74LV4799D-T NXP Semiconductors, 74LV4799D-T Datasheet - Page 10

• Manufacturer Part Number: 74LV4799D-T
• Description: Timers & Support Products 3.3V TIMER NICD AND NIMH CHARGER
• Manufacturer: NXP Semiconductors

Specifications of 74LV4799D-T

• Mounting Style: SMD/SMT
• Package / Case: SOT-109
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 74LV4799D,118

Philips Semiconductors
Charge discharge times
LED frequency
The frequency of the LED output (pin1) is determined by the oscillator frequency.
Three modes of operation, each with its own frequency, are possible.
MOLLI pulse duration
The MOLLI output gives an output signal of four periods with a 50%
duty cycle. The duration of one period is determined by: 16/f
Timing accuracy.
The timing accuracy depends on the accuracy of the on–chip
oscillator and on the external R and C components. The inaccuracy
of the on–chip oscillator is specified as maximum +/–7%. In most
cases the actual inaccuracy will be significantly lower. This depends
on the supply voltage as well as the value of the external
components.
Influence of Resistor value.
Low resistor values cause some spread because the RC
combination is biased by a 3–State push–pull output. The spread of
SPREAD-CAUSING FACTORS
1998 Apr 20
Charge time
Discharge time
Self-discharge time
Timer for NiCd and NiMH chargers
SYMBOL
SYMBOL
R
R
R
R
R
R
R
R
V
V
t
t
ON
ON
ON
ON
ON
ON
ON
ON
off
P
P
ff
PARAMETER
Trickle charge
Charge
Mode
Alarm
Offset voltage
Offset voltage
Propagation delay
Pro agation delay
P-channel resistance R
P-channel resistance R
N-channel resistance R
N-channel resistance R
P-channel resistance R
P-channel resistance R
N-channel resistance R
N-channel resistance R
PARAMETER
PARAMETER
C
C
C
C
S
S
S
S
, R
, R
output
out ut
output
out ut
R
R
4 hours to 16 hours
15 minutes to to 4.7 hours
50 days to 100 days
D
D
D
D
outputs
out uts
outputs
out uts
s
TIME RANGE
H or open
SEL
10
H
L
the R
spread. When high–value resistors are used, any possible output
leakage of the not–selected 3–State outputs will cause a frequency
deviation. For these reasons, the resistor values must be within the
specified ranges.
Influence of supply voltage
The trip levels of the oscillator are fixed at 20% and 80% of V
higher supply voltages the spread of the trip levels decreases in
greater proportion because the offset voltage remains constant, and
the propagation delay decreases. Furthermore, the R
the push–pull driving stage decrease at higher voltages.
on
V
1.0
6.0
1.0
6.0
1.0
6.0
1.0
6.0
1.0
6.0
1.0
6.0
(V)
CC
CC
of the push–pull stage will contribute to the frequency
MIN
Components ranges are within the values
Components ranges are within the values
given in Section “External components range”
given in Section External com onents range
T
amb
1300
1300
TYP
170
250
180
180
5.5
22
25
35
7
7
( C)
LED frequency
CONDITIONS
f
8
C
32
f
256
)
D
1
f
C
MAX
f
6
S
Product specification
74LV4799
on
values of
UNIT
UNIT
mV
mV
ms
ms
W
W
W
W
W
W
W
W
cc
. At