Rainbow Electronics ATR0601 User Manual

Features

•

Very Low Power Design (40 mW)

•

Single IF Architecture

•

Excellent Noise Performance

•

1.5-bit ADC On Chip

•

Small QFN Package (4 mm × 4 mm, 24 pins)

•

Highly integrated, Few External Components

•

Advanced BiCMOS Technology (UHF6s)

•

Non ESD Sensitive Device

1. Description

The ATR0601 is a single IF GPS front-end IC, designed to meet the requirements of
mobile and automotive applications. Excellent RF performance combined with low
noise figure enables high quality GPS solutions and it's very low power consumption
fits perfectly to portable devices. Featuring a balanced XTO and a fully integrated bal­anced frequency synthesizer, only few external components are required. The
ATR0601 offers a complete autonomous mode, utilizing the on chip AGC in closed
loop operation, to set the gain of the IF VGA. Alternatively, in combination with the
baseband processor ATR0621 the optimum gain of the IF VGA can be computed and
set by software, using the digital SDI interface.

Figure 1-1. Block Diagram

GPS Front-end
IC

ATR0601

Preliminary

PUXTO

PURF

RF

NRF

XTO

NXTO

NX

MO

AGCO

EGC

SDI

1

A

D

A

D

SL

SH

SC

Rev. 4866A–GPS–08/05

VCC

VCC

VDIG

PMSS

Logic

X

GND

BP

NBP

VCO

XTO

PLL

BPI

NBPI

EST

2. Pin Configuration

Figure 2-1. Pinning QFN24

SDI

NRF

EGC

RF

19

12

VCC

NC

18
17
16
15
14
13

PURF
PUXTO
NBPI
BPI
NBP
BP

VDIG

AGCO

NXTO

NX

XTO

SCSHSL

24

222120

23

1
2
3
4

X

5
6

7

VCC

Paddle

GND

91011

8

MO

TEST

Table 2-1. Pin Description

Pin Symbol Type

Paddle GND S Common ground

1 VDIG S Digital supply
2 AGCO A_I/O AGC: gain control voltage output/corner frequency determination
3 NXTO A_I XTO interface (optional: TCXO input)
4 NX A_O XTO interface
5 X A_O XTO interface
6 XTO A_I XTO interface (optional: TCXO input)
7 VCC S Analog supply
8 MO A_O Testbuffer output (f

9 TEST A_I Enable testbuffer
10 NRF A_I RF input complementary
11 RF A_I RF input
12 NC – Not connected
13 BP A_O IF-Filter interface (mixer output, open collector)
14 NBP A_O IF-Filter interface (mixer output complementary, open collector)
15 BPI A_I IF-Filter interface (IF-input)
16 NBPI A_I IF-Filter interface (IF-input complementary)
17 PUXTO D_I Power-up XTO
18 PURF D_I Power-up RF
19 VCC S Analog supply
20 EGC D_I Enable external gain control (high = external; low = internal)
21 SDI D_I Input for external gain control signal (Σ∆ modulation)
22 SL D_O Data output: “low”
23 SH D_O Data output: “high”
24 SC D_O Sample clock

Note: 1. Type: A_I Analog input, A_O Analog output, D_I Digital input, D_O Digital output, S Supply

(1)

Function

)

IF

2

ATR0601 [Preliminary]

4866A–GPS–08/05

3. Functional Description

3.1 General Description

The ATR0601 GPS receiver IC has been especially designed for GPS applications in both
mobile phone and automotive applications. From this system point of view, it incorporates high­est isolation between GPS and cellular bands, as well as very low power consumption.

ATR0601 [Preliminary]

3.2 PMSS Logic

3.3 XTO

3.4 VCO/PLL

The L1 input signal (f
quency of: f

= 1575.42 MHz. The digital modulation scheme is Bi-Phase-Shift-Keying (BPSK)

RF

) is a Direct Sequence Spread Spectrum (DSSS) signal with a centre fre-

RF

with a chip rate of 1.023 Mbps. As the input signal power at the antenna is approximately
–140 dBm, the desired signal is below the thermal noise floor.

The Power Management, Startup and Shutdown Logic ensures reliable operation within the rec­ommended operating conditions. The external power control signals PUrf and PUxto are passed
thru Schmitt-trigger inputs to eliminate voltage ripple and prevent undesired behaviour during
startup and shutdown. Digital and analog supply voltages are analyzed by a monitoring circuit,
enabling the startup of the IC only within a secure operating area.

The XTO is designed for minimum phase noise and frequency perturbations. The balanced
topology gives maximum isolation from external and ground coupled noise. The built-in jump
start circuitry ensures reliable start-up behaviour of any specified crystal. For use with an exter­nal TCXO, the XTO circuitry can be used as a single-ended or balanced input buffer.

The recommended reference frequency is: f

= 23.104 MHz.

XTO

The frequency synthesizer features a balanced VCO and a fully integrated loop filter, thus no
external components are required. The VCO combines very good phase noise behaviour and
excellent spurious suppression. The relation between the reference frequency (f
VCO centre frequency (f

) is given by: f

VCO

VCO

= f

× 64 = 23.104 MHz × 64 = 1478.656 MHz.

XTO

) and the

XTO

3.5 RF-Mixer/Image-filter

Combined with the antenna an external LNA provides a first band path filtering of the signal. For
the LNA, Atmel’s ATR0610 is recommended, due to it’s low Noise Figure, high linearity an low
power consumption. The output of the LNA drives an SAW filter, which provides image rejection
for the mixer and the required isolation of all GSM bands. The output of the SAW filter is fed into
a highly linear mixer with high conversion gain and excellent noise performance.

The IF frequency (f

3.6 IF-filter

The mixer directly drives an external LC-Bandpath filter via open collector outputs. In order to
provide highest selectivity and conversion gain, it is recommended to design the external filter,
according to the application proposal, as a 2-pole filter with a quality factor Q > 25.

4866A–GPS–08/05

) is given by: fIF = fRF – f

IF

= 1575.42 MHz – 1478.656 MHz = 96.764 MHz.

VCO

3

3.7 VGA/AGC

The output of the IF-Filter drives an on-chip Variable Gain Amplifier (VGA) which is combined
with additional low-pass filtering. The on-chip Automatic Gain Control (AGC) stage sets the gain
of the VGA in order to optimally charge the input of the following analog-to-digital converter. The
AGC control loop can be selected for on-chip closed loop operation or for external gain control
mode. For external gain control mode, the loop needs to be closed by the baseband IC
ATR0621.

3.8 A/D Converter

The analog-to-digital converter stage has a total resolution of 1.5 bit. It comprises balanced com­parators and a sub sampling unit, clocked by the reference frequency (f
spectrum of the digital output signal (f
by: f

= ⏐ fIF – f

OUT

digital output signal, with a centre frequency given by:
f

= fIF – f

OUT

3.9 Clock and Data Driver

CMOS output drivers are providing sign and magnitude bits as well as the system clock to the
baseband IC ATR0621. The rail-to-rail output signal level is determined by the digital supply volt­age (VDIG).

), present at the data outputs SL and SH, is then given

OUT

× n⏐ . The selected sub sampling factor (n = 4) leads to the designated

XTO

× 4 = 96.764 MHz – 23.104 MHz – 4 = 4.348 MHz.

XTO

). The frequency

XTO

4

ATR0601 [Preliminary]

4866A–GPS–08/05

ATR0601 [Preliminary]

4. Absolute Maximum Ratings

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Parameters Symbol Value Unit

Analog supply voltage V
Digital supply voltage V
Input voltage V
Operating temperature T
Storage temperature T

CC

DIG

in

op

stg

5. Thermal Resistance

Parameters Symbol Value Unit

Junction ambient R

th

6. Operating Range

Parameters Symbol Value Unit

Analog supply voltage V
Digital supply voltage V

= V

– V

Supply voltage difference (V

∆

CC

)V

DIG

Temperature range Temp –40 to +85 °C
Input frequency f
Reference frequency f

CC

DIG

∆

RF

XTO

–0.3 to +3.7 V
–0.3 to +3.7 V
–0.3 to +3.7 V

–40 to +85 °C

–55 to +125 °C

125 K/W

2.70 to 3.30 V

1.65 to 2.00 V

≥ 0.80 V

1575.42 MHz

23.104 MHz

7. Electrical Characteristics

No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*

1 Common

(1)

V

= V

1.1 Analog supply current

1.2 Digital supply current
Analog supply current in

1.3
XTO mode

Digital supply current in

1.4
XTO mode

Supply current in power

1.5
down mode

(1)

(1),(3)

(1)

(1),(2)

1.6 Maximum total gain V

V
V

V
V

V

V

PUxto

PUxto

PUxto
PUrf

PUxto
PUrf

PUxto

AGCO

= V

= V

= V

PUrf

PU,on

= V

= V

PUrf

PU,on

= V

= V

= V

PU,on

PU,off

PU,on

PU,off

PUrf

,

,

= V

PU,off

= 2.2V G

1.7 Noise figure (SSB) NF

*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Notes: 1. Conditions: V

2. Capacitive load (C

3. Capacitive load (C

4866A–GPS–08/05

= 2.7V; V

CC

= 3.3 pF) at pins 22, 23, 24

L

= 3.3 pF) at pin 24

L

= 1.65V; Temperature = 27°C

DIG

7, 19 I

1I

7, 19 I

1I

DIG

S_XTO

DIG_XTO

1, 7, 19 I

max_tot

PD

S

14.2 mA A
700 µA A

2.9 mA A

500 µA A

2µAA

90 dB B

tot

6.8 dB C

5

7. Electrical Characteristics (Continued)

No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type*

2Mixer

2.1 Output frequency f
Input impedance

2.2
(balanced)

2.3 Conversion Gain Recommended IF-filter 8 G

2.4 Noise figure (SSB) 8 NF

= 23.104 MHz 13, 14 f

XTO

f

= 1575.42 MHz 10, 11 Z

RF

IF

11

MIX

MIX

3 VGA/AGC

3.1 Minimum gain V

3.2 Maximum gain V

3.3 Control-voltage sensitivity

3.4 AGC cut-off frequency C

3.5 AGC cut-off frequency C
Gain-control output

3.6
voltage

= 1.0V G

AGCO

= 2.2V G

AGCO

= 2.2V N

V

AGCO

= 1.0V N

V

AGCO

= open 2 f

ext

= 100 pF 2 f

ext

VGA,min

VGA, max

VGA,min

VGA, max

3dB_AGC

3dB_AGC

2V

AGCO

0.9 2.3 V B

4 Reference Oscillator

XTO phase noise at

4.1
100 Hz

4.2 XTO phase noise at 1 kHz With specified crystal 24 Pn

With specified crystal 24 Pn

100

1k

5 Clock and Data Driver

5.1 Clock driver frequency f

5.2 Clock output level C

5.3 Clock output level C

5.4 Data output level C

5.5 Data output level C

= 23.104 MHz 24 f

XTO

= 10 pF 24 V

load,max

= 10 pF 24 V

load.max

= 10 pF 22, 23 V

load,max

= 10 pF 22, 23 V

load,max

CLK

CLK,high

CLK,low

Data,high

Data,low

6PMSS

6.1 Voltage level power-on 17, 18 V

6.2 Voltage level power-off 17, 18 V

PU,on

PU,off

1.3 V A

*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Notes: 1. Conditions: V

= 2.7V; V

CC

= 1.65V; Temperature = 27°C

DIG

2. Capacitive load (CL = 3.3 pF) at pins 22, 23, 24

3. Capacitive load (C

= 3.3 pF) at pin 24

L

96.764 MHz A

10-j80 Ω C

20 dB B

5.8 dB C

0dBB

70 dB B

6.6 dB/V D
150 dB/V D
250 kHz D

33 kHz D

–80 dBc/Hz C

–100 dBc/Hz C

23.104 MHz A

0.9 × V

0.1 × V

0.9 × V

0.1 × V

DIG

DIG

DIG

DIG

VB
VB
VB
VB

0.5 V A

6

ATR0601 [Preliminary]

4866A–GPS–08/05