HMC981LP3E Просмотр технического описания (PDF) - Hittite Microwave

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HMC981LP3E

ACTIVE BIAS CONTROLLER

Hittite Microwave 

v01.0411

HMC981LP3E

ACTIVE BIAS CONTROLLER

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Figure 1. Daisy Chain Operation

Operation Modes

HMC981LP3E can be configured to bias both enhancement and depletion mode external amplifiers. The mode of

operation can be selected by setting two pins (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 HMC981LP3E.

The HMC981LP3E 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, HMC981LP3E will stay in standby mode.

Please note that the external negative voltage should be between -2.5V to -3.5V for HMC981LP3E 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)

FLOAT

MODE2

(Depletion/Slave Mode)

---

MODE3

(Enhancement Mode)

GND

FLOAT

GND

VGATEFB

FLOAT

FLOAT

GND

GND

VNEGIN

Connected to

VNEGOUT

Connected to

External VSS

N/A

Connected to

GND

Description

Depletion mode transistor. Internal negative voltage generator is

active and generates -2.5V. Sample application schematic given

shown in Fig.2a.

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.

Not allowed. HMC981LP3E stays in standby.

Enhancement mode transistor. Internal negative voltage generator is

disabled. Sample application schematic given shown in Fig.2c.

For price, delivery, and to place orders, please contact Hittite Microwave Corporation:

2 Elizabeth Drive, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

Order On-line at www.hittite.com

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