MC34271
ELECTRICAL CHARACTERISTICS (continued) (VDD = 6.0 V, for typical values TA = Low to High [Note 1], for min/max values TA is
the operating ambient temperature range that applies, unless otherwise noted.)
Characteristic
Symbol
Min
Typ
Max
Unit
AUXILIARY VOLTAGE OUTPUTS
V1, V2, V3, V4 Outputs
1–V1/V0 Ratio
1–V2/V0 Ratio
V3/V0 Ratio
V4/V0 Ratio
Output Resistance (Isource = 4.0 mA)
Output Short Circuit Current
0.0500 0.0520 0.0535
0.1010 0.1035 0.1065
0.1010 0.1035 0.1065
0.0500 0.0520 0.0535
Ro
20
40
60
Ω
Iss
5.0
10
20
mA
LOGIC INPUTS (EN1, EN2, MODE)
Input Low State
VIL
0
–
0.8
V
Input High State
VIH
2.0
–
6.0
V
Input Impedance
Rin
25
50
100
kΩ
SOFT START CONTROL (SS1,SS2)
Charge Current (Capacitor Voltage = 1.0 V to 4.0 V)
Ichg
0.5
1.0
2.5
µA
Discharge Current (Capacitor Voltage = 1.0 V)
Idschg
250
650
–
µA
TOTAL SUPPLY CURRENT
VDD Current
Standby Mode (EN1 = EN2 = 0)
VDD = 6.0 V
ICC
VDD = 16 V
VDD Current
ICC
Backlight “On” (EN1 = 1; EN2 = 0)
VDD Current
ICC
LCD “On” (No Inductor) (EN1 = 0; EN2 = 1)
VB Current (V0 = 35 V)
IO
–
2.0
5.0
µA
–
3.0
15
–
0.7
3.0
mA
–
0.9
2.0
mA
–
1.2
3.0
mA
NOTE: 1. Low duty pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
1.0
VDD = 6.0 V
TA = 25°C
0.8
0.6
0.4
0.2
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
VComp, COMPENSATION VOLTAGE (V)
Figure 1. Switch Output Duty Cycle versus
Compensation Voltage
100
80
Gain
60
0
VDD = 6.0 V
VComp = 2.5 V
RL = Open
30
TA = 25°C
60
Phase
40
90
20
120
0
150
– 20
10
180
100
1.0 k
10 k
100 k
1000 k
f, FREQUENCY (Hz)
Figure 2. Error Amp Open Loop Gain and
Phase versus Frequency
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