CALLM FA13843P, FA13843N, FA13842P, FA13842N, FA13844P Datasheet

FA13842,13843,13844,13845

CMOS IC

F A13842, 13843, 13844, 13845

For Switching Power Supply Control

■ Description

The FA1384X series are CMOS current mode control ICs for
off-line and DC-to-DC converters.
These ICs can reduce start-up circuit loss and are optimum for
high efficiency power supplies because of the low power
dissipation achieved through changes in the CMOS fabrication
process.
These ICs can drive a power MOSFET directly.
The high-performance, compact power supply can be
designed with minimal external components .

■ Features

• CMOS process

• Low-power dissipation

• Standby current 2µA (max.), start-up current 30µA (max.)

• Pulse-by-pulse current limiting

• 5V bandgap reference

• UVLO (Undervoltage lockout) with hysteresis

• Maximum duty cycle FA13842, 13843: 96%
FA13844, 13845: 48%

• Pin-for-pin compatible with UC384X

Note: Pins are fully compatible, but characteristics are not.

When our ICs are applied to a power supply circuit
designed for other manufactures' 384X series, the
characteristics and safety features of the power supply
must be checked.

■ Dimensions, mm

Á SOP-8

5

4

4.9

1.27

0.4

8

1

±0.1

Á DIP-8

8

5

±0.2

6.4

3.9

±0.2

6.0

+0.1

–0.05

0.20

0~8°

1.7max

■ Types of FA1384X series

Type UVLO Maximum duty Package

Start threshold Stop threshold cycle

FA13842P 16.5V±1V 9V±1V 96% DIP
FA13842N SOP
FA13843P 9.6V±1V 9V±1V 96% DIP
FA13843N SOP
FA13844P 16.5V±1V 9V±1V 48% DIP
FA13844N SOP

FA13845P 9.6V±1V 9V±1V 48% DIP
FA13845N SOP

1

2.54

±0.25

9.3

1.5

4

0.46

±0.1

3.3

4.5max

3.0min

0~15˚

7.62

0.25

0~15˚

+0.1

–0.05

1

F A13842, 13843, 13844, 13845

■ Block diagram

Á FA13842, 13843

7

VCC

30V

RT/CT

4

ER AMP

2

FB

1

COMP

ISNS

3

Á FA13844, 13845

7

VCC

30V

UVLO

UVLO

2R

1R

UVLO

UVLO

1V

VCC

5V REF

ENB

2.5V

OSC

5V Controlled block

VCC

5V REF

ENB

2.5V

Pin No. Symbol Function Description

1 COMP Compensating Error amplifier output, available

8

VREF

2 FB Feedback Inverting input of the error

for loop compensation circuit

amplifier

OUTPUT
ENB

6

OUT

3 ISNS Current sensing Input voltage proportional to

inductor current

4 RT/CT Oscillator control Setting oscillation frequency

5

GND

and maximum duty-cycle with
resistor RT and capacitor CT

5 GND Ground Ground

S

Q

FF

QB

R

6 OUT Output Output for driving a power

MOSFET
7 VCC Power supply Power supply
8 VREF Reference voltage Reference voltage and

current source charging

capacitor CT through resistor

RT

VREF

8

OUTPUT

6

ENB

OUT

RT/CT

FB

COMP

ISNS

4

ER AMP

2
1

3

2R

1R

1V

OSC

5V ControlIed block

S

FF

QB

R

TFF

Q

CLK

QB

5

GND

Q

■ Absolute maximum ratings (Ta=25˚C)

Item Symbol Test condition Rating Unit

Supply voltage VCC Low impedance source 28 V

Zener clamp (Icc<10mA) Self limiting V
Zener current IZ 10 mA
Output peak current IO Source current 400 mA

Sink current 1 A
FB/ISNS terminal input voltage VIN FB, ISNS –0.3 to 5.3 V
Error amplifier sink current ISINK 10 mA
Total power dissipation Pd at Ta < 50˚C DIP 800 mW

SOP 400

Thermal resistance Rθ j-a Junction-air DIP 125 ˚C/W

SOP 250
Junction temperature Tj 150 ˚C
Ambient temperature Ta –25 to 85 ˚C
Storage temperature Tstg –40 to 150 ˚C

2

F A13842, 13843, 13844, 13845

■ Recommended operating conditions

Item Symbol Min. Max. Unit

Supply voltage VCC 10 25 V
Oscillation timing capacitor CT 0.47 10 nF
Oscillation timing resistor RT 2.0 100 kΩ
Oscillation frequency fOSC 10 500 kHz

■ Electrical characteristics (Vcc=15V, RT=10kΩ, CT=3.3nF, Ta=25˚C)
Reference voltage section

Item Symbol Test condition Min. Typ. Max. Unit

Reference voltage VREF Tj=25˚C, IL=1mA 4.75 5.00 5.25 V
Line regulation LINE Vcc=10 to 25V ±3 ±20 mV
Load current regulation LOAD IL=0 to 20mA ±3 ±25 mV
Temperature regulation VTC Ta=–25 to 85˚C ±0.3 mV/˚C
Output current at short-circuit IOS Tj=25˚C 60 mA

Oscillator section

Item Symbol Test condition Min. Typ. Max. Unit

Oscillation frequency fOSC Tj=25˚C 49 52 55 kHz

Ta=–25 to 85˚C 47 57 kHz
Voltage stability fdv Vcc=10 to 25V ±0.25 ±1%
Temperature stability fdt Ta=–25 to 85˚C –0.07 %/˚C
Oscillation amplitude VOSC Tj=25˚C 1.6 V
Discharge current IDISCHG Tj=25˚C 8.4 mA

Error amplifier section

Item Symbol Test condition Min. Typ. Max. Unit

Input voltage VFB COMP=2.5V, Tj=25˚C 2.4 2.5 2.6 V
Input leak current IFB ±2 µA
Open-loop gain AV 65 72 dB
Unity gain bandwidth fT 0.7 1 MHz
Output source current ISOURCE FB=2.3V, COMP=0V –0.8 –1.0 mA
Output sink current ISINK FB=2.7V, COMP=1V 2 15 mA
Output voltage VH COMP FB=2.3V, RL=15kΩ to GND 4.0 4.5 V

VL COMP FB=2.7V, RL=15kΩ to VREF 80 500 mV

Current sensing section

Item Symbol Test condition Min. Typ. Max. Unit

Voltage gain AV IS Tj=25˚C 2.85 3 3.15 V/V
Maximum input signal VTH IS FB=0V 0.9 1.0 1.1 V
Input bias current IIS –1 –5 µA
Delay to output TPD Tj=25˚C, ISNS to OUT 150 300 ns

3

F A13842, 13843, 13844, 13845

Output section

Item Symbol Test condition Min. Typ. Max. Unit

High-level output VOH I source=–20mA 14.5 14.75 V

I source=–100mA 12 13.5 V

Low-level output V OL I sink=20mA 0.15 0.3 V

I sink=200mA 1.5 3 V
Rise time tr CL=1nF, Tj=25˚C 40 150 ns
Fall time tf CL=1nF, Tj=25˚C 20 150 ns

Under-voltage lockout section

Item Symbol Test condition Min. Typ. Max. Unit

Start threshold VTH ON FA13842, 13844 15.5 16.5 17.5 V

FA13843, 13845 8.6 9.6 10.6 V
Min. operating voltage VTH OFF 8910V
Hysteresis VHYS FA13842, 13844 7.5 V

FA13843, 13845 0.6 V

PWM section

Item Symbol Test condition Min. Typ. Max. Unit

Maximum duty cycle Dmax FA13842, 13843 94 96 98 %

FA13844, 13845 47 48 50 %
Minimum duty cycle Dmin FB=5V, COMP=Open 0 %

Overall device

Item Symbol Test condition Min. Typ. Max. Unit

Standby current ICCL FA13842, 13844 Vcc=14V 2 µA

FA13843, 13845 Vcc=7V 2 µA
Start-up current ICC ST Vcc=Start threshold 12 30 µA
Operating current ICC OP 35mA
Zener voltage (Vcc) VZ Icc=5mA 28 30 34 V

4

F A13842, 13843, 13844, 13845

1

1025

R

T

timing resistance (kΩ)

Output maximum duty cycle (%)

40

50

60

70

80

90

100

■ Characteristic curves (Ta=25˚C)

Timing resistance vs. oscillation frequency Output dead time vs. oscillation frequency

FA13842, FA13843 FA13842, FA13843

100

10

resistance (kΩ)

T

R

1

1

CT=10nF

VCC= 15V
Ta= 25˚C

2.2nF

10 100 1000

Oscillation frequency (kHz)

470pF

100

VCC= 15V
Ta= 25˚C

10

Output dead time (%)

1

10

2.2nF

CT=10nF

100 1000

Oscillation frequency (kHz)

Timing resistance vs. oscillation frequency Output dead time vs. oscillation frequency

FA13844, FA13845 FA13844, FA13845

100

470pF

2.2nF

CT=10nF

100

VCC= 15V
Ta= 25˚C

90

80

470pF

10

resistance (kΩ)

T

R

VCC= 15V
Ta= 25˚C

1

101 100 1000

Oscillation frequency (kHz)

70

60

Output dead time (%)

50

40

10

CT=10nF

2.2nF

100 1000

Oscillation frequency (kHz)

470pF

RT/CT discharge current vs. temperature Output max. duty cycle vs. timing resistance

FA13842, FA13843

10

9.5

9

8.5

8

RT/CT discharge current (mA)

7.5

7
–50

0 50 100 150

Temperature (˚C)

5