EVAL-AD5560EBUZ Analog Devices Inc, EVAL-AD5560EBUZ Datasheet - Page 39

• Manufacturer Part Number: EVAL-AD5560EBUZ
• Description: Evaluation Board
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD5560EBUZ

• Main Purpose: Power Management, Power Supply Supervisor/Tracker/Sequencer
• Utilized Ic / Part: AD5560
• Primary Attributes: *
• Secondary Attributes: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Embedded: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REFERENCE SELECTION
The voltage applied to the VREF pin determines the output
voltage range and span applied to the force amplifier, clamp,
and comparator inputs and the current ranges.
This device can be used with a reference input ranging from
2 V to 5 V. However, for most applications, a reference input
of 5 V is able to meet all voltage range requirements. The DAC
amplifier gain is 5.125, which gives a DAC output span of
25.625 V. The DACs have gain and offset registers that can
be used to calibrate out system errors. In addition, the gain
register can be used to reduce the DAC output range to the
desired force voltage range.
Using a 5 V reference and setting the m (gain) register to one-
fourth scale or 0x4000 gives an output voltage span of 6.25 V.
Because the force DAC has 18 bits of resolution even with only
one-fourth of the output voltage span, it is still possible to
achieve 16-bit resolution in this 6.25 V range.
The measure current amplifier has two gain settings, 10 and 20.
The two gain settings allow users to achieve the quoted/speci-
fied current ranges with large or small voltage swings. The 20
gain setting is intended for use with a 5 V reference, and the 10
gain setting is for use with a 2.5 V reference. Both combinations
ensure the specified current ranges. Other VREF/gain setting
combinations should be used only to achieve smaller current
ranges. See Table 27 for suggested references for use with the
AD5560.
CHOOSING AV
As noted in the Specifications section, the minimum supply
variation across the part is |AV
AV
operate correctly, the supply rails must take into account not
only the force voltage range but also the internal DAC
minimum voltage level, as well as headroom/footroom.
The DAC amplifier gains VREF by 5.125, and the offset DAC
centers that range about some chosen point. Because the DAC
minimum voltage (V
(MEASOUT gain of 0.2), it is important that AV
based on the following:
where:
AV
voltage drop).
V
R
I
LOAD
CABLE
DUTGND
SS
DD
AV
AV
_Headroom is the 2.75 V headroom (includes the R
is the maximum load current.
≥ 8 V, and AV
is the cable/path resistance.
SS
SS
is the voltage range anticipated at DUTGND.
_Headroom − V
≤ −5.125 × (VREF × (OFFSET_DAC_CODE/2
DD
SS
/AV
MIN
≤ −5 V. For the AD5560 circuits to
) is used in other parts of the circuit
DUTGND
SS
POWER SUPPLY RAILS
DD
− (R
− AV
CABLE
SS
| ≥ 16 V and ≤ 33 V,
× I
LOAD
)
SS
be chosen
SENSE
16
)) −
Rev. C | Page 39 of 60
When choosing AV
specified current ranges. The measure current block has either
a gain of 20 or 10 and must have sufficient headroom/
footroom to operate correctly.
As the nominal, V
current flowing for all ranges. If this is gained by 20, the
measure current amplifier output (internal node) voltage
range is ±10 V with full-scale current and the default offset
DAC setting. The measure current block needs ±2.25 V
footroom/headroom for correct operation in addition to
the ±0.5 V V
For simplicity, when V
31.125 V (VREF × 5.125 + headroom + footroom); otherwise,
there can be unanticipated effects resulting from headroom/
footroom issues. This does not take into account cable loss or
DUTGND contributions.
Similarly, when V
and, when V
The AD5560 is designed to settle fast into large capacitive loads;
therefore, when slewing, the device draws 2× to 3× the current
range from the AV
chosen, they should be capable of supplying each DPS channel
with sufficient current to slew.
CHOOSING HCAV
Selection of HCAV
the EXTFORCE1 and EXTFORCE2 output ranges. The supply
rails chosen must take into account headroom and footroom,
DUTGND voltage range, cable loss, supply tolerance, and
V
HCAV
drop should also be factored into the supply rail calculation.
The AD5560 is designed to settle fast into large capacitive loads
in high current ranges; therefore, when slewing, the device draws
2× to 3× the current range from the HCAV
supplies. When choosing supply rails, ensure that they are
capable of supplying each DPS channel with sufficient current
to slew.
All output stages of the AD5560 are symmetrical; they can
source and sink the rated current. Supply design/bypassing
should account for this.
POWER DISSIPATION
The maximum power dissipation allowed in the EXTFORCE1
stage is 10 W, whereas in the EXTFORCE2 stage, it is 5 W.
Take care to ensure that the device is adequately cooled to
remove the heat. The quiescent current is ~0.8 W with an
internal current range enabled and ~1 W with external current
ranges, EXTFORCE1 or EXTFORCE2, enabled. This device is
specified for performance up to 90°C junction temperature (T
RSENSE
. If diodes are used in series with the HCAV
DD
x supplies pins (shown in Figure 57), the diode voltage
RSENSE
REF
= 2 V, minimum |AV
REF
.
RSENSE
DD
SS
DD
= 2.5 V, minimum |AV
x and HCAV
/AV
, remember to take into account the
SS
REF
is ±0.5 V for the full-scale specified
x AND HCAV
SS
= 5 V, minimum |AV
supplies. When supply rails are
DD
x supplies is determined by
DD
− AV
DD
DD
x SUPPLY RAILS
SS
x and HCAV
− AV
SS
| = 16 V.
DD
− AV
SS
SS
| = 18.3 V
AD5560
x and
SS
| =
DD
x
J
).