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RF210A

Dual-Band, Image-Reject Downconverters For GSM Applications

Conexant Systems 

RF210(A/B)

Technical Description

The RF210(A/B) dual-band, image-reject downconverters

implement the front-end functions of a dual-band super-

heterodyne receiver. These devices consist of two receive

paths, one for GSM900 and the other for DCS1800 (or

PCS1900). Each receive path contains an LNA and an image-

reject mixer. The IF and LO ports are common to both receive

paths. The image-reject mixers can provide 30 dB of image

rejection for both the GSM900 and the DCS1800 (or PCS1900)

bands without using any post-LNA image reject filters.

The LNA/mixer combination has a switchable gain. The RF210A

and RF210B both have 22 dB of gain in the high gain mode. For

the RF210A, the gain is reduced by 10 dB (GSM band) and by

8 dB (DCS/PCS band) in the low gain mode. For the RF210B,

the gain is reduced by 20 dB (GSM band) and by 16 dB

(DCS/PCS band) in the low gain mode. The gain mode is

selected using the GAINSEL pin (Pin 7). Low gain mode is

selected by driving the GAINSEL signal high; high gain mode is

selected by driving the signal low. In addition, small adjustments

Image-Reject Downconverter

of the mixer gain can be accomplished by varying the quiescent

current on the ADJMIX pin (Pin 11). This pin can be connected

to VCC or ground through resistors. The current will increase if

the pin is connected to GND and decrease if connected to VCC.

For optimal performance, this pin should be left unconnected.

The band of operation for RF210(A/B) is selected by the

BANDSEL signal on Pin 14. It switches the receive path

between GSM900 and DCS1800 (or PCS1900) bands.

The device can operate from a three-cell battery pack (2.7 V to

5.0 V). Standby mode current is extremely low at 20 µA, which

maximizes handset standby time.

The signal pin assignments and functional pin descriptions are

found in Table 1. The absolute maximum ratings of the

RF210(A/B) are provided in Table 2, the operating conditions

are specified in Table 3, and electrical specifications are

provided in Table 4. Figure 3 shows the diagram for a typical

application circuit using the RF210(A/B) downconverter. Figure

4 provides the package dimensions for the 20-pin TSSOP

device and Figure 5 provides the tape and reel dimensions.

Pin #

1

2

3

4

5

6

7

8

9

10

Name

NC

LNA900GND

BIASGND

LNA900IN

BIASVCC

LNAVCC

GAINSEL

LNA1800IN

LNA1800GND

ENA

Table 1. RF210(A/B) Signal Description

Description

No connect

900 MHz LNA ground

Bias ground

900 MHz LNA input

Bias supply

LNA supply

LNA gain select

1800 MHz LNA input

1800 MHz LNA ground

Device enable (active high)

Pin #

11

12

13

14

15

16

17

18

19

20

Name

ADJMIX

LOGND

LOIN

BANDSEL

BYP1800

IFOUT–

IFOUT+

BYP900

MIXGND

MIXVCC

Description

Mixer bias adjust pin

LO input ground

LO input

Band selection pin

Bypass capacitor for 1800 MHz band

Mixer output (negative)

Mixer output (positive)

Bypass capacitor for 900 MHz band

Mixer ground

Mixer supply

Parameter

Storage Temperature

LNA Input Power

Supply Voltage (VCC)

Input Voltage Range

Table 2. Absolute Maximum Ratings

Minimum

–40

–0.3

–0.3

Maximum

+125

+5

+6

Vcc

Units

°C

dBm

V

V

2

October 20, 1999

Conexant

Proprietary Information and Specifications are Subject to Change

100775A

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