Cherry Semiconductor CS3865CGN16, CS3865CGDWR16, CS3865CGDW16 Datasheet

1

Features

■ Oscillator has Precise

Duty Cycle
Limit and Frequency
Control

■ 500kHz Current Mode

Operation

■ Automatic Feed Forward

Compensation

■ Separate Latching PWMs

for Cycle-By-Cycle
Current Limiting

■ Internally Trimmed

Reference with
Undervoltage Lockout

■ Switchable Second

Output

■ Two High Current Totem

Pole Outputs

■ Input Undervoltage

Lockout with Hysteresis

■ Low Start-Up and

Operating Current

Package Options

16L PDIP & SO Wide

CS3865C

High Performance Dual Channel

Current Mode Controller with ENABLE

1

SYNC

2
3
4
5
6
7
8

C

T

R

T

V

FB

1

COMP

1

Sense

1

V

OUT

1

Gnd

16
15
14
13
12
11
10

9

V

CC

V

REF

ENABLE

2

V

FB

2

COMP

2

Sense

2

V

OUT

2

Pwr Gnd

CS3865C

Description

The CS3865C is a high perfor­mance, fixed frequency, dual cur­rent mode controller. It is used in
Off-Line and DC to DC converter
applications and require a mini­mum number of external compo­nents. This integrated circuit fea­tures a unique oscillator for precise
duty cycle limit and frequency con­trol, a temperature compensated
reference, two high gain error
amplifiers, two current sensing
comparators, and two high current
totem pole outputs ideally suited

for driving power MOSFETs. One
of the outputs V

OUT

2

is switchable

via the ENABLE

2

pin.

Also included are protective fea­tures consisting of input and refer­ence undervoltage lockouts each
with hysteresis, cycle-by-cycle cur­rent limiting, and a latch for single
pulse metering of each output.

The CS3865C has a 14V start volt­age and is pin compatible with the
MC34065H.

Block Diagram

Rev. 12/16/96

Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: [phone] Fax: [phone]

Email: [e-mail]

Web Site: www.cherry-semi.com

A Company

®

V

REF

Undervoltage

Lockout

V

5.0V Ref

V

REF

CC

Undervoltage

Lockout

V

CC

SYNC

V

COMP

ENABLE

V

COMP

V

OUT

Latching

C

T

R

T

FB

1

1

2

FB

2

2

+

-

Error
Amp 1

+

-

Error

Amp 2

Oscillator

Gnd

PWM 1

Latching

PWM 2

Pwr Gnd

1

Sense

1

V

OUT

2

Sense

2

2

Electrical Characteristics: V

CC

= 15V, RT = 8.2kΩ, CT = 3.3nF, for typical values TA=25˚C, for min/max values TAis the operating

ambient temperature range that applies [Note 3].

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Absolute Maximum Ratings

Total Power Supply and Zener Current .........................................................................................................................50mA

Output Current, Source or Sink (Note 1)...........................................................................................................................1.0A

Output Energy (capacitive load per cycle) .......................................................................................................................5.0µJ

Current Sense, Enable and Voltage......................................................................................................................-0.3 to +5.5V

Feedback Inputs

High State (Voltage)..........................................................................................................................................5.5V

Low State (Reverse Current) ......................................................................................................................-5.0mA

Error Amp Output Sink Current......................................................................................................................................10mA

Storage Temperature Range ................................................................................................................................-65 to +150°C

Operating Junction Temperature...................................................................................................................................+150°C

Operating Ambient Temperature.............................................................................................................................0 to +70°C

Lead Temperature Soldering

Wave Solder (through hole styles only) .................................................................................10 sec. max, 260°C peak

Reflow (SMD styles only) ..................................................................................60 sec. max above 183°C, 230°C peak

CS3865C

■ Reference Section

Reference Output Voltage, I

OUT

=1.0mA, TJ=25°C 4.9 5.0 5.1 V

V

REF

Line Regulation 11V≤VCC≤15V 2.0 20.0 mV
Load Regulation 1.0mA≤I

OUT

≤10mA 3.0 25.0 mV

Total Output Variation over 4.85 5.15 V
Line, Load and Temperature

Output Short Circuit Current 30 100 mA

■ Oscillator and PWM Sections

Total Frequency Variation 11V≤VCC≤15V, T

low≤TA≤Thigh

46.5 49.0 51.5 kHz

over Line and Temperature
Frequency Change with 11V≤VCC≤15V 0.2 1.0 %

Voltage
Duty Cycle at each Output Maximum 46.0 49.5 52.0 %
Sync Input Current High State VIN=2.4V 170 250 µA

Low State VIN=0.8V 80 160

■ Error Amplifiers

Voltage Feedback Input V

OUT

=2.5V 2.42 2.50 2.58 V
Input Bias Current VFB=5.0V -0.1 -1.0 µA
Open-Loop Voltage Gain V

OUT

=2.0 to 4.0V 65 100 dB
Unity Gain Bandwidth TJ=25°C (note 6) 0.7 1.0 MHz
Power Supply Rejection Ratio VCC=11V to 15V 60 90 dB
Output Current Source V

OUT

=3.0V, VFB=2.3V -0.45 -1.00 mA

Sink V

OUT

=1.2V, VFB=2.7V 2.00 12.00 mA

Output Voltage Swing High State, RL=15k to ground,

VFB=2.3V 5.0 6.2 V

Low State, RL=15k to V

REF

,

VFB= 2.7V 0.8 1.1

3

CS3865C

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Note 1: Maximum package power dissipation limits must be observed.

Note 3: Adjust VCCabove the Start-Up threshold before setting to 15V.

Note 4: This parameter is measured at latch trip point with VFB=0V.

Note 5: Comparator gain is defined as:

AV =

Note 6: These parameters are guaranteed by design but not 100% tested
in production.

Note 7: Low duty cycle pulse techniques are used during test to main­tain junction temperature as close to ambient as possible: T

low

=0°C ;

T

high

=+70°C

∆V Compensation

∆V Current Sense

■ Current Sense Section

Current Sense Input (Notes 4 and 5) 2.75 3.00 3.25 V/V
Voltage Gain

Maximum Current Sense (Note 4) 430 480 530 mV
Input Threshold

Input Bias Current -2.0 -10.0 µA
Propagation Delay Current Sense Input to Output (Note 6) 150 300 ns

■ Output 2 Enable Pin

Enable Pin Voltage
High State Output 2 enabled 3.5 V

REF

V

Low State Output 2 disabled 0.0 1.5 V
Low State Input Current V

IL

= 0V 100 250 400 µA

■ Drive Outputs

Output Voltage

Low State I

SINK

=20mA 0.1 0.4 V

I

SINK

=200mA 1.6 2.5 V

High State I

SOURCE

=20mA 13.0 13.5 V

I

SOURCE

=200mA 12.0 13.4 V

Output Voltage with VCC=6.0V, I

SINK

=1.0mA 0.1 1.1 V

UVLO Activated
Output Voltage Rise Time CL=1.0nF (Note 6) 28 150 ns
Output Voltage Fall Time CL=1.0nF (Note 6) 25 150 ns

■ Undervoltage Lockout Section

Start-Up Threshold CS3865C 13 14 15 V
Minimum Operating Voltage 9.0 10.0 11.0 V

After Turn-On
Hysteresis 4V

■ Total Device

Start-Up Current V

CC

=12V 0.6 1.0 mA

Operating Current (Note 7) 20 25 mA
Power Supply Zener Voltage I

CC

=30mA 15.5 17.0 19.0 V

Electrical Characteristics: V

CC

= 15V, RT = 8.2kΩ, CT = 3.3nF, for typical values TA=25˚C, for min/max values TAis the operating

ambient temperature range that applies [Note 3].