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HMC980
v00.0312
Active Bias Controller
High Current
Bias Controllers - Chip
Typical Applications
Features
•
Automatic Gate voltage adjustment (No Calibration required)
•
Microwave Radio & VSAT
•
Military & Space
•
Supply Voltage (5V to 16.5V)
•
Test Instrumentation
•
Bias both Enhancement or Depletion type
devices
•
Fiber Optic Modulator Driver Biasing
•
CATV Laser Driver Biasing
•
Cellular Base Station
•
Wireless Infrastructure Equipment
Functional Diagram
•
Adjustable Drain Current up to 1.6 A
•
Sink or source gate current
•
Internal negative voltage generation
•
Can be disabled to use external negative rail
•
Fast Enable/Disable
•
Trigger-out Output for Daisy Chain
•
Power-Up and Power-Down Sequencing
•
Over/Under Current Alarm with built-in hystresis
•
Die Size: 1.4 x 2.26 x 0.25mm
General Description
HMC980 is an active bias controller that can
automatically adjust the gate voltage of an external
amplifier to achieve constant bias current. With an
integrated controller, HMC980 achieves safe power on/
off, disable/enable and automatic supply sequencing
ensuring the safety of the external amplifier. It can
be used to bias any enhancement and depletion
type amplifier operating in Class-A regime with
drain voltages (VDRAIN) from 5V to 16.5V and drain
currents (IDRAIN) up to 1.6 A, offering a complete
biasing solution.
HMC980 achieves excellent bias stability over supply,
temperature and process variations, and eliminates
the required calibration procedures usually employed
to prevent RF performance degradation due to
such variations. All data shown herein is taken with
appropriate probes.
1
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
Order On-line at www.hittite.com
Application Support: Phone: 978-250-3343 or apps@hittite.com
HMC980
v00.0312
Active Bias Controller
High Current
Electrical Specifications, TA = +25°C, VDD=12V, VDIG= 3.3V, Depletion Master
Unless Otherwise Noted
Symbol
Conditions
Vdd
IDIG
Charge Pump Oscillator Frequency
FOSC
Voltage Reference
VREF
ALMTRIG Input Threshold
Enable Input Threshold
S0, S1 Input Threshold
ALMTRIG
ENTHRS
SWTHRS
Max.
16.5
Units
V
EN = VDIG
19
mA
EN = GND
7.5
mA
EN = VDIG
20
mA
EN = GND
9
mA
VDIG= 3.3 V
3.5
mA
VDIG= 5 V
6.5
mA
300
kHz
IDD
VDD = 12V
VDIG Quiescent Current
Typ.
5
VDD = 5V
VDD Quiescent Current
Min.
1.44
Vinlow
Vinhigh
V
1
V
1
V
1.4
V
Vinlow
Vinhigh
V
1
1.4
V
Vinlow
Vinhigh
1.4
V
VDRAIN Characteristics
DRAIN Current Adjustment Range
DRAIN Current Change Over Digital Voltage
DRAIN Current Change Over Temperature
DRAIN Range
VDRAIN Change Over Temperature
IDRAIN
ΔIDRAINV
S1=S0=GND
0.05
0.3
A
S1=GND, S0=VDIG
0.3
0.6
A
S1=VDIG, S0=GND
0.6
1.2
A
S1=VDIG, S0=VDIG
1.2
1.6
VDRAIN set to 12V,
IDRAIN set to 400 mA
VDRAIN
ΔVDRAIN
%/V
0.023
%/C
5
VDRAIN set to 12V,
IDRAIN set to 400 mA
A
0.4
16.5
0.02
Bias Controllers - Chip
Parameter
Supply Voltage
V
%/C
VNEG Characteristics
Negative Voltage Output
VNEG
VNEG Current Sink
INEG
0
-2.46
IG
-4
V
60
mA
4
mA
VGATE Characteristics
GATE Current Supply
VGATE Low Level
VG_MIN
VNEG
V
VGATE High Level
VG_MAX
VNEG+4.5
V
VG2 Characteristics
VG2 Current Supply
VG2 Adjustment Range
IG2
VG2VG2>2V
-1
1
mA
VG2>6V
-5
5
mA
1
VDD-1.3
V
3.3
5
V
VG2
VDIG Characteristics
Adjustment Range
VDIG Quiescent Current
VDIG
IDIG
VDD= 12V,
VDIG=EN =3.3 V
3.5
mA
SW Characteristics
Internal Switch Resistance
RDS_ON
S1=S0=GND
2.8
Ohm
S1=GND, S0=VDIG
1.55
Ohm
S1=VDIG, S0=GND
0.85
Ohm
S1=VDIG, S0=VDIG
0.7
Ohm
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Application Support: Phone: 978-250-3343 or apps@hittite.com
2
HMC980
v00.0312
Active Bias Controller
High Current
Bias Current Accuracy[1]
Bias Current Accuracy[2]
1475
IDrain is set to: 388mA
400
1425
IDRAIN (mA)
IDRAIN (mA)
IDrain is set to: 1409mA
1450
395
390
385
1400
1375
1350
380
+25 C
+85 C
-55 C
375
+25 C
+85 C
-55 C
1325
1300
370
3.3
3.5
3.6
3.8
4.0
4.2
4.3
4.5
4.7
4.8
3.3
5.0
3.5
3.6
3.8
4
4.3
4.5
4.7
4.8
5
Shutdown Waveform
Power Up Waveform
14
14
12
12
VDD (V)
VDRAIN (V)
VDIG(V)
VG2 (V)
VNEG (V)
VGATE (V)
8
VDD(V)
VDRAIN (V)
VDIG (V)
VG2 (V)
VNEG (V)
VGATE (V)
10
VOLTAGE (V)
10
6
4
2
8
6
4
2
0
0
-2
-2
-4
-4
0
10
20
30
40
50
60
TIME (ms)
70
80
90
100
Enable Waveform
0
20
40
60
80 100 120
TIME (ms)
140
160
180
200
Disable Waveform
14
16
12
12
EN(V)
VDRAIN (V)
VG2 (V)
VNEG (V)
VGATE (V)
10
VOLTAGE (V)
8
VOLTAGE (V)
4.2
VDIG (V)
VDIG (V)
VOLTAGE (V)
Bias Controllers - Chip
405
4
0
8
6
4
2
0
-4
EN(V)
VDRAIN (V)
VG2 (V)
VNEG (V)
VGATE (V)
-8
-2
-4
-6
-12
0
1
2
3
4
5
TIME (ms)
6
4
5
6
7
8
9
10
TIME (ms)
[1] HMC637LP5 is used as external amplifier
[2] HMC591LP5 is used as external amplifier
3
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Application Support: Phone: 978-250-3343 or apps@hittite.com
HMC980
v00.0312
Active Bias Controller
High Current
6
6
5
5
4
3
2
100
150
200
+25C
+85C
-55C
3
+25C
+85C
-55C
50
4
250
2
300
300
350
400
Load Regulation @ VDD=16.5V,
VDIG=5.0V, SW0=GND, SW1=VDIG
500
550
17
17
16
16
15
15
+25C
+85C
-55C
14
14
+25C
+85C
-55C
13
600
700
800
900
1000
1100
13
1200
1200
1300
1400
1500
1600
IDRAIN (mA)
IDRAIN (mA)
VNEG Load Regulation @ VDD=5V
VNEG Load Regulation @ VDD=16.5V
-2
-2
-2.1
-2.1
-2.2
-2.2
VNEG (V)
VNEG (V)
600
Load Regulation @ VDD=16.5V,
VDIG=5.0V, SW0=VDIG, SW1=VDIG
VDRAIN (V)
VDRAIN (V)
450
IDRAIN (mA)
IDRAIN (mA)
Bias Controllers - Chip
Load Regulation @ VDD=5V, VDIG=3.3V,
SW0=3.3V, SW1=GND
VDRAIN (V)
VDRAIN (V)
Load Regulation @ VDD=5V, VDIG=3.3V,
SW0=GND, SW1=GND
-2.3
-2.4
+25 C
+85 C
-55 C
-2.3
-2.4
+25 C
+85 C
-55 C
-2.5
-2.5
0
5
10
15
INEG (mA)
20
25
30
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
INEG (mA)
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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4
HMC980
v00.0312
Active Bias Controller
High Current
40
-2.2
40
-2.25
30
-2.25
30
20
-2.3
20
10
-2.35
10
-2.4
0
-2.4
0
VNEG (V)
-2.3
-2.35
-2.45
-10
-20
-2.5
-20
-2.55
-30
-2.55
-30
-2.6
-40
-2.6
-2.45
-10
-2.5
0
1
2
3
4
5
6
7
8
9
10
-40
0
1
2
3
4
TIME (ms)
6
7
8
9
10
VG2 Load Regulation @ VDD=12V [1]
0
10
9
-0.25
IDrain is set to : 388mA
VG2=0.97V
VG2=1.81V
VG2=3.73V
VG2=6.68V
8
7
VG2 (V)
-0.5
-0.75
-1
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
IDrain is set to : 388mA
6
5
4
3
+25C
+85C
-55C
-1.25
-1.5
5
TIME (ms)
VGATE Load Regulation @ VDD=12V [1]
VGATE (V)
INEG (mA)
VNEG (V)
VNEG Load Transient VDD=16.5V
-2.2
INEG (mA)
Bias Controllers - Chip
VNEG Load Transient VDD=5V
2
1
6
7
0
-8
-6
-4
-2
0
2
4
6
8
IG2 (mA)
IG (mA)
VNEG Line Regulation vs. Supply Voltage
-2.44
No load condition
VNEG (V)
-2.46
-2.48
+25C
+85C
-55C
-2.5
5
7
9
11
13
15
17
SUPPLY VOLTAGE (V)
[1] HMC637LP5 is used as external amplifier
5
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Application Support: Phone: 978-250-3343 or apps@hittite.com
HMC980
v00.0312
Active Bias Controller
High Current
VDD
18V
S0, S1, EN, ALM,ALMTRG, VREF,
VNEGFB, VGATEFB, TRIG_OUT,
ISENSE, ALML, ISET, ALMH, FIXBIAS
-0.5V to VDIG + 0.5V
CP_VDD
VDD-0.5V to VDD+0.5V
CP_OUT, VG2_CONT, VG2, VDRAIN
-0.5V to VDD + 0.5V
VDIG
5.5V
VNEG
-4V to GND
VGATE
VNEG to GND
Junction Temperature
125 °C
Continuous Pdiss (T = 85 °C)
(Derate 94.79 mW/°C above 85 °C)
3.8 Watt
Thermal Resistance (RTH)
(Junction to package bottom)
10.6 °C/W
Storage Temperature
-65 to +150 °C
Operating Temperature
-55 to +85 °C
ESD Sensitivity (HBM)
Class 1A
Note that there are two different voltage domains on HMC980; a
high voltage domain Vdd, and a low voltage domain VDIG. Take
necessary precautions not to violate ABS MAX ratings of each
subdomains.
ELECTROSTATIC SENSITIVE DEVICE
OBSERVE HANDLING PRECAUTIONS
Outline Drawing
Bias Controllers - Chip
Absolute Maximum Ratings
NOTES:
1. ALL DIMENSIONS ARE IN INCHES [MM]
2. DIE THICKNESS IS .010”
3. BOND PAD PER TABLE
4. BOND PAD METALIZATION: ALUMINUM
5. NO BACKSIDE METAL
6. OVERALL DIE SIZE ±.002”
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Application Support: Phone: 978-250-3343 or apps@hittite.com
6
HMC980
v00.0312
Active Bias Controller
High Current
Bias Controllers - Chip
Pad Descriptions
7
Pad Number
Function
Description
1,12,13,20,21,
35
GND
These pads and the die bottom must be connected to a
high quality RF/DC ground.
2
ALM
Over/under current alarm. Provides an active high signal
(VDIG) if the quiescent bias exceed the upper threshold
or drops below the lower threshold.
19
TRIGOUT
Trigger out signal. Generates a HIGH (3.3V) signal when
the active bias system stabilizes. This signal can be
used to trigger next device (ENABLE) if more than one
HMC980 is used in a daisy chain.
3
ALMTRG
Dummy alarm trigger signal to create test alarm when
taken HIGH (3.3V). Defaults to LOW (GND) when left
floating.
4
EN
Enable pad. Bias control loop is enabled when Ven
is HIGH(VDIG). If left floating, Ven defaults to HIGH
(enabled).
5,6
S1,S0
Control pads for internal switch resistance. If left floating, default to HIGH.
Refer to Table-1 in Application Notes for recommended
settings.
7,8,9,10,11
VDD
Bias supply Pad. Connect supply voltage to this pad
with appropriate filtering.
14
FIXBIAS
A high precision (e.g. 0.5%, ±25 ppm TCR) 10K resistor
to ground is recommended for good bias accuracy.
Interface Schematic
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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HMC980
v00.0312
Active Bias Controller
High Current
Pad Descriptions (Continued)
Function
Description
15
ALMH
A high precision resistor (e.g. 0.5%, ±25 ppm TCR) to
ISet pad is recommended for good bias accuracy. The
value of the resistor sets the threshold. If alarm feature
is not used ALMH can be shorted to ISet.
ISET
A high precision resistor (e.g. 0.5%, ±25 ppm TCR)
between ALML and ISet is recommended for good bias
accuracy. The total external resistance from ISet pad to
GND should always be equal to 5 k Ω.
ALML
A high precision resistor (e.g. 0.5%, ±25 ppm TCR)
to GND is recommended for good bias accuracy. The
value of the resistor sets the threshold value for under
current alarm. If alarm feature is not used ALML can be
shorted to ISet.
ISENSE
Drain current adjustment pad. To adjust the bias current
of the external amplifier connect a resistor (Rsense)
from ISENSE pad to GND according to eqn(2) on page
13-15. A high precision resistor (e.g. 0.5%, ±25 ppm
TCR) is recommended for good bias accuracy.
16
17
18
Interface Schematic
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Bias Controllers - Chip
Pad Number
8
HMC980
v00.0312
Active Bias Controller
High Current
Bias Controllers - Chip
Pad Descriptions (Continued)
9
Pad Number
Function
Description
22,23,24,25
26
VDRAIN
Drain voltage. Should be connected to the supply terminal of the external amplifier. A minimum 10 nF capacitor
has to be placed close to the external amplifier to
improve load regulation.
VGATE
Gate Control pad for external amplifier. Connect to the
gate (base) of the external amplifier. In order to guarantee stability, a 2.2μF capacitor should be connected
between the gate (base) terminal of the external amplifier and GND as close to the amplifier as possible.
28
VNEG
Negative input to the chip. Should be supplied with
CPOUT when negative voltage generator is enabled, or
connect to external VSS when negative voltage generator is enabled. Defaults to -2.5V. If a value different than
-2.5V required, please contact factory.
29
VG2
Second gate control.
30
VG2_CONT
Control voltage of the second gate pad VG2. Use a
resistor divider between VDD and GND to set the voltage. VG2 is typically 1.3V lower than the VG2CONT.
27
Interface Schematic
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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HMC980
v00.0312
Active Bias Controller
High Current
Pad Descriptions (Continued)
Function
Description
31
VGATEFB
Control pad for VGATEFB. Float VGATEFB when a
depletion mode transistor is biased. Selects the mode
of operation along with VNEGFB pad.
32
VNEGFB
Feedback (Control) pad for Negative Voltage Generator Charge Pump. Float to activate the negative voltage
generator / Short to GND to disable the negative voltage
generator.
33
VREF
1.44V reference voltage.
34
VDIG
3.3V-5V Digital Bias supply Pad. Connect supply voltage to this pad with appropriate filtering.
37
CP_OUT
Negative voltage generator charge pump output. Negative voltage generator requires a flying capacitor, a
reservoir capacitor and two diodes to operate.
38
CP_VDD
Bias supply for negative voltage generator. Connect
supply voltage with appropriate filtering. CP_VDD
supply voltage should be same as VDD.
Interface Schematic
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Bias Controllers - Chip
Pad Number
10
HMC980
v00.0312
Active Bias Controller
High Current
Bias Controllers - Chip
Application Circuit
Notes:
[1] A variable resistor is assembled on RSENSE slot to adjust bias current for evaluating various different amplifiers
without soldering.
11
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
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Application Support: Phone: 978-250-3343 or apps@hittite.com
HMC980
v00.0312
Active Bias Controller
High Current
Detailed Description
All amplifiers require stable quiescent current to operate at their specifications. Many amplifiers in the market require
external biasing to achieve stable quiscent current. HMC980 is a fully integrated biasing solution for such amplifiers.
With an internal feedback, the automatic gate voltage control achieves constant quiescent bias through the amplifier
under bias, independent of temperature and amplifier threshold variations. The quiescent current is adjusted with
a resistor connected externally. The HMC980 employs an integrated control circuitry to manage safe power-up
and power-down sequencing of the targeted amplifier. The HMC980 can provide auto-bias solution to virtually any
amplifier in the market (both enhancement and depletion type) with a quiescent current of up to 1.6A and a supply
voltage of up to 16.5V.
The HMC980 has an integrated negative voltage generator to create negative voltages required to drive depletion
mode amplifiers. If an external negative supply is already available or an enhancement mode device is targeted, the
negative voltage generator can be disabled.
The HMC980 achieves excellent bias stability over supply and temperature variations. The gate control can both sink
and source current (±4 mA) which is required to compensate for charging gate current of the amplifier over input power
variations. The HMC980 also generates a second gate voltage VG2. VG2 can be adjusted through a resistor divider
connected to VDD for the amplifiers which require second gate voltage.
The HMC980 ensures safety of the external amplifier during turn on/off by automatically adjusting the sequence of
VDRAIN, VGATE and VG2 outputs.
Bias Controllers - Chip
Application Notes
The HMC980 has a built-in over-under current alarm feature. If a fault conditions arises (either under or over current)
an alarm signal is generated (ALM, active HIGH). The current alarm signal provided in HMC980 does not affect the
operation of the controller. It is included for monitoring purposes where a system level protection can be implemented
with external control circuitry.
The HMC980 employs S0, S1 pads to control RDS_ON resistance of the internal switch between VDD and VDRAIN.
Refer to the section under the “Supply and Drain Voltage” section for details.
The HMC980 has a built-in self protection feature to protect itself against short circuit conditions at the VDRAIN
output. The HMC980 has also a built-in VNEG fault protection feature to protect both itself and the amplifier under
bias against short circuit conditions at the VNEG pad.
Digital Power Supply (VDIG)
The HMC980 requires an external low voltage bias rail (3.3V to 5.0V). VDIG powers the internal logic circuitry. VDIG
draws and average of 3.5 mA from a 3.3V. VDIG can accept voltages up to 5.0V.
Supply and Drain Voltage (VDD and VDRAIN)
The VDD supply to the HMC980 is directly connected to the VDRAIN output through an internal MOSFET switch. This
internal MOSFET is controlled through power-up sequencing which ensures that no voltage is applied to the drain of
the external amplifier until the gate voltage is pulled down to VNEG (ensuring external amplifier is pinched-off). The
VDRAIN output of the HMC980 should be connected to the drain (collector) of the amplifier under bias for the active
bias control feedback and power-up/down sequencing to operate properly.
There will be a voltage drop from VDD to VDRAIN due to finite RDS_ON resistance of the internal switch. To
compensate for this voltage drop choose the VDD value as shown in equation (1).
VDD = VDRAIN + IDRAIN x RDS_ON
(1)
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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12
HMC980
v00.0312
Active Bias Controller
High Current
Bias Controllers - Chip
where VDRAIN is the supply voltage of the external amplifier and IDRAIN is the desired constant bias current through
the external amplifier.
Note that RDS_ON resistance of the internal FET switch can be adjusted through S0, S1 pads based on the DRAIN
current requirement as shown in table-1. RDS_ON is typically equal to 0.7 Ohm when S0 and S1 are pulled up to
VDIG, and is typically equal to 2.8 Ohm when S0 and S1 are pulled down to GND. If S0 and S1 pads are left floating,
it is pulled up to VDIG through an internal weak pull-up. Recommended settings for the S0 and S1 positions are given
in Table-1. Not using the HMC980 in the recommended settings may increase the power dissipation of the part and
the part-to-part variation.
Table 1. Recomended Current Range Configuration
Current Range (A)
Condition
RD_ON Value (Ohm)
0.05 to 0.3
S1=S0=GND
2.8
0.3 to 0.6
S1=GND, S0=VDIG
1.55
0.6 to 1.2
S1=VDIG, S0=GND
0.85
1.2 to 1.6
S1=VDIG, S0=VDIG
0.7
Negative Voltage Generator (VNEGOUT)
The HMC980 has internal regulated charge pump circuitry to generate the negative voltage (VNEGOUT) required for
depletion mode devices. The HMC980 generates -2.5V at the VNEGOUT output in default configuration. It requires
two diodes and two capacitors connected externally as shown in the sample application schematics. It can be disabled through the VGATEFB and VNEGFB pads, if an enhancement device is targeted or a negative supply is already
available in the system. In this configuration, simply connect the available negative supply to the VNEG pad. See
Table-2 for the operation mode selection. The HMC980 is designed to reject the ripple on the VNEGOUT pad by isolating VNEGOUT from the VGATE. Thus, switching noise of the charge-pump is effectively isolated from the external
amplifier.
Enable/Disable (EN)
The active bias control loop is enabled when EN is pulled up to VDIG, and it is disabled when it is pulled down to GND.
If EN is left floating HMC980 is enabled through an internal weak pull-up. Note that VNEG operation is independent
of EN condition. EN signal controls the operation of only VGATE, VG2 and VDRAIN outputs. When EN pulled down
to GND, the HMC980 discharges VDRAIN and VG2 down to GND and it pulls the VGATE down to VNEG. When EN
pulled high to VDIG, HM980 enables, VDRAIN and VG2, and enables the bias control loop to automatically adjust the
VGATE voltage. Please see the “Active Bias Control Loop” section for detailed explanation and refer to the Enable and
Disable waveforms for transient characteristics.
Active Bias Control Loop
The HMC980 regulates the bias current (IDRAIN) of the amplifier under bias through VGATE output connected to
the gate of the external amplifier. In this closed loop operation the current passing through the amplifier under bias is
sampled and is used to automatically adjust VGATE to achieve constant quiescent bias through the external amplifier.
The HMC980 continuously adjusts VGATE voltage to achieve constant DRAIN current over any supply, temperature, process variations and threshold drifts due to aging. The part-to-part, temperature, and supply variation of the
HMC980 is excellent. Thus, by using an accurate sense resistor connected to the ISENSE pad, expensive calibration
procedures in high volume production could be avoided.
The gate control of the HMC980 is designed to both sink and source current in to the gate of the targeted amplifier (at
least ±4 mA). This unique feature is important to achieve nearly constant quiescent bias through the amplifier under
varying gate current at different input power values.
13
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Phone: 978-250-3343
Fax: 978-250-3373
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HMC980
v00.0312
Active Bias Controller
High Current
IDRAIN=150/Rsense (A)
(2)
VG2 Voltage Adjustment
The HMC980 generates a second gate voltage (VG2). VG2 can be adjusted through a resistor divider connected to
VG2_CONT for the amplifiers which require second gate voltage. Eqn. (3) gives the formula to adjust VG2
:
VG2(V)= VDD*R4/(R3+R4) - 1.3
(3)
For instance, choosing 5.1k Ohm as R3 and 3.3k Ohm as R4 sets VG2 voltage to 3.4V when VDD=12V. For improved
accuracy, choose resistor values below 5k Ohm on R3.
Self Protection Feature
Due to the small resistance of the internal switch FET between VDD and VDRAIN, a large amount of current may flow
through the HMC980. HMC980 limits the maximum current to self protect itself under such fault conditions, by turning
off VDRAIN and VGATE.
The HMC980 will remain in this protection mode until a full power-cycle or enable/disable cycle is applied.
VNEG Fault Detection Feature
In depletion mode operation VNEG is continuously monitored against short circuit fault to GND. If VNEG rises above
a preset value (typically -0.6V) the system and the external amplifier are disabled by pulling VDRAIN and VG2 to GND
and VGATE to VNEG. The system will stay in this stand-by mode until short fault at VNEG is fixed.
Bias Controllers - Chip
The bias current passing through the external amplifier can be adjusted with RSENSE, where RSENSE is the R10
connected from ISENSE to GND. Use the relation given in equation (2) to set the desired bias current through the
external amplifier.
Over/Under Current Alarm
The HMC980 provides over and under current alarm indicator ALM (pad#2) signal. The ALM is pulled up to VDIG
when the IDRAIN current exceeds ± 6% (With the given R11, R12, and R13 values in application circuit) of IDRAIN
regulation target value as shown in Figure 1. The alarm threshold level is user adjustable through R11,R12, and R13
according to the following equations:
Over current ALM Threshold = Iocth = IDRAIN (1+R11/(R12+R13)),
Under current ALM Threshold = Iucth = IDRAIN (1-R12/(R12+R13)) ,
where R12+R13 should always be equal to 5 kΩ (%1 accuracy)
Threshold values possess a small built-in hysterisis. The condition of ALM signal does not effect the operation of
HMC980. It is provided only for monitoring purposes.
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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14
HMC980
v00.0312
Bias Controllers - Chip
Active Bias Controller
High Current
Over current
Set current
Under current
ALARM
Figure 1. Current Alarm Behavior
Power-up and Enable Sequencing
To ensure the safety of the external amplifier, the HMC980 provides an automatic power-up sequence for enabling the
active bias control loop. During start-up VDRAIN and VG2 are kept at GND while VGATE is taken to the most negative supply available (VGATE=VNEG). This ensures that external amplifier is completely pinched-off before VDRAIN
is applied. When EN signal is received, VDRAIN is applied and the active bias loop is enabled. After the VDRAIN
is applied, VG2 is generated. The power-up sequence is completed by increasing the VGATE linearly until the set
IDRAIN value is reached.
For power-down and disabling, the same sequencing is applied in the reverse order.
Daisy-Chain Operation
HMC980 produces a trigger out signal (TRIGOUT pad#19) when the quiscent current is in regulation. This trigger
signal can be used to enable additional HMC980 chips in a chain of amplifiers. The triggering sequence can be routed
in any way, from input to output, or from output to input depending on the use. Figure-2 shows a sample use of three
HMC980s in an amplification chain. Please note that, only one of the HMC980 (in master mode) is used to generate
the negative voltage and the remaining HMC980 (in slave mode) is set to receive external negative voltage (which is
provided from the master depletion mode HMC980). Generating negative voltage from a single HMC980 reduces the
number of the components in the system, and decreases the over all current consumption.
Please note that, to ensure proper start-up, the system enable signal should be applied to the depletion master mode
device that has the negative voltage generator.
15
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
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HMC980
v00.0312
Bias Controllers - Chip
Active Bias Controller
High Current
Figure 2. Daisy Chain Operation
Operation Modes
HMC980 can be configured to bias both enhancement and depletion mode external amplifiers. The mode of operation
can be selected by setting two pads (VNEGFB, VGATEFB) as tabulated in Table-2. The connection to the VNEGIN
should be adjusted accordingly.
In order not to bias external amplifier in a wrong region, please make sure that the correct mode of operation is
selected before powering up the HMC980.
The HMC980 does not allow the internal negative voltage generator to work if an enhancement mode is selected.
Therefore, if VNEGFB is left floating while VGATEFB is grounded, HMC980 will stay in standby mode.
Please note that in depletion slave mode the external negative voltage should be between -2.3V to -3.5V for HMC980
to operate. If your application requires negative voltages outside this range please contact Hittite application support.
Table 2. Mode Selection
VNEGFB
MODE1
(Depletion/Master Mode)
MODE2
(Depletion/Slave Mode)
--MODE3
(Enhancement Mode)
VNEGIN
Description
FLOAT
Connected to
VNEGOUT
Depletion mode transistor. Internal negative voltage generator is
active and generates -2.5V. Sample application schematic given
shown in Fig.3a.
GND
FLOAT
Connected to
External VSS
Depletion mode transistor. Internal negative voltage generator is
disabled. An external negative voltage less than -2.3V should be
connected to VNEGIN. Sample application schematic given shown
in Fig.3b.
FLOAT
GND
N/A
Not allowed. HMC980 stays in standby.
GND
Connected to
GND
Enhancement mode transistor. Internal negative voltage generator is
disabled. Sample application schematic given shown in Fig.3c.
FLOAT
GND
VGATEFB
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16
HMC980
v00.0312
Bias Controllers - Chip
Active Bias Controller
High Current
Figure 3a. Depletion/Master Mode Amplifier Typical Application Circuit (Mode 1)
Figure 3b. Depletion/Slave Mode Amplifier Typical Application Circuit (Mode 2)
17
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
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HMC980
v00.0312
Bias Controllers - Chip
Active Bias Controller
High Current
Figure 3c. Enhancement Mode Amplifier Typical Application Circuit (Mode 3)
For biasing Hittite amplifiers compatable with HMC980 refer to the Table 3, where values of the external components
are provided on typical application circuit shown in Figure 3a.
Table 3 - List of Bias Settings for Various Hittite Amplifiers
Hittite Part Number
VDRAIN
(V)
VDD
(V)
IDRAIN
(mA)
5
5.83
295
RSENSE
(kOhm)
R4
(kOhm)
R3
(kOhm)
VG2
(V)
S1
S0
open
open
-
GND
GND
GND
Gain Blocks & Drivers
HMC-AUH256
0.508
LNAs
HMC-ALH435
5
5.08
30
5.000
6.13
5
1.5
GND
HMC-ALH444
5
5.15
55
2.727
5.95
5
1.5
GND
GND
HMC490
5
5.56
200
0.750
open
open
-
GND
GND
HMC490LP5
5
5.56
200
0.750
open
open
-
GND
GND
HMC594
6
6.28
100
1.500
open
open
-
GND
GND
HMC594LC3B
6
6.28
100
1.500
open
open
-
GND
GND
HMC609
6
6.48
170
0.882
open
open
-
GND
GND
HMC609LC4
6
6.48
170
0.882
open
open
-
GND
GND
HMC753LP4E
5
5.15
55
2.727
5.95
5
1.5
GND
GND
Linear & Power
HMC-ABH209
5
5.22
80
1.875
open
open
-
GND
GND
HMC-ABH264
5
5.34
120
1.250
open
open
-
GND
GND
HMC442
5
5.24
85
1.765
open
open
-
GND
GND
HMC442LC3B
5
5.24
84
1.786
open
open
-
GND
GND
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
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Application Support: Phone: 978-250-3343 or apps@hittite.com
18
HMC980
v00.0312
Active Bias Controller
High Current
Table 3 - List of Bias Settings for Various Hittite Amplifiers (Continued)
Bias Controllers - Chip
Hittite Part Number
HMC442LM1
VDRAIN
(V)
VDD
(V)
IDRAIN
(mA)
RSENSE
(kOhm)
R4
(kOhm)
R3
(kOhm)
VG2
(V)
S1
S0
5
5.24
85
1.765
open
open
-
GND
GND
HMC499
5
5.56
200
0.750
open
open
-
GND
GND
HMC499LC4
5
5.56
200
0.750
open
open
-
GND
GND
HMC-ABH241
5
5.62
220
0.682
open
open
-
GND
GND
HMC-APH403
5
5.74
475
0.316
open
open
-
GND
VDIG
HMC-APH460
5
5.77
900
0.167
open
open
-
VDIG
GND
HMC-APH462
5
6.22
1440
0.104
open
open
-
VDIG
GND
HMC-APH473
5
5.92
1080
0.139
open
open
-
VDIG
GND
HMC-APH478
5
5.77
900
0.167
open
open
-
VDIG
GND
HMC-APH510
5
5.99
640
0.234
open
open
-
GND
VDIG
HMC-APH518
5
5.81
950
0.158
open
open
-
VDIG
GND
HMC-APH596
5
6.12
400
0.375
open
open
-
GND
GND
HMC-APH608
5
5.81
950
0.158
open
open
-
VDIG
GND
HMC486
7
8.11
1300
0.115
open
open
-
VDIG
GND
HMC486LP5 /
HMC486LP5E
7
8.11
1300
0.115
open
open
-
VDIG
GND
HMC487LP5 /
HMC487LP5E
7
8.11
1300
0.115
open
open
-
VDIG
GND
HMC489LP5 /
HMC489LP5E
7
8.11
1300
0.115
open
open
-
VDIG
GND
HMC498
5
5.70
250
0.600
open
open
-
GND
GND
HMC498LC4
5
5.70
250
0.600
open
open
-
GND
GND
HMC590
7
7.70
820
0.183
open
open
-
VDIG
GND
HMC590LP5 /
HMC590LP5E
7
7.70
820
0.183
open
open
-
VDIG
GND
HMC591
7
8.14
1340
0.112
open
open
-
VDIG
GND
HMC591LP5 /
HMC591LP5E
7
8.14
1340
0.112
open
open
-
VDIG
GND
HMC592
7
8.16
750
0.200
open
open
-
GND
VDIG
HMC608LC4
5
5.87
310
0.484
open
open
-
GND
GND
HMC693
5
6.24
800
0.188
open
open
-
GND
VDIG
HMC756
7
8.22
790
0.190
open
open
-
GND
VDIG
HMC757
7
8.11
395
0.380
open
open
-
GND
GND
HMC757LP4E
5
6.12
400
0.375
open
open
-
GND
GND
HMC863
6
7.05
375
0.400
open
open
-
GND
GND
HMC863LP4E
6
7.05
375
0.400
open
open
-
GND
GND
HMC864
6
7.16
750
0.200
open
open
-
GND
VDIG
HMC906
6
7.02
1200
0.125
open
open
-
VDIG
GND
5.5
6.52
1200
0.125
open
open
-
VDIG
GND
HMC949
7
8.02
1200
0.125
open
open
-
VDIG
GND
HMC965LP5E
6
7.02
1200
0.125
open
open
-
VDIG
GND
HMC968
6
6.77
900
0.167
open
open
-
VDIG
GND
HMC969
6
6.77
900
0.167
open
open
-
VDIG
GND
HMC943LP5E
Wideband (Distributed)
19
HMC-AUH232
5
5.50
180
0.833
5.18
5
1.5
GND
GND
HMC-AUH249
5
5.56
200
0.750
5.07
5
1.5
GND
GND
HMC-AUH312
8
8.17
60
2.500
3.06
5
1.8
GND
GND
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
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HMC980
v00.0312
Active Bias Controller
High Current
Hittite Part Number
VDRAIN
(V)
VDD
(V)
IDRAIN
(mA)
RSENSE
(kOhm)
R4
(kOhm)
R3
(kOhm)
VG2
(V)
S1
S0
HMC460
8
8.17
60
2.500
open
open
-
GND
GND
HMC460LC5
8
8.21
75
2.000
open
open
-
GND
GND
HMC463
5
5.17
60
2.500
open
open
-
GND
GND
HMC463LH250
5
5.17
60
2.500
open
open
-
GND
GND
HMC463LP5
5
5.17
60
2.500
open
open
-
GND
GND
HMC465
8
8.45
160
0.938
2.48
5
1.5
GND
GND
HMC465LP5
8
8.45
160
0.938
2.48
5
1.5
GND
GND
HMC562
8
8.22
80
1.875
open
open
-
GND
GND
HMC633
5
5.50
180
0.833
open
open
-
GND
GND
HMC633LC4
5
5.50
180
0.833
open
open
-
GND
GND
HMC634
5
5.50
180
0.833
open
open
-
GND
GND
HMC634LC4
5
5.50
180
0.833
open
open
-
GND
GND
HMC-930
10
10.49
175
0.857
4.22
5
3.5
GND
GND
HMC-459
8
8.81
290
0.517
4.77
5
3
GND
GND
HMC-464
8
8.81
290
0.517
4.77
5
3
GND
GND
HMC464LP5 /
HMC464LP5E
8
8.81
290
0.517
4.77
5
3
GND
GND
HMC559
10
11.12
400
0.375
4.55
5
4
GND
GND
HMC619
12
12.84
300
0.500
4.82
5
5
GND
GND
HMC619LP5 /
HMC619LP5E
12
12.84
300
0.500
4.82
5
5
GND
GND
HMC635
5
5.78
280
0.536
open
open
-
GND
GND
HMC635LC4
5
5.78
280
0.536
open
open
-
GND
GND
HMC637
12
13.12
400
0.375
6.27
5
6
GND
GND
HMC637LP5 /
HMC637LP5E
12
13.12
400
0.375
4.62
5
5
GND
GND
HMC659
8
8.84
300
0.500
4.74
5
3
GND
GND
HMC659LC5
8
8.84
300
0.500
4.74
5
3
GND
GND
HMC797
10
11.12
400
0.375
3.80
5
3.5
GND
GND
HMC797LP5E
10
11.12
400
0.375
3.80
5
3.5
GND
GND
Bias Controllers - Chip
Table 3 - List of Bias Settings for Various Hittite Amplifiers (Continued)
Microwave & Optical Drivers
HMC870LC5
7
7.46
165
0.909
open
open
-
GND
GND
HMC871LC5
8
8.21
75
2.000
open
open
-
GND
GND
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343
Fax: 978-250-3373
Order On-line at www.hittite.com
Application Support: Phone: 978-250-3343 or apps@hittite.com
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