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Details, datasheet, quote on part number:ZNBG2001
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Datasheet text preview:
ZNBG2000 ZNBG2001
FET BIAS CONTROLLER
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 2 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 ZNBG2000/1 contains two bias stages. A single resistor allows FET drain current to be set to the desired level. The series also offers the choice of drain voltage to be set for the FETs, the ZNBG2000 gives 2.2 volts drain whilst the ZNBG2001 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 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 ZNBG2000/1 are available in MSOP10 packages for the minimum in devices size. Device operating temperature is -40 to 80°C to suit a wide range of environmental conditions.
FEATURES
· Provides bias for GaAs and HEMT FETs · Drives up to two FETs · Dynamic FET protection · Drain current set by external resistor · Regulated negative rail generator requires only 2
external capacitors
APPLICATIONS
· Satellite receiver LNBs · Private mobile radio (PMR) · Single in single out C Band LNB · Cellular telephones
· Choice in drain voltage · Wide supply voltage range · MSOP surface mount package
ISSUE 1 - AUGUST 2001 1
ZNBG2000 ZNBG2001
ABSOLUTE MAXIMUM RATINGS
Supply Voltage Supply Current Drain Current (per FET) (set by RCAL1 and RCAL2) -0.6V to 15V 100mA 0 to 15mA Output Current Operating Temperature Storage Temperature 100mA -40 to 80°C -40 to 85°C 500mW
Power Dissipation (Tamb 25 C)
MSOP10
ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise
SYMBOL PARAMETER CONDITIONS Min VCC ICC VSUB END ENG fO Supply Voltage Supply Current Substrate Voltage (Internally generated) Output Noise Drain Voltage Gate Voltage Oscillator Freq. ID1 and ID2=0 ID1 and ID2=10mA ISUB= 0 ISUB= -200µA CG=4.7nF, CD=10nF CG=4.7nF, CD=10nF 150 330 -3.5 5 5 24 -2.8
LIMITS
Typ Max 12 10 30 -2 -2 0.02 0.005 800
UNITS
V mA mA V V Vpkpk Vpkpk kHz
DRAIN CHARACTERISTICS
IDO ID Output Current Range Current Current Change Set by RCAL1 0 8 10 15 12 mA mA
IDV
IDT VD
with VCC with Tj Voltage
VCC=5 to 12V Tj=-40 to +80°C ZNBG2000 ID1 and ID2=10mA ZNBG2001 2 1.8
0.5 0.05 2.2 2 2.4 2.2
%/V %/°C V V
Voltage Change
VDV VDT
IGO VOL
with VCC with Tj
VCC= 5 to 12V Tj = -40 to +80°C
0.5 50
%/V ppm
GATE CHARACTERISTICS
Output Current Range Output Voltage Output Low ID1 IG1 and ID2=12mA and IG2=0 -3.5 -3.5 0.4 -2 -2 1 V V V -40 2000 µA
ID1 and ID2=12mA IG1 and IG2= -10µA VOH Output High ID1 and ID2= 8mA IG1 and IG2= 0
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 resistors RCAL1 of value 16k wired from pin RCAL1 to ground. 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
ISSUE 1 - AUGUST 2001 2
ZNBG2000 ZNBG2001
TYPICAL CHARACTERISTICS
16
Vcc = 5V
Drain Current (mA)
14 12 10 8 6 4 2 0 0 10 20 30 40 50
0.0 -0.5
Note:- Operation with loads > 200µA is not guaranteed.
Vsub (V)
-1.0 -1.5 -2.0 -2.5 -3.0 0 0.2
Vcc = 5V 6V 8V 10V
0.4
0.6
0.8
1.0
Rcal (k)
External Vsub Load (mA)
JFET Drain Current v Rcal
Vsub v External Load
2.4
ZNBG2000
2.2
ZNBG2001
Drain Voltage (V)
2.3
Drain Voltage (V)
2.1
2.2
Vcc = 5V 6V 8V 10V
2.0
Vcc = 5V 6V 8V 10V
2.1
1.9
2.0 2 4 6 8 10 12 14 16
1.8 2 4 6 8 10 12 14 16
Drain Current (mA)
Drain Current (mA)
JFET Drain Voltage v Drain Current
JFET Drain Voltage v Drain Current
5
ISSUE 1 - AUGUST 2001 3
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