Features: OutSmarts technology tames clipping behavior into single-ended loads
Pin-compatible with SSM2142
Balanced, floating output delivers transformer-like behavior
Stable when driving long cables and capacitive loads
THAT 1430 delivers low output offset voltage using single capacitorApplication Differential Line Driver
Audio Mix Consoles
Distribution Amplifiers
Audio Equalizers
Dynamic Range Processors
Digital Effects Processors
Telecommunications Systems
Instrumentation
Hi-Fi Equipment
Circuit implementations using the THAT1420/1430 are relatively straightforward. A quiet,solid ground reference, stiff voltage supplies, and adequate supply bypassing are all that is required to achieve excellent performance out of both ICs. Both devices are stable into any capacitive load, and the maximum capacitance is limited only by slew rate and frequency response considerations.
For the purposes of the frequency response calculation,the line driver's 50 sense resistors can be lumped into a single 100 resistor. The correct cable
capacitance to use is the sum of the inter-conductor capacitance and the two conductor-to-shield capacitances. Unfortunately, some manufacturers only specify the inter-conductor capacitance and the capacitance of one conductor to the other while connected to the shield, and some extraction may be required.
As an example, one manufacturer supplies a shielded, twisted pair with 30pF/ft of inter-conductor +capacitance and 25pF/ft of conductor to shield capacitance
Specifications
| Positive Supply Voltage (Vcc) |
+18 V |
Operating Temperature Range (TOP) |
-40 to +85C |
| Negative Supply Voltage (Vee) |
-18 V |
Storage Temperature (TST) |
-40 to +150C |
| Output Short Circuit Duration |
Continuous |
Junction Temperature (TJ) |
150C |
| Power Dissipation (PD) |
TBD mW |
Lead Temperature (TLEAD)(Soldering 60 sec) |
300C |
DescriptionThe THAT 1420 and 1430 are a new generation of audio differential line drivers with improved performance over conventional cross-coupled monolithic designs. Both models THAT 1420, 1430 exhibit low noise and distortion, high slew rate,stability under difficult loads, wide output swing,and have outputs which are short-circuit protected.
In addition both models THAT 1420, 1430 incorporate patented OutSmarts technology, a dual feedback-loop design that prevents the excessive ground currents typical of cross-coupled output stages (CCOS) when clipping into single-ended loads1.
To overcome this problem, the THAT 1420 and 1430 use two individual negative-feedback loops to separately control the differential output voltage and common mode output currents, makingthe design inherently more stable and less sensitive to component tolerances than the CCOS.Most importantly, the dual-feedback design prevents the loss of common-mode feedback that plagues the CCOS designs, avoiding the excessive ground currents and overly distorted output waveform that can result when driving single-ended loads.
Where minimum output offset voltage with minimum parts count is desired, the THAT 1430 further improves over existing designs. In conventional CCOS circuits, two relatively high-value electrolytic capacitors are required to reduce the offset voltage. By contrast, the THAT 1430 topology requires only a resistor and a single film or ceramic capacitor to achieve the same effect at lower parts count and price.
THAT 1420, 1430 Data Sheet
