MAXIM MAX2510 Technical data

________________General Description

The MAX2510 is a highly integrated IF transceiver for
digital wireless applications. It operates from a +2.7V to
+5.5V supply voltage and features four operating
modes for advanced system power management.
Supply current is reduced to 0.2µA in shutdown mode.

In a typical application, the receiver downconverts a
high IF/RF (up to 600MHz) to a low IF (up to 30MHz)
using a double-balanced mixer. Additional functions
included in the receiver section are an IF buffer that
can drive an off-chip filter, an on-chip limiting amplifier
offering 90dB of received-signal-strength indication
(RSSI), and a robust differential limiter output driver
designed to directly drive a CMOS input. The transmit­ter section upconverts I and Q baseband signals to an
IF in the 100MHz to 600MHz range using a quadrature
modulator. The transmit output is easily matched to
drive a SAW filter with an adjustable output from 0dBm
to -40dBm and excellent linearity.

The MAX2511 has features similar to the MAX2510, but
upconverts a low IF with an image-reject mixer. The
MAX2511 downconverter also offers image rejection
with a limiter/RSSI stage similar to that of the MAX2510.

________________________Applications

PWT1900, Wireless Handsets, and Base Stations

PACS, PHS, DECT, and Other PCS Wireless
Handsets and Base Stations

400MHz ISM Transceivers

IF Transceivers

Wireless Data Links

____________________________Features

♦ +2.7V to +5.5V Single-Supply Operation

♦ Complete Receive Path: 600MHz (max) 1st IF to

30MHz (max) 2nd IF

♦ Unique, Wide-Dynamic-Range Downconverter

Mixer Offers -8dBm IIP3, 11dB NF

♦ 90dB Dynamic-Range Limiter with High-Accuracy

RSSI Function

♦ Differential Limiter Output Directly Drives

CMOS Input

♦ 100MHz to 600MHz Transmit Quadrature

Modulator with 41dB Sideband Suppression

♦ 40dB Transmit Gain-Control Range; Up to +1dBm

Output Power

♦ Advanced Power Management (four modes)

♦ 0.2µA Shutdown Supply Current

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

________________________________________________________________ Maxim Integrated Products 1

___________________Pin Configuration

19-1296; Rev 2; 1/01

PART

MAX2510EEI -40°C to +85°C

TEMP. RANGE PIN-PACKAGE

28 QSOP

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

_______________Ordering Information

Typical Operating Circuit appears on last page.

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

TOP VIEW

LIMIN

RSSI

GND

V

GND

TXEN

RXEN

LIMOUT

LIMOUT

1

2

CZ

3

CZ

4

5

GC

LO

CC

LO

MAX2510

6

7

8

9

10

11

12

13

14

QSOP

28

27

26

25

24

23

22

21

20

19

18

17

16

15

VREF

MIXOUT

GND

RXIN

TXOUT

TXOUT

RXIN

V

CC

GND

V

CC

Q

Q

I

I

MAX2510

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +2.7V to +5.5V; 0.01µF across CZ and CZ; LO, LO open; MIXOUT tied to VREF through a 165Ω resistor; GC = 0.5V; RXIN,
RXIN open; LIMIN tied through 50Ω to VREF; LIMOUT, LIMOUT = open; RXEN, TXEN = high; bias voltage at I, I, Q, Q = 1.4V;

T

A

= -40°C to +85°C; unless otherwise noted. Typical values are at TA= +25°C.)

AC ELECTRICAL CHARACTERISTICS

(MAX2510 test fixture; VCC= +3.0V; RXEN = TXEN = low; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor;
TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω, LO AC grounded; GC open; LIMOUT, LIMOUT are AC
coupled to 250Ω load; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input

matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I, Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I,Q

= 200kHz; f

LO, LO

= 230MHz; P

LO

= -13dBm;

T

A

= +25°C; unless otherwise noted.)

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.

VCCto GND .............................................................-0.3V to 8.0V

V

CC

to Any Other VCC........................................................±0.3V

I, I, Q, Q to GND.........................................-0.3V to (V

CC

+ 0.3V)

I to I, Q to Q Differential Voltage............................................±2V

RXIN to RXIN Differential Voltage..........................................±2V

LOIN to LOIN Differential Voltage..........................................±2V

LIMIN Voltage .............................(VREF - 1.3V) to (VREF + 1.3V)

RXEN, TXEN, GC Voltage...........................-0.3V to (V

CC

+ 0.3V)

RXEN, TXEN, GC Input Current ............................................1mA

RSSI Voltage...............................................-0.3V to (V

CC

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)

QSOP (derate 10mW/°C above +70°C)........................650mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +165°C

Lead Temperature (soldering, 10sec) .............................+300°C

CONDITIONS

V2.7 3.0 5.5Operating Voltage Range

UNITSMIN TYP MAXPARAMETER

RXEN, TXEN V2.0Digital Input Voltage High

RXEN, TXEN = 2.0V µA

630

Digital Input Current High

RXEN, TXEN V0.4Digital Input Voltage Low

Receive mode, RXEN = high, TXEN = low

14 20

Standby mode, RXEN = high, TXEN = high

mA

0.5 1

RXEN, TXEN = 0.4V

Transmit mode, RXEN = low, TXEN = high

17 25

µA-5 0.1Digital Input Current Low

Shutdown mode, RXEN = low, TXEN = low µA

0.2 5

Supply Current

V

VCC/ 2 -

V

CC

/ 2

V

CC

/ 2 +

100mV 100mV

VREF Voltage

(Note 1) kΩ

50 85

GC Input Resistance

(Note 2) MHz100 600Input Frequency Range

Single sideband dB11Noise Figure

TA= +25°C

dB

20.5 22.5 25

Conversion Gain

CONDITIONS

(Note 4) dBm-18.5Input 1dB Compression Point

Two tones at 240MHz and 240.2MHz,

-30dBm per tone

dBm-8Input Third-Order Intercept

UNITSMIN TYP MAXPARAMETER

dBc49LO to RXIN Isolation

Standby to RX or TX (Note 5) µs5Power-Up Time

DOWNCONVERTER (RXEN = high)

19.9 25.5

TA= -40°C to +85°C (Note 3)

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS (continued)

(MAX2510 test fixture; VCC= +3.0V; RXEN = TXEN = low; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor;
TXOUT and TXOUT loaded with 100Ω differential; LO terminated with 50Ω, LO AC grounded; GC open; LIMOUT, LIMOUT are AC
coupled to 250Ω load; 330pF at RSSI pin; 0.1µF connected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input

matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I, Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I,Q

= 200kHz; f

LO, LO

= 230MHz; P

LO

= -13dBm;

T

A

= +25°C; unless otherwise noted.)

Note 1: This pin is internally terminated to approximately 1.35V through the specified resistance.
Note 2: Downconverter gain is typically greater than 20dB. Operation outside this frequency range is possible but has not been

characterized.

Note 3: Guaranteed by design and characterization.

LIMOUT, LIMOUT

mV±270 ±300 ±350

-85dBm to 5dBm

Limiter Output Voltage Swing

-75dBm to 5dBm degrees±4.5

dB

Phase Variation

90Minimum Monotonic RSSI Range

-75dBm to 5dBm from 50Ω mV/dB20RSSI Slope

CONDITIONS

-75dBm to 5dBm dB80Minimum Linear RSSI Range

UNITSMIN TYP MAXPARAMETER

(Note 6) dBm-86

At LIMIN input of +5dBm

RSSI Maximum Zero-Scale Intercept

TA= +25°C

dB

±0.5 ±2.0

V

RSSI Relative Error (Notes 6, 7)

1.8Maximum-Scale RSSI Voltage

At LIMIN input of -75dBm V0.25Minimum-Scale RSSI Voltage

I, I, Q, Q inputs are 250mVp-p centered around
this voltage, GC = 2.0V (Note 9)

(Note 8) MHz100 600Frequency Range

1.3

V

CC

-

1.2

I, I, Q, Q Allowable Common-Mode
Voltage Range

GC = 0.5V -41

GC = 2.0V (Note 9)

GC = open -16

-3

90° phase difference between I and Q inputs;
GC = 2V

dBc30 40Unwanted Sideband Suppression

dBm

-2.5 1

Output Power

GC = 2V (Note 11) -33

Output IM3 Level

GC = 2V (Note 11) dBc-51Output IM5 Level

GC = 0.5V (Note 11)

dBc

-49

I, Q are 500mVp-p while I, Q are held at this DC
voltage (Note 9)

1.4

V

CC

-

1.3

90° phase difference between I and Q inputs;
measured to fundamental tone; GC = 2V

dBc30 44LO Rejection

V

TA= -40°C to +85°C (Note 3) ±3.0

TA= +25°C

(Note 3) MHz70 80

I, I, Q, Q 1dB Bandwidth

LIMITING AMPLIFIER AND RSSI (RXEN = high, f

LIMIN

= 10MHz, P

LIMIN

= -30dBm from 50Ω source, unless otherwise noted)

TRANSMITTER (TXEN = high)

TA= -40°C to +85°C

MAX2510

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(MAX2510 EV kit; VCC= +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded
with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF con­nected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I,

Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I, Q

= 200kHz; f

LO, LO

= 230MHz; PLO= -13dBm; TA= +25°C; unless otherwise noted.)

0

5

15

10

20

Rx

Tx

25

-40 0-20 20406080100

SUPPLY CURRENT

vs. TEMPERATURE

MAX2510toc01

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

STANDBY

0

6

4

2

8

10

12

14

16

18

20

2.5 3.53.0 4.0 4.5 5.0 5.5

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX2510toc02

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

Rx

STANDBY

Tx

10

5

0

15

25

20

30

35

00.40.2 0.6 1.21.00.8 1.4 1.6 1.8 2.0

TRANSMITTER SUPPLY CURRENT

vs. GC VOLTAGE

MAX2510toc03

GC VOLTAGE (V)

SUPPLY CURRENT (mA)

Note 4: Driving RXIN or RXIN with a power level greater than the 1dB compression level forces the input stage out of its linear

range, causing harmonic and intermodulation distortion. The RSSI output increases monotonically with increasing input
levels beyond the mixer’s 1dB compression level. Input 1dB compression point is limited by MIXOUT voltage swing, which
is approximately 2Vp-p into a 165Ω load.

Note 5: Assuming the supply voltage has been applied, this includes limiter offset-correction settling and Rx or Tx bias stabilization

time. Guaranteed by design and characterization.

Note 6: The RSSI maximum zero-scale intercept is the maximum (over a statistical sample of parts) input power at which the RSSI

output would be 0V. This point is extrapolated from the linear portion of the RSSI Output Voltage vs. Limiter Input Power
graph in the Typical Operating Characteristics. This specification and the RSSI slope define the RSSI function’s ideal
behavior (the slope and intercept of a straight line), while the RSSI relative error specification defines the deviations from
this line. See the Typical Operating Characteristics for the RSSI Output Voltage vs. Limiter Input Power graph.

Note 7: The RSSI relative error is the deviation from the best-fitting straight line of the RSSI output voltage versus the limiter input

power. This number represents the worst-case deviation at any point along this line. A 0dB relative error is exactly on the
ideal RSSI transfer function. The limiter input power range for this test is -75dBm to 5dBm from 50Ω. See the Typical
Operating Characteristics for the RSSI Relative Error graph.

Note 8: Transmit sideband suppression is typically better than 35dB. Operation outside this frequency range is possible but has

not been characterized.

Note 9: Output IM3 level is typically better than -29dBc.
Note 10: The output power can be increased by raising GC above 2V. Refer to the Transmitter Output Power vs. GC Voltage and

Frequency graph in the Typical Operating Characteristics.

Note 11: Using two tones at 400kHz and 500kHz, 250mVp-p differential per tone at I, I, Q, Q.

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

_______________________________________________________________________________________ 5

____________________________ Typical Operating Characteristics (continued)

(MAX2510 EV kit; VCC= +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded
with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF con­nected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I,

Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I, Q

= 200kHz; f

LO, LO

= 230MHz; PLO= -13dBm; TA= +25°C; unless otherwise noted.)

SHUTDOWN SUPPLY CURRENT

vs. SUPPLY VOLTAGE

1.2

1.0

0.8

0.6

0.4

SHUTDOWN SUPPLY CURRENT (µA)

0.2

0

TA = +85°C

TA = -40°C

TA = +25°C

2.5 3.5 4.03.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)

DOWNCONVERTER MIXER CONVERSION

GAIN vs. SUPPLY VOLTAGE

AND TEMPERATURE

25

TA = -40°C

MAX2510toc04

24

23

22

GAIN (dB)

21

20

19

18

2.5 3.5 4.03.0 4.5 5.0 5.5

T

= +25°C

A

VOLTAGE (V)

TA = +85°C

MAX2510toc05

DOWNCONVERTER MIXER CONVERSION

GAIN vs. RXIN FREQUENCY

25

20

15

GAIN (dB)

10

5

0

0 400 500200 300100 600 700 800 900 1000

RF FREQUENCY (MHz)

MISMATCH LOSS
COMPENSATED

MAX2510toc06

RECEIVE MIXER INPUT 1dB

COMPRESSION POINT vs. SUPPLY VOLTAGE

-12

-13

-14

-15

-16

-17

-18

-19

INPUT 1dB COMPRESSION (dBm)

-20

-21

-22

2.5 3.53.0 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)

TA = +85°C

TA = +25°C

TA = -40°C

MAX2510toc07

RXIN INPUT IMPEDANCE

500

450

400

)

350

Ω

300

250

200

REAL IMPEDANCE (

150

100

50

0

30 150 21090 270 330 390 450 510

vs. FREQUENCY

SINGLE-ENDED

IMAGINARY

REAL

FREQENCY (MHz)

MAX2510toc08

MAX2510

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

6 _______________________________________________________________________________________

____________________________ Typical Operating Characteristics (continued)

(MAX2510 EV kit; VCC= +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded
with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF con­nected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I,

Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I, Q

= 200kHz; f

LO, LO

= 230MHz; PLO= -13dBm; TA= +25°C; unless otherwise noted.)

RSSI OUTPUT VOLTAGE vs. LIMIN INPUT

2.0

1.8

1.6

1.4

1.2

1.0

0.8

RSSI VOLTAGE (V)

0.6

0.4

0.2

0

-120 -100 -80 -60 -40 -20 0 20

POWER AND TEMPERATURE

V

= +85°C

OUT

V

= -40°C

OUT

LIMITER INPUT POWER (dBm, 50Ω)

10

0

-10

-20

-30

OUTPUT POWER (dBm)

-40

-50

-60

0.5 0.9 1.10.7 1.3 1.5 1.7 1.9

-30

V

= +25°C

OUT

TRANSMITTER OUTPUT POWER

vs. GC VOLTAGE AND FREQUENCY

230MHz

200MHz

GC VOLTAGE (V)

TRANSMITTER IM3 LEVELS

vs. GC VOLTAGE

RSSI RELATIVE ERROR vs. LIMIN INPUT

POWER AND TEMPERATURE

5

4

MAX2510toc10a

RSSI ERROR (dB)

500MHz

3

2

1

0

-1

-2

-3

-4

-5

-95 -75 -55 -35 -15 5

TA = -40°C

T

A

TA = +25°C

TA = +85°C

LIMITER INPUT POWER (dBm, 50Ω)

MAX2510toc12

= +25°C

MAX2510toc10

5

0

-5

-10

-15

OUTPUT POWER (dBm)

-20

-25
0400200 600 800 1000

TRANSMITTER OUTPUT 1dB COMPRESSION

10

RSSI OUTPUT VOLTAGE

2.0

1.8

1.6

1.4

1.2

1.0

0.8

RSSI VOLTAGE (V)

0.6

0.4

0.2

0

vs. RXIN INPUT POWER

-80 -60 -50 -40-70 -30 -20 -10 0
RXIN INPUT POWER (dBm)

TRANSMITTER OUTPUT POWER

vs. FREQUENCY

GC = 2.0V

FREQUENCY (MHz)

POINT vs. GC VOLTAGE

MAX2510toc12a

MAX2510toc11

-35

-40

-45

IM3 LEVELS (dBc)

-50

-55
0 0.8 1.00.4 0.60.2 1.2 1.4 1.6 1.8 2.0

GC VOLTAGE (V)

MAX2510toc13

0

-10

-20

-30

-40

OUTPUT 1dB COMPRESSION (dBm)

-50

-60

TA = +85°C

TA = -40°C

TA = +25°C

0 0.40.2 0.6 1.21.00.8 1.4 1.6 1.8 2.0

GC VOLTAGE (V)

MAX2510toc15

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

_______________________________________________________________________________________ 7

____________________________ Typical Operating Characteristics (continued)

(MAX2510 EV kit; VCC= +3.0V; 0.01µF across CZ and CZ; MIXOUT tied to VREF through 165Ω resistor; TXOUT and TXOUT loaded
with 100Ω differential; LO terminated with 50Ω; LO AC grounded; GC open; LIMOUT, LIMOUT open; 330pF at RSSI pin; 0.1µF con­nected from VREF pin to GND; P

RXIN, RXIN

= -30dBm differentially driven (input matched); f

RXIN, RXIN

= 240MHz; bias voltage at I, I,

Q, Q = 1.4V; V

I,Q

= 500mVp-p; f

I, Q

= 200kHz; f

LO, LO

= 230MHz; PLO= -13dBm; TA= +25°C; unless otherwise noted.)

TRANSMITTER OUTPUT POWER

1.0

0.8

0.6

0.4

OUTPUT POWER (dBm)

0.2

0

2.5 3.53.0 4.0 4.5 5.0 5.5

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

TRANSMITTER DIFFERENTIAL

OUTPUT IMPEDANCE vs. FREQUENCY

100

Tx MODE REAL

0

-100

-200

-300

-400
Tx OFF

-500
IMAGINARY

-600

-700

-800

REAL AND IMAGINARY IMPEDANCE (Ω)

-900

-1000
200 400300 500

Tx OFF REAL

Tx MODE
IMAGINARY

FREQUENCY (MHz)

TA = +25°C

TA = +85°C

TA = -40°C

vs. BASEBAND INPUT VOLTAGE

-10
GC = OPEN

-12

MAX2510toc15

-14

-16

-18

-20

-22

OUTPUT POWER (dBm)

-24

-26

-28

-30

50 100 150 200 250 300 350 400

-134
Af = 200kHz

-136

MAX2510toc18

-138

-140

-142

-144

-146

-148

OUTPUT NOISE POWER (dBm/Hz)

-150

-152

-154

0 0.4 0.6 0.80.2 1.0 1.2 1.4 1.81.6 2.0

OUTPUT POWER

BASEBAND INPUT VOLTAGE (mVp)

TRANSMIT NOISE POWER

vs. GC VOLTAGE

GC VOLTAGE (V)

TRANSMITTER SIDEBAND SUPPRESSION

50

MAX2510toc16

40

30

20

SIDEBAND SUPPRESSION (dB)

10

0

0 400200 600 800 1000

-13.0

-13.5

MAX2510toc19

-14.0

-14.5

-15.0

-15.5

-16.0

OUTPUT POWER (dBm)

-16.5

-17.0

-17.5

-18.0

-20 -16 -14 -12-18 -10 -8 -6 -2-4 0

vs. RF FREQUENCY

MAX2510toc17

RF FREQUENCY (MHz)

TRANSMITTER OUTPUT POWER

vs. LO POWER

MAX2510toc20

LO POWER (dBm)

MAX2510

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

8 _______________________________________________________________________________________

Pin Description

PIN

Offset-Correction Capacitor Pins. Connect a 0.01µF capacitor between CZ and CZ.CZ, CZ

2, 3

Limiter Input. Connect a 330Ω (typical) resistor to VREF for DC bias, as shown in the Typical Operating

Circuit.

LIMIN1

FUNCTIONNAME

Gain-Control Pin. Applying a DC voltage to GC between 0V and 2.0V adjusts the transmitter gain by
more than 40dB. GC is internally terminated to 1.35V via an 85kΩ resistor.

GC5

Received Signal-Strength Indicator Output. The voltage on RSSI is proportional to the signal power at
LIMIN. The RSSI output sources current pulses into a 330pF (typical) external capacitor. This output is
internally terminated with 11kΩ, and this RC time constant sets the decay time.

RSSI4

Local-Oscillator Input Ground. Connect to PC board ground plane with minimal inductance.GND7

Differential LO Inputs. In a typical application, externally terminate LO with 50Ω to ground, then AC cou­ple into LO. AC terminate LO directly to ground for single-ended operation, as shown in the Typical

Operating Circuit.

LO, LO

6, 9

Baseband In-Phase Inputs. The differential voltage across these inputs forms the quadrature modulator’s
I-channel input. The signal input level is typically up to 500mVp-p centered around a 1.4V (typical) DC
bias level on I.

I, I

15, 16

Differential Outputs of the Limiting Amplifier. These outputs are complementary emitter followers capable
of driving 250Ω single-ended loads to ±300mV.

LIMOUT,

LIMOUT

13, 14

Baseband Quadrature-Phase Inputs. The differential voltage across these inputs forms the quadrature
modulator’s Q-channel input. The signal input level is typically up to 500mVp-p, centered around a 1.4V
(typical) DC bias level on Q.

Q, Q

17, 18

Receiver Enable Pin. When high, RXEN enables the receiver if TXEN is low. If both RXEN and TXEN are
high, the part is in standby mode; if both are low, the part is in shutdown. See the Power Management
section for details.

RXEN12

Transmitter-Enable Pin. When high, TXEN enables the transmitter if RXEN is low. If both TXEN and
RXEN are high, the part is in standby mode; if both are low, the part is in shutdown. See the Power
Management section for details.

TXEN11

Differential Outputs of the Upconverter. In a typical application, these open-collector outputs are pulled
up to V

CC

with two external inductors and AC coupled to the load. See the Applications Information sec-

tion for more details, including information on impedance matching these outputs to a load.

TXOUT,

TXOUT

23, 24

Differential Inputs of the Downconverter Mixer. An impedance-matching network may be required in
some applications. See the Applications Information section for details.

RXIN,

RXIN

22, 25

Reference Voltage Pin. VREF provides an external bias voltage for the MIXOUT and LIMIN pins. Bypass
this pin with a 0.1µF capacitor to ground. The VREF voltage is equal to V

CC

/ 2. See the Typical

Operating Circuit for more information.

VREF28

Receiver Mixer Ground. Connect to PC board ground plane with minimal inductance.GND26

General-Purpose VCCPins. Bypass with a 0.047µF low-inductance capacitor to GND.V

CC

19, 21

Local-Oscillator Input VCCPin. Bypass directly to local-oscillator input ground (pin 8).V

CC

8

Limiter Ground. Connect to PC board ground plane with minimal inductance.GND10

Receiver/Transmitter Ground. Connect to PC board ground plane with minimal inductance.GND20

Single-Ended Output of the Downconverter Mixer. This pin is high-impedance and must be biased to the
VREF pin through an external terminating resistor whose value depends on the interstage filter character­istics. See the Applications Information section for details.

MIXOUT27

_______________Detailed Description

The following sections describe each of the blocks
shown in Figure 1.

Receiver

The receiver consists of two basic blocks: the down­converter mixer and the limiter/received-signal-strength
indicator (RSSI) section.

The receiver inputs are the RXIN and RXIN pins, which
should be AC coupled and may require a matching
network as shown in the Typical Operating Circuit. To
design a matching network for a particular application,
consult the RXIN Input Impedance plots in the Typical

Operating Characteristics, as well as the Applications
Information sections.

Downconverter Mixer

The downconverter consists of an a double-balanced
mixer and an output buffer. The MIXOUT output, a single­ended current source, can drive a shunt-terminated

330Ω filter (165Ω load) to more than 2Vp-p over the
entire supply range, providing excellent dynamic
range. The local oscillator (LO) input is buffered and
drives the mixer.

Limiter

The signal passes through an external IF bandpass fil­ter into the limiter input (LIMIN). LIMIN is a single­ended input that is biased at the VREF pin voltage. The
open-circuit input impedance is typically greater than
10kΩ to VREF. For proper operation, LIMIN must be
tied to VREF through the filter-terminating impedance
(which should be less than 1kΩ). The limiter provides a
constant output level, which is largely independent of
the limiter input signal level over a 90dB input range.
The low-impedance limiter outputs provide 600mVp-p
single-ended swing (1.2Vp-p differential swing) and
can drive CMOS inputs directly.

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

_______________________________________________________________________________________ 9

Figure 1. Functional Diagram

RXIN

RXIN

LO
LO

RXEN

TXEN

GC

TXOUT

TXOUT

POWER

MANAGEMENT

PA

TRANSMIT VGA/PA

MIXOUT

g

m

VGA

IF BPF

LIMIN

VREF

VREF = V

Σ

/ 2

CC

0°

LO PHASE

90°

SHIFTER

CZ CZ

OFFSET

CORRECTION

LIMITER

RSSI

MAX2510

LIMOUT

LIMOUT

RSSI

I

I

Q

Q

MAX2510

Received Signal-Strength Indicator

The RSSI output provides a linear indication of the
received power level on the LIMIN input. The RSSI
monotonic dynamic range exceeds 90dB while provid­ing better than 80dB linear range. The RSSI output
pulses current into a 330pF (typical) external filter
capacitor. The output is internally terminated to ground
with 11kΩ, and this R-C time constant sets the decay
time. The rise time is limited by the RSSI pin’s output
drive current. The rise time is typically less than 100ns
with no capacitor connected. Larger capacitor values
slow the rise time.

Transmitter

The I, I and Q, Q baseband signals are input to a pair
of double-balanced mixers, which are driven from a
quadrature LO source. The quadrature LO is generated
on-chip from the oscillator input present at the LO and
LO pins. The two mixers’ outputs are summed. With
quadrature baseband inputs at the I, I and Q, Q pins,
the unwanted sideband is largely canceled. The result­ing signal from the mixers is fed through a variable-gain
amplifier (VGA) with more than 40dB of gain-adjust
range.

The VGA output is connected to a driver amplifier with
an output 1dB compression point of +2dBm. The out­put power can be adjusted from approximately +2dBm
to -40dBm by controlling the GC pin. The resulting sig­nal appears as a differential output on the TXOUT and
TXOUT pins.

TXOUT and TXOUT are open-collector outputs and
need external pull-up inductors to VCCfor proper oper­ation, as well as a DC block so the load does not affect
DC biasing. A shunt resistor across TXOUT and TXOUT
(100Ω typical) can be used to back terminate an exter­nal filter, as shown in the Typical Operating Circuit.
Alternatively, a single-ended load can be connected to
TXOUT, as long as TXOUT is tied directly to VCC. Refer
to the Applications Information section for details.

Local-Oscillator Inputs

The MAX2510 requires an external LO source for the
mixers. LO and LO are high-impedance inputs (>1kΩ).
The external LO signal is buffered internally and fed to
both the receive mixer and the LO phase shifter used
for the transmit mixers.

In a typical application, externally terminate the LO
source with a 50Ω resistor and then AC couple into LO.
Typically, the LO power range should be -13dBm to

0dBm (into 50Ω). Connect a bypass capacitor from LO
to ground. Alternatively, a differential LO source (exter­nally terminated) can drive LO and LO through series
coupling capacitors.

Power Management

To provide advanced system power management, the
MAX2510 features four operating modes that are
selected via the RXEN and TXEN pins, according to
Table 1 (supply currents assume GC = 0.5V).

In shutdown mode, all part functions are off. Standby
mode allows fastest enabling of either transmit or receive
mode by keeping the VREF generator active. This avoids
delays in stabilizing the limiter input circuitry and the off­set correction loop. Transmit mode enables the LO
buffer, LO phase shifter, upconverter mixer, transmit
VGA, and transmit output driver amplifier. Receive mode
enables the LO buffer, downconverter mixer, limiting
amplifier, and RSSI functions.

__________Applications Information

RX Input Matching

The RXIN, RXIN port typically needs an impedance
matching network for proper connection to external cir­cuitry, such as a filter. See the Typical Operating Circuit
for an example circuit topology. Note that the receiver
input can be driven either single-ended or differentially.

The component values used in the matching network
depend on the desired operating frequency as well as
on filter impedance. The following table indicates the
RXIN, RXIN single-ended input impedance (that is,
the impedance looking into either RXIN or RXIN). The
information in Table 2 is also plotted in the Typical
Operating Characteristics.

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

10 ______________________________________________________________________________________

High

Low

High

TXEN

STATE

Low

0.5m

14m

17m

TYPICAL

SUPPLY

CURRENT (A)

0.2µ

Standby

Receive

Transmit

MODE

Shutdown

High

High

Low

RXEN

STATE

Low

Table 1. Power-Supply Mode Selection

Table 2. RXIN or RXIN Input Impedance

Receive IF Filter

The interstage filter, located between the MIXOUT pin
and the LIMIN pin, is typically a three-terminal, 330Ω,

10.7MHz bandpass filter. This filter prevents the limiter
from acting on any undesired signals that are present
at the mixer’s output, such as LO feedthrough, out-of­band channel leakage, and spurious mixer products.
The filter connections are also set up to feed DC bias
from VREF into LIMIN and MIXOUT through two 330Ω
filter-termination resistors. (See the Typical Operating
Circuit for more information).

Transmit Output Matching

The transmit outputs, TXOUT and TXOUT, are open­collector outputs and therefore present a high
impedance.

For differential drive, TXOUT and TXOUT are connected
to V

CC

via chokes, and each side is AC coupled to the

load. A terminating resistor between TXOUT and
TXOUT sets the output impedance. This resistor pro­vides a stable means of matching to the load.

TXOUT and TXOUT are voltage-swing limited, and
therefore cannot drive the specified maximum power
across more than 150Ω load impedance. This load
impedance typically consists of a shunt-terminating
resistor in parallel with a filter load impedance. To drive
higher output load impedances, the gain must be
reduced (via the GC pin) to avoid saturating the TX out­put stage.

For single-ended applications, connect the unused TX
output output pin directly to VCC.

400MHz ISM Applications

The MAX2510 can be used as a front-end IC in appli­cations where the RF carrier frequency is in the
400MHz ISM band. In this case, Maxim recommends
preceding the MAX2510 receiver section with a low-

noise amplifier (LNA) that can operate over the same
supply voltage range. The MAX2630–MAX2633 family
of amplifiers meets this requirement. In many applica­tions, the MAX2510’s transmit output power is sufficient
to eliminate the need for an external power amplifier.

______________________Layout Issues

A well-designed PC board is an essential part of an RF
circuit. Use the MAX2510 evaluation kit and the recom­mendations below as guides to generate your own
layout.

Power-Supply Layout

A star topology, which has a heavily decoupled central
VCCnode, is the ideal power-supply layout for minimiz­ing coupling between different sections of the chip. The
VCCtraces branch out from this node, each going to
one VCCconnection in the MAX2510 typical operating
circuit. At the end of each of these traces is a bypass
capacitor that presents low impedance at the RF fre­quency of interest. This method provides local decou­pling at each VCCpin. At high frequencies, any signal
leaking out of a supply pin sees a relatively high imped­ance (formed by the VCCtrace impedance) to the cen­tral VCCnode, and an even higher impedance to any
other supply pin, minimizing Vcc supply-pin coupling.

A single ground plane suffices. Where possible, multi­ple parallel vias aid in reducing inductance to the
ground plane.

Place the VREF decoupling capacitor (0.1µF typical) as
close to the MAX2510 as possible for best interstage fil­ter performance. For best results, use a high-quality,
low-ESR capacitor.

Matching/biasing networks around the receive and
transmit pins should be symmetric and as close to the
chip as possible. A cutout in the ground plane under
the matching network components can be used to
reduce parasitic capacitance.

Decouple pins 19 and 21 (VCC) directly to pin 20 (Rx,
Tx ground), which should be directly connected the
ground plane. Similarly, decouple pin 8 directly to pin 7.
Refer to the Pin Description table for more information.

MAX2510

Low-Voltage IF Transceiver with

Limiter/RSSI and Quadrature Modulator

______________________________________________________________________________________ 11

64 - j109

94 - j143

149 - j184

SERIES IMPEDANCE

(Ω)

275 - j203

400

300

200

FREQUENCY

(MHz)

100

53 - j87500

MAX2510

Low-Voltage IF Transceiver with
Limiter/RSSI and Quadrature Modulator

12 ______________________________________________________________________________________

Typical Operating Circuit

V

CC

FOR SINGLE-ENDED

TX OPERATION

100Ω

TX OUTPUT
(TO FILTER)

0.001µF

10pF

V

CC

0.001µF 0.001µF

220nH

MATCH

FOR SINGLE-ENDED

RX OPERATION

330pF

V

CC

100pF

V

CC

BpF, Z

23

24

25

22

26

21

19

20

27

10.7MHz

TXOUT

TXOUT

RXIN

RXIN

GND

V

CC

V

CC

GND

MIXOUT

= 330Ω

0

I

I

Q

MAX2510

LIMIN

128 2

VREF CZ

LIMOUT

LIMOUT

RXEN

TXEN

V

CC LO

GND

LOIN

LOIN

GND

RSSI

Q

LO

GC

CZ

15

16

18

17

13

14

12

11

8

7

6

9

10

5

4

3

0.01µF

47pF

V

CC

0.001µF

BASEBAND
I INPUT

BASEBAND
Q INPUT

RECEIVE IF
OUTPUT

CONTROL
LOGIC

47pF

330pF

5OΩ

0.001µF

FROM
LOCAL
OSCILLATOR

GAIN CONTROL

RSSI OUTPUT

IF

BYPASS

FILTER

330Ω

0.1µF

330Ω