HMC981

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HMC981
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ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
Typical Applications
Features
• Military & Space
Automatic Gate voltage adjustment (No Calibration
required)
Supply Voltage: 4V to 12V
• Test Instrumentation
Digital Voltage: 3.3V to 5V
• Fiber Optic Modulator Driver Biasing
• CATV Laser Driver Biasing
Controls both Enhancement and Depletion type
devices
• Cellular Base Station
Adjustable Drain Current up to 200mA
• Wireless Infrastructure Equipment
Sink/Source Gate Current Capability
• Microwave Radio & VSAT
Optional Internal negative voltage generation that
can be disabled to use external negative rail
Fast Enable/Disable
Trigger-out Output for Daisy Chain Power-Up and
Power-Down Sequencing
Functional Diagram
General Description
HMC981 is an active bias controller that automatically
adjusts the gate voltage of an external amplifier
to achieve constant bias current. It can be used to
bias any enhancement and depletion type amplifiers
operating in Class-A regime with Drain voltages from
4V to 12V and drain currents up to 200mA, offering a
complete biasing solution.
HMC981 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 [email protected]
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

Electrical Specifications, TA = +25°C, VDD=8V, VDIG= 3.3V, Depletion Master
Unless Otherwise Noted
Symbol
Conditions
Vdd
IDD
VDD = 8V
VDIG Quiescent Current
IDIG
Typ.
4
VDD = 4V
VDD Quiescent Current
Min.
Max.
12
Units
V
EN = VDIG
7
mA
EN = GND
3
mA
EN = VDIG
7.5
mA
EN = GND
4
mA
VDIG= 3.3 V
3
mA
VDIG= 5 V
5
mA
Negative Voltage Output
VNEG
-2.5
V
Oscillator Frequency
FOSC
300
kHz
Voltage Reference
VREF
1.42
V
Enable Input Threshold
Switch Input Threshold
Short Circuit Disable Input Threshold
ENTHRS
SWTHRS
DSCTHRS
Vinlow
Vinhigh
1
1.4
V
Vinlow
Vinhigh
1
1.4
1
1.4
SW=GND
20
SW=VDIG
80
V
V
Vinlow
Vinhigh
V
V
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
VDRAIN set to 8V,
IDRAIN set to 160 mA
VDRAIN
ΔVDRAIN
80
200
mA
0.4
%/V
0.02
%/C
4
VDRAIN set to 8V,
IDRAIN set to 160 mA
mA
12
BIAS CONTROLLERS - CHIP
Parameter
Supply Voltage
V
1.5
%/C
-2.5
V
VNEG Characteristics
Negative Voltage Output
VNEG
VNEG Current Sink
INEG
VDD= 4V
0
8
mA
VDD= 8V
0
15
mA
0.8
mA
VGATE Characteristics
GATE Current Supply
IG
-0.8
VGATE Low Level
VG_MIN
VNEG
V
VGATE High Level
VG_MAX
VNEG+4.5
V
VG2 Characteristics
VG2 Current Supply
IG2
VG2 Adjustment Range
VG2
VG2<1.5V
-0.1
0.1
mA
VG2>1.5V
-1
1
mA
1
VDD-1.3
V
3.3
5
V
VDIG Characteristics
Adjustment Range
VDIG Quiescent Current
VDIG
IDIG
VDD= 8 V,
3
mA
SW= GND
10
Ohm
SW=VDIG
5
Ohm
VDIG=EN =3.3 V
SW Characteristics
Internal Switch Resistance
RDS_ON
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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2
HMC981
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ACTIVE BIAS CONTROLLER

8.5
6
8
VDRAIN (V)
VDRAIN (V)
Load Regulation @ VDD=8V,
SW=VDIG=3.3V
6.5
5.5
5
4.5
30
7.5
7
+25C
+85C
-55C
20
+25C
+85C
-55C
40
50
60
70
6.5
80
80
100
120
55
-2.45
54
-2.47
VNEG (V)
53
52
+25C
+85C
-55C
50
3.3
3.7
No load condition
-2.49
-2.51
4.1
4.5
-2.55
4.9
4
6
-2.4
VNEG (V)
VNEG (V)
-2.4
-2.5
+25C
+85C
-55C
4
6
10
12
VNEG Load Regulation @ VDD=12V
-2.3
-2.6
8
SUPPLY VOLTAGE (V)
-2.3
2
200
-2.53
VNEG Load Regulation @ VDD=4V
0
180
+25C
+85C
-55C
VDIG (V)
-2.7
160
VNEG Line Regulation vs. Supply Voltage
IDRAIN vs. VDIG[1][2]
51
140
IDRAIN (mA)
IDRAIN (mA)
IDRAIN (mA)
BIAS CONTROLLERS - CHIP
Load Regulation @ VDD=6V, VDIG=3.3V,
SW=GND
8
INEG (mA)
-2.5
+25C
+85C
-55C
-2.6
10
-2.7
0
4
8
12
16
INEG (mA)
[1] IDRAIN is set to 53 mA
[2] HMC465LP5 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 [email protected]
HMC981
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ACTIVE BIAS CONTROLLER

8
6
6
4
4
2
0
-2
-4
2
4
6
8
EN
VDRAIN
VG2
VNEG
VGATE
-6
-8
12
-8
0
0
-2
-4
EN
VDRAIN
VG2
VNEG
VGATE
-6
2
10
12
14
Power Up Waveform
20
8
VDD
VDRAIN
VDIG
VG2
VNEG
VGATE
4
VDD
VDRAIN
VDIG
VG2
VNEG
VGATE
6
VOLTAGE (V)
6
VOLTAGE (V)
18
Shutdown Waveform
8
2
0
4
2
0
-2
-2
-4
-4
10
20
30
TIME (ms)
40
0
50
VNEG Load Transient VDD=4V
20
40
60
TIME (ms)
80
100
VNEG Load Transient VDD=6V
-0.8
20
-1.3
10
-2.3
-10
15
-2.425
10
-2.45
5
-2.475
0
-5
-2.5
-10
-2.525
-20
-2.8
0
0.5
1
TIME (ms)
1.5
2
INEG (mA)
0
INEG (mA)
-1.8
-2.4
VNEG (V)
0
VNEG (V)
16
TIME (ms)
TIME (ms)
BIAS CONTROLLERS - CHIP
Disable Waveform
8
VOLTAGE (V)
VOLTAGE (V)
Enable Waveform
-15
-2.55
0
0.5
1
1.5
2
TIME (ms)
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 [email protected]
4
HMC981
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ACTIVE BIAS CONTROLLER

5
VG2 Load Regulation @ VDD=6V
1
5
0.5
4.5
4
0
3.5
-0.5
VG2 (V)
VGATE (V)
BIAS CONTROLLERS - CHIP
VGATE Load Regulation @ VDD=6V
-1
-1.5
-2
-3
-1.25
-1
-0.75 -0.5 -0.25
0
0.25
IG (mA)
0.5
0.75
1
2
1.5
+25C
+85C
-55C
-2.5
3
2.5
1
VG2=0.9V
VG2=1.78V
VG2=2.74V
VG2=3.71V
0.5
1.25
0
-2
-1.5
-1
-0.5
0
0.5
1
1.5
IG2 (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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Application Support: Phone: 978-250-3343 or [email protected]
2
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

VDD
12V
VG2_CONT, VDRAIN
-0.5V to VDD + 0.5V
SW, EN, CP_OUT, VGATEFB,
VNEGFB, TRIG_OUT, DISBL_SC,
ISENSE
-0.5V to VDIG + 0.5V
VDIG
5.5V
VNEG
-4V to GND
VG2
-0.5V to VDD + 0.5V
Junction Temperature
125 °C
Continuous Pdiss (T = 85 °C)
(Derate 19.19 mW/°C above 85 °C)
0.77 Watts
ELECTROSTATIC SENSITIVE DEVICE
OBSERVE HANDLING PRECAUTIONS
Thermal Resistance (RTH)
(Junction to package bottom)
52.1 °C/W
Storage Temperature
-65 to +150 °C
Operating Temperature
-55 to +85 °C
ESD Sensitivity (HBM)
Class 1B
Note that there are two different voltage domains on HMC981; a
high voltage domain Vdd, and a low voltage domain VDIG. Take
necessary precautions not to violate ABS MAX ratings of each
subdomains.
NOTES:
1. ALL DIMENSIONS IN INCHES [MILLIMETERS]
2. DIE THICKNESS IS 0.010 (0.254)
3. TYPICAL BOND PAD IS 0.0039 SQUARE
4. BOND PAD METALLIZATION: ALUMINUM
5. NO BACKSIDE METAL
6. NO CONNECTION REQUIRED FOR UNLABELED BOND PADS
7. OVERALL DIE SIZE IS ±.002
Outline Drawing
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 [email protected]
BIAS CONTROLLERS - CHIP
Absolute Maximum Ratings [1]
6
HMC981
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ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
Pad Descriptions
7
Pad Number
Function
Description
1, 5, 8, 10,
13, 15, 20,
23, 25, 26,
Die Bottom
GND
These pads and the die bottom must be connected to a
high quality RF/DC ground.
2
EN
Enable pad. System is enabled when Ven is HIGH (VDIG).
If left floating, Ven defaults to HIGH (enabled).
3
SW
Internal switch resistance control pad. If left floating, VSW
defaults to HIGH.
12
DISBLSC
Disables short circuit lock down when pulled to ground.
Leave it floating to enable short circuit lock down.
4
VG2CONT
Control voltage of the VG2. Use a resistor divider between
VDD and GND to set the voltage. VG2 is typically 1.3V
lower than the VG2CONT
19
VG2
Second gate control.
6-7, 29-30
VDD, VDIG
Bias supply pan. Connect supply voltage
to this pad with appropriate filtering.
9
VREF
1.5V reference voltage. 0.1uF or greater capacitor to GND
is needed for noise filtering.
11
ISENSE
To adjust the bias current of the external amplifier connect
a resistor (Rsense) from ISENSE pad to GND. Use Eqn.2
to
determine the required Rsense value.
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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Application Support: Phone: 978-250-3343 or [email protected]
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

Pad Descriptions (Continued)
Function
Description
14
TRGOUT
Trigger out signal. Generates a HIGH (3.5V) signal when
the active bias system stabilizes. This signal can be
used to trigger next device (ENABLE) if more than one
HMC981 is used in a daisy chain.
16, 17
VDRAIN
Drain voltage. Should be connected to the supply
terminal of the external amplifier. A minimum 100 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 10μF capacitor should be connected between
the gate (base) terminal of the external amplifier and GND
as close to the amplifier as possible.
21
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.
For detailed usage please refer to the “Negative Voltage
Generator” section.
22
VNEGFB
Feedback (Control) pad for Negative Voltage Generator
Charge Pump. Float to activate the negative voltage
generator / Sort to GND to disable the negative voltage
generator.
24
VGATEFB
Control pad for VGATEFB. Float VGATEFB when a
depletion mode transistor is biased. Selects the mode of
operation along with VNEGFB pad. For detailed usage
please refer to the Table 2.
27, 28
CPOUT
Negative voltage generator charge pump output. Negative
voltage generator needs a flying capacitor, a reservoir
capacitor and two diodes to operate. Please refer to the
application schematic for more info.
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
HMC981
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ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
Application Circuit
Notes:
[1] Adjust R10 with respect to equation (2).
9
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 [email protected]
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

Mounting & Bonding Techniques for MMICs
The die should be attached directly to the ground plane with epoxy (see HMC general Handling, Mounting , Bonding Note).
Follow these precautions to avoid permanent damage.
Storage: All bare die are placed in either Waffle or Gel based ESD protective containers, and then sealed in an ESD protective
bag for shipment. Once the sealed ESD protective bag has been opened, all die should be stored in a dry nitrogen environment.
Cleanliness: Handle the chips in a clean environment. DO NOT attempt to clean the chip using liquid cleaning systems.
Static Sensitivity: Follow ESD precautions to protect against ESD strikes.
Transients: Suppress instrument and bias supply transients while bias is applied. Use shielded signal and bias cables to minimize
inductive pick-up.
General Handling: The chip may be handled by a vacuum collet or with a sharp pair of tweezers.
Mounting
Epoxy Die Attach: Apply a minimum amount of epoxy to the mounting surface so that a thin epoxy fillet is observed around the
perimeter of the chip once it is placed into position. Cure epoxy per the manufacturer’s schedule.
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 [email protected]
BIAS CONTROLLERS - CHIP
Handling Precautions
10
HMC981
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ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
Application Notes
Detailed Description
The HMC981 is a fully-integrated Active Bias Controller (ABC) that automatically adjusts the gate voltage of amplifiers
operating in the Class-A regime. 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 HMC981 employs an integrated control circuitry
to achieve safe power-up and power-down sequencing of the targeted amplifier. The HMC981 can provide auto-bias
solution virtually any amplifier in the market (both enhancement and depletion type) with a quiescent current of up to
200 mA and a supply voltage of up to 12V.
The HMC981 has an integrated negative voltage generator to synthesize 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 HMC981 achieves excellent bias stability over supply and temperature variations with low supply voltage down
to 4V. The gate control can both sink and source current (±0.8 mA) to achieve constant bias current over input power
variations applied to the amplifier. The HMC981 also generates a second gate voltage (VG2). VG2 can be adjusted
through a resistor divider connected to VDD for amplifiers which require second gate voltage.
The HMC981 ensures the protection of the external amplifier during turn on/off by adjusting the sequence of VDRAIN,
VGATE and VG2 outputs. HMC981 controls the bias current of the amplifier under bias with the gate control driver. The
current passing through the amplifier is continuously sampled and is used to control the VGATE voltage connected to
the gate of the amplifier.
The HMC981 employs a SW pad 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 HMC981 has a built-in short circuit protection feature to protect both itself and the amplifier under bias against
short circuit conditions at the VDRAIN output. Refer to the section under the “Short Circuit Protection” section for
details.
Digital Power Supply (VDIG)
The HMC981 requires an external low voltage bias rail (3.3V to 5.0V). VDIG powers the internal logic circuitry. VDIG
draws an average of 3 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 HMC981 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 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 HMC981 should be connected to the drain (collector) of the amplifier under bias for the active
bias control feedback and power-up/down sequencing to work.
11
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 [email protected]
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

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).
(1)
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 SW pad. RDS_ON is typically equal
to 5 Ohms when SW is pulled up to VDIG, and is typically equal to 10 Ohms when SW is pulled down to GND. If SW
is left floating, it is pulled up to VDIG through an internal weak pull-up. Recommended settings for the SW position
are given in Table-1. Not using the HMC981 in the recommended settings will increase the power dissipation of the
part and may increase the part-to-part variation.
Table 1. Recommended Current Range Configuration
Current Range (mA)
Condition
RDS_ON (Ohm)
20 to 80
SW=GND
10
80 to 200
SW=VDIG
5
Negative Voltage Generator (VNEGOUT)
The HMC981 has an internally regulated charge pump block to generate negative voltage (VNEGOUT) required for
depletion mode devices. The HMC981 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. The HMC981 is
designed to reject the ripple on the VNEGOUT by isolating VNEGOUT from the VGATE. The negative voltage is only
required for depletion mode devices, and it can be disabled through the VGATEFB and VNEGFB pads. Where an
enhancement device is targeted or a negative supply is already available in the system, simply connect the available
negative supply to the VNEG pad. See Table-2 for detail on how to set this operation mode.
BIAS CONTROLLERS - CHIP
VDD = VDRAIN + IDRAIN x RDS_ON
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 HMC981 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 HMC981 discharges VDRAIN and VG2 down to GND and it pulls the VGATE down to VNEG. Please see
the “Active Bias Control Loop” section for detailed explanation.
Active Bias Control Loop
The HMC981 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 adjust VGATE to achieve constant quiescent bias through the external amplifier.
The HMC981 continuously compensates for any supply, temperature, process variations and threshold drifts due to
aging. The part-to-part, temperature, and supply variation of the HMC981 is excellent. Thus, by using an accurate
sense resistor connected to the ISENSE pad, expensive calibration procedures in high volume production could be
avoided.
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 [email protected]
12
HMC981
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ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
The gate control of the HMC981 is designed to both sink and source current in to the gate of the targeted amplifier (at
least ±0.8 mA). This unique feature is important to achieve nearly constant quiescent bias through the amplifier under
varying gate current at different input power values.
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.
IDRAIN=32/Rsense (A)
(2)
Self Protection Feature
Due to the small resistance of the internal switch FET a large amount of current may flow through the HMC981.
HMC981 limits the maximum current to protect itself under such fault conditions, by turnung of VDRAIN and VGATE.
The HMC981 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 -1V) 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.
Power-up and Enable Sequencing
To ensure the protection of the external amplifier, the HMC981 provides a power-up sequence for enabling 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 final phase of the power-up sequence is completed by increasing the VGATE linearly until the set
IDRAIN value is achieved.
For power-down and disabling the same sequencing is applied in the reverse order.
Daisy-Chain Operation
HMC981 produces a trigger out signal (TRIGOUT pad#13) when VDRAIN output is enabled. This trigger signal can
be used to enable additional HMC981 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-1 presents a sample use of three
HMC981s in an amplification chain. Please note that, only one of the HMC981 is used to generate the negative
voltage and the remaining HMC981 is set to receive external negative voltage (which is provided from the master
HMC981). Generating negative voltage from a single HMC981 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 chip that has the
negative voltage generator.
13
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 [email protected]
HMC981
v00.0611
BIAS CONTROLLERS - CHIP
ACTIVE BIAS CONTROLLER

Figure 1. Daisy Chain Operation
Operation Modes
HMC981 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 HMC981.
The HMC981 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, HMC981 will stay in standby mode.
Please note that the external negative voltage should be between -2.5V to -3.5V for HMC981 to operate. If your
application requires negative voltages outside this range please contact Hittite application support.
Table 2 - Mode Selection
MODE1
(Depletion/Master Mode)
MODE2
(Depletion/Slave Mode)
--MODE3
(Enhancement Mode)
VNEGFB
VGATEFB
VNEGIN
Description
FLOAT
FLOAT
Connected to
VNEGOUT
Depletion mode transistor. Internal negative voltage generator is
active and generates -2.5V. Sample application schematic given
shown in Fig.2a.
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.2b.
FLOAT
GND
N/A
Not allowed. HMC981 stays in standby.
GND
GND
Connected to
GND
Enhancement mode transistor. Internal negative voltage generator is
disabled. Sample application schematic given shown in Fig.2c.
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 [email protected]
14
HMC981
v00.0611
BIAS CONTROLLERS - CHIP
ACTIVE BIAS CONTROLLER

Figure 2a. Depletion/Master Mode Amplifier Typical Application Circuit (Mode 1)
Figure 2b. Depletion/Slave Mode Amplifier Typical Application Circuit (Mode 2)
15
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 [email protected]
HMC981
v00.0611
Figure 2c. Enhancement Mode Amplifier Typical Application Circuit (Mode 3)
Table 3 - List of Bias Settings for Various Hittite Amplifiers
Hittite Part Number
VDRAIN (V)
VDD (V)
IDRAIN (mA)
RSENSE (kOhm)
R2 (kOhm)
R1 (kOhm)
VG2 (V)
LNAs
HMC-ALH140
4
4.60
60
0.53
open
open
-
HMC-ALH216
4
4.45
90
0.36
open
open
-
HMC-ALH244
4
4.45
45
0.71
open
open
HMC-ALH310 [1]
2.5
3.02 [1]
52
0.62
open
open
-
HMC-ALH311[1]
2.5
3.04 [1]
54
0.59
open
open
-
HMC-ALH313 [1]
2.5
3.02 [1]
52
0.62
open
open
-
HMC-ALH382 [1]
2.5
3.14 [1]
64
0.50
open
open
-
5
5.30
30
1.07
5.60
5
1.5
HMC-ALH435
HMC-ALH444
5
5.55
55
0.58
5.09
5
1.5
HMC-ALH476
4
4.45
90
0.36
open
open
-
HMC490
5
6.00
200
0.16
open
open
-
HMC490LP5
5
6.00
200
0.16
open
open
-
HMC504LC4B
4
4.45
90
0.36
open
open
-
HMC594
6
6.50
100
0.32
open
open
-
HMC594LC3B
6
6.50
100
0.32
open
open
-
HMC609
6
6.85
170
0.19
open
open
-
HMC609LC4
6
6.85
170
0.19
open
open
-
HMC752LC4[1]
3
3.70 [1]
70
0.46
open
open
-
HMC753LP4E
5
5.55
55
0.58
5.09
5
1.5
HMC772LC4
4
4.45
45
0.71
open
open
-
BIAS CONTROLLERS - CHIP
ACTIVE BIAS CONTROLLER

Linear & Power
HMC-ABH209
5
5.80
80
0.40
open
open
-
HMC-ABH264
5
5.60
120
0.27
open
open
-
HMC-AUH317
4
4.80
160
0.20
open
open
-
[1] For applications below 4V supply please contact factory.
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 [email protected]
16
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

Table 3 - List of Bias Settings for Various Hittite Amplifiers (Continued)
BIAS CONTROLLERS - CHIP
Hittite Part Number
VDRAIN (V)
VDD (V)
IDRAIN (mA)
RSENSE (kOhm)
R2 (kOhm)
R1 (kOhm)
HMC-AUH318
4
4.80
160
0.20
open
open
VG2 (V)
-
HMC-AUH320
4
4.65
130
0.25
open
open
-
HMC442
5
5.43
85
0.38
open
open
-
HMC442LC3B
5
5.42
84
0.38
open
open
-
HMC442LM1
5
5.43
85
0.38
open
open
-
HMC499
5
6.00
200
0.16
open
open
-
HMC499LC4
5
6.00
200
0.16
open
open
-
Wideband (Distributed)
HMC-ALH482
4
4.45
45
0.71
open
open
-
HMC-AUH232
5
5.90
180
0.18
4.52
5
1.5
HMC-AUH249
5
6.00
200
0.16
4.38
5
1.5
HMC-AUH312
8
8.60
60
0.53
2.82
5
1.8
HMC460
8
8.60
60
0.53
open
open
-
HMC460LC5
8
8.75
75
0.43
open
open
-
HMC463
5
5.60
60
0.53
open
open
-
HMC463LH250
5
5.60
60
0.53
open
open
-
HMC463LP5
5
5.60
60
0.53
open
open
-
HMC465
8
8.80
160
0.20
2.33
5
1.5
HMC465LP5
8
8.80
160
0.20
2.33
5
1.5
HMC562
8
8.80
80
0.40
open
open
-
HMC633
5
5.90
180
0.18
open
open
-
HMC633LC4
5
5.90
180
0.18
open
open
-
HMC634
5
5.90
180
0.18
open
open
-
HMC634LC4
5
5.90
180
0.18
open
open
-
HMC-930
10
10.88
175
0.18
3.95
5
3.5
HMC870LC5
7
7.83
165
0.19
open
open
-
HMC871LC5
8
8.38
75
0.43
open
open
-
Microwave & Optical Drivers
17
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 [email protected]
HMC981
v00.0611
ACTIVE BIAS CONTROLLER

BIAS CONTROLLERS - CHIP
Notes:
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 [email protected]
18