Functional Description

LP1072 Advance Information, Rev. 0.3

Freescale Semiconductor

7

PRELIMINARY

3.4

Analog Front End (AFE)

The Analog Front End (AFE) block consists of three Analog-to-Digital Converters (ADCs) and two

Digital-to-Analog Converters (DACs) as given in Table 2.

3.4.1

I/Q ADC

I/Q ADC specifications are shown in Table 3.

Table 2. AFE Components

Component

Description

Resolution

Clock

I/Q ADC

A 2-channel ADC whose digital output serves as input to digital baseband

and whose input is the differential signal from the RF (RX mode).

8-bit

22 Msps

I/Q DAC

A 2-channel DAC whose digital input is from baseband and output is a

differential signal for the RF (TX mode).

8-bit

44 Msps

RSSI ADC

A single ended, single channel ADC

6-bit

10 Msps

Auxiliary ADC

A single ended, single channel ADC

8-bit

1 Msps

Auxiliary DAC

A single ended, single channel DAC

8-bit

20 Msps

Table 3. I/Q ADC Specifications

Parameter

Condition

Min

Typ

Max

Units

Resolution

—

—

8

—

bit

Maximum Sampling Frequency

—

22

—

—

MHz

Signal Bandwidth

—

—

11

—

MHz

Input impedance

Fixed capacitance

—

1—

pF

Switched capacitance @Fs

—

1—

pF

Latency

—

—

4—

cycles

Integral Nonlinearity (INL)

—

—

±1.0

—

LSB

Differential Nonlinearity (DNL)

—

—

± 0.5

—

LSB

Total Harmonic Distortion (THD)

Fin= 1MHz

—

-48.5

—

dB

Fin= 10MHz

—

-47

—

dB

SNR

Fin= 1MHz

—

48.5

—

dB

Fin= 10MHz

—

47

—

dB

ENOB

Fin= 1MHz

—

7.2

—

bit

Fin= 10MHz

—

7.0

—

bit

Channel-to-Channel mismatch

Gain

—

0.2

—

dB

Phase

—

0.5

—

Degree

DC offset after calibration

—

-1

—

+1

LSB