19-3764; Rev 0; 8/05
10-Bit, 11Msps, Ultra-Low-Power
Analog Front-End
General Description
Features
♦ Dual 10-Bit, 11Msps Rx ADC and Dual 10-Bit,
The MAX19708 is an ultra-low-power, mixed-signal ana-
log front-end (AFE) designed for TD-SCDMA handsets
and data cards. Optimized for high dynamic perfor-
mance at ultra-low power, the device integrates a dual
10-bit, 11Msps receive (Rx) ADC; dual 10-bit, 11Msps
transmit (Tx) DAC with TD-SCDMA baseband filters;
three fast-settling 12-bit aux-DAC channels for ancillary
RF front-end control; and a 10-bit, 333ksps housekeep-
ing aux-ADC. The typical operating power in Tx-Rx
FAST mode is 36.9mW at a 5.12MHz clock frequency.
11Msps Tx DAC
♦ Ultra-Low Power
36.9mW at fCLK = 5.12MHz, Fast Mode
19.8mW at fCLK = 5.12MHz, Slow Mode
Low-Current Standby and Shutdown Modes
♦ Integrated TD-SCDMA Filters with > 55dB
Stopband Rejection
♦ Programmable Tx DAC Common-Mode DC Level
and I/Q Offset Trim
The Rx ADCs feature 55dB SNR and 77.4dBc SFDR at a
1.87MHz input frequency with an 11MHz clock frequen-
cy. The analog I/Q input amplifiers are fully differential
♦ Excellent Dynamic Performance
SNR = 55dB at fIN = 1.87MHz (Rx ADC)
SFDR = 73dBc at fOUT = 620kHz (Tx DAC)
and accept 1.024V
full-scale signals. Typical I/Q
P-P
♦ Three 12-Bit, 1µs Aux-DACs
channel matching is 0.08° phase and 0.02dB gain.
♦ 10-Bit, 333ksps Aux-ADC with 4:1 Input Mux and
The Tx DACs with TD-SCDMA lowpass filters feature -3dB
cutoff frequency of 1.32MHz and > 55dB stopband rejec-
Data Averaging
♦ Excellent Gain/Phase Match
0.08ꢀ Phase, 0.02dB Gain (Rx ADC) at
fIN = 1.87MHz
tion at f
= 4.32MHz. The analog I-Q full-scale output
IMAGE
voltage range is selectable at 410mV or 500mV differ-
ential. The output DC common-mode voltage is selec-
table from 0.9V to 1.4V. The I/Q channel offset is
adjustable to optimize radio lineup sideband/carrier sup-
pression. Typical I-Q channel matching is 0.02dB gain
and 0.04° phase.
♦ Multiplexed Parallel Digital I/O
♦ Serial-Interface Control
♦ Versatile Power-Control Circuits
Shutdown, Standby, Idle, Tx/Rx Disable
The Rx ADC and Tx DAC share a single, 10-bit parallel,
high-speed digital bus allowing half-duplex operation
for time-division duplex (TDD) applications. A 3-wire
serial interface controls power-management modes, the
aux-DAC channels, and the aux-ADC channels.
♦ Miniature 48-Pin Thin QFN Package
(7mm x 7mm x 0.8mm)
Pin Configuration
The MAX19708 operates on a single +2.7V to +3.3V
analog supply and +1.8V to +3.3V digital I/O supply.
The MAX19708 is specified for the extended (-40°C to
+85°C) temperature range and is available in a 48-pin,
thin QFN package. The Selector Guide at the end of the
data sheet lists other pin-compatible versions in this
AFE family.
TOP VIEW
36 35 34 33
31 30 29 28 27 26 25
32
24
23
22
21
20
19
18
17
16
15
14
13
DAC2 37
DAC1 38
D9
D8
D7
D6
OV
V
DD
39
IDN 40
IDP 41
Applications
DD
GND
42
43
OGND
D5
TD-SCDMA Handsets
V
DD
MAX19708
D4
QDN 44
QDP 45
REFIN 46
TD-SCDMA Data Cards
D3
Portable Communication Equipment
EXPOSED PADDLE (GND)
D2
COM
47
D1
D0
Ordering Information
REFN 48
1
2
3
4
6
7
8
9
10 11 12
5
PART*
PIN-PACKAGE
48 Thin QFN-EP**
48 Thin QFN-EP**
PKG CODE
T4877-4
MAX19708ETM
MAX19708ETM+
T4877-4
THIN QFN
*All devices are specified over the -40°C to +85°C operating range.
**EP = Exposed paddle.
+Denotes lead-free package.
Functional Diagram and Selector Guide appear at end of
data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.