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Электронный компонент: THAT1256

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THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
600068 Rev 00
T H A T
C o r p o r a t i o n
THAT
1250, 1253, 1256
FEATURES
Good CMRR: typ. 50dB at 60Hz
Low cost, self contained
Excellent audio performance
Wide bandwidth: typ. >8.6 MHz
High slew rate: typ. 12 V/s
Low distortion: typ. 0.0006 % THD
Low noise: typ. -103 dBu (re: input)
Low current: typ. 2 mA
Several gains: 0 dB, 3 dB, & 6 dB
Industry-standard pinout
APPLICATIONS
Balanced Audio Line Receivers
Instrumentation Amplifiers
Differential Amplifiers
Precision Summers
Current Shunt Monitors
Description
The THAT 1250-series of pre ci sion dif fer en -
tial am pli fi ers was de signed pri mar ily for use
as bal anced line re ceiv ers for au dio ap pli ca -
tions. Gains of 0 db, 3 dB, and 6 dB are
avail able to suit var i ous ap pli ca tions re quire -
ments.
These de vices in clude on-board pre ci sion thin-
film re sis tors which of fer good match ing and ex cel -
lent track ing due to their mono lithic con struc tion.
Man u fac tured in THAT Cor po ra tion's pro pri etary
com ple men tary di elec tric iso la tion (DI) pro cess, the
THAT 1250-series pro vides the sonic ben e fits of
dis crete de signs with the sim plic ity, re li abil ity,
match ing and small size of an in te grated so lu tion.
All three ver sions of the part typ i cally ex -
hibit 50 dB of com mon-mode re jec tion. With
12 V/s slew rate, >8.6 MHz band width, and
0.0006% THD, these de vices are sonically
trans par ent. More over, cur rent con sump tion is
typ i cally a low 2 mA. Both sur face-mount and
DIP pack ages are avail able.
The THAT 1256 is pin-compatible with the
TI INA137 and An a log De vices SSM2143, while
the THAT 1250 is pin-compatible with the TI
INA134 and An a log De vices SSM2141.
Sense
Vout
Ref
Vcc
Vee
In+
In-
NC
R
1
R
2
R
3
R
4
Gain
R , R
9 k
1
3
O
O
O
10.5 k
12 k
R , R
9 k
2
4
O
O
O
7.5 k
6 k
Part no.
THAT1250
THAT1253
THAT1256
0 dB
-3 dB
-6 dB
Fig ure 1. THAT1250-series equiva lent cir cuit dia gram
Gain
Plas tic DIP
Plas tic SO
0 dB
1250P08-U
1250S08-U
3 dB
1253P08-U
1253S08-U
6 dB
1256P08-U
1256S08-U
Ta ble 2. Or der ing infor ma tion
Pin
Name
DIP Pin
SO Pin
Ref
1
1
In-
2
2
In+
3
3
Vee
4
4
Sense
5
5
Vout
6
6
Vcc
7
7
NC
8
8
Ta ble 1. 1250 Se ries pin assign ments
Low Cost, Bal anced
Line Re ceiver ICs
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
Page 2
THAT 1250 Se ries
Low Cost Bal anced Line Re ceiver ICs
SPEC I FI CA TIONS
1
Ab so lute Max i mum Rat ings
Pos i tive Sup ply Volt age (V
CC
)
+20 V
Neg a tive Sup ply Volt age (V
EE
)
-20 V
Stor age Tem per a ture Range (T
ST
)
-40 to +125C
Out put Short-Circuit Du ra tion (t
SH
)
Con tin u ous
In put Volt ages (In+, In-)
50 V
Power Dis si pa tion (P
D
) (T
A
= 85C)
400 mW (DIP)
Power Dis si pa tion (P
D
) (T
A
= 85C)
260 mW (SO)
Op er ating Tem per a ture Range (T
OP
)
0 to 85C
Junc tion Tem per a ture (T
J
)
125C
Lead Tem per a ture (Sol dering 10 sec onds)
300 C
Elec tri cal Char ac ter is tics
2
Pa ram e ter
Sym bol
Con di tions
Min
Typ
Max
Units
Sup ply Cur rent
I
CC
No sig nal
--
2.0
2.8
mA
Sup ply Volt age
V
CC
+3
+18
V
V
EE
-3
-18
V
In put Volt age Range
V
IN-DIFF
Dif fer en tial (equal and op po site swing)
THAT 1250 (0 dB gain)
--
21.5
--
dBu
3
THAT 1253 (-3 dB gain)
--
24.4
--
dBu
THAT 1256 (-6 dB gain)
--
27.5
--
dBu
V
IN-CM
Com mon mode
THAT 1250 (0 dB gain)
--
27.5
--
dBu
THAT 1253 (-3 dB gain)
--
29.1
--
dBu
THAT 1256 (-6 dB gain)
--
31.5
--
dBu
In put Im ped ance
4
Z
IN-CM
Com mon mode (all ver sions)
--
9
--
k
Z
IN-DIFF
Dif fer en tial
THAT 1250 (0 dB gain)
--
18
--
k
THAT 1253 (-3 dB gain)
--
21
--
k
THAT 1256 (-6 dB gain)
--
24
--
k
Com mon Mode Re jec tion Ra tio
CMRR
Matched source im ped ances; V
CM
= 10 V
DC
40
50
--
dB
60 Hz
40
50
--
dB
20 kHz
40
50
--
dB
Power Sup ply Re jec tion Ra tio
5
PSR
at 60 Hz, with V
CC
= -V
EE
THAT 1250 (0 dB gain)
--
90
--
dB
THAT 1253 (-3 dB gain)
--
90
--
dB
THAT 1256 (-6 dB gain)
--
90
--
dB
To tal Har monic Dis tor tion
THD
V
IN-DIFF
= 10V; BW = 20 kHz;
f = 1 kHz, R
L
= 2 k
--
0.0006
--
%
Small Sig nal Band width
BW
-3dB
R
L
= 2 k
; C
L
= 10 pf
THAT 1250 (0 dB gain)
--
8.6
--
MHz
THAT 1253 (-3 dB gain)
--
12.2
--
MHz
THAT 1256 (-6 dB gain)
--
18
--
MHz
R
L
= 2 k
; C
L
= 300 pf
THAT 1250 (0 dB gain)
--
10.3
--
MHz
THAT 1253 (-3 dB gain)
--
11.8
--
MHz
THAT 1256 (-6 dB gain)
--
13.4
--
MHz
Doc u ment 600068 Rev. 00
Page 3
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
Out put Noise
e
(OUT)
22 Hz to 22 kHz band width
THAT 1250 (0 dB gain)
--
-103
--
dBu
THAT 1253 (-3 dB gain)
--
-105
--
dBu
THAT 1256 (-6 dB gain)
--
-106
--
dBu
Slew Rate
SR
R
L
= 2 k
; C
L
= 300 pf
7
12
--
V/
s
Out put Gain Er ror
G
ER(OUT)
f = 1 kHz
-0.1
0
+0.1
dB
Out put Volt age Swing
V
O+
R
L
= 2 k
V
CC
- 2.5
V
CC
-2
--
V
V
O+
R
L
= 2 k
--
V
EE
+ 2 V
EE
+ 2.5
V
Out put Off set Volt age
V
OFF
No sig nal
-7
--
+7
mV
Out put Short Cir cuit Cur rent
I
SC
R
L
= 0
--
25
--
mA
Re sis tive Load
R
L
2
--
--
k
Ca pac i tive Load
C
L
--
--
300
pF
Pack age Char ac ter is tics
Pa ram e ter
Sym bol
Con di tions
Min
Typ
Max
Units
Through-hole Pack age
Type
See Fig ure 13
8-Pin PDIP
Ther mal Re sis tance
JA
DIP pack age sol dered to board
-
100
-
C/W
Sur face Mount Pack age
Type
See Fig ure 14
8-Pin SOP
Ther mal Re sis tance
JA
SO pack age sol dered to board
-
150
-
C/W
Sol dering Reflow Pro file
JEDEC JESD22-A113-B (220 C)
1
All spec i fi ca tions are sub ject to change with out no tice.
2
Un less oth er wise noted, T
A
=25C, V
CC
= +15V, V
EE
= -15V, Test cir cuit is as shown in Fig ure 2.
3
0 dBu = 0.775Vrms.
4
While spe cific re sis tor ra tios are very closely matched, ab so lute re sis tance val ues can vary 25% from the
typ i cal val ues shown. In put im ped ance is mon i tored by lot sam pling.
5
De fined with re spect to dif fer en tial gain.
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
Page 4
THAT 1250 Se ries
Low Cost Bal anced Line Re ceiver ICs
Theory of Operation
The THAT1250-series ICs con sist of high per for -
mance opamps with in te grated, thin-film re sis tors.
These de signs take full ad van tage of THAT fully
com ple men tary di elec tric iso la tion (DI) pro cess to
de liver ex cel lent per for mance with low cur rent con -
sump tion. The de vices are sim ple to ap ply in many
ap pli ca tions.
Re sis tor Matching, Values, and CMRR
The 1250-series de vices rely upon the in her ent
match ing of sil i con-chromium (Si-Cr), thin-film, in -
te grated re sis tors to achieve a 50 dB com mon mode
re jec tion ra tio and tight gain ac cu racy. No trim ming
is per formed. As a re sult of their mono lithic con -
struc tion, the R3/R4 ra tio gen er ally matches within
0.1% of the R1/R2 ra tio.
How ever, while the re sis tor ra tios are tightly con -
trolled, the ac tual value of any in di vid ual re sis tor is
not. Lot-to-lot vari a tions of up to 25 % are to be ex -
pected.
If higher CMRR is re quired in a sim ple in put
stage, con sider the THAT 1240-series ICs. These
parts are la ser trimmed to im prove the in her ent pre -
ci sion of our thin-film re sis tor pro cess. For de-
manding ap pli ca tions in which the source im ped -
ance bal ance may be less than per fect, the
1200-series ICs of fer ex cep tional CMRR per for -
mance via a pat ented method of in creas ing com -
mon-mode in put im ped ance.
In put Con sid er ations
The 1250-series de vices are in ter nally pro tected
against in put over load via an un usual ar range ment
of di odes con nect ing the + and - In put pins to the
power sup ply pins. The cir cuit of Fig ure 3 shows the
ar range ment used for the R
3
/ R
4
side; a sim i lar one
ap plies to the other side. The zener di odes pre vent
the pro tec tion net work from con duct ing un til an in -
put pin is raised at least 50 V above V
CC
or be low
V
EE
. Thus, the pro tec tion net works pro tect the de -
vices with out con strain ing the al low able sig nal swing
at the in put pins. The ref er ence (and sense) pins are
pro tected via more con ven tional re verse-biased di -
odes which will con duct if these pins are raised
above V
CC
or be low V
EE
.
Be cause the 1250-series de vices are in put stages,
their in put pins are of ne ces sity con nected to the
out side world. This is likely to ex pose the parts to
ESD when ca bles are con nected and dis con nected.
Our test ing in di cates that the 1250-series de vices
will typ i cally with stand ap pli ca tion of up to 1,000
volts un der the hu man body ESD model.
To re duce risk of dam age from ESD, and to pre -
vent RF from reach ing the de vices, THAT rec om -
mends the cir cuit of Fig ure 4. C
3
through C
5
should
be lo cated close to the point where the in put sig nal
R
2
R
1
R
4
R
3
Sense
Vout
Ref
V
CC
V
EE
V
IN(CM)
In+
In-
R
L
v
IN(DIFF)
~
~
~
b
a
C
L
v
IN(DIFF)
Fig ure 2. THAT1250 se ries test cir cuit
co mes into the chas sis, pref er a bly di rectly on the in -
put con nec tor. The un usual cir cuit de sign min i mizes
the un bal anc ing im pact of dif fer ences in the val ues
of C
4
and C
5
by forc ing the ca pac i tance from each in -
put to chas sis ground to de pend pri mar ily on the
value of C
3
. The cir cuit shown is ap prox i mately ten
times less sen si tive to mis matches be tween C
4
and
C
5
than the more con ven tional ap proach in which
the junc tion of C
4
and C
5
is grounded di rectly
6
.
De signers fre quently seek to im prove RF by pass -
ing through the ad di tion of R-C net works at the in -
puts (se ries re sis tor fol lowed by a ca pac i tor to
ground at each in put). Gen erally, THAT rec om -
mends keep ing any such se ries resistances un der
50
, so as not to up set the in trin sic bal ance be -
tween the 1250's in ter nal R
1
/R
2
and R
3
/R
4
re sis tor
ra tios. Be cause the in ter nal re sis tor ab so lute val ues
are not well con trolled, the ex ter nal re sis tors can in -
ter act with the in ter nal ones in un ex pected ways. As
an al ter na tive to a re sis tor as ad di tional build-out
im ped ance, THAT rec om mends the use of a fer rite
bead or balun in stead.
If it is nec es sary to ac-couple the in puts of the
1250-series parts, the cou pling ca pac i tors should be
sized to pres ent neg li gi ble im ped ance at any fre -
quen cies of in ter est for com mon mode re jec tion. Re -
gard less of the type of cou pling ca pac i tor cho sen,
vari a tions in the val ues of the two ca pac i tors, work -
ing against the 1250-series in put im ped ance, can
un bal ance com mon mode in put sig nals, con vert ing
them to bal anced sig nals which will not be re jected
by the CMRR of the de vices. For this rea son, THAT
rec om mends dc-coupling the in puts of the
1250-series de vices.
In put Volt age Lim i ta tions
When con fig ured, re spec tively, for -3 dB and
-6 dB gain, the 1253 and 1256 de vices are ca pa ble
of ac cept ing in put sig nals above the power sup ply
rails. This is be cause the in ter nal opamp's in puts
con nect to the out side world only through the
on-chip re sis tors R
1
through R
4
at nodes a and b as
shown in Fig ure 2. Con sider the fol low ing anal y sis.
Dif fer en tial In put Sig nals
For dif fer en tial sig nals (v
IN(DIFF)
), the lim i ta tion to
sig nal han dling will be out put clip ping. The out puts
of all the de vices typ i cally clip at within 2V of the
sup ply rails. There fore, max i mum dif fer en tial in put
sig nal lev els are di rectly re lated to the gain and sup -
ply rails.
Com mon Mode In put Sig nals
For com mon-mode in put sig nals, there is very lit -
tle out put sig nal. The lim i ta tion on com mon-mode
han dling is the point at which the in puts are over -
loaded. So, we must con sider the in puts of the
opamp.
For com mon mode sig nals (V
IN(CM)
), the com mon
mode in put cur rent splits to flow through both R
1
/R
2
and through R
3
/R
4
. Be cause v
b
is con strained to
fol low V
a
, we will con sider only the volt age at node a.
The volt age at a can be cal cu lated as:
v
v
a
IN CM
R
R
R
=


+
(
)
4
3
4
.
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com
Doc u ment 600068 Rev. 00
Page 5
-
+
In+
Ref
V
CC
V
EE
V
CC
V
EE
R
3
R
4
Fig ure 3. Rep re sen ta tive In put Pro tec tion Circuit
C4
470p
C5
470p
C3
47p
In+
In-
Out
C1
100n
C2
100n
V
CC
V
EE
In-
2
In+
3
Out
6
U1
THAT1256/1253/1250
Ref
Sens
V
EE
V
CC
5
7
4
1
Fig ure 4. RFI and Sup ply Bypassing
6
An ex cel lent dis cus sion of in put stage ground ing can be found in the June 1995 is sue of the Jour nal of the Au dio En gi neering So ci ety,
Vol. 43, No. 6, in ar ti cles by Ste phen Macatee, Bill Whitlock, and oth ers.