ELECTRICAL CHARACTERISTICS (VCC = 5 V, VCC2 = 24 V, TA = 25°C)
Notes:
1. Optional Output Frequency of 43.75 MHz Available
2. 110 Channels at +15 dBmV/tone
PART NUMBER ISG2000
SYMBOLS PARAMETERS UNITS MIN TYP MAX
RF Performance (RX)
fOP Operating Frequency Range MHz 91 860
Input Signal Level dBmV -20 15
Gain Range dB 25 75
VAGC Automatic Gain Control Voltage RF 0 3.3
VAGC Automatic Gain Control Voltage IF 0 3.3
NFMAX Noise Figure (Max Gain) dB 8 10
Phase Noise at 10 kHz Offset dBc/Hz -83 -80
LO Radiation at RF Input dBm -40
Resolution KHz 62.5
Lock Time (end to end channel) msec. 18
Input Impedance (Nominal) ohms 75
RLIN Input Return Loss dB 5
Channel Bandwidth USA MHz 6
Output Frequency1MHz 5.70 5.75 5.80
Passband Ripple dB 1 2
Image Rejection dB 50
Inband Group Delay ns 100
CSO2dBc 45
CTB2dBc 45
Frequency Offset KHz -50 +50
ISG2000
5 V CATV MODEM RF TRANSCEIVER
05/10/2000
FEATURES
• TWO WAY DOCSIS BASED DESIGN:
91-860 MHz Downstream
5-42 MHz Upstream
• INTERFACES DIRECTLY WITH QAM DEMOD/MOD ICs
• BUILT IN RF TRANSMITTER:
50 dB AGC Driver
• LOW PHASE NOISE:
-83 dBc/Hz @ 10 KHz
• BUSINESS CARD SIZE:
3.4" x 2.0" x 0.5"
• RUGGED DESIGN/NO MICROPHONICS:
All SMD Components "Coiless"
• LOW POWER CONSUMPTION:
RX: 1.2 Watts, TX: 0.6 Watts
• EUROPEAN AND JAPANESE VERSIONS AVAILABLE
DESCRIPTION AND APPLICATIONS
The ISG2000 is a complete RF transceiver designed for use in
cable modem applications. The transceiver integrates a diplex
filter, triple conversion receiver and transmit AGC amplifier
(see Figure 1). The diplex filter provides over 40 dB of isolation
between the TX band and the RX band. The receiver section
provides channel selectivity and converts QAM carriers to low
IF sampling frequency for digital signal processing. The trans-
mitter section provides 50 dB of gain control while maintaining
excellent linearity performance.
ABSOLUTE MAXIMUM RATINGS
(TC = 25 °C unless otherwise noted)
SYMBOLS PARAMETERS UNITS RATINGS
VIN RF Input Voltage dBmV 60
VCC1 (RX) Supply Voltage 1 (RX)V 6
VCC2 (RX) Supply Voltage 2 (RX)V35
VCC (TX) Supply Voltage (TX)V6
TOP Operating Temperature °C -10 to 60
TSTG Storage Temperature °C -40 to 75
TSOL Soldering Temperature °C 260
tSOL Soldering Time sec. 4
Note:
1. Operation in excess of any one of these parameters may result
in permanent damage.
ISG2000
ELECTRICAL CHARACTERISTICS (VCC = 5 V, VCC2 = 24 V, TA = 25°C)
PART NUMBER ISG2000
SYMBOLS PARAMETERS UNITS MIN TYP MAX
RF Performance (TX)
fOP Operating Frequency Range MHz 5 42
Gain (VAGC = 0 V) dB 35
Gain (VAGC = 3.3 V) dB -30
VAGC Automatic Gain Control Voltage V 0 3.3
2nd Harmonic Level (Single Tone, POUT = +58 dBmV) dBc -53 -56
3rd Harmonic Level (Single Tone, POUT = +58 dBmV) dBc -53 -56
RLOUT Output Return Loss dB 10 6
TX ON On/Off Setting Time (See Figure 1) µS12
TX OFF On/Off Setting Time (See Figure 1) µS5
Power Requirements
Supply Voltage V1 RX ( 5 V) V 4.75 5 5.25
Supply Voltage V2 RX ( 30 V)mA V 22 24 31.5
Supply Voltage V1 TX ( 5 V) V 4.75 5 9
Supply Current
ICC1 (RX) Supply Current 1 (RX) mA 240 320
ICC2 (RX) Supply Current 2 (RX) mA 1.5 2
ICC1 (TX) Supply Current 1 (TX) mA 120 160
Physical Interface
To the CATV Network Female
F-Connector
To the Motherboard 16 Pin Header
Physical Dimensions
L x W x H 3.4 x 2.0 x 0.5"
Environmental Specs
TOP Operating Temperature1°C-5 60
TSTG Storage Temperature °C -40 75
Note:
1. Temperature performance parameters will vary slightly.
TX ENABLE APPLICATION CIRCUIT (Figure 1)
ISG2000
PSAVE
pin 3
5 Volt
3.0 K ohm
Square Wave (1)
0-3.3 Volts R2
R1
4.7 K ohm
C1
1000 pF
2 2
2 2
22
1
0
3
ISG2000
Pin No. Pin Name Description Equivalent Circuit
1RF
AGC
2VCC (TX)
3 TXEN
4 TXIN-
5 TXIN+
6 TXAGC
7 VCC2 (RX)
8 VCC1 (RX)
9 IFAGC
10 GND
PIN FUNCTIONS
The RFAGC pin is used to adjust gain in the
dual conversion tuner. This pin has a
positive gain vs. AGC slope. 20 dB of gain
control is available by varying the voltage
from 0.5 V to 3.3 V.
The VCC (TX) pin powers the TX amplifier. A
5 V bias is required and nominal current is
125 mA.
The TXEN pin is used to enable/disable the
TX amplifier. When TXEN is set LOW, the
TX amplifier is disabled. In this state, a
standby current of 3 mA is required from
VCC (TX). When TXEN is set HIGH, the TX
amplifier is enabled. In this state, a
nomimal current of 125 mA is required from
VCC (TX).
TXIN- is the inverting input to the TX
amplifier. The input frequency range spans
5-42 MHz.
TXIN+ is the non-inverting input to the TX
amplifier. The input frequency range spans
5-42 MHz.
The TXAGC pin is used to adjust gain in the
TX amplifier. The pin has a positive gain vs.
AGC slope. 50 dB of gain control is
available by varying the voltage from 0.5 V
to 3.0 V.
The VCC2 (RX) pin powers the loop filter for
the first LO. A bias of 24 V - 30 V is
required and maximum current draw is
2 mA.
The VCC1 (RX) pin powers the entire RX
section. A bias of 5 V is required and
nominal current draw is
250 mA.
The IFAGC pin is used to adjust gain in the
final downconverter stage of the RX section.
The pin has a positive gain vs. AGC slope.
30 dB of gain control is available by varying
the voltage from 0.5 to 2.0 V.
Ground.
1
1 K
1 K
0.1 µF
310 K
4 5
4 5
6
10 K
1000 p
9
1 K
1000 p
ISG2000
Note:
1. For programming information, refer to National LMX2336 data sheet (http://www.national.com)
Pin No. Pin Name Description Equivalent Circuit
11 CLK
12 DATA
13 LDEN
14 GND
15 IFOUT+
16 IFOUT–
PIN FUNCTIONS
Clock pin for the dual PLL. High impedance
CMOS input. Data for the various latches is
clocked in on the rising edge into a 20-bit
shift register.
Serial data pin for the dual PLL. High
impedance CMOS input. MSB entered first.
The last two bits are the control bits.
Latch enable pin for the dual PLL. High
impedance CMOS input. When LE goes
HIGH, data stored in the shift registers is
loaded into one of the 4 latches determined
by the 2 control bits.
Ground.
Non-Inverting final IF output.
Inverting final IF output.
15
240
39 p 68 p
5.6 µH
16
240
39 p 68 p
5.6 µH
FIGURE 1
DUAL PLL
CABLE
IN/OUT
91-860 MHz
5-65 MHz
TX IN RX OUT
CLK DATA LD EN
43.75 MHz
OUTLINE DIMENSIONS (Units in mm)
ISG2000
Pin Connections
1. RF AGC
2. VCC (TX)
3. TXEN
4. TX IN –
5. TX IN +
6. TXAGC
7. VCC2 Rx)
8. VCC1 (Rx)
9. IF AGC
10. GND
11. CLK
12. DATA
13. LDEN
14. GND
15. IF OUT+
16. IF OUT–
Note: All tolerances ±0.15 mm unless otherwise specified.
ISGXXX 98017 00056
1.6
4.0
2.2
3.5
0.4–0.1
2.0 MAX
2.5 7.7
1.7 14.0
54.0
52.4
17.3
19.9
19.9
0.6–0.1
89.3
88.2
2.54 x 15 = 38.1–0.2
26.7–0.2
0.4–0.1
DATE CODE
SERIAL NUMBER
MODEL
DATUM LINE
DATUM LINE
24.5–0.2 43.3 3.0
4.1 2.9
13.2
PIN 1
87.5 [3.445]
3.0 [0.118] PIN 1
26.8 [1.055]
2.54 [0.100] 15 PLS
50.2 [1.976] 56.8 [2.236]
92.5 [3.642]
φ3.2 [φ0.125] 4 PLS
φ0.9 [φ0.035]
16 PLS
RECOMMENDED PAD LAYOUT (Units in mm [inches])
(1)
(2)
VCO CHARACTERISTICS
VCO Input Voltage
VCO Output Frequency
RF1 R (19) RF2 R (19) RF1 R (20) RF2 R (20) FOLD
(RF1 LD) (RF2 LD) (RF1 FO) (RF2 FO) Output State
0 0 0 0 Disabled1
0 1 0 0 RF2 Lock
Detect2
1 0 0 0 RF1 Lock
Detect2
1 1 0 0 RF1/RF2
Lock Detect2
X 0 0 1 RF2 Reference
Divider Output
X 0 1 0 RF1 Reference
Divider Output
X 1 0 1 RF2
Programmable
Divider Output
X 1 1 0 RF1
Programmable
Divider Output
0 0 1 1 Fastlock3
0 1 1 1 For internal
use only
1 0 1 1 For internal
use only
1 1 1 1 Counter Reset4
X - Don’t care condition
Table 3. The FOLD Output Truth Table
Notes:
1. When the FOLD output is disabled, it is actively pulled to a
low logic state.
2. Lock detect output provided to indicate when the VCO fre-
quency is in “lock”. When the loop is locked and a lock
detect mode is selected, the pin's output is HIGH, with nar-
row pulses LOW. In the RF1/RF2 lock detect mode a locked
condition is indicated when RF2 and RF1 are both locked.
3. The Fastlock mode utilized the FOLD output pin to switch a
second loop filter damping resistor to ground during fastlock
operation. Activation of Fastlock occurs whenever the RF
loop’s Icpo magnitude bit #17 is selected HIGH (while the
#19 and #20 mode bits are set for Fastlock).
4. The Counter Reset mode bits R19 and R20 when activated
reset all counters. Upon removal of the Reset bits the N
counter resumes counting in “close” alignment with R
counter. (The maximum error is one prescaler cycle). If
the Reset bits are activated the R counter is also forced to
Reset, allowing smooth acquisition upon powering up.
ISG2000
Table 1. Programmable Modes
Table 2. Mode Select Truth Table
C1 C2 R16 R17 R18 R19 R20
0 0 RF2 Phase RF2 I CPO RF2 DO RF2 LD RF2 FO
Detector TRI-STATE
Polarity
0 1 RF1 Phase RF1 ICPO RF1DO RF1 LD RF1 FO
Detector TRI-STATE
Polarity
C1 C2 N19 N20
1 0 RF2 Prescaler Pwdn RF2
1 1 RF1 Prescaler Pwdn RF1
Phase DO TRI-STA TE ICPO1 RF1 RF2 Pwdn2
Detector Prescaler Prescaler
Polarity3
0 Negative Normal LOW 64/65 64/65 pwrd up
Operation
1 Positive TRI-STA TE HIGH 128/129 128/129 pwrd dn
Notes:
1. The ICPO LOW Current State = 1/4 x ICPO HIGH
Current.
2. Activitation of the RF2 PLL or RF1 PLL powerdown
modes result in the disabling of the respective N counter
divider and debiasing of its respective fIN inputs (to a
high impedance state). The powerdown function is
gated by the charge pump to prevent unwanted
frequency jumps. Once the powerdown program mode
is loaded, the part will go into powerdown mode when
the charge pump reaches a TRI-STATE condition. The
R counter and Oscillator functionality does not become
disabled until both RF2 and RF1 powerdown bits are
activated. The OSCIN is connected to VCC through a 100
kΩ resistor and the OSCOUT goes HIGH when this con-
dition exists. The MICROWAVETM control register re-
mains active and capable of loading and latching data
during all the powerdown modes.
3. Phase Detector Polarity
Depending upon VCO characteristics, the R16 bits
should be set accordingly:
When VCO characteristics are positive like (1), R16
should be set HIGH, when VCO characteristics are
negative like (2), R16 should be set LOW.
Serial Data Input Timing
DATA N20: WSB
(R20: WSB) C1: LSB
(C1: LSB)
N19
(R19) N10
(R10) N9
(R9) (R8) C2
(C2)
LE
OR LE
CLOCK tCWL
tCS tCH tEWtCWH tES
Notes:
1. Parenthesis data indicates programmable reference
divider data.
2. Data shifted into register on clock rising edge.
3. Data is shifted in MSB first.
Test Conditions:
The Serial Data Input Timing is tested using a symmetrical
waveform around VCC/2. The test waveform has an edge
rate of 0.6V/ns with amplitudes of 2.2 V @ VCC = 2.7 V and
2.6 V @ VCC = 5.5 V.
Phase Comparator and Internal Charge Pump Character-
istics.
fr
fp
LD
DoHZL
f > f
rp f = f
rp f < f
rp f < f
rp f < f
rp
Notes:
1. Phase difference detection range: -2π to +2π
2. The minimum width pump up and pump down current pulses
occur at the DO pin when the loop is locked.
ISG2000
ISG BROADBAND, Inc.
4701 Patrick Henry Drive • SUITE #701 • Santa Clara, CA 95054-1863 • (408) 330-6660
FAX (408) 330-6688 • www.isgbroadband.com
DATA SUBJECT TO CHANGE WITHOUT NOTICE 05/10/2000
