ST TSH343 User Manual

280MHz single-supply triple video buffer

Features

■ Bandwidth: 280MHz

■ 5V single-supply operation

■ Internal input DC level shifter

■ No input capacitor required

■ 6dB internal gain for a matching between 3

channels

■ Very low harmonic distortion

■ Slew rate: 780V/μs

■ Specified for 150Ω and 100Ω loads

■ Min. and max. data tested during production

Applications

Pin1 identification

1

IN1

IN2

2

Top View

6dB

6dB

TSH343

8

OUT1

7

OUT2

■ High-end video systems

■ High definition TV (HDTV)

■ Broadcast and graphic video

■ Multimedia products

Description

The TSH343 is a triple single-supply video buffer
featuring an internal gain of 6dB and a large
280MHz bandwidth.

The main advantage of this circuit is that its input
DC level shifter allows for video signals on 75Ω
video lines without damage to the synchroniza tion
tip of the video signal, while using a single 5V
power supply with no input capacitor. The DC
level shifter is internally fixed and optimized to
keep the output video signals between low and
high output rails in the best position for the
greatest linearity.

This datasheet provides information on using the
TSH343 as a Y-Pb-Pr driver for video DAC output
on a video line. See the TSH344 datasheet for R­G-B signals.

IN3

+Vcc

3

4

6dB

DC Shifter

6

5

OUT3

GND

SO8

The TSH343 is available in the compact SO8
plastic package for optimum space-saving.

March 2007 Rev 4 1/17

www.st.com

17

TSH343

Contents

1 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 3

2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.1 Using the TSH343 to drive Y-Pb-Pr video components . . . . . . . . . . . . . . 10

3.2 PSRR and improvement of power supply noise rejection . . . . . . . . . . . . 12

3.3 Delay between channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2/17

TSH343 Absolute maximum ratings and operating conditions

1 Absolute maximum ratings and operating conditions

Table 1. Absolute maximum ratings (AMR)

Symbol Parameter Value Unit

V

T

T

R
R
P

V

oper

T

max

Supply voltage

CC

Input voltage range

in

Operating free air temperature range -40 to +85 °C
Storage temperature -65 to +150 °C

stg

Maximum junction temperature 150 °C

j

SO8 thermal resistance junction to case 28 °C/W

thjc

SO8 thermal resistance junction to ambient area 157 °C/W

thja

Maximum power dissipation (@T
CDM: charged device model

ESD

HBM: human body model
MM: machine model

1. All voltage values, except differential voltage, are with respect to network terminal.

2. The magnitude of input and output voltages must never exceed VCC +0.3V.

Table 2. Operating conditions

(1)

(2)

6V

0 to +1.4 V

=25°C) for Tj=150°C 800 mW

amb

2

1.5

200

kV
kV

V

Symbol Parameter Value Unit

V

CC

1. Tested in full production at 0V/5V single power supply.

Power supply voltage 3 to 5.5

(1)

V

3/17

Electrical characteristics TSH343

2 Electrical characteristics

Table 3. VCC= +5V single supply, T

= 25°C (unl es s otherwise specified)

amb

Symbol Parameter Test conditions Min. Typ. Max. Unit

DC performance

Input DC shift

V

DC

Figure 16 for the behaviour in

(see
temperature)

I

Input bias current

ib

Input resistance T

R

in

C

Input capacitance T

in

R

=150Ω, T

L

-40°C < T
T

, input to GND 18.2 35

amb

-40°C < T

amb

amb

400 600 670

amb

< +85°C 530

amb

< +85°C 20.7

amb

4GΩ
1pF

no load, input to GND 14.4 18

Supply current per buffer

I

CC

PSRR

Power supply rejection ratio
20 log (ΔV

out

/ΔVCC)

(1)

G DC voltage gain R

Variation of the DC voltage gain

DG

between inputs of 0.3V and 1V

-40°C < T

F=1MHz -45 dB

=150Ω, Vin= 1V 1.92 1.99 2.05 V/V

L

Input step from 0.3V to 1V 0.26 0.8 %

< +85°C 14.9

amb

MG1Gain matching between 3 channels Input = 1V 0.5 2 %

MG

Gain matching between 3 channels Input = 0.3V 0.5 2 %

0.3

Dynamic performance and output characteristics

mV

μA

mA

-3dB bandwidth

Bw

Gain flatness @ 0.1dB

FPBW Full power bandwidth

D Delay between each channel

SR Slew rate

V
V

High level output voltage V

OH

Low level output voltage RL=150Ω 40 mV

OL

(3)

Output current

I

OUT

Output short-circuit current (I

(2)

source

Small signal V

=150Ω

R

L

Small signal V
R

=150Ω

L

V

=2V

out

=150Ω

R

L

0 to 30MHz 0.5 ns
Input step from 0V to 1V,

=150Ω

R

L

in DC

V

=2V, T

out

-40°C < T

) 100 mA

4/17

= 20mVp

out

160 280

MHz

= 20mVp

p-p

, V

out

ICM

=0.5V,

130 200 MHz

65

500 780 V/μs

= +1.5V, RL=150Ω 3.7 3.9 V

amb

< +85°C 82

amb

45 90

mA

TSH343 Electrical characteristics

Table 3. VCC= +5V single supply, T

= 25°C (un l es s ot h erw is e sp e ci fie d ) (c on t inued )

amb

Symbol Parameter Test conditions Min. Typ. Max. Unit

Noise and distortion

=50Ω 29 nV/√Hz

IN

158
290

, RL=150Ω

-58

-45

-72

-50

μVrms

eN Total input voltage noise

HD2 2nd harmonic distortion

HD3 3rd harmonic distortion

1. See Figure28 and Figure 29.

2. See Figure30 and Figure 31.

3. Non-tested value, guaranteed by design.

F = 100kHz, R
10kHz to 30MHz

10kHz to 100MHz
V

=2V

out

p-p

F= 10MHz
F= 30MHz

=2Vp-p, RL=150Ω

V

out

F= 10MHz
F= 30MHz

dBc

dBc

5/17

Electrical characteristics TSH343

Figure 1. Frequency response Figure 2. Gain flatness

10

8

6

4

2

0

-2

Gain (dB)

-4

-6

Vcc=5V

-8

Load=150

-10
1M 10M 100M 1G

Ω

Frequency (Hz)

6,20

6,15

6,10

6,05

6,00

5,95

5,90

Gain (dB)

5,85

5,80

Vcc=5V

5,75

Load=150

5,70

1M 10M 100M 1G

Ω

Frequency (Hz)

Figure 3. Cross-talk vs. frequency (amp1) Figure 4. Cross-talk vs. frequency (amp2)

0

Small Signal

-10

Vcc=5V
Load=150

-20

-30

-40

-50

-60

Gain (dB)

-70

-80

-90

-100

1M 10M 100M

Ω

1/2

1/3

Frequency (Hz)

0

Small Signal

-10

Vcc=5V
Load=150

-20

-30

-40

-50

-60

Gain (dB)

-70

-80

-90

-100
1M 10M 100M

Ω

2/1

2/3

Frequency (Hz)

Figure 5. Cross-talk vs. frequency (amp3) Figure 6. Input noise vs. frequency

0

Small Signal

-10

Vcc=5V
Load=150

-20

-30

-40

-50

-60

Gain (dB)

-70

-80

-90

-100
1M 10M 100M

Ω

3/1

3/2

Frequency (Hz)

6/17

100

Input Noise (nV/VHz)

10

10 100 1k 10k 100k 1M 10M

Vcc=5V
input in short-circuit

NA

Frequency (Hz)