CMOS Current-Mode PWM Voltage Controller
Copyright
ANPEC Electronics Corp.
Rev. A.7 - Jan., 2003
APW38HC42A/3A/4A/5A
www.anpec.com.tw
1
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise
customers to obtain the latest version of relevant information to verify before placing orders.
Features
General Description
The APW38HC4XA family are fixed frequency, high
performance, current-mode PWM controller with 1.2
A drive current capability. Undervoltage lockout cir-
cuitry allows the APW38HC42A and APW38HC44A
versions to start up at 14.5V and operate down to
9V, and the APW38HC43A and APW38HC45A ver-
sions start at 8.4V with operateion down to 7.6V. All
versions operate up to 24V. The ultra low start-up
current 25
A (typical), and operating current 2mA
(typical) have been designed to improve the converter
efficiency. High output driving capability up to 1.2A
ensures the fast switching to minimize the switching
losses. The APW38HC4XA features a trimmed and
temperature compensated oscillator discharge cur-
rent and bandgap reference. APW38HC4XA is avail-
able in both 8-pin plastic DIP and SOP packages.
Applications
Current-mode , Off-line , Switched-mode Power
Supplies
Current-mode , DC-to-DC converters
Various converters ( step-down, step-up, flyback
, forward, and synchronous FET)
Ordering and Marking Information
Ultralow start-up current (25
A typical)
Low operating current (2mA typical)
Fast output rise/fall times :
-
15ns rise/10ns fall
High output drive (1.2A peak current)
CMOS outputs with rail-to-rail swing
Current-mode operation up to 1MHz
Trimmed 5V bandgap reference
Pin-to-pin compatible with MIC38HC4X
Trimmed oscillator discharge current
UVLO with hysteresis
Low cross-conduction currents
APW 38HC4XA
Package Code
J : DIP - 8 K : SOP-8
Temp. Range
C : 0 to 70 C I : -40 to 85 C
Handling Code
TU : Tube TR : Tape & Reel
Lead Free Code
L : Lead Free Device Blank : Original Device
Handling Code
Temp. Range
Package Code
X - 2/3/4/5 XXXXX - Date Code
APW 38HC4XA
XXXXX
APW 384XA J :
APW 38HC4XA
XXXXX
APW 384XA K :
X - 2/3/4/5 XXXXX - Date Code
Lead Free Code
Pin Description
I S N S
R T / C T
V D D
G N D
C O M P
F B
O U T
1
2
3
4
V R E F
5
6
7
8
Copyright
ANPEC Electronics Corp.
Rev. A.7 - Jan., 2003
APW38HC42A/3A/4A/5A
www.anpec.com.tw
2
Duty Cycle
Startup 8.4V
Minimum Operating 7.6V
Startup 14.5V
Minimum Operating 9V
0~96%
APW38HC43A
APW38HC42A
0~50%
APW38HC45A
APW38HC44A
Block Diagram
Functional Pin Description
Pin Name
Pin Number
Function Description
1
COMP
Compensation: Connect external compensation network to
modify the error amplifier output.
2
FB
Feedback (Input): Error amplifier input. Feedback is 2.5V at
desired output voltage.
3
ISNS
Current Sense (Input): Current sense comparator input.
Connect to current sensing resistor or current transformer.
4
RT/CT
Timing Resistor/Timing Capacitor: Connect external RC
network to select switching frequency.
5
GND
Ground: Combined analog and power ground.
6
OUT
Power Output: Totem-pole output.
7
VDD
Analog Supply (Input): Controller circuitry supply input. Return
to analog ground (AGND).
8
VREF
5V Reference (Output): Connect external RC network.
U V L O
T Q
Oscillator
5 V
Reference
S
Q
R
+
-
+
-
O U T
ISNS
G N D
C O M P
2.5V
F B
R T / C T
V R E F
V D D
R
2 R
E. A.
Selection Guide
Copyright
ANPEC Electronics Corp.
Rev. A.7 - Jan., 2003
APW38HC42A/3A/4A/5A
www.anpec.com.tw
4
V
DD
=15V, Note3 ; RT=9.09K
; CT=3.3nF; -40
o
C
T
A
85
o
C; unless noted
APW38HC4XA
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
ERROR AMPLIFIER
I
FB
Input Bias Current
V
FB
=5V
0.1
A
A
VOL
Open Loop Gain
2
V
O
4V
60
70
dB
BW
Unity Gain Bandwidth
0.7
1.0
MHz
PSRR
12
V
DD
18V
60
dB
Output Sink Current
V
FB
=2.7V, V
COMP
=1.1V
2
7
mA
Output Source Current
V
FB
=2.3V, V
COMP
=5V
-0.5
-1
mA
V
OH
Output Voltage (High)
V
FB
=2.3V, R
L
=15k to GND
5
5.4
V
V
OL
Output Voltage (Low)
V
FB
=2.7V, R
L
=15k to VREF
0.01
1.1
V
CURRENT SENSE
A
Gain
Notes 1,2
2.85
3.0
3.15
V/V
V
THM
Maximum Threshold
V
COMP
=5V, Note 1
0.9
1.0
1.1
V
PSRR
12
V
DD
18V, Note 1
70
dB
I
ISNS
Input Bias Current
V
ISNS
=5V
0.1
A
T
D
Delay to Output
120
250
ns
OUTPUT
R
DS(ON)
High
Sourcing Current = 200mA
6.3
R
DS(ON)
Low
Sinking Current = 200mA
4
t
R
Rise Time
T
A
=25
C, C
L
=1nF
15
30
ns
t
F
Fall Time
T
A
=25
C, C
L
=1nF
10
20
ns
UNDERVOLTAGE LOCKOUT
APW38HC42/4A
13.5
14.5
15.5
V
DD(ST)
Start Threshold
APW38HC43/5A
7.8
8.4
9.0
V
APW38HC42/4A
8.0
9.0
10.0
V
DD(MIN)
Minimum Operating Voltage
APW38HC43/5A
7.0
7.6
8.2
V
PULSE WIDTH MODULATOR
APW38HC42/3A
94
96
D
MAX
Maximum Duty Cycle
APW38HC44/5A
46
50
%
D
MIN
Minimum Duty Cycle
0
%
TOTAL STANDBY CURRENT
V
DD
=13V, APW38HC42/4A
30
150
I
DD(ST)
Start-Up Current
V
DD
=7.5V, APW38HC43/5A
25
150
A
I
DD(OP)
Operating Supply Current
V
FB
=V
ISNS
= 0V, C
L
=1nF
2.0
4.0
mA
Electrical Characteristics (Cont.)
Note 1 : Parameter measured at trip point of latch with V
FB
=0V.
Note 2 : Gain defined as :
A = , 0<V
TH(ISNS)
<0.8V
Note 3 : Adjust V
DD
above the start threshold before setting at 15V.
Note 4 : Output frequency equals oscillator frequency for the APW38HC42A and APW38HC43A. Output
frequency for APW38HC44A and APW38HC45A equals one half of the oscillator frequency.
V
COMP
V
TH(ISNS)
Copyright
ANPEC Electronics Corp.
Rev. A.7 - Jan., 2003
APW38HC42A/3A/4A/5A
www.anpec.com.tw
5
1
10
100
10
100
1000
200pF
470pF
1nF
10nF
4.7nF
1.8nF
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0
1
2
3
4
5
6
7
125
o
C
25
o
C
-50
o
C
7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0
-60
-30
0
30
60
90
120
150
1
10
100
10
100
1000
2 0
0pF
4 7
0pF
1 nF
1 .8
n F
4 .7
n F
1 0
n F
Typical Characteristics
Oscillator Frequency (kHz)
RT Resistance (k
)
Oscillator Frequency Configuration
Output Dead Time vs. Oscillator Frequency
Oscillator Frequency (kHz)
Output Dead Time ( %)
Oscillator Discharge Current vs.
Temperature
Temperature (
C)
Oscillator Discharge Current (mA)
Current Sense Amplifier Threshold vs.
Error Amplifier Output
Error Amplifier Output (V)
Current Sense AMP Threshold (V)
V
DD
= 15V
V
RTCT
= 2V
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