ISL6296ADRTZ-T Intersil, ISL6296ADRTZ-T Datasheet - Page 18

• Manufacturer Part Number: ISL6296ADRTZ-T
• Description: IC AUTHENTICATION DEVICE 8-TDFN
• Manufacturer: Intersil
• Series: FlexiHash™r

Specifications of ISL6296ADRTZ-T

• Function: Battery Authentication
• Battery Type: Li-Ion, Li-Pol, NiMH
• Voltage - Supply: 2.6 V ~ 4.8 V
• Operating Temperature: -25°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

XSD Pin Series Resistor Selection
A series resistor may be used to improve ESD performance
of the XSD input. In Figure 13, resistor R1 and zener diode
D1 provide ESD protection for the ISL6296A XSD pin.
Resistor R1 must be selected to provide valid V
the host processor (point ‘A’ in Figure 13) when the ISL6296A is
asserting the bus low by turning on Q1. The maximum
resistance value of R1 can be calculated if one knows the
VDD
the Rpu resistor value, and the R
The maximum R
the XSD pin VOL specification in the “Electrical
Specifications” on page 3. Point ‘A’ voltage, with Q1 on, is
given by Equation 2.
To be detected as a logic '0' by the host, voltage at point ‘A’
must be no greater than the host’s VIL input voltage.
Therefore,
For example, suppose the XSD pull-up voltage is 2.6V, a
4.7kΩ pull-up is used, and the host’s VIL threshold is 35% of
its supply voltage.
Plugging these constants into Equation 4:
V
V
VDD
VDD
Rpu
V
2.6V
A
A
IL HOST
≤
(
=
HOST
HOST
HOST
V
=
-------------------------------------------------------- -
(
VDD
IL
R1
4.7k Ω
)
(
+
R1
voltage, the V
HOST
=
----------------------------------------------------
(
=
400 Ω
R1
VDD
2.6V
+
(
R1
+
400 Ω
DS(ON)
400 Ω
+
----------------------------------------------------
(
R1
HOST
+
4.7k Ω
(
400 Ω
)
R1
+
+
400 Ω
×
IL
+
Rpu
of Q1 in Figure 13 is 400Ω, as per
)
HOST PROCESSOR
LOGIC
)
35
400 Ω
requirements of the host processor,
≤
%
0.91V
+
)
18
VDD
Rpu
≤
=
)
DS(ON)
V
0.91V
IL
HOST
)
FIGURE 13. TYPICAL APPLICATION BLOCK DIAGRAM
of Q1.
IL
logic level at
A
Rpu
(EQ. 2)
(EQ. 3)
(EQ. 4)
(EQ. 5)
(EQ. 6)
(EQ. 7)
(EQ. 8)
ISL6296A
Solving for R1:
VDD Pin Series Resistor Selection
A series resistor may be used to improve ESD performance
of the VDD input as shown by R2 in Figure 13.
Resistor R2 must be selected to allow operation of the
ISL6296A at the minimum VBAT voltage at which
communication must be successful. The maximum
resistance of R2 can be calculated if one knows the
minimum VBAT voltage, maximum ISL6296A supply current,
and minimum ISL6296A supply voltage, using the formula in
Equation 10.
For example, suppose the minimum VBAT voltage in the
application is 2.8V. The minimum ISL6296A VDD voltage is
2.6V, and maximum supply current is 55
“Electrical Specifications” table on page 3. The maximum
value for R2 can then be calculated.
Additional Application Information
See “Related Literature” on page 1 for additional application
information.
R1 2131 Ω
R2
R2
R2 3.636k Ω
≤
≤
≤
≤
R1
(
--------------------------------------------------------------
(
----------------------------------- -
D1
VBAT
2.8V 2.6V
55 μ A
–
XSD
MIN
IDD
MAX
–
)
VDD
VSS
Q1
MIN
ISL6296A
VBAT
)
VDD
LOGIC
R2
µ
A, as per the
April 15, 2010
(EQ. 10)
(EQ. 12)
(EQ. 11)
FN6567.3
(EQ. 9)