E6420BBG Semtech, E6420BBG Datasheet - Page 17

• Manufacturer Part Number: E6420BBG
• Manufacturer: Semtech

Specifications of E6420BBG

• Lead Free Status / RoHS Status: Not Compliant

Temperature Coefficient Effect on DACs
There is a gain and offset temperature coefficient that
should be taken into account in the system design that
will affect calibration and performance.
The equation for voltage drift on output DACs is as follows:
Current outputs drift follow the following equation:
Average values for TC
the specifications.
Compliance of Current Output DACs (Groups E, F)
The compliance of the current output DACs (Groups E and
F) is governed by the following two equations:
See Figure 8 for a graphical depiction.
Note: I
HIGH-PERFORMANCE PRODUCTS – ATE
Application Information (continued)
V
V
2000 Semtech Corp.
OUT_A,B,C,D
COMPLIANCE
V
I
OUT_E,F
COMPLIANCE
CODE * LSB * TC
CODE * LSB * TC
OUT
is current sourced from output of DAC.
= T * TC
= T * TC
= (–250
= (–600
I
I
OUT
OUT
OFFSET
GAIN_A,B,C,D
GAIN_E,F
OFFSET_E,F
< 2.5 mA:
OFFSET_A,B,C,D
2.5 mA:
* I
and TC
* I
OUT
(%/˚C)
OUT
) + AVDD – 1.875V
GAIN
(%/˚C)
) + AVDD – 1V
˚C
A
can be found in
˚C
+
V
+
Care should be taken to ensure that devices being driven
by Group E and F DACs are designed to be within the
compliance specification.
Caution Regarding Power Dissipation of the 6420
During Parallel Load:
The Voltage DAC output amplifiers, for a FAST process,
can:
Caution must be taken during a parallel load, particularly
when the voltage DACs are loaded with a large filtering
capacitor (10 to 100 nF). In this scenario, a large voltage
change can induce a large current peak. For example,
the currents calculated below can be induced in the VCC/
VEE supplies:
Therefore, the user must take care of extra power
dissipation due to these currents peaks
large voltage changes during a parallel load.
17
• Source up to 10 mA (8 mA @ TJ = 100˚C)
• Sink up to 4.5 mA (3.5 mA @ TJ = 100˚C)
• Source case:
• Sink case:
Figure 8. Compliance of Current Output DACs
44 DACs * 10 mA / DAC + 40 mA = 480 mA
44 DACs * 4.5 mA / DAC + 120 mA = 320 mA
(or 280 mA @ TJ = 100˚C) in the VEE supply
(or 400 mA @ TJ = 100˚C) in the VCC supply
(Groups E and F)
Edge6420
,
and should avoid
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