ZNBG3113 [ZETEX]
FET BIAS CONTROLLER WITH POLARISATION SWITCH AND TONE DETECTION; 与偏振开关与音调检测FET偏置控制器型号: | ZNBG3113 |
厂家: | ZETEX SEMICONDUCTORS |
描述: | FET BIAS CONTROLLER WITH POLARISATION SWITCH AND TONE DETECTION |
文件: | 总17页 (文件大小:687K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
FET BIAS CONTROLLER WITH POLARISATION
SWITCH AND TONE DETECTION
ISSUE 1 - OCTOBER 1998
ZNBG3113
ZNBG3114
DEVICE DESCRIPTION
Drain current setting of the ZNBG3113/14 is
user selectable over the range 0 to 15mA, this
is achieved with addition of a single resistor.
The series also offers the choice of drain
voltage to be set for the FETs, the 3113 gives
2.2 volts drain whilst the 3114 gives 2 volts.
The ZNBG 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.
With the addition of two capacitors and a
resistorthedevicesprovide drainvoltageand
current control for three 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.
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.
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.
The ZNBG3113/14 includes bias circuits to
drive up to three external FETs. A control
input to the device selects either one of two
FETs as operational, the third FET is
permanently active. This feature is
particularly used as an LNB polarisation
switch. Also specific to LNB applications is
the 22kHz tone detection and logic output
feature which is used to enable high and low
band frequency switching.
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 -3.5V to 1V.
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 facility to control the tone switching
delay is provided. This allows the rejection
of other lower frequency tones tat may be
present in multiple LNB applications.
The ZNBG3113/14 are available in QSOP20
for the minimum in device size. Device
operating temperature is -40 to 70°C to suit
a wide range of environmental conditions.
FEATURES
APPLICATIONS
Provides bias for GaAs and HEMT FETs
Satellite receiver LNBs
•
•
Drives up to three FETs
Private mobile radio (PMR)
•
•
Dynamic FET protection
Cellular telephones
•
•
Drain current set by external resistor
•
Regulated negative rail generator
requires only 2 external capacitors
•
Choice in drain voltage
•
Wide supply voltage range
•
Polarisation switch for LNBs
•
•
22KHz tone detection for band
switching
Programmable tone delay
•
•
Compliant with ASTRA control
specifications
QSOP surface mount package
•
4-123
ZNBG3113
ZNBG3114
ABSOLUTE MAXIMUM RATINGS
Supply Voltage
Supply Current
Input Voltage (VPOL
-0.6V to 12V
100mA
25V Continuous
0 to 15mA
Power Dissipation (Tamb= 25°C)
QSOP20 500mW
)
Drain Current (per FET)
(set by RCAL
)
Operating Temperature
Storage Temperature
-40 to 70°C
-50 to 85°C
ELECTRICAL CHARACTERISTICS. TEST CONDITIONS
(Unless otherwise stated):T = 25°C,V =5V,I =10mA (R =33kΩ)
CAL
amb
CC
D
LIMITS
SYMBOLPARAMETER
CONDITIONS
UNITS
V
MIN. TYP. MAX.
VCC
ICC
Supply Voltage
Supply Current
5
10
ID1 to ID3=0
ID1=0,ID2 to ID3=10mA, VPOL=14V
ID2=0,ID1 to ID3=10mA, VPOL=15.5V
15
35
35
45
45
mA
mA
mA
mA
mA
I
D1 to ID3=0, ILB=10mA
ID1 to ID3=0, IHB=10mA
VSUB
Substrate Voltage (Internally generated) ISUB=0
ISUB=-200µA
-3.5
200
-3.0
350
-2.5
-2.4
V
V
Output Noise
Drain Voltage
Gate Voltage
END
ENG
CG=4.7nF, CD=10nF
CG=4.7nF, CD=10nF
0.02
0.005 Vpkpk
Vpkpk
fO
Oscillator
Frequency
800 kHz
4-124
ZNBG3113
ZNBG3114
LIMITS
SYMBOLPARAMETER
CONDITIONS
UNITS
MIN. TYP. MAX.
GATE CHARACTERISTICS
IGO
Output Current
Range
-30
2000
µA
IDx
(mA)
VPOL
(V)
IGOx
(µA)
Output Voltage
VG1O
VG1L
VG1H
Gate 1
Off
Low
High
ID1=0 VPOL=14 IGO1=-10
D1=12 VPOL=15.5 IGO1=-10
ID1=8 VPOL=15.5 IGO1=0
-2.7
-2.7
0.4
-2.4
-2.4
0.75
-2.0
-2.0
1.0
V
V
V
I
Output Voltage
VG2O
VG2L
VG2H
Gate 2
Off
Low
High
I
D2=0 VPOL=15.5 IGO2=-10
-2.7
-2.7
0.4
-2.4
-2.4
0.75
-2.0
-2.0
1.0
V
V
V
ID2=12 VPOL=14 IGO2=-10
ID2=8 VPOL=14 IGO2=0
Output Voltage
VG3L
VG3H
Gate 3
Low
High
ID3=12
D3=8
IGO3=-10
IGO3=0
-3.5
0.4
-2.9
0.75
-2.0
1.0
V
V
I
DRAIN CHARACTERISTICS
ID
Current
8
10
12
mA
Current Change
with VCC
⌬IDV
⌬IDT
VCC= 5 to 10V
Tj=-40 to +70°C
0.2
0.05
%/V
%/°C
with Tj
VD1
VD2
VD3
Drain 1 Voltage:
High
ZNBG3113
ZNBG3114
ID1=10mA, VPOL=15.5V
D1=10mA, VPOL=15.5V
2.0
1.8
2.2
2.0
2.4
2.2
V
V
I
Drain 2 Voltage:
High
ZNBG3113
ZNBG3114
ID2=10mA, VPOL=14V
ID2=10mA, VPOL=14V
2.0
1.8
2.2
2.0
2.4
2.2
V
V
Drain 3 Voltage:
High
ZNBG3113
ZNBG3114
ID3=10mA, VPOL=15.5V
ID3=10mA, VPOL=15.5V
2.0
1.8
2.2
2.0
2.4
2.2
V
V
Voltage Change
with VCC
⌬VDV
⌬VDT
VCC= 5 to 10V
Tj=-40 to +70°C
0.5
50
%/V
ppm
with Tj
Leakage Current
Drain 1
IL1
IL2
VD1=0.1V, VPOL=14V
10
10
µA
µA
Drain 2
VD2=0.1V, VPOL=15.5V
4-125
ZNBG3113
ZNBG3114
SYMBOLPARAMETER
LIMITS
CONDITIONS
UNITS
MIN. TYP. MAX.
TONE DETECTION CHARACTERISTICS
Filter Amplifier
IB
Input Bias Current
Output Voltage 5
Output Current 5 VOUT=1.96V, VFIN=2.1V
0.04
1.75
400
0.15
1.95
520
46
1.0
RF1=150kΩ
RF1=150kΩ
µA
V
VOUT
IOUT
GV
2.05
650
µA
dB
Voltage Gain
f=22kHz,VIN=1mV
Rectifier
VOUT
ILEAK
Output Voltage 5
Leakage Current 5
1.8
2.0
20
2.2
RF1=150kΩ IL=-10µA
RF1=150kΩ VOUT=3V
V
200
nA
Comparator
Threshold
Voltage 5
VTH
f=0
2.95
3.2
3.45
V
Output Stage
VLOV
ILOV
LOV Volt. Range
IL=50mA(LB or HB)
VLOV=0
-0.5
VCC-1.8 V
LOV Bias Current
LB Output Low
0.04
0.15
1.0
µA
VLOV=0 IL=-10µA
VLOV=3V IL=0
Enabled 6
Enabled 7
VLBL
-3.5
-0.01
-2.75 -2.5
V
V
0
0.01
VLBH
VHBL
VHBH
LB Output High
HB Output Low
HB Output High
VLOV=0 IL=10mA
VLOV=3V IL=50mA
Disabled 6
-0.025 0
0.025
3.1
V
V
Disabled 7
2.9
3.0
Enabled 6
Enabled 7
-3.5
-2.75 -2.5
V
V
VLOV=0 IL=-10µA
VLOV=3V IL=0
-0.01
0
0.01
VLOV=0 IL=10mA
VLOV=3V IL=50mA
Disabled 6
-0.025 0
0.025
3.1
V
V
Disabled 7
2.9
3.0
POLARITY SWITCH CHARACTERISTICS
IPOL
Input Current
10
14
20
40
VPOL=25V (Applied via RPOL=10kΩ)
µA
VTPOL
Threshold
Voltage
14.75 15.5
V
VPOL=25V (Applied via RPOL=10kΩ)
VPOL=25V (Applied via RPOL=10kΩ)
TSPOL
Switching Speed
100
ms
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 an external reference resistor RCAL of value 33k wired from pins RCAL to ground.
3. Noise voltage is not measured in production.
4. Noisevoltagemeasurement ismadewith FETsandgateanddraincapacitors in placeonalloutputs. CG, 4.7nF, are connected between
gate outputs and ground, CD, 10nF, are connected between drain outputs and ground.
5 . These parameters are lneearly related to VCC
6. These parameters are measured using Test Circuit 1
7. These parameters are measured using Test Circuit 2
4-126
ZNBG3113
ZNBG3114
TEST CIRCUIT 1
V2 Characteristics
Type
Frequency
Voltage
AC source
22kHz
350mV p/p enabled
100mV p/p disabled
TEST CIRCUIT 2
V2 Characteristics
Type
AC source
Frequency
Voltage
22kHz
350mV p/p enabled
100mV p/p disabled
4-127
ZNBG3113
ZNBG3114
TYPICAL CHARACTERISTICS
16
14
12
10
8
Note:- Operation with loads > 200µA
is not guaranteed.
Vcc = 5V
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
Vcc = 5V
6V
8V
10V
6
4
2
0
0
20
40
Rcal (k)
60
80
100
0
0.2
0.4
0.6
0.8
1.0
External Vsub Load (mA)
JFET Drain Current v Rcal
Vsub v External Load
2.4
2.3
2.2
2.1
2.0
Vcc = 5V
6V
8V
10V
2
4
6
8
10
12
14
16
Drain Current (mA)
JFET Drain Voltage v Drain Current
4-128
ZNBG3113
ZNBG3114
TYPICAL CHARACTERISTICS
70
60
50
40
30
20
10
0
VCC = 5V
VLOV = 0V
Vcc = 5V
4
Tamb = 70°C
Tamb = 25°C
Tamb = -40°C
2
0
-2
-4
-6
-8
100
1k
10k
100k
1M
10M
10M
1M
0
10
20
30
40
50
Frequency (Hz)
Load Current (mA)
Open Loop Gain v Frequency
LB/HB Offset Voltage v Load Current
2.0
VCC = 5V
180
150
120
90
1.9
Tamb = -40 C
1.8
1.7
1.6
1.5
60
Tamb = 25°C
30
1.4
Tamb = 70°C
0
1.3
VCC = 5V
1.2
100
1k
10k
100k
1M
0
10
20
30
40
50
Frequency (Hz)
Load Current (mA)
Open Loop Phase v Frequency
LB/HB Dropout Voltage v Load Current
100
1.4
1.2
1.0
VCC = 5V
VCC = 5V
VIN=0.1Vpkpk
Test Circuit 1
Stable region
10
0.8
0.6
0.4
0.2
0
Unstable Region
1.0
0.1
100
1k
10k
100k
10pF
100pF
1nF
10nF
100nF
1uF
Frequency (Hz)
LB/HB Load Capacitance
Filter Response
Stability Boundary
4-129
ZNBG3113
ZNBG3114
FUNCTIONAL DIAGRAM
FUNCTIONAL DESCRIPTION
The ZNBG 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 ZNBG series. The ZNBG3113/14 contains 3 such stages. The
negative rail generator is common to both devices.
The drain voltage of the external FET QN is set by the ZNBG device to its normal operating voltage.
This is determined by the on board VD Set reference, for the ZNBG3113 this is nominally 2.2 volts
whilst the ZNBG3114 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
.
Since the FET is a depletion mode transistor, it is often 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
.
4-130
ZNBG3113
ZNBG3114
The following schematic shows the function of the VPOL input. Only one of the two external FETs
numberd Q1 and Q2 are powered at any one time, their selection is controlled by the input VPOL
.
This input is designed to be wired to the power input of the LNB via a high value (10k) resistor.
With the input voltage of the LNB set at or below 14V, FET Q2 will be enabled. With the input
voltage at or above 15.5V, FET Q1 will be enabled. The disabled FET has its gate driven low and
its drain terminal is switched open circuit. It is permissible to connect the drain pins D1 and D2
together if required by the application circuit. FET number Q3 is always active regardless of the
voltage applied to VPOL
.
Control Input Switch Function
Input Sense Polarisation Select
Vertical
FET Q2
FET Q1
≤14 volts
Horizontal
≥ 15.5 volts
4-131
ZNBG3113
ZNBG3114
For many LNB applications tone detection and band switching is required. The ZNBG3113/14
includes the circuitry necessary to detect the presence of a 22kHz tone modulated on the supply
input to the LNB. Referring to the following schematic diagram, the main elements of this detector
are an op-amp enabling the construction of a Sallen Key filter, a rectifier/smoother and a
comparator. Full control is given over the centre frequency and bandwidth of the filter by the
selection of two external resistors and capacitors (one of these resistors, R2, shares the function
of overvoltage protection of pin VPOL).
Pin Crec makes accessible the output of the tone switch rectifier and provides a means of
controlling tone switch delays (mainly HB-LB). For correct operation of the IC, a capacitor and a
parallel connected resistor should be connected between this pin and ground. A capacitor of
100nF and resistor of 1MW will give a LB-HB delay of around 100µs and a HB-LB delay of 30ms.
The comparator circuit utilises no external components.
4-132
ZNBG3113
ZNBG3114
APPLICATIONS CIRCUIT
APPLICATIONS INFORMATION
The above is a partial application circuit for the ZNBG 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 ZNBG 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 ZNBGs 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.
Resistor RCAL sets the drain current at which all external FETs are operated. 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.
The ZNBG 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 1V 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.
4-133
ZNBG3113
ZNBG3114
APPLICATIONS INFORMATION(cont)
The following block diagram shows the main section of an LNB designed for use with the Astra
series of satellites. The ZNBG3113/14 is the core bias and control element of this circuit. The
ZNBG provides the negative rail, FET bias control, polarisation switch control, tone detection and
band switching with the minimum of external components. Compared to other discrete
component solutions the ZNBG circuit reduces component count and overall size required.
Single Universal LNB Block Diagram
Tone detection and band switching is provided on the ZNBG3113/14 devices. The following
diagrams describes how this feature operates in an LNB and the external components required.
The presence or absence of a 22kHz tone applied to pin FIN enables one of two outputs, LB and
HB. A tone present enables HB and tone absent enables LB. The LB and HB outputs are designed
to be compatible with both MMIC and discrete local oscillator applications, selected by pin LOV
.
Referring to Figure 1 wiring pin LOV to ground will force LB and HB to switch between -2.6V
(disabled) and 0V (enabled). Referring to Figure 2 wiring pin LOV to a positive voltage source (e.g.
a potential divider across VCC and ground set to the required oscillator supply voltage, VOSC) will
force the LB and HB outputs to provide the required oscillator supply, VOSC, when enabled.
Tone Detection Function
LOV
FIN
LB
HB
LB
HB
GND
22kHz
—
Disabled
Enabled
Disabled
Enabled
Enabled
Disabled
Enabled
Disabled
-2.6 volts
GND
GND
-2.6 volts
VOSC
VOSC
22kHz
—
Note 1
VOSC
Note 1
Note 1: 0 volts in typical LNB applications but ependent on extenal circuits.
4-134
ZNBG3113
ZNBG3114
Figure 1
LOV grounded
Figure 2
LOV connected to VOSC
4-135
ZNBG3113
ZNBG3114
CONNECTION DIAGRAM
ORDERING INFORMATION
Part Number
ZNBG3113Q20
ZNBG3114Q20
Package
QSOP20
QSOP20
Part Mark
ZNBG3113
ZNBG3114
4-136
ZNBG3113
ZNBG3114
PACKAGE DIMENSIONS
A
IDENTIFICATION
RECESS
C
B
FOR PIN 1
D
PIN No.1
K
PIN
Millimetres
Inches
MIN
8.55
0.635
1.42
0.20
3.81
1.35
0.10
5.79
0°
MAX MIN
MAX
A
B
C
D
E
F
8.74
0.337 0.344
0.025 NOM
1.52
0.30
3.99
1.75
0.25
6.20
8°
0.056 0.06
0.008 0.012
0.15
0.157
0.053 0.069
0.004 0.01
0.228 0.244
G
J
K
0°
8°
Page Number
ZNBG3113
ZNBG3114
Zetex plc.
Fields New Road, Chadderton, Oldham, OL9-8NP, United Kingdom.
Telephone: (44)161 622 4422 (Sales), (44)161 622 4444 (General Enquiries)
Fax: (44)161 622 4420
Zetex GmbH
Zetex Inc.
Zetex (Asia) Ltd.
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Hing Fong Road,
Kwai Fong, Hong Kong
Telephone:(852) 26100 611
Fax: (852) 24250 494
These are supported by
agents and distributors in
major countries world-wide
Zetex plc 1998
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Telefon: (49) 89 45 49 49 0
Fax: (49) 89 45 49 49 49
47 Mall Drive, Unit 4
Commack NY 11725
USA
Telephone: (516) 543-7100
Fax: (516) 864-7630
Internet:http://www.zetex.com
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