THAT1420 Datasheet, PDF (3/8 Pages) List of Unclassifed Manufacturers – Balanced Line Drivers

Rev. 4/24/01
Preliminary Information
Page 3
Electrical Characteristics (cont’d.)
Parameter
Differential Output Offset
Differential Output
Voltage Swing,Pos
Differential Output
Voltage Swing,Neg
Output Impedance
Quiescent Supply Current
Short Circuit Output Current
Voltage Supply Range
Symbol
V_OOD
Z_O
I_S
I_SC
Conditions
R_L=600W
V_IN = ±18V
V_IN = ±18V
Unloaded, V_IN = 0
Min.
Typ.
Max.
-10
±4
10
V_CC-2
V_EE+2
40
50
60
4
5.2
60
70
±4
±18
Units
mV
V
V
W
mA
mA
V
Theory of Operation
OutSmartsÔ technology
The THAT 1420 and 1430 are similar devices,
both employing the OutSmarts topology, a variation
of circuitry originally developed at Audio Toys, Inc.
OutSmarts topology employs two negative-feedback
loops -- one to control the differential signal, and a
separate loop to control the common mode output
levels.
pressions, A_D(s) and A_C(s). The first pair of differen-
tial inputs, D_in+/-, are connected to the differential
feedback network between the outputs and the input
signal. The second differential input pair, C_in+/-, is
connected to a bridge circuit which generates an er-
ror signal that is used to servo the common-mode be-
havior of the outputs. The loop equations are then,
D_OUT+ - D_OUT- = D D_OUT = A_D(D_{IN +} - D_{IN -} )
Figures 2 and 3 show the gain core common to
both the THAT 1420 and 1430. The gain core is a
single amplifier that includes two differential input
pairs, C_in+/- and D_in+/-, and complementary outputs,
V_out+ and V_out-, related to each other by two gain ex-
where A_D is the differential open-loop gain, and
Ã¥ ^DOUT+ ^{+ D}OUT- ^{= D}OUT ^{= A}C^(CIN + ^{- C}IN - ⁾
where A_C is the common-mode open-loop gain.
THAT 1420
10k
Vcc
5k
Din+
In+
Cin+
10k
Dout-
Cin- ^A_D ^{& A}_C
Gnd
5k
Din-
Dout+
10k
10k
Vee
50
Out-
CEXT
Sens+
10k
20k
10p
10k
50
20k
Sens-
CEXT
Out+
Figure 2. THAT 1420 Equivalent Circuit Diagram
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: [phone]; Fax: [phone]; Web: www.thatcorp.com