Diodes ZNBG3211 User Manual

FET BIAS CONTROLLER WITH POLARISATION
SWITCH AND TONE DETECTION

ISSUE 2 - FEBRUARY 2000

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 ZNBG3210/11 includes bias circuits to
drive up to three external FETs. A control
input to the device selects either one of two
FETs as operational using 0V gate switching
methodology, the third FET is permanently
active. This feature is particularly used as an
LNB polarisation switch. Also specific to LNB
applications is the enhanced 22kHz tone
detection and logic output feature which is
used to enable high and low band frequency
switching. The detector has been specifically
designed to reject inerference such as low
frequency signals and DiSEqC tone bursts

- without the use of additional external
components.

Drain current setting of the ZNBG3210/11 is
user selectable over the range 0 to 15mA, this

is achieved with the addition of a single
resistor. The series also offers the choice of
FET drain voltage, the 3210 gives 2.2 volts
drain whilst the 3211 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 ZNBG3210/11 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.

ZNBG3210
ZNBG3211

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 -

•

supporting zero volt gate switching
topology.

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

•

67-1

ZNBG3210
ZNBG3211

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

Substrate
Voltage

Output Noise
Drain Voltage
Gate Voltage

Oscillator
Frequency

= 25°C,VCC=5V,ID=10mA (R

amb

=0,ID2 to ID3=10mA, V

I

D1

=0,ID1 to ID3=10mA, V

I

D2
D1 to ID3
D1 to ID3

=0, ILB=10mA
=0, IHB=10mA

I
I

(Internally generated) I

I

=4.7nF, CD=10nF

C

G

=4.7nF, CD=10nF

C

G

POL
POL

SUB
SUB

=14V
=15.5V

=0
=-200µA

=33kΩ)

CAL

LIMITS

UNITS

MIN. TYP. MAX.

6

15

mA

25

35

mA

25

35

mA

16

25

mA

16

25

mA

-3.5 -3.0 -2.5

-2.4VV

0.02

Vpkpk

0.005

Vpkpk

200 350 800 kHz

67-2

ZNBG3210
ZNBG3211

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

I

V

Dx

POL

(mA) (V) (µA)

=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

∆I
∆I

V

V

V

∆V
∆V

I
I

D

DV
DT

D1

D2

D3

DV
DT

L1
L2

Current 8 1012mA
Current Change

with V
with T

VCC= 5 to 10V

CC

T

j

j

=-40 to +70°C

Drain 1 Voltage:
High
ZNBG3210
ZNBG3211

=10mA, V

I

D1

=10mA, V

I

D1

Drain 2 Voltage:
High
ZNBG3210
ZNBG3211

=10mA, V

I

D2

=10mA, V

I

D2

Drain 3 Voltage:
High
ZNBG3210
ZNBG3211

I

D3

I

D3

=10mA
=10mA

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

=0.5V, V
=0.5V, 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

=14V

POL

=15.5V

POL

I

GOx

GO1
GO1
GO1

GO2
GO2
GO2

GO3
GO3

=0
=-10
=0

=0
=-10
=0

=-10
=0

LIMITS

MIN. TYP. MAX.

-30 2000

-0.05

0

0.05

-2.7

-2.4

-2.0

0.4

0.75

1.0

-0.05

0

0.05

-2.7

-2.4

-2.0

0.4

0.75

1.0

-3.5

-2.9

-2.0

0.4

0.75

1.0VV

0.5

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

67-3

ZNBG3210
ZNBG3211

SYMBOL PARAMETER CONDITIONS

LIMITS

UNITS

MIN. TYP. MAX.

TONE DETECTION CHARACTERISTICS

Filter Amplifier

I

B

V
I

OUT

G

f

R

OUT

V

8

Input Bias Current
Output Voltage
Output Current 5V

R

=150kΩ

F1

5

RF1=150kΩ

OUT

=1.96V, V

=2.1V 400 520 650

FIN

Voltage Gain f=22kHz,VIN=1mV 46 dB
Rejection

Frequency V

=1V p/p sq.w

(AC)in

6

0.02 0.07 0.25

µA

1.75 1.95 2.05 V

µA

1.0 7.5 kHz

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 0.02 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 Disabled

V

LOV

V

=3V IL=0 Disabled

LOV

=0 IL=10mA Enabled

LOV

V

=3V IL=50mA Enabled

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

-1.8 V

CC

0.01VV

0.025

3.1VV

0.01VV

0.025

3.1VV

µA

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, CNB and 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 outputs. CG, 4.7nF, are conne cted between
gate outputs and ground, CD, 10nF, are connected between drain outputs and ground.
5 . These parameters are linearly related to V

6. These parameters are measured using Test Circuit 1

7. These parameters are measured using Test Circuit 2

8. The ZNBG32 series will also reject DiSEqC and other common switching bursts.

Input Current
Threshold

Voltage
Switching Speed

=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

µA

, of

SUB

67-4

TEST CIRCUIT 1

TEST CIRCUIT 2

ZNBG3210
ZNBG3211

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

67-5