBc Typical ACPR at ±1.125MHz Offset

♦ 100dB Power-Control Range

♦ Dual Synthesizer for RF and IF Local Oscillators

♦ SPI/QSPI/MICROWIRE-Compatible 3-Wire

Interface Bus

♦ Single-Sideband Upconverter

♦ Directly Drives External Power Amplifier

MAX2370

Complete 450MHz Quadrature Transmitter

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-0222; Rev 0; 5/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX2370ETM

(7mm x 7mm)

T4877-3

MAX2370ETM+

(7mm x 7mm)

T4877+3

SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
cdma2000 is a registered trademark of Telecommunications
Industry Association.

*EP = Exposed paddle.
+Denotes lead-free package.

REF
N.C.

N.C.
N.C.

IFLO

V

CC

I+

I-

TANK+
TANK-

N.C.

LOCK

V

CCDRV

V

CC

IFIN+

IFIN-

RBIAS

N.C.

N.C.

N.C.

RFOUT

1

2

3

4

5

6

7

8

9

10

11

12

36

35

34

33

32

31

30

29

28

27

26

25

N.C.

IFOUT-

IFOUT+

V

CC

Q-

Q+

V

CC

N.C.

DI

CLK

N.C.

GND

GNDLON.C.

RFPLL

V

CCRFCP

RFCP

VCCV

CCIFCP

IFCP

GND

GC

4847464544434241403938

37

1314151617181920212223

24

CS

SHDN

IDLE

TXGATE

TOP VIEW

MAX2370

+45 -45

90°

0°

IF PLLRF PLL

Σ

Σ

SPI

INTERFACE

EP

/2

90°

0°

Pin Configuration/

Functional Diagram

-40°C to +85°C

-40°C to +85°C

48 Thin QFN-EP*

48 Thin QFN-EP*

MAX2370

Complete 450MHz Quadrature Transmitter

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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.

VCC, RFOUT, V

CCIFCP

, V

CCRFCP

,

V

CCDRV

to GND.................................................-0.3V to +3.6V

DI, SCLK,

CS, GC, SHDN, TXGATE, IDLE,

LOCK to GND.........................................-0.3V to (V

CC

+ 0.3V)

AC Input Pins (IFIN_, Q_, I_, TANK_, REF,

RFPLL, LO) to GND.....................................................1V Peak

Digital Input Current (SHDN, TXGATE, IDLE,

SCLK, DI, CS) ...............................................................±10mA

Continuous Power Dissipation (T

A

= +70°C)

48-Pin Thin QFN (derate 38.5mW/°C above +70°C).....3077mW

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

DC ELECTRICAL CHARACTERISTICS

(VCC= +2.7V to +3.3V, SHDN = IDLE = TXGATE = high, VGC= 2.5V, R

BIAS

= 10kΩ, registers set according to Table 1, f

REF

=

19.2MHz, no AC signals applied, T

A

= -40°C to +85°C. Typical values are at VCC= +3.0V, TA= +25°C, unless otherwise noted.)

(Note 1)

PARAMETER CONDITIONS

UNITS

Supply Voltage Range V

CC

2.7 3.3 V

VGC = 0.6V 53 79

VGC = 1.95V 57 87

P

RFOUT

= +5.5dBm, IFG[2:0] = 011 118

P

RFOUT

= +8dBm, IFG[2:0] = 011 134

Addition for IFLO buffer 3.4 7.7
IDLE = low 6 10

Operating Supply Current

TXGATE = low 5 7

mA

Sleep-Mode Supply Current SHDN = 0V 0.5 20 µA

Logic-High Voltage

V

Logic-Low Voltage

V

Logic Input Current -5 +5 µA

GC Input Current VGC = 0.5V to 2.5V 3.3 5 µA
GC Input Current During Shutdown SHDN = low, VGC = 2.5V 7 11 µA

Lock Indicator High Voltage (Locked) 47kΩ pullup load

V

CC

­V

Lock Indicator Low Voltage (Unlocked)

47kΩ pullup load 0.5 V

CAUTION! ESD SENSITIVE DEVICE

MIN TYP MAX

0.7 x V

CC

0.3 x V

0.4V

CC

MAX2370

Complete 450MHz Quadrature Transmitter

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS

(MAX2370 EV kit, VCC= +2.7V to +3.3V, SHDN = IDLE = TXGATE = high, VGC= 2.5V, R

BIAS

= 10kΩ, 50Ω system, TA= -40°C to

+85°C. Typical values are at V

CC_

= SHDN = IDLE = TXGATE = CS = 3.0V, f

REF

= 19.2MHz, LO input power = -15dBm, fLO= 575MHz,

f

RFOUT

= 455MHz, fIF= 120MHz, registers set according to Table 1, input voltage at I and Q = 130mV

RMS

differential,

cascade specifications assume 400Ω IF filter with 5dB insertion loss, T

A

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER CONDITIONS

MIN

TYP

MAX

UNITS

MODULATOR

IF Frequency Range

Typically meets 30dB sideband suppression over this
frequency range

95 to 195

MHz

I/Q Common-Mode Input Voltage

(Notes 2, 3)

VCC -

V

I/Q Input Current VCM = 1.4V 6 µA

+25°C < TA < +85°C7087

Gain-Control Range

TA = -40°C85

dB

Gain Variation Over Temperature

Relative to +25°C, TA = -40°C to +85°C -2.4, +3.4 dB

Carrier Suppression VGC = 2.5V 30 40 dB

Sideband Suppression VGC = 2.5V 30 40 dB

IF Output Noise at Rx Band

V

GC

set to give -12dBm IF output power, noise

measured at 10MHz offset (Note 4)

dBm/Hz

f

OFFSET

= ±885kHz in 30kHz BW -66

-69

f

OFFSET

= ±1.98MHz in 30kHz BW -84

IF Adjacent Channel Power Ratio
IS-95 Reverse Modulation

V

GC

set to give

-12dBm IF output
power, IFG[2:0] =
011

f

OFFSET

= ±4MHz in 30kHz BW -89

dBc

UPCONVERTER AND PREDRIVER

RFOUT Frequency Range

See the Typical Operating Characteristics for typical gain
vs. frequency

410 to 500

MHz

LO Frequency Range

530 to 695

MHz

LO and RFPLL Input Power -15 -7 0

dBm

Conversion Gain 23 dB

MPL Gain Change MPL = 0, gain relative to MPL = 1

dB

+25°C < TA < +85°C3044

RF Gain-Control Range

TA = -40°C46

dB

RF Image Suppression At maximum output power -20 dBc

Rx Band Noise Power

P

RFOUT

= +8dBm, noise measured at +10MHz offset

(Note 4)

dBm/Hz

CASCADED MODULATOR, UPCONVERTER, AND PREDRIVER

RFOUT Output Power Meets ACPR specifications (Note 4) 5.5 10

dBm

f

OFFSET

= ±885kHz in 30kHz BW -64 -57

-66 -61

f

OFFSET

= ±1.98MHz in 30kHz BW -82 -78

P

OU T

= + 8d Bm ,

IFG[2:0] = 011

f

OFFSET

= ±4MHz in 30kHz BW -86 -78

f

OFFSET

= ±885kHz in 30kHz BW -64 -58

-67 -62

f

OFFSET

= ±1.98MHz in 30kHz BW -81 -78

Ad j acent C hannel P ow er Rati o

IS - 95 Rever se M od ul ati on ( N ote 4)

P

OUT

= +5.5dBm,

IFG[2:0] = 011

f

OFFSET

= ±4MHz in 30kHz BW -86 -85

dBc

VGC = 0.5V to 2.5V

f

= ±1.125MHz in 30kHz BW

OFFSET

Typically meets 30dB image suppression over this range

VGC = 0.5V to 2.5V

f

= ±1.125MHz in 30kHz BW

OFFSET

f

= ±1.125MHz in 30kHz BW

OFFSET

1.35

-138 -135

-3.4

-130 -128.5

1.25

MAX2370

Complete 450MHz Quadrature Transmitter

4 _______________________________________________________________________________________

Note 1: Guaranteed by production test at TA= +25°C to +85°C, design and characterization at TA= -40°C.
Note 2: ACPR is met over the specified V

CM

range.

Note 3: V

CM

must be supplied by the I/Q baseband source with ±8µA current capability.

Note 4: Guaranteed by design and characterization to 6σ.
Note 5: When enabled with RCP_TURBO1 and RCP_TURBO2 (see Tables 3 and 4), the total charge-pump current is specified.

For all values of RCP, the total turbolock current is 1.63 times the corresponding nonturbo current value.

AC ELECTRICAL CHARACTERISTICS (continued)

(MAX2370 EV kit, VCC= +2.7V to +3.3V, SHDN = IDLE = TXGATE = high, VGC= 2.5V, R

BIAS

= 10kΩ, 50Ω system, TA= -40°C to

+85°C. Typical values are at V

CC_

= SHDN = IDLE = TXGATE = CS = 3.0V, f

REF

= 19.2MHz, LO input power = -15dBm, fLO= 575MHz,

f

RFOUT

= 455MHz, fIF= 120MHz, registers set according to Table 1, input voltage at I and Q = 130mV

RMS

differential,

cascade specifications assume 400Ω IF filter with 5dB insertion loss, T

A

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER CONDITIONS

UNITS

Output Power Variation Over
Temperature

Relative to +25°C, T

A

= -40°C to +85°C

dB

IF PLL

Reference Frequency 530

MHz

Refer ence Fr eq uency S i g nal Level 0.1 0.6

V

P-P

IF Main-Divide Ratio 256

IF Reference-Divide Ratio 2

VCO Operating Range 190 to 390

MHz

ICP = 00 96 139 174

ICP = 01 135 192 240

ICP = 10 190 278 348

Charge-Pump Source/Sink
Current

ICP = 11 267 390 488

µA

Turbolock Boost Current ICP = 11, ICP_MAX = 1 533 774 968 µA

Charge-Pump Source/Sink
Current Matching

All values of ICP, over compliance range 6 %

IF Charge-Pump Compliance 0.5

V

C C I FC P

-

0.5V

V

RF PLL

RF PLL Frequency Range RF PLL operated at 2x LO frequency

MHz

Reference Frequency 530

MHz

RF Main-Divide Ratio

RF Reference-Divide Ratio 2

RCP = 00 220 325 406

RCP = 01 441 650 813

RCP = 10 499 738 923

Charge-Pump Source/Sink
Current

RCP = 11 717

µA

Turbolock Boost Current (Note 5)

µA

Charge-Pump Source/Sink
Current Matching

All values of RCP, over compliance range 6 %

RF Charge-Pump Compliance 0.5

V

C C R FC P

-

0.5V

V

Phase-Detector Noise Floor

RCP = 11, RCP_TURBO1 = RCP_TURBO2 = 0, 50kHz
comparison frequency

dBc/Hz

MIN TYP MAX

0, -2

16,383

2047

4096 262,143

1063 1329

1152 1694 2118

-162

1300

8191

MAX2370

Complete 450MHz Quadrature Transmitter

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(MAX2370 EV kit, V

CC_

= SHDN = IDLE = TXGATE = CS = 3.0V, f

REF

= 19.2MHz, LO input power = -15dBm, fLO= 575MHz, f

RFOUT

=

455MHz, f

IF

= 120MHz, R

BIAS

= 10kΩ, VGC= 2.5V, registers set according to Table 1, input voltage at I and Q = 130mV

RMS

differential,

TA= +25°C, unless otherwise noted.)

-100

-40

-60

-80

-20

0

20

1.0 1.81.61.2 1.4 2.0 2.2 2.4 2.6 2.8 3.0

RF OUTPUT POWER AND SUPPLY CURRENT

vs. GAIN-CONTROL VOLTAGE

MAX2370 toc01

V

GC

(V)

RF OUTPUT POWER (dBm)

50

110

90

70

130

150

170

SUPPLY CURRENT (mA)

POWER

CURRENT

-90

-70

-80

-40

-50

-60

-10

-20

-30

0

2.1 2.32.2 2.4 2.5 2.6 2.7

IF OUTPUT POWER AND IF ACPR

vs. GAIN-CONTROL VOLTAGE

MAX2370 toc02

VGC (V)

IF OUTPUT POWER AND IF ACPR (dBm, dBc)

POWER

ACPR ±885kHz

ACPR ±1.125MHz

ACPR ±1.98MHz

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

2.1 2.2 2.3 2.4 2.5 2.6 2.7

RF OUTPUT POWER AND RF ACPR

vs. GAIN-CONTROL VOLTAGE

MAX2370 toc03

VGC (V)

RF OUTPUT POWER AND RF ACPR (dBm/dBc)

POWER

ACPR ±885kHz

ACPR ±1.125MHz

ACPR ±1.98MHz

0

15

10

5

20

25

30

400 440430410 420 450 460 470 480 490 500

RF GAIN, IMAGE SUPPRESSION, AND LO

SUPPRESSION vs. FREQUENCY

MAX2370 toc04

RF FREQUENCY (MHz)

RF GAIN (dB)

-60

-30

-40

-50

-20

-10

0

SUPPRESSION (dBc)

LO SUPPRESSION

IMAGE SUPPRESSION

GAIN

NORMALIZED IF OUTPUT POWER vs. IFG[2:0]

MAX2370 toc05

-16

-14

-10

-12

-4

-2

-6

-8

0

NORMALIZED IF OUTPUT POWER (dB)

0231

4

567

IFG[2:0] (DECIMAL)

0

0.2

0.1

0.4

0.3

0.6

0.5

0.7

0.9

0.8

1.0

400 420 430 440410 450 460 470 490480 500

RFOUT PORT S22

MAX2370 toc06

FREQUENCY (MHz)

S22 MAGNITUDE

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

S22 PHASE (°)

MAGNITUDE

PHASE

0

0.2

0.1

0.4

0.3

0.6

0.5

0.7

0.9

0.8

1.0

1050 1100 1150 1200 1250 1300

RFPLL PORT S11

MAX2370 toc07

FREQUENCY (MHz)

S11 MAGNITUDE

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

S11 PHASE (°)

MAGNITUDE

PHASE

0

0.2

0.1

0.4

0.3

0.6

0.5

0.7

0.9

0.8

1.0

500 540 560 580520 600 620 640 680660 700

LO PORT S11

MAX2370 toc08

FREQUENCY (MHz)

S11 MAGNITUDE

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

S11 PHASE (°)

MAGNITUDE

PHASE

-100

-110

-80

-90

-60

-70

-40

-50

-30

-10

-20

FREQUENCY

IF OUTPUT SPECTRUM

MAX2370 toc9

POWER (dBm)

CENTER: 120MHz, SPAN: 5MHz, RBW: 30kHz

P

OUT

= -12dBm

MAX2370

Complete 450MHz Quadrature Transmitter

6 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1 RFOUT

Transmitter RF Output. This open-collector output requires a pullup inductor to the supply voltage,
which can be part of the output matching network.

2, 10, 11, 16,

17, 32–35,

43, 47

N.C. No Connection. Leave these pins open-circuit. Some of these pins are internally connected.

3LOCK

Open-Drain Output Indicating LOCK Status of the IF and/or the RF PLLs. Requires an external
pullup resistor. Control using configuration register bits LD_MODE[1:0].

4V

CCDRV

Power Supply for the RF Driver Stage. Bypass to PC board ground with a capacitor placed as
close to the pin as possible. Do not share capacitor ground vias with other ground connections.

5 IDLE

Digital Input. Drive to logic-high for normal operation. Logic-low on IDLE shuts down everything
except the RF PLL. A small RC lowpass filter can be used to filter digital noise.

6V

CC

Power Supply for the Upconverter Stage. Bypass to PC board ground with a capacitor placed as
close to the pin as possible. Do not share capacitor ground vias with other ground connections.

7 TXGATE

D i g i tal Inp ut. D r i ve to logic-high for nor m al op er ati on. Logic-low on TXG ATE shuts d ow n ever ythi ng
excep t the RF P LL, IF P LL, IF V C O. A sm al l RC l ow p ass can b e used to fi l ter d i g i tal noi se.

8, 9 IFIN+, IFIN-

Differential IF Inputs to the RF Upconverter. IFIN+ and IFIN- are internally biased to typically V

CC

-

1.5V. The input impedance for this port is nominally 400Ω differential. AC-couple the output of the
differential IF filter to this port. Keep the differential lines as short as possible to minimize the
effects of stray pickup.

12 RBIAS

Bias Resistor Connection. Internally biased to typically 1.18V. An external resistor must be
connected from RBIAS to ground to set the bias current for the upconverters and PA driver
stages. The nominal resistor value is 10kΩ. This value can be altered to optimize the linearity of
the driver stage.

Typical Operating Characteristics (continued)

(MAX2370 EV kit, V

CC_

= SHDN = IDLE = TXGATE = CS = 3.0V, f

REF

= 19.2MHz, LO input power = -15dBm, fLO= 575MHz, f

RFOUT

=

455MHz, f

IF

= 120MHz, R

BIAS

= 10kΩ, VGC= 2.5V, registers set according to Table 1, input voltage at I and Q = 130mV

RMS

differential,

TA= +25°C, unless otherwise noted.)

-90

-70

-80

-50

-60

-30

-40

-20

0

-10

10

FREQUENCY

RF OUTPUT SPECTRUM

MAX2370 toc10

POWER (dBm)

P

OUT

= +8dBm

CENTER: 455MHz, SPAN: 5MHz, RBW: 30kHz

-100

-80

-90

-60

-70

-50

-40

-20

-30

-10

239.8 239.9 240.0 240.1 240.2 240.3

IF LOCAL OSCILLATOR SPECTRUM

MAX2370 toc11

FREQUENCY (MHz)

IF LO POWER (dBm)

P

REF

= -10dBm