ZXCT1009T8TA Diodes Zetex, ZXCT1009T8TA Datasheet - Page 5

• Manufacturer Part Number: ZXCT1009T8TA
• Description: IC CURRENT MONITOR 1% SM8
• Manufacturer: Diodes Zetex

Specifications of ZXCT1009T8TA

• Function: Current Monitor
• Sensing Method: High-Side
• Accuracy: ±1%
• Voltage - Input: 2.5 ~ 20 V
• Current - Output: 10.2mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (8 leads), SM8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ZXCT1009T8TR

Application Information
The above figure shows the ZXCT1009 supporting the
Benchmarq bq2954 Charge Management IC. Most of the
support components for the bq2954 are omitted for clarity.
This design also uses the Diodes FZT789A high current
Super-ß PNP as the switching transistor in the DC-DC step
down converter and the FMMT451 as the drive NPN for the
FZT789A. The circuit can be configured to charge up to four
Li-Ion cells at a charge current of 1.25A. Charge can be
terminated on maximum voltage, selectable minimum
current, or maximum time out. Switching frequency of the
PWM loop is approximately 120kHz.
The
replacement for the ZDS1009, which is featured in a
complete design from Unitrode/Texas Instruments on the
Li-Ion
DVS2954S1H Li-Ion Charger Development System.
ZXCT1009
Document number: DS33441 Rev. 12 - 2
Li-Ion Charger Circuit
ZXCT1009
charger
is
circuit
intended
shown
(cont.)
as
a
above.
direct
Reference:
functional
www.diodes.com
5 of 8
Transient Protection
An additional resistor, R
(as below), to limit the current from I
connected to V
transients. This can be of particular use in automotive
applications where load dump and other common transients
need to be considered.
Assuming the worst case condition of V
low impedance to a transient, the minimum value of R
given by:-
V
V
I
The maximum value of R
the dropout voltage (see transfer characteristic on page 3) of
the ZXCT1009 :-
V
V
V
PK
PK
MAX
IN(MIN)
DP
OUT(MAX)
ZXCT1009 with additional current limiting Resistor R
R
= Peak output current = 40mA
= Peak transient voltage to be withstood
= Dropout Voltage
LIM(MAX)
= Maximum working voltage = 20V
= Minimum Supply Operating Voltage
= Maximum Operating Output Voltage
= R
HIGH-SIDE CURRENT MONITOR
V
V
R
IN
IN
LIM(min)
OUT
OUT
2
2
[V
V
V
SENSE+
SENSE+
will be protected from input voltage
ZXCT1009
ZXCT1009
IN(MIN)
= (V
LIM
R
R
LIM
SENSE
SENSE
1
1
I
I
OUT
OUT
can be added in series with R
PK
is set by V
– (V
R
R
R
R
V
V
– V
SENSE-
SENSE-
LIM
LIM
OUT
OUT
DP
3
3
MAX
ZXCT1009
+ V
V
V
To load
To load
)/I
OUT
OUT
IN(MIN)
OUT
PK
OUT(MAX)
OUT
© Diodes Incorporated
= 0V; providing a
, V
. Any circuit
OUT(MAX)
)]/V
April 2011
OUT(MAX)
LIM
LIM
OUT
and
.
is