ap3421 BCD Semiconductor Manufacturing Limited, ap3421 Datasheet - Page 6

• Manufacturer Part Number: ap3421
• Description: 1.3mhz, Dual 1.0a Synchronous Step-down Converters
• Manufacturer: BCD Semiconductor Manufacturing Limited

Electrical Characteristics
V
Aug. 2010 Rev. 1.2
1.3MHz, Dual 1.0A Synchronous Step-down Converters
Parameter
Operating Input Voltage
Supply Current
Shutdown Supply Current
Under Voltage Lockout Threshold
Under Voltage Lockout Hysteresis
POR Threshold VMON
Feedback Voltage
Switch Current Limit
Oscillator Frequency
Soft-start Time
POR Threshold FB1
POR Threshold FB2
Discharge Complete Threshold
E/S Pin Threshold
Frequency Lock-in Range
POR Assert Delay Time
POR Release Delay Time
POR Low Voltage
VO2 Start Threshold
SW1, SW2 Discharge Resistance
Internal
MOSFET
Resistance
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
IN
=V
E/S
=5V, T
on
A
=25℃, unless otherwise specified.
AP3421,
AP3421A
AP3421A
V
V
IN
UVLO
V
f
R
Symbol
V
t
R
R
R
R
R
R
R
R
V
OSC1
t
V
POR_DELAY
V
V
f
POR_HOLD
V
STOP_SW1,2
VMON_POR
f
V
DS_SW1_U
DS_SW2_U
DS_SW1_U
DS_SW2_U
FB1,
E/S_MAX
DS_SW1_L
DS_SW2_L
DS_SW1_L
DS_SW2_L
t
V
POR_LOW
V
T
I
E/S_MIN
FB1_POR
FB2_POR
FB1_DCT
SS_FB1
T
I
I
HUVLO
FB1_ST
SHDN
AP3421A
I
LIM1
LIM2
OTSD
EN_L
EN_H
HYS
AP3421
CC
, f
AP3421A
V
AP3421
OSC2
FB2
6
V
V
Rising Edge
V
FB11Falling1
FB21Falling1
FB1
Discharge Cycle Is
Terminated
f
When
Clocked
Fault Flag Set to POR
Pull Low
Fault Flag Reset to
POR Hi-Z State
POR Sinking 4mA
FB1 Rising Voltage
for FB2 to Initiate
Soft-start
Discharge1Resistan-c
e for SW1, SW2
V
I
V
I
V
I
V
I
SWITCHING
SW
SW
SW
SW
FB1
E/S
VMON
IN
IN
IN
IN
Conditions
=100mA
=-100mA
=100mA
=-100mA
=5.0V
=5.0V
=3.3V
=3.3V
=0V, V
=V
Level
Falling
FB2
=50%×f
=1.2V
IN
Externally
=5.0V
Where
BCD Semiconductor Manufacturing Limited
E/S
Preliminary Datasheet
Min Typ Max
0.975
0.97
4.5
3.0
3.0
2.4
1.2
1.2
1.0
0.5
0.6
3.0
86
86
50
10
10
86
15
10
1.00
1.30
300
277
260
249
160
300
280
260
180
160
5.0
3.3
3.5
2.7
1.0
1.6
1.6
1.0
89
89
75
25
20
89
30
20
AP3421/A
1.025
1.03
1.60
100
300
5.5
5.5
1.0
4.0
3.0
2.0
1.5
1.5
10
92
92
40
30
92
45
30
%V
%V
%V
Unit
MHz
MHz
mA
mV
mV
mV
mΩ
µA
V
ms
ms
µs
ºC
ºC
V
V
V
A
V
Ω
FB1
FB2
FB1