LTC6602
Dual Matched, High
Frequency Bandpass/Lowpass Filters
FEATURES
DESCRIPTION
TheLTC®6602isadual,matched,programmablebandpass
orlowpassfilteranddifferentialdriver.Theselectivityofthe
LTC6602, combined with its phase matching and dynamic
range, make it ideal for filtering in RFID systems. With two
degreephasematchingbetweenchannels,theLTC6602can
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.
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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
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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.
APPLICATIONS
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Multiprotocol RFID Readers: EPC-GEN2, ISD and IPX
The LTC6602 operates on a single 2.7V to 3.6V supply
and features a low power shutdown mode.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
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IDEN, PHS, GSM Basestations
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Repeaters, Radio Links, and Modems
Wireless Telemetry
JTRS
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TYPICAL APPLICATION
UHF RFID Reader Dual Baseband Filter and Dual ADC
3V
0.1µF
V+
0.1µF
+
100Ω
100Ω
A
IN
Gain vs Frequency
100pF
100pF
14-BIT
ADC
20
10
V+
V+
D
100pF
IN
A
EXTERNAL CLOCK = 90MHz
–
A
–OUTA
+OUTA
–OUTB
+OUTB
CLKIO
SER
IN
+INA
–INA
+INB
–INB
15kHz-150kHz BPF
90kHz-900kHz BPF
I INPUT
Q INPUT
0.1µF
I OUTPUT
Q OUTPUT
0
V
CM
2.2µF
LTC2297
–10
–20
–30
–40
–50
–60
+
100Ω
100Ω
LTC6602
B
IN
R
V
BIAS
38.3k
100pF
100pF
OCM
14-BIT
ADC
100pF
CLKCNTL
HPF0(SDO)
HPF1(SDI)
LPF0(SCLK)
LPF1(CS)
MUTE
–
B
IN
GAIN0(D0)
GAIN1
GND
MUTE
INPUT
FROM
45kHz-300kHz BPF
1k 10k
CLK IN
6602 TA01
TRANSMITTER
100k
1M
10M
GND
FREQUENCY (Hz)
÷4
6602 TA01b
CS SCLK SDI
SPI CONTROL INPUT
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)
6602fc
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