ZETEX ZNBR4000Q16

ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
FET BIAS CONTROLLER
DRAFT ISSUE A - DECEMBER 2000
DEVICE DESCRIPTION
The ZNBR series of devices are designed to
meet the bias requirements of GaAs and
HEMT FETs commonly used in satellite
receiver LNBs, PMR, cellular telephones etc.
with a minimum of external components
and a VCC of 3-6V for improved efficiency.
These devices are unconditionally stable
over the full working temperature with the
FETs in place, subject to the inclusion of the
recommended gate and drain capacitors.
These ensure RF stability and minimal
injected noise.
With the addition of two capacitors and
resistors the devices provide drain voltage
and current control for a number of external
grounded source FETs, generating the
regulated negative rail required for FET gate
biasing whilst operating from a single
supply. This negative bias, at -3 volts, can
also be used to supply other external
circuits.
It is possible to use less than the devices full
complement of FET bias controls, unused
drain and gate connections can be left open
circuit without affecting operation of the
remaining bias circuits.
In order to protect the external FETs the
circuits have been designed to ensure that,
under any conditions including power
up/down transients, the gate drive from the
bias circuits cannot exceed the range -2.5V
to 0.7V. Furthermore if the negative rail
experiences a fault condition, such as
overload or short circuit, the drain supply to
the FETs will shut down avoiding excessive
current flow.
The ZNBR4000/1 and ZNBR6000/1 contain
four and six bias stages respectively. In
setting drain current the ZNBR4000/1 two
resistors allows individual FET pair control
to different levels, the ZNBR6000/1 two
resistors split control between two and four
FETs. This allows the operating current of
input FETs to be adjusted to minimise noise,
whilst the following FET stages can
separately be adjusted for maximum gain.
The series also offers the choice of drain
v o lta g e t o b e s e t f or t he F E Ts, the
ZNBR4000/6000 gives 2.2 volts drain whilst
the ZNBR4001/6001 gives 2 volts.
The ZNBR4000/1 and ZNBR6000/1 are
available in QSOP16 and 20 pin packages
respectively for the minimum in devices size.
Device operating temperature is -40 to 70°C
to suit a wide range of environmental
conditions.
FEATURES
APPLICATIONS
•
•
•
•
•
•
•
•
•
•
•
•
VCC of 3-6V for improved efficiency
Provides bias for GaAs and HEMT FETs
Drives up to four or six FETs
Dynamic FET protection
Drain current set by external resistor
Regulated negative rail generator
requires only 2 external capacitors
Choice in drain voltage
Wide supply voltage range
QSOP surface mount package
1
Satellite receiver LNBs
Private mobile radio (PMR)
Cellular telephones
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
ABSOLUTE MAXIMUM RATINGS
Supply Voltage
Supply Current
Drain Current (per FET)
(set by RCAL1 and RCAL2)
Output Current
Operating Temperature
Storage Temperature
Power Dissipation (Tamb= 25°C)
QSOP16
500mW
QSOP20
650mW
-0.6V to 15V
100mA
0 to 15mA
100mA
-40 to 70°C
-50 to 85°C
ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated):
Tamb= 25°C,VCC=4V,ID=10mA (RCAL1 =33kΩ;RCAL2 =33kΩ)
SYMBOL PARAMETER
LIMITS
CONDITIONS
Min
VCC
Supply Voltage
ZNBR4000/6000
ZNBR4001/6001
ICC
Supply Current
ZNBR4000/1
ICC
VSUB
Typ
3.5
3.0
UNITS
Max
12
V
ID1 to ID4=0
ID1 to ID4=10mA
10
50
mA
mA
Supply Current
ZNBR6000/1
ID1 to ID6=0
ID1 to ID6=10mA
15
75
mA
mA
Substrate Voltage
(Internally generated)
ISUB= 0
ISUB= -200µA
-1.8
-1.8
V
V
END
ENG
Output Noise
Drain Voltage
Gate Voltage
CG=4.7nF, CD=10nF
CG=4.7nF, CD=10nF
0.02
0.005
Vpkpk
Vpkpk
fO
Oscillator Freq.
200
350
800
kHz
8
10
12
mA
DRAIN CHARACTERISTICS
ID
Current
Current Change
∆IDV
with VCC
VCC=5 to 12V
0.02
%/V
∆IDT
with Tj
Tj=-40 to +70°C
0.05
%/°C
VD
Voltage
ZNBR4000, ZNGB6000
ZNBR4001, ZNBR6001
2
1.8
2.2
2
2.4
2.2
V
V
Voltage Change
∆VDV
with VCC
VCC= 5 to 12V
0.5
%/V
∆VDT
with Tj
Tj = -40 to +70°C
50
ppm
2
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
SYMBOL PARAMETER
LIMITS
CONDITIONS
Min
Typ
UNITS
Max
GATE CHARACTERISTICS
IGO
-30
2000
µA
ID1 to ID4=12mA
IG1 to IG4=0
-2.5
-1.8
V
ID1 to ID4=12mA
IG1 to IG4= -10µA
-2.5
-1.8
V
ID1 to ID4= 8mA
IG1 to IG4= 0
0
1
V
ID1 to ID6=12mA
IG1 to IG6= 0
-2.5
-1.8
V
ID1 to ID6=12mA
IG1 to IG6= -10µA
-2.5
-1.8
V
ID1 to ID6= 8mA
IG1 to IG6= 0
0
1
V
Output Current Range
Output Voltage
ZNBR4000/1
VOL
VOH
Output Low
Output High
Output Voltage
ZNBR6000/1
VOL
VOH
Output Low
Output High
Notes:
1. The negative bias voltages specified are generated on-chip using an internal oscillator. Two external capacitors, CNB and CSUB, of
47nF are required for this purpose.
2. The characteristics are measured using two external reference resistors RCAL1 and RCAL2 of value 33kΩ wired from pins RCAL1/2 to
ground. For the ZNBR4000, resistor RCAL1 sets the drain current of FETs 1 and 2, resistor RCAL2 sets the drain current of FETs 3 and 4.
For the ZNBR6000, resistor RCAL1 sets the drain current of FETs 1 and 4, resistor RCAL2 sets the drain current of FETs 2, 3, 5 and 6.
3. Noise voltage is not measured in production.
4. Noise voltage measurement is made with FETs and gate and drain capacitors in place on all outputs. CG, 4.7nF, are connected between
gate outputs and ground, CD, 10nF, are connected between drain outputs and ground.
3
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
TYPICAL CHARACTERISTICS
16
Drain Current (mA)
Vcc = 5V
14
12
10
8
6
4
2
0
0
20
40
60
80
100
Rcal (k)
JFET Drain Current v R cal
4
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
FUNCTIONAL DIAGRAM
FUNCTIONAL DESCRIPTION
The ZNBR devices provide all the bias requirements for external FETs, including the generation
of the negative supply required for gate biasing, from the single supply voltage.
The diagram above shows a single stage from the ZNBR series. The ZNBR4000/1 contains 4 such
stages, the ZNBR6000/1 contains 6. The negative rail generator is common to all devices.
The drain voltage of the external FET QN is set by the ZNBR device to its normal operating voltage.
This is determined by the on board VD Set reference, for the ZNBR4000/6000 this is nominally
2.2 volts whilst the ZNBR4001/6001 provides nominally 2 volts.
The drain current taken by the FET is monitored by the low value resistor ID Sense. The amplifier
driving the gate of the FET adjusts the gate voltage of QN so that the drain current taken matches
the current called for by an external resistor RCAL. Both ZNBR devices have the facility to program
different drain currents into selected FETs. Two RCAL inputs are provided. For the ZNBR4000,
resistor RCAL1 sets the drain current of FETs 1 and 2, resistor RCAL2 sets the drain current of FETs
3 and 4. For the ZNBR6000, resistor RCAL1 sets the drain current of FETs 1 and 4, resistor RCAL2
sets the drain current of FETs 2, 3, 5 and 6.
Since the FET is a depletion mode transistor, it is usually necessary to drive its gate negative with
respect to ground to obtain the required drain current. To provide this capability powered from
a single positive supply, the device includes a low current negative supply generator. This
generator uses an internal oscillator and two external capacitors, CNB and CSUB.
5
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
TYPICAL APPLICATION CIRCUIT
* L1
CD
10nF
* C2
Q1
ZNBR
* L2
VCC
GN
* C3
CG
4.7nF
DN
GND
* Stripline Elements
CNB1
RCAL2
RCAL1
CNB2
CSUB
CNB
47nF
CSUB
47nF
RCAL1
RCAL2
33k
33k
APPLICATIONS INFORMATION
The above is a partial application circuit for the ZNBR series showing all external components
required for appropriate biasing. The bias circuits are unconditionally stable over the full
temperature range with the associated FETs and gate and drain capacitors in circuit.
Capacitors CD and CG ensure that residual power supply and substrate generator noise is not
allowed to affect other external circuits which may be sensitive to RF interference. They also
serve to suppress any potential RF feedthrough between stages via the ZNBR device. These
capacitors are required for all stages used. Values of 10nF and 4.7nF respectively are
recommended however this is design dependent and any value between 1nF and 100nF could
be used.
The capacitors CNB and CSUB are an integral part of the ZNBRs negative supply generator. The
negative bias voltage is generated on-chip using an internal oscillator. The required value of
capacitors CNB and CSUB is 47nF. This generator produces a low current supply of approximately
-3 volts. Although this generator is intended purely to bias the external FETs, it can be used to
power other external circuits via the CSUB pin.
Resistors RCAL1/2 sets the drain current at which all external FETs are operated. Both ZNBR devices
have the facility to program different drain currents into selected FETs. Two RCAL inputs are
provided. For the ZNBR4000, resistor RCAL1 sets the drain current of FETs 1 and 2, resistor RCAL2
sets the drain current of FETs 3 and 4. For the ZNBR6000, resistor RCAL1 sets the drain current of
FETs 1 and 4, resistor RCAL2 sets the drain current of FETs 2, 3, 5 and 6. If the same drain current
is required for all FETs on either device then pins RCAL1 and RCAL2 can be wired together and
shunted to ground by a single calibration resistor of half normal value.
If any bias control circuit is not required, its related drain and gate connections may be left open
circuit without affecting the operation of the remaining bias circuits. If all FETs associated with
a current setting resistor are omitted, the particular RCAL should still be included. The supply
current can be reduced, if required, by using a high value RCAL resistor (e.g. 470k).
6
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
APPLICATIONS INFORMATION (Continued)
The ZNBR devices have been designed to protect the external FETs from adverse operating
conditions. With a JFET connected to any bias circuit, the gate output voltage of the bias circuit
can not exceed the range -3.5V to 0.7V, under any conditions including powerup and powerdown
transients. Should the negative bias generator be shorted or overloaded so that the drain current
of the external FETs can no longer be controlled, the drain supply to FETs is shut down to avoid
damage to the FETs by excessive drain current.
The following diagrams show the ZNBR4000/1 and ZNBR6000/1 in typical LNB applications.
Within each FET gain stage the numbering system indicates how the bias stages relate to the
application circuits. This is important when RCAL values are used to set differing drain currents.
Dual standard or enhanced LNB block diagram
Regulator
ZHR Series
Vertical
Antenna
Gain Stage
GaAs/HEMTFET
Gain Stage
+
3
1
ASTRA
10.95 GHz-11.7 GHz
Standard Band
10.7 GHz-11.8 GHz
Enhanced Band
Mixer
Vertical Channels
Local Osc
10.00 GHz - Standard Band
9.75 GHz - Enhanced Band
IF down feed
950-1750 MHz - Standard Band
950-2050 MHz - Enhanced Band
ZNBR4000/1
Horizontal
Antenna
2
+
4
Gain Stage
GaAs/HEMTFET
Mixer
7
Horizontal Channels
Gain Stage
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
Dual standard or enhanced LNB block diagram. High Gain
Regulator
ZHR Series
Vertical
Antenna
Gain Stage
GaAs/HEMTFET
2
1
ASTRA
10.95 GHz-11.7 GHz
Standard Band
10.7 GHz-11.8 GHz
Enhanced Band
Mixer
Gain Stage
+
3
Vertical Channels
Local Osc 2
10.00 GHz - Standard Band
9.75 GHz - Enhanced Band
IF down feed
950-1750 MHz - Standard Band
950-2050 MHz - Enhanced Band
ZNBR6000/1
Horizontal
Antenna
4
5
+
6
Gain Stage
GaAs/HEMTFET
Mixer
8
Horizontal Channels
Gain Stage
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
CONNECTION DIAGRAMS
ZNBR4000
ZNBR4001
ZNBR6000
ZNBR6001
ORDERING INFORMATION
Part Number
Package
Part Mark
ZNBR4000Q16
QSOP16
ZNBR4000
ZNBR4001Q16
QSOP16
ZNBR4001
ZNBR6000Q20
QSOP20
ZNBR6000
ZNBR6001Q20
QSOP20
ZNBR6001
9
ZNBR4000 ZNBR4001
ZNBR6000 ZNBR6001
PACKAGE DIMENSIONS
A
IDENTIFICATION
RECESS
FOR PIN 1
C
E
J
B
D
F
PIN No.1
G
K
QSOP16
PIN
QSOP20
Millimetres
Inches
PIN
Millimetres
Inches
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
A
4.80
4.90
0.033
0.039
A
8.55
8.74
0.337
0.344
B
0.635
0.025 NOM
B
0.635
C
0.177
0.267
0.007
0.011
C
1.42
1.52
0.056
0.06
D
E
0.20
0.30
0.008
0.012
D
0.20
0.30
0.008
0.012
3.81
3.99
0.15
0.157
E
3.81
3.99
0.15
0.157
F
1.35
1.75
0.053
0.069
F
1.35
1.75
0.053
0.069
G
0.10
0.25
0.004
0.01
G
0.10
0.25
0.004
0.01
J
5.79
6.20
0.228
0.244
J
5.79
6.20
0.228
0.244
K
0°
8°
0°
8°
K
0°
8°
0°
8°
0.025 NOM
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This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied
or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or
services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of
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