# US 8,487,695 B2 · Differential source follower having 6dB gain with applications to WiGig baseband filters

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- Number: US 8,487,695 B2
- Document ID: US8487695B2
- Status: Granted
- Kind: B2
- Application number: 13/243,880
- Filed: 2011-09-23
- Published: 2013-03-28
- Granted: 2013-07-16
- Earliest claimed: 2011-09-23
- Assignees: Tensorcom, Inc.
- Applicants: Zaw Soe
- Inventors: Zaw Soe
- Web page: https://patentgrep.com/patent/US8487695B2

## CPC

- H03H 11/1217: {using a plurality of operational amplifiers (H03H11/1204 takes precedence; parallel-T filters H03H11/1295)}
- H03F 3/195: in integrated circuits
- H03F 3/301: {CMOS common drain output SEPP amplifiers (H03F3/3008 takes precedence)}
- H03F 3/45179: {using MOSFET transistors as the active amplifying circuit (H03F3/45278 takes precedence)}
- H03F 3/505: {with field-effect devices}
- H03H 3/00: Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H 11/1213: {using transistor amplifiers (H03H11/1204 takes precedence; parallel-T filters H03H11/1295)}
- H03H 11/1286: {Sallen-Key biquad}
- H03F 2203/45528: the FBC comprising one or more passive resistors and being coupled between the LC and the IC
- H03F 2203/45544: the IC comprising one or more capacitors, e.g. coupling capacitors
- H03F 2203/45594: the IC comprising one or more resistors, which are not biasing resistor
- Y10T 29/49016: Antenna or wave energy "plumbing" making
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H03F: AMPLIFIERS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A differential amplifier comprising a first upper device and a first lower device series coupled between two power supplies and a second upper device and a second lower device series coupled between the two power supplies. A first DC voltage enables the first upper device and the second upper device and a second DC voltage regulates current flow in the first lower device and the second lower device. An AC signal component is coupled to the first upper device and the second lower device while the AC signal complement is coupled to the first lower device and the second upper device. A first output signal between the first upper device and the first lower device. Separate RC networks couple the AC signals to their respective device. A first and second output signal forms between the upper device and the lower device, respectively. All the devices are same channel type.

## Claims

### Claim 1

A differential amplifier comprising:
a first upper device and a first lower device series coupled between two power supplies;
a second upper device and a second lower device series coupled between said two power supplies;
a first DC voltage enables said first upper device and said second upper device;
a second DC voltage regulates current flow in said first lower device and said second lower device;
said first upper device and said second lower device coupled to an AC signal component;
said first lower device and said second upper device coupled to a complement of said AC signal component;
a first output signal between said first upper device and said first lower device;
a second output signal between said second upper device and said second lower device;
all said devices are same channel type;
a first RC network coupling said AC signal component to said first upper device;
a second RC network coupling said AC signal component to said second lower device;
a third RC network coupling said complement of said AC signal component to said first lower device;
and
a fourth RC network coupling said complement of said AC signal component to said second upper device, whereby
said first RC network is equivalent to said fourth RC network and said second RC network is equivalent to said third RC network.

### Claim 2 (depends on 1)

The differential amplifier of claim 1, further comprising:
said first RC network coupling said first DC voltage to said first upper device;
said second RC network coupling said second DC voltage to said second lower device;
said third RC network coupling said second DC voltage to said first lower device; and
said fourth RC network coupling said first DC voltage to said second upper device.

### Claim 3 (depends on 2)

The differential amplifier of claim 2, further comprising:
a reference current; and
a first device connected in saturation providing a load for said reference current; thereby generating said second DC voltage.

### Claim 4 (depends on 3)

The differential amplifier of claim 3, whereby
all devices are N-MOS devices.

### Claim 5 (depends on 3)

The differential amplifier of claim 3, wherein
a third, output signal is generated between said first output signal and said second output, signal.

### Claim 6 (depends on 3)

The differential amplifier of claim 3, whereby
said two power supplies are VDD and GRD.

### Claim 7 (depends on 5)

The differential amplifier of claim 5, wherein
said first output signal is the inverse of said second output signal.

### Claim 8 (depends on 7)

The differential amplifier of claim 7, wherein
said third output signal is a differential signal.

### Claim 9 (depends on 1)

The differential amplifier of claim 1, wherein
said AC signal components are coupled to said upper and lower devices by a corresponding capacitor of said corresponding RC network.