or lowpass filter and differential driver. The selectivity of the
LTC6602, combined with its phase matching and dynamic
range, make it ideal for filtering in RFID systems. With two
degree phase matching between channels, the LTC6602 can
be used in applications requiring highly matched filters,
such as transceiver I and Q channels. Gain programmabil-
ity, and the fully differential inputs and outputs, simplify
implementation in most systems.
Both channels of the LTC6602 consist of a programmable
lowpass and highpass filter. For bandpass functionality,
the lowpass filters are programmed for the upper cutoff
frequency. For lowpass functionality, the highpass filters
can be bypassed. The filter cutoff frequencies can be set
with a guaranteed accuracy of 3% with the use of a single
resistor. Alternatively, the filter cutoff frequencies can be
controlled with an external clock.
The LTC6602 operates on a single 2.7V to 3.6V supply
and features a low power shutdown mode.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners..
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Matched Dual Filter/Driver, Ideal for RFID Readers
Guaranteed Phase Matching to Within 2 Degrees
Guaranteed Gain Matching to Within 0.2dB
Configurable as Lowpass or Bandpass
Programmable 5th Order Lowpass: 42kHz to 900kHz
Programmable 4th Order Highpass: 4.2kHz to 90kHz
Programmable Gain: 1×, 4×, 16×, 32×
Simple Pin Programming or SPI Interface
Low Noise: –145dBm/Hz (Input Referred)
Low Distortion: –75dBc at 200kHz
Differential, Rail-to-Rail Inputs and Outputs
Input Range Extends from 0V to 5V
Low Voltage Operation: 2.7V to 3.6V
Shutdown Mode
4mm × 4mm QFN Package
APPLICATIONS
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Multiprotocol RFID Readers:
EPC-GEN2, ISD and IPX
IDEN, PHS, GSM Basestations
Repeaters, Radio Links, and Modems
Wireless Telemetry
JTRS
TYPICAL APPLICATION
UHF RFID Reader Dual Baseband Filter and Dual ADC
3V
0.1μF
0.1μF
20
100Ω
100pF
V+
IN
+INA
I INPUT
Q INPUT
38.3k
0.1μF
–INA
+INB
–INB
R
BIAS
V
OCM
MUTE
MUTE
INPUT
FROM
TRANSMITTER
LTC6602
V+
A
V+
D
–OUTA
+OUTA
–OUTB
+OUTB
CLKIO
SER
CLKCNTL
100Ω
100pF
100pF
100pF
B
IN–
Q OUTPUT
100Ω
2.2μF
B
IN+
14-BIT
ADC
I OUTPUT
V
CM
LTC2297
100Ω
100pF
100pF
A
IN–
A
IN+
14-BIT
ADC
10
0
GAIN (dB)
–10
–20
–30
–40
–50 45kHz-300kHz BPF
–60
1k
10k
100k
1M
FREQUENCY (Hz)
10M
6602 TA01b
Gain vs Frequency
EXTERNAL CLOCK = 90MHz
15kHz-150kHz BPF
90kHz-900kHz BPF
GAIN0(D0) HPF0(SDO)
GAIN1
GND
GND
HPF1(SDI)
LPF0(SCLK)
LPF1(CS)
CS
SCLK SDI
SPI CONTROL INPUT
÷4
CLK IN
6602 TA01
CLOCK INPUT
24MHz TO 128MHz
(COVERS THE TAG BACKSCATTER LINK FREQUENCY RANGE OF 40kHz to 640kHz
OF THE CLASS 1 GENERATION 2 UHF RFID COMMUNICATION PROTOCOL)
6602fa
1
LTC6602
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
GAIN0(D0)
+OUTA
18 –OUTA
17
SER
25
16 V+
D
15 CLKIO
14 GND
13 +OUTB
7
+INB
8
–INB
9 10 11 12
LPFO(SCLK)
HPF1(SDI)
HPFO(SDO)
–OUTB
GAIN1
MUTE
+INA
V+
IN
1
V+
A
2
V
OCM
3
R
BIAS
4
CLKCNTL 5
LPF1(CS) 6
–INA
V+
IN
to GND ................................................................6V
V+
A,
V+
D
to GND .........................................................4V
Filter Inputs to GND ....................... –0.3V to V+
IN
+ 0.3V
All Other Pins to GND.............. –0.3V to V+
A
, V+
D
+ 0.3V
Maximum Input Current .......................................±10mA
Output Short Circuit Duration........................... Indefinite
Operating Temperature Range (Note 2)
LTC6602CUF ........................................ –40°C to 85°C
LTC6602IUF ......................................... –40°C to 85°C
Specified Temperature Range (Note 3)
LTC6602CUF ............................................ 0°C to 70°C
LTC6602IUF ......................................... –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
24 23 22 21 20 19
UF PACKAGE
24-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO THE PCB.
ORDER INFORMATION
LEAD FREE FINISH
LTC6602CUF#PBF
LTC6602IUF#PBF
TAPE AND REEL
LTC6602CUF#TRPBF
LTC6602IUF#TRPBF
PART MARKING*
6602
6602
PACKAGE DESCRIPTION
24-Lead (4mm × 4mm) Plastic QFN
24-Lead (4mm × 4mm) Plastic QFN
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which app ly over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V+
A
= V+
D
= V+
IN
= 3V, V
ICM
= V
OCM
= 1.5V, Gain = 0dB, lowpass cutoff =
300kHz, highpass cutoff = 45kHz, internal clocking with R
BIAS
= 54.9k unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Filter Gain Either Channel External Clock = 90MHz, Highpass Filter Cutoff = 45kHz,
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