RF210(A/B)

Image-Reject Downconverter

2

Conexant

100775A

October 20, 1999

Proprietary Information and Specifications are Subject to Change

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

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.

Table 1. RF210(A/B) Signal Description

Pin #

Name

Description

Pin #

Name

Description

1

NC

No connect

11

ADJMIX

Mixer bias adjust pin

2

LNA900GND

900 MHz LNA ground

12

LOGND

LO input ground

3

BIASGND

Bias ground

13

LOIN

LO input

4

LNA900IN

900 MHz LNA input

14

BANDSEL

Band selection pin

5

BIASVCC

Bias supply

15

BYP1800

Bypass capacitor for 1800 MHz band

6

LNAVCC

LNA supply

16

IFOUT–

Mixer output (negative)

7

GAINSEL

LNA gain select

17

IFOUT+

Mixer output (positive)

8

LNA1800IN

1800 MHz LNA input

18

BYP900

Bypass capacitor for 900 MHz band

9

LNA1800GND

1800 MHz LNA ground

19

MIXGND

Mixer ground

10

ENA

Device enable (active high)

20

MIXVCC

Mixer supply

Table 2. Absolute Maximum Ratings

Parameter

Minimum

Maximum

Units

Storage Temperature

–40

+125

°C

LNA Input Power

+5

dBm

Supply Voltage (VCC)

–0.3

+6

V

Input Voltage Range

–0.3

Vcc

V