MAX2059 查看數據表（PDF） - Maxim Integrated

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MAX2059

1700MHz to 2200MHz High-Linearity, SPI-Controlled DVGA with Integrated Loopback Mixer

Maxim Integrated 

1700MHz to 2200MHz High-Linearity,

SPI-Controlled DVGA with Integrated Loopback Mixer

Detailed Description

The MAX2059 high-linearity DVGA consists of two 5-bit

digital attenuators, a fixed-gain two-stage driver amplifi-

er, a loopback mixer, and a serial interface to control

the attenuators. This high level of component integra-

tion makes the MAX2059 ideal for base-station trans-

mitter applications. The MAX2059 is designed to

operate in the 1700MHz to 2200MHz frequency range.

The overall cascaded performance of the MAX2059

produces a typical 10.9dB gain, a +31.8dBm OIP3, an

18.4dBm OP1dB, and a total 56dB gain-control range.

5-Bit Attenuators

The MAX2059 integrates two 5-bit digital attenuators to

achieve a high dynamic range. Each attenuator is pro-

grammed with a 3-wire SPI interface, with a total effec-

tive range of 28dB and step size of 1dB. See the

Applications Information section and Table 1 for attenu-

ator programming details. The attenuators can be used

for both static and dynamic power control.

Table 1. Attenuator Programming

ATTENUATOR A (5 MSBs)

Bit 9 = 16dB step

Bit 8 = 8dB step

Bit 7 = 4dB step

Bit 6 = 2dB step

Bit 5 = 1dB step

ATTENUATOR B (5 LSBs)

Bit 4 = 16dB step

Bit 3 = 8dB step

Bit 2 = 4dB step

Bit 1 = 2dB step

Bit 0 = 1dB step

Note: Due to finite circuit isolation, the total effective range of

each attenuator is limited to 28dB.

DATA MSB BIT 9 BIT 8

BIT 1 BIT 0

LSB

CLOCK

CS

tCS

tCH

tEWN

NOTES:

DATA ENTERED ON CLOCK RISING EDGE.

ATTENUATOR STATE CHANGE ON CS RISING EDGE.

Figure 1. SPI Timing Diagram

tCW

tES

tEW

Driver Amplifier

The MAX2059 includes a two-stage medium power

amplifier with a fixed 18.5dB gain. The driver amplifier

circuit is optimized for high linearity and medium output

power capability for the 1800MHz to 2000MHz frequen-

cy range. The driver amplifier is intended to amplify a

modulated signal and drive a high-power amplifier in

base-station transmitters. In a typical application, the

driver amplifier is cascaded in between the two digital

attenuators. See the Typical Application Circuit.

The two-stage amplifier stage can be disabled for

applications where only the digital attenuators and/or

loopback mixer are used. To disable the two-stage

amplifier, ground or leave unconnected the amplifier

supplies VCCBIAS2, VCCAMP, VCCBIAS1, and also

the inputs for setting the amplifier bias currents RSET1,

RSET2. This reduces the supply current by approxi-

mately 187mA under typical conditions.

Loopback Mixer

The MAX2059 loopback mixer uses a double-balanced

active architecture designed to operate with a

1700MHz to 2200MHz RF frequency range, and a

40MHz to 100MHz LO frequency range. The RF port of

the mixer is connected internally (with an on-chip

switch) to the input of the first attenuator stage. The

mixer’s IF port is matched for a single-ended 50Ω

impedance, while the LO port requires a differential

input impedance of 100Ω.

The loopback mixer facilitates a self-diagnostic mode

for cellular transceivers, whereby the Tx band signal at

the input of the mixer can be translated up or down to

the corresponding Rx band. This translated signal can

then be fed back to the radio’s receiver for complete

Tx/Rx loop diagnostics. The loopback mixer is enabled

and disabled with LB_EN. Set LB_EN to a logic-low 0 to

enable the mixer, set LB_EN to a logic-high 1 to disable

the mixer.

The MAX2059 loopback mixer accepts a nominal -6dBm

LO input power and exhibits a -12.6dBm output power

and an output IP3 of 6.2dBm (PIN = +5dBm).

Applications Information

SPI Interface and Attenuator Settings

The two 5-bit attenuators are programmed with the 3-

wire SPI/MICROWIRE-compatible serial interface using

10-bit words. Bit 9 of the 10-bit data is shifted in first,

along with all remaining data bits, on the rising edge of

the clock regardless of CS being high or low. Once all

the data bits are shifted in, all will be sent to the attenua-

tors on the rising edge of CS, thus changing the attenua-

tion state. For standard SPI operation, pull CS low for the

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