Zetex ZNBG3110Q20, ZNBG3111Q20 Datasheet

FET BIAS CONTROLLER WITH POLARISATION SWITCH AND TONE DETECTION
ISSUE 2 - APRIL 1998
ZNBG3110 ZNBG3111
DEVICE DESCRIPTION
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 resistor the devices provide drain voltage and 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.
The ZNBG3110/11 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.
Drain current setting of the ZNBG3110/11 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 3110 gives
2.2 volts drain whilst the 3111 gives 2 volts.
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.
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 -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 ZNBG3110/11 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
Provides bias for GaAs and HEMT FETs
Drives up to three 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
Polarisation switch for LNBs
22KHz tone detection for band
switching Compliant with ASTRA control
specifications QSOP surface mount package
APPLICATIONS
Satellite receiver LNBs
Private mobile radio (PMR)
Cellular telephones
4-123
ZNBG3110 ZNBG3111
ABSOLUTE MAXIMUM RATINGS
Supply Voltage -0.6V to 12V Supply Current 100mA Input Voltage (V Drain Current (per FET) 0 to 15mA
(set by R
CAL
Operating Temperature -40 to 70°C Storage Temperature -50 to 85°C
) 25V Continuous
POL
)
Power Dissipation (T
amb
= = 25°C)
QSOP20 500mW
ELECTRICAL CHARACTERISTICS. TEST CONDITIONS (Unless otherwise stated):T
SYMBOL PARAMETER CONDITIONS
V
CC
I
CC
V
SUB
E
ND
E
NG
f
O
Supply Voltage 5 10 V Supply Current ID1 to ID3=0
I I I I
Substrate
(Internally generated) I
Voltage Output Noise
Drain Voltage Gate Voltage
C C
Oscillator Frequency
= = 25°C,VCC=5V,ID=10mA (R
amb
=0,ID2 to ID3=10mA, V
D1
=0,ID1 to ID3=10mA, V
D2
=0, ILB=10mA
D1 to ID3
=0, IHB=10mA
D1 to ID3
I
=4.7nF, CD=10nF
G
=4.7nF, CD=10nF
G
POL POL
SUB SUB
=14V =15.5V
=0 =-200µA
=33kΩΩ)
CAL
LIMITS
UNITS
MIN. TYP. MAX.
15
mA
35
mA
35
mA
45
mA
45
mA
-3.5 -3.0 -2.5
-2.4VV
0.02
Vpkpk
0.005
Vpkpk
200 350 800 kHz
4-124
ZNBG3110 ZNBG3111
SYMBOL PARAMETER CONDITIONS
GATE CHARACTERISTICS
I
GO
V
G1O
V
G1L
V
G1H
V
G2O
V
G2L
V
G2H
V
G3L
V
G3H
Output Current Range
Output Voltage Gate 1 Off Low High
Output Voltage Gate 2 Off Low High
Output Voltage Gate 3 Low High
V
I
Dx
POL
(mA) (V) (µµA)
=0 V
I
D1
I
D1
I
D1
I
D2
I
D2
I
D2
I
D3
I
D3
POL
=12 V
POL
=8 V
POL
=0 V
POL
=12 V
POL
=8 V
POL
=12 I =8 I
DRAIN CHARACTERISTICS
I
DI DI
V
V
V
DV DV
I I
D
DV DT
D1
D2
D3
DV DT
L1 L2
Current 8 10 12 mA Current Change
with V with T
VCC= 5 to 10V
CC
T
j
j
=-40 to +70°C
Drain 1 Voltage: High ZNBG3110 ZNBG3111
=10mA, V
I
D1
I
=10mA, V
D1
Drain 2 Voltage: High ZNBG3110 ZNBG3111
=10mA, V
I
D2
=10mA, V
I
D2
Drain 3 Voltage: High ZNBG3110 ZNBG3111
=10mA, V
I
D3
=10mA, V
I
D3
Voltage Change with V with T
VCC= 5 to 10V
CC
T
j
j
=-40 to +70°C
Leakage Current Drain 1 Drain 2
V
D1
V
D2
=0.1V, V =0.1V, V
=14 I =15.5 I =15.5 I
=15.5 I =14 I =14 I
=15.5V
POL
=15.5V
POL
=14V
POL
=14V
POL
=15.5V
POL
=15.5V
POL
=14V
POL
=15.5V
POL
I
GOx
GO1 GO1 GO1
GO2 GO2 GO2
GO3 GO3
=-10 =-10 =0
=-10 =-10 =0
=-10 =0
LIMITS
MIN. TYP. MAX.
-30 2000
-2.7
-2.4
-2.0
-2.7
-2.4
-2.0
0.4
0.75
1.0
-2.7
-2.4
-2.0
-2.7
-2.4
-2.0
0.4
0.75
1.0
-3.5
-2.9
-2.0
0.4
0.75
1.0VV
0.2
0.05
2.0
2.2
2.4
1.8
2.0
2.2VV
2.0
2.2
2.4
1.8
2.0
2.2VV
2.0
2.2
2.4
1.8
2.0
2.2VV
0.5 50
10 10
UNITS
µA
V V V
V V V
%/V %/°C
%/V ppm
µA µA
4-125
ZNBG3110 ZNBG3111
SYMBOL PARAMETER CONDITIONS
LIMITS
MIN. TYP. MAX.
TONE DETECTION CHARACTERISTICS
Filter Amplifier
I
B
V I
OUT
G
OUT
V
Input Bias Current Output Voltage Output Current 5V
=150k
R
F1
5
RF1=150k
OUT
=1.96V, V
=2.1V 400 520 650
FIN
Voltage Gain f=22kHz,VIN=1mV 46 dB
0.04 0.15 1.0
1.75 1.95 2.05 V
Comparator
V
TH
Threshold Voltage
5
f=0 2.95 3.2 3.45 V
Output Stage
V I V
V
V
V
LOV
LOV
LBL
LBH
HBL
HBH
Volt. Range IL=50mA(LB or HB)-0.5V
L
OV
LOV Bias Current V LB Output Low
LB Output High V
HB Output Low
HB Output High V
=0 0.04 0.15 1.0
LOV
=0 IL=-10µA Enabled
V
LOV
V
=3V IL=0 Enabled
LOV
=0 IL=10mA Disabled
LOV
V
=3V IL=50mA Disabled
LOV
=0 IL=-10µA Enabled
V
LOV
V
=3V IL=0 Enabled
LOV
=0 IL=10mA Disabled
LOV
V
=3V IL=50mA Disabled
LOV
6 7
6 7
6 7
6 7
-3.5
-0.01
-0.025
2.903.0
-3.5
-0.01
-0.025
2.903.0
-2.750-2.5
-2.750-2.5
CC
0.01VV
0.025
3.1VV
0.01VV
0.025
3.1VV
POLARITY SWITCH CHARACTERISTICS
I
POL
V
TPOL
T
SPOL
NOTES:
1. The negative bias voltages specified are generated on-chip using an internal oscillator. Two external capacitors, C 47nF are required for this purpose.
2. The characteristics are measured using an external reference resistor R
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 o utputs. C gate outputs and ground, C 5 . These parameters are lneearly related to V
6. These parameters are measured using Test Circuit 1
7. These parameters are measured using Test Circuit 2
Input Current Threshold
Voltage Switching Speed
, 10nF, are connected between drain outputs and ground.
D
=25V (Applied via R
V
POL
=25V (Applied via R
V
POL
=25V (Applied via R
V
POL
CC
=10kΩ)
POL
=10kΩ)
POL
=10kΩ)
POL
of value 33k wired from pins R
CAL
10 20 40 14 14.75 15.5 V
100 ms
to ground.
CAL
, 4.7nF, are connected between
G
-1.8 V
and C
NB
UNITS
µA
µA
µA
µA
SUB
, of
4-126
TEST CIRCUIT 1
TEST CIRCUIT 2
ZNBG3110 ZNBG3111
V2 Characteristics Type AC source Frequency 22kHz Voltage 350mV p/p enabled
100mV p/p disabled
V2 Characteristics Type AC source Frequency 22kHz Voltage 350mV p/p enabled
100mV p/p disabled
4-127
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