AAC242 Datasheet, PDF (4/8 Pages) List of Unclassifed Manufacturers – Current Mode PWM Contoller

Power Management AAC242/243
PARAMETER
OUTPUT SECTION
PARAMETERS
MIN.
TYP.
MAX.
Voltage Out Low
0.4
Voltage Out Low
2.2
Voltage Out High
13.5
14
Voltage Out High
12.5
13.5
Voltage Out UVLO
1.1
Voltage Output Rise Time
30
50
Voltage Output Fall Time
30
50
Current Output Source Peak
1.2
Current Output Sink Peak
0.7
UNDER-VOLTAGE LOCKOUT SECTION
Voltage Start Threshold (142)
15
16
17
Voltage Start Threshold (143)
7.8
8.4
9
Voltage Turnoff Threshold (142)
9
10
11
Voltage Turnoff Threshold (143)
7
7.6
8.2
Zener Clamp Voltage
30
34
TOTAL DEVICE SECTION
Start-up Supply Current
0.4
0.6
Operating Supply Current
11
UNITS
V
V
V
V
V
ns
ns
A
A
V
V
V
V
V
mA
mA
CONDITIONS
Isink = 20mA
Isink = 200mA
Isink = 20mA
Isink = 200mA
Vcc=6V, Isink = 1mA
C_L=1000pF
C_L=1000pF
I_cc≤25mA
The improved switching performance increases the high peak current associated with internal and external
capacitances and will require careful grounding and PCB trace routing. Bypass and timing capacitors should be of
high quality and located carefully with short traces. The reference capacitor must be located very close to the IC
with minimum trace lengths. A single point ground should be located at pin 5 ground. The use of a good ground
plane is recommended. Under certain conditions of high peak currents it may be advisable to isolate the Vref pin
from the bypass capacitor with a resistor to prevent interaction of the high current with the internal oscillator
operation.
Charge and discharge times are given by the following formulas:
T_C=0.55R_tC_t
T_D=R_tC_tLn[(0.0063R_t-2.7)/(0.0063R_t-4)]
Frequency =( T_C+ T_D)^-1
Oscillator simplified circuit.
1 _COMP
Vref ⁸
Rt
2 _FB
Vcc ⁷
3 _Isense
OUT ⁶
4
R/C
5
GND
Ct
© Copyright 2010- ASIC Advantage, Inc. – AADS00012 / R127B - Preliminary - October 2010 4 / 8