Diodes AP3421/A/B - Manual (Page 6)

Preliminary Datasheet
1.3MHz, Dual 1.0A Synchronous Step-down Converters AP3421/A/B
Feb. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
6
Electrical Characteristics
V
IN
=V
E/S
=5V, T
A
=25℃, unless otherwise specified.
Parameter Symbol Conditions Min Typ Max Unit
Operating Input Voltage V
IN
AP3421 4.5 5.0 5.5
V
AP3421A/B 3.0 3.3 5.5
Supply Current I
CC
V
FB1
=V
FB2
=1.2V 1.0 mA
Shutdown Supply Current I
SHDN
V
E/S
=0V, V
IN
=5.0V 10
µA
Under Voltage Lockout Threshold
AP3421
Rising Edge
3.0 3.5 4.0
V
AP3421A/B 2.4 2.7 3.0
Under Voltage Lockout Hysteresis V
HUVLO
300 mV
POR Threshold VMON V
VMON_POR
V
VMON
Falling 0.97 1.00 1.03 V
Feedback Voltage V
FB1,
V
FB2
0.975 1.0 1.025 V
Switch Current Limit
I
LIM1
1.2 1.6
A
I
LIM2
1.2 1.6
Oscillator Frequency f
OSC1
, f
OSC2
1.0 1.30 1.60 MHz
Soft-start Time t
SS_FB1
0.5 1.0 2.0 ms
POR Threshold FB1 V
FB1_POR
FB11Falling1 86 89 92 %V
FB1
POR Threshold FB2 V
FB2_POR
FB21Falling1 86 89 92 %V
FB2
Discharge Complete Threshold
(AP3421/A )
V
FB1_DCT
FB1 Level Where
Discharge Cycle Is
Terminated
50 75 100 mV
E/S Pin Threshold
V
EN_L
0.6 V
V
EN_H
1.5
Frequency Lock-in Range
f
E/S_MIN
f
SWITCHING
=50%×f
E/S
When Externally
Clocked
1.5
MHz
f
E/S_MAX
3.0
POR Assert Delay Time t
POR_DELAY
Fault Flag Set to
POR Pull Low
10 25 40
µs
POR Release Delay Time t
POR_HOLD
Fault Flag Reset to
POR Hi-Z State
10 20 30 ms
POR Low Voltage V
POR_LOW
POR Sinking 4mA 300 mV
VO2 Start Threshold (AP3421/A ) V
FB1_ST
FB1 Rising Voltage
for FB2 to Initiate
Soft-start
86 89 92 %V
FB1
SW1, SW2 Discharge Resistance R
STOP_SW1,2
Discharge1Resistan-
ce for SW1, SW2
15 30 45
Ω
Internal
MOSFET on
Resistance
AP3421,
AP3421A/B
R
DS_SW1_U
V
IN
=5.0V
I
SW
=100mA
277
m
Ω
R
DS_SW2_U
260
R
DS_SW1_L
V
IN
=5.0V
I
SW
=-100mA
249
R
DS_SW2_L
160
AP3421A/B
R
DS_SW1_U
V
IN
=3.3V
I
SW
=100mA
300
R
DS_SW2_U
280
R
DS_SW1_L
V
IN
=3.3V
I
SW
=-100mA
260
R
DS_SW2_L
180
Thermal Shutdown Threshold T
OTSD
160 ºC
Thermal Shutdown Hysteresis T
HYS
10 20 30 ºC