Diodes ZNBG3114 User Manual

FET BIAS CONTROLLER WITH POLARISATION SWITCH AND TONE DETECTION

ISSUE 1 - OCTOBER 1998

ZNBG3113 ZNBG3114

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 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.

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.

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 Programmable tone delay

•

Compliant with ASTRA control

•

specifications QSOP surface mount package

•

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. 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.

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 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.

APPLICATIONS

Satellite receiver LNBs

•

Private mobile radio (PMR)

•

Cellular telephones

•

4-123

ZNBG3113 ZNBG3114

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

SYMBOLPARAMETER CONDITIONS

V I

CC

V

E E

f

O

Supply Voltage 5 10 V

CC

Supply Current ID1 to ID3=0

I I I I

Substrate Voltage (Internally generated) I

SUB

Output Noise

ND NG

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

ZNBG3113 ZNBG3114

SYMBOLPARAMETER CONDITIONS

GATE CHARACTERISTICS

I

GO

V V V

V V

G1O G1L G1H

G2O G2L G2H

G3L 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

DV DV

I I

D

L1 L2

Current 8 10 12 mA Current Change

DV DT

D1

with V with T

Drain 1 Voltage:

CC j

VCC= 5 to 10V

=-40 to +70°C

T

j

High

=10mA, V

I

D1

I

=10mA, V

D1

D2

ZNBG3113 ZNBG3114

Drain 2 Voltage: High

=10mA, V

I

D2

=10mA, V

I

D2

D3

ZNBG3113 ZNBG3114

Drain 3 Voltage: High ZNBG3113 ZNBG3114

=10mA, V

I

D3

=10mA, V

I

D3

Voltage Change

DV DT

with V with T

CC j

VCC= 5 to 10V

=-40 to +70°C

T

j

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 =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 %/°C

%/V ppm

µA µA

4-125

ZNBG3113 ZNBG3114

SYMBOLPARAMETER CONDITIONS

LIMITS

MIN. TYP. MAX.

TONE DETECTION CHARACTERISTICS

Filter Amplifier

I

B

V I

OUT

G

V I

LEAK

Input Bias Current Output Voltage

OUT

Output Current 5V Voltage Gain f=22kHz,VIN=1mV 46 dB

V

Rectifier

Output Voltage

OUT

Leakage Current

=150kΩ

R

F1

5

RF1=150kΩ

=1.96V, V

OUT

5

RF1=150kΩ IL=-10µA

5

RF1=150kΩ V

=2.1V 400 520 650

FIN

=3V

OUT

0.04 0.15 1.0

1.75 1.95 2.05 V

1.8 2.0 2.2 20 200 nA

Comparator

TH

Threshold Voltage

5

f=0 2.95 3.2 3.45 V

V

Output Stage

V I V

V

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

-3.5

-0.01

-0.025

2.903.0

-3.5

-0.01

-0.025

2.903.0

-2.750-2.5

CC

0.01VV

0.025

3.1VV

0.01VV

0.025

3.1VV

POLARITY SWITCH CHARACTERISTICS

I

POL

V

T

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

TPOL

SPOL

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

V

µA

SUB

, of

4-126

TEST CIRCUIT 1

TEST CIRCUIT 2

ZNBG3113 ZNBG3114

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

ZNBG3113 ZNBG3114

TYPICAL CHARACTERISTICS

16

14

12

10

8

6

4

2

0

0204060 100

R

(k)

cal

Vcc = 5V

80

JFET Drain Current v Rcal

2.4

2.3

2.2

2.1

2.0

Vcc = 5V

6V 8V 10V

2468 16

10

12 14

Drain Current (mA)

JFET Drain Voltage v Drain Current

Note:- Operation with loads > 2 00µA

0.0

-0.5

-1.0

-1.5

-2.0

-2.5

-3.0

0 0.2 0.4 0 .6 1.0

is not guaranteed.

Vcc = 5V

6V 8V

10V

External Vsub Load (mA)

Vsub v External Load

0.8

4-128