Datasheet SG1846F-DESC, SG1846J, SG1846J-883B, SG1846J-DESC, SG1846L Datasheet (Microsemi Corporation)

CURRENT MODE PWM CONTROLLER

FEATURES

••

••

• Automatic feed forward compensation

••

••

• Programmable pulse by pulse current limiting

••

••

• Automatic symmetry correction in push-pull

configuration

••

••

• Enhanced load response characteristics

••

••

• Parallel operation capability for modular power

systems

••

••

• Differential current sense amplifier with wide

common mode range

••

••

• Double pulse suppression

••

••

• 200mA totem-pole outputs

••

••

• ± 1% bandgap reference

••

••

• Under-voltage lockout

••

••

• Soft-start capability

••

••

• Shutdown capability

••

••

• 500KHz operation

HIGH RELIABILITY FEATURES - SG1846

♦♦

♦♦

♦ Available to MIL-STD - 883
♦♦

♦♦

♦ Radiation data available
♦♦

♦♦

♦ LMI level "S" processing available

DESCRIPTION

The SG1846 family of control ICs provides all of the necessary
features to implement fixed frequency, current mode control
schemes while maintaining a minimum external parts count. The
superior performance of this technique can be measured in im­proved line regulation, enhanced load response characteristics,
and a simpler, easier-to-design control loop. Topological advan­tages include inherent pulse-by-pulse current limiting capability,
automatic symmetry correction for push-pull converters, and the
ability to parallel “power modules” while maintaining equal current
sharing.

Protection circuitry includes built-in under-voltage lockout and
programmable current limit in addition to soft start capability. A
shutdown function is also available which can initiate either a
complete shutdown with automatic restart or latch the supply off.

Other features include fully latched operation, double pulse sup­pression, deadtime adjust capability, and a ±1% trimmed bandgap
reference.

BLOCK DIAGRAM

SG1846/SG2846/SG3846

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SG1846

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ABSOLUTE MAXIMUM RATINGS (Note 1 and 2)

Sync Output Current ...........................................................5mA

Error Amplifier Output Current ............................................5mA

Oscillator Charging current (Pin 9) .....................................5mA

Operating Junction Temperature

Hermetic (J, L, F Packages)........................................ 150°C

Plastic (N, DW Package)............................................. 150°C

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

Lead Temperature (Soldering, 10 Seconds) .................. 300°C

Supply Voltage (+V

IN

).......................................................... 40V

Collector Supply Voltage(V

C

) .............................................. 40V

Analog Inputs (Pins 3, 4, 5, 6, & 16) ......................-0.3V to +V

IN

Logic Input ...........................................................-0.3V to 5.5V

Soure/Sink Load current (continuous) .......................... 200mA

Source/Sink Load Current (peak, 200ns) ...................... 500mA

Reference Load Current .................................................. 30mA

Soft Start Sink Current ..................................................... 50mA

Note 1. Values beyond which damage may occur.
Note 2. Pin numbers refer to ceramic J package.

THERMAL DATA

J Package:

Thermal Resistance-

Junction to Case, θ

JC

.................. 30°C/W

Thermal Resistance-

Junction to Ambient, θ

JA

.............. 80°C/W

N Package:

Thermal Resistance-

Junction to Case, θ

JC

.................. 40°C/W

Thermal Resistance-

Junction to Ambient, θ

JA

............. 65°C/W

DW Package:

Thermal Resistance-

Junction to Case, θ

JC

................... 40°C/W

Thermal Resistance-

Junction to Ambient, θ

JA

............. 95°C/W

F Package:

Thermal Resistance-

Junction to Case, θ

JC

.................. 70°C/W

Thermal Resistance-

Junction to Ambient, θ

JA

........... 115°C/W

L Package:

Thermal Resistance-

Junction to Case, θ

JC

.................. 35°C/W

Thermal Resistance-

Junction to Ambient, θ

JA

........... 120°C/W

Note A. Junction Temperature Calculation: TJ = TA + (PD x θJA).
Note B. The above numbers for

θJC are maximums for the limiting

thermal resistance of the package in a standard mount­ing configuration. The θ

JA

numbers are meant to be
guidelines for the thermal performance of the device/pc­board system. All of the above assume no ambient
airflow.

5.10
5
3

0.4

100

5

-45

Reference Section

TJ = 25°C, IO = 1mA
V

IN

= 8V to 40V

I

L

= 1mA to 10mA

Line, Load and Temperature
10Hz ≤ f ≤ 10KHz. T

J

= 25°C

T

J

= 125°C, 1000Hrs.

V

REF

= 0V

5.05

5.00

-10

Output Voltage
Line Regulation
Load Regulation
Temperature Stability

(Note 4)

Total Output Variation (Note 4)
Output Noise Voltage (Note 4)
Long Term Stability (Note 4)
Short Circuit Output Current

Oscillator Timing Resistor (RT)........................... 2KΩ to 100KΩ

Oscillator Timing Capacitor (C

T

) .................... 1000 pF to 0.1µF

Operating Ambient Temperature Range

SG1846 ........................................................... -55°C to 125°C

SG2846 ............................................................. -25°C to 85°C

SG3846 ................................................................0°C to 70°C

Note 3. Range over which the device is functional.

RECOMMENDED OPERATING CONDITIONS (Note 3)

Supply Voltage Range ............................................... 8V to 40V

Collector Supply Voltage Range............................. 4.5V to 40V

Source/Sink Output Current (continuous)...................... 100mA

Source/Sink Output Current (peak 200ns) .................... 200mA

Reference Load Current ........................................... 0 to 10mA

Oscillator Frequency Range ........................... 1KHz to 500KHz

ELECTRICAL CHARACTERISTICS

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1846/SG1847 with -55°C ≤ TA ≤ 125°C, SG2846
with -25°C ≤ T

A

≤ 85°C, SG3846 with 0°C ≤ TA ≤ 70°C, +VIN = 15V. Low duty cycle pulse testing techniques are used which maintains junction and

case temperatures equal to the ambient temperature.)

Units

SG1846
SG2846

SG3846

Parameter Test Conditions

5.15
20
15

5.20

5.00

4.95

-10

Min. Typ. Max.Min. Typ. Max.

5.10
5
3

0.4

100

5

-45

5.20
20
15

5.25

V
mV
mV

mV/°C

V

µV
mV
mA

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Collector Emitter Voltage
Collector Leakage Current
Output Low Level

Output High Level
Rise Time

(Note 4)

Fall Time (Note 4)

Threshold Voltage
Input Voltage Range
Minimum Latching Current

(I

PIN 1

) (Note 7)

Maximum Non-Latching Current

(I

PIN 1

) (Note 8)

Delay to Outputs (Note 4) TJ = 25°C

250

0

3.0

350

1.5

1.5

300

400

V

IN

0.8

600

250

0

3.0

350

1.5

1.5

300

400

V

IN

0.8

600

mV

V
mA
mA

ns

Output Section

V

C

= 40V

I

SINK

= 20mA

I

SINK

= 100mA

I

SOURCE

= 20mA

I

SOURCE

= 100mA

C

L

= 1nF, TJ = 25°C

C

L

= 1nF, TJ = 25°C

40

13
12

0.1

0.4

13.5

13.5
50
50

200

0.4

2.1

300
300

40

13
12

0.1

0.4

13.5

13.5
50
50

200

0.4

2.1

300
300

V

µA

V
V
V

V
ns
ns

Amplifier Gain (Notes 5 & 6)
Maximum Differential (Note 6)

Input Signal (V

PIN 4

- V

PIN 3

)(Note 5)
Input Offset Voltage (Note 5)
CMRR
PSRR
Input Bias Current

(Note 5)

Input Offset Current (Note 5)
Input Common Mode Range
Delay to Outputs

(Note 4)

2.5

1.1
60

60

0

2.75

1.2
5

83
84

-2.5

0.08
200

3.0

25

-10
1

V

IN

-3

500

2.5

1.1
60

60

0

2.75

1.2
5

83
84

-2.5

0.08
200

3.0

25

-10
1

V

IN

-3

500

Input Offset Voltage
Input Bias Current
Input Offset Current
Common Mode Range
Open Loop Voltage Gain
Unity Gain Bandwidth (Note 4)
CMRR
PSRR
Output Sink Current
Output Source Current
High Level Output Voltage
Low Level Output Voltage

V

IN

= 8V to 40V

V

O

= 1.2V to 3V, VCM = 2V

T

J

= 25°C

V

CM

= 0V to 38V, V

IN

= 40V

V

IN

= 8V to 40V

V

ID

= - 15mV to -5V, V

PIN 7

= 1.2V

V

ID

= 15mV to 5V, V

PIN 7

= 2.5V

R

L

= 15KΩ (Pin 7)

RL = 15KΩ (Pin 7)

0

80

0.7
75
80

2

-0.4

4.3

0.5

-0.6
40

105

1.0
100
105

6

-0.5

4.6

0.7

5

-1

250

VIN-2V

1

0.5

-0.6
40

105

1.0
100
105

6

-0.5

4.6

0.7

10

-2

250

VIN-2V

1

Error Amp Section

ELECTRICAL CHARACTERISTICS (continued)

Min. Typ. Max. Min. Typ. Max.

SG1846
SG2846

Parameter Test Conditions Units

SG3846

39

3.9

3.9

Initial Accuracy
Voltage Stability
Temperature Stability

(Note 4)

Sync Output High Level
Sync Output Low Level
Sync Input High Level
Sync Input Low Level
Sync Input Current

TJ = 25°C
V

IN

= 8V to 40V

Over Operating Range

Pin 8 = 0V
Pin 8 = 0V
Sync Voltage = 5.25V, Pin 8 = 0V

43

1
1

4.35

2.3

1.2

47

2

2.5

2.5

1.5

39

3.9

3.9

43

1
1

4.35

2.3

1.2

47

2

2.5

2.5

1.5

KHz

%
%

V
V
V
V

mA

Oscillator Section

(Note 9)

mV

µA
nA

V

dB

MHz

dB

dB
mA
mA

V
V

0

80

0.7
75
80

2

-0.4

4.3

Current Sense Amplifier Section

V

PIN 3

= 0V, Pin 1 Open

Pin 1 Open R

L

= 15KΩ (Pin 7)

V

PIN 1

= 0.5V, Pin 7 Open

V

CM

= 1V to 12V

V

IN

= 8V to 40V

V

PIN 1

= 0.5V, Pin 7 Open

V

PIN 1

= 0.5V, Pin 7 Open

T

J

= 25°C

V
V

mV

dB
dB
µA
µA

V

ns

Current Limit Adjust Section

Current Limit Offset Voltage(Note 5)
Input Bias Current

0.55

-30

0.5

-10

0.55

-30

0.450.5

-10

0.45V

PIN 3

= 0, V

PIN 4

= 0V, Pin 7 Open

V

PIN 5

= V

REF

, V

PIN 6

= 0V

Shutdown Terminal Section

V

µA

SG1846

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ELECTRICAL CHARACTERISTICS (continued)

Max. Min. Typ. Max.Typ.

SG3846

Parameter

Test Conditions

Units

SG1846
SG2846

7.7

0.75

8.0

7.7

0.75

8.0

V
V

Note 4.These parameters although guaranteed over the recommended

operating conditions, are not tested in production.

Note 5.Parameter measured at trip point of latch with V

PIN 5

= V

REF

,

V

PIN 6

= 0V.

Note 6.Amplifier gain defined as : G = ; V

PIN 4

= 0V to 1.0V

Note 7.Current into Pin 1 guaranteed to latch circuit in shutdown state.
Note 8. Current into Pin 1 guaranteed not to latch circuit in shutdown

state.

Note 9.R

T

= 10KΩ, CT = 4.7nF

Min.

CHARACTERISTIC CURVES

FIGURE 1.
REFERENCE VOLTAGE VS. TEMPERATURE

FIGURE 2.
V

REF

SHORT CIRCUIT CURRENT VS. TEMPERATURE

FIGURE 3.
CURRENT SENSE THRESHOLD
VS. ERROR AMPLIFIER OUTPUT

FIGURE 4.
CURRENT SENSE GAIN VS. TEMPERATURE

FIGURE 5.
OSCILLATOR VALLEY VOLTAGE VS. TEMPERATURE

FIGURE 6.
OSCILLATOR PEAK VOLTAGE VS. TEMPERATURE

Under-Voltage Lockout Section

Start-Up Threshold
Threshold Hysteresis

Total Standby Current

Supply Current 17 21 17 21 mA

∆ V

PIN 7

∆ V

PIN 4

SG1846

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CHARACTERISTIC CURVES (continued)

FIGURE 9.
SHUTDOWN DELAY TO OUTPUT VS. TEMPERATURE

FIGURE 7.
MINIMUM SCR LATCH CURRENT

FIGURE 8.
CURRENT SENSE DELAY VS. TEMPERATURE

FIGURE 10.
ERROR AMPLIFIER INPUT OFFSET VOLTAGE
VS. TEMPERATURE

FIGURE 12.
OUTPUT TRANSISTOR SATURATION VOLTAGE
VS. OUTPUT CURRENT (SINK TRANSISTOR)

FIGURE 11.
ERROR AMP SINK CURRENT VS. TEMPERATURE

FIGURE 14.
SYNC PULSEWIDTH VS. TEMPERATURE

FIGURE 13.
OUTPUT TRANSISTOR SATURATION VOLTAGE
VS. OUTPUT CURRENT (SOURCE TRANSISTOR)

FIGURE 15.
SYNC PULSEWIDTH VS. TEMPERATURE

SG1846

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CHARACTERISTIC CURVES (continued)

APPLICATION INFORMATION

FIGURE 19- OSCILLATOR FREQUENCY CURVES

FIGURE 20 - OSCILLATOR CIRCUIT

2.2

R

TCT

Oscillator frequency is approximated by the formula: fT ≈

FIGURE 17.
OSCILLATOR FREQUENCY VS. TEMPERATURE

FIGURE 18.
DUTY CYCLE VS. TEMPERATURE

FIGURE 16.
OSCILLATOR FREQUENCY VS. TEMPERATURE

SG1846

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APPLICATION INFORMATION (continued)

FIGURE 21 - ERROR AMP OUTPUT CONFIGURATION

(Error amplifier can source up to 0.5mA)

FIGURE 22 - CURRENT SENSE AMPCONNECTIONS

A small RC filter may be required in some applications to reduce switch

transients. Differential input allows remote, noise free switching.

FIGURE 23 - SINGLE ENDED BOOST CONFIGURATION

SG1846

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APPLICATIONS INFORMATION (continued)

FIGURE 24 - BUCK CONVERTER WITH CURRENT SENSE WINDING

FIGURE 25 - PUSH/PULL CONVERTER WITH SLOPE COMPENSATION

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APPLICATIONS INFORMATION (continued)

V

REF

R

1

< 0.8mA

If < 0.8mA the shutdown latch will commutate
when I

SS

< 0.8mA and a restart cycle will be initiated.

V

REF

R

1

If > 3mA the device will latch off
until power is recycled.

V

REF

R

1

V

REF

R

1

>3mA (LATCHED OFF)

FIGURE 29 - SHUTDOWN WITHOUT AUTO-RESTART (LATCHED)FIGURE 28 - SHUTDOWN WITH AUTO-RESTART

FIGURE 26 - PULSE BY PULSE CURRENT LIMITING

FIGURE 27 - SOFT START AND SHUTDOWN/RESTART FUNCTIONS

SG1846

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CONNECTION DIAGRAMS & ORDERING INFORMATION (See Notes Below)

Ambient

Temperature Range

Part No.

Connection Diagram

Package

16-PIN CERAMIC DIP
J - PACKAGE

SG1846J/883B -55°C to 125°C
SG1846J/DESC -55°C to 125°C
SG1846J -55°C to 125°C
SG2846J -25°C to 85°C
SG3846J 0°C to 70°C

Notes: 1. Contact factory for JAN and DESC part availability.

2. All parts are viewed from the top.

3. Consult factory for product availability.

SHUTDOWN
+V

IN

OUTPUT B
V

C

GROUND
OUTPUT A
SYNC
R

T

C

T

COMPENSATION

(-) ERROR AMP

(+) ERROR AMP

(+) C.S.

(-) C.S.

V

REF

C.L./SOFTSTART

2
3
4
5
6
7
8

1

11

14

15

16

9

12

10

13

16-PIN PLASTIC DIP
N - PACKAGE

SG2846N -25°C to 85°C
SG3846N 0°C to 70°C

2
3
4
5
6
7
8

1

13
12
11

14

15

10

9

16

11.N.C.

12.R

T

13.SYNC

14.OUTPUT A

15.GROUND

16.N.C.

17.V

C

18.OUTPUT B

19.V

IN

20.SHUTDOWN

C

T

COMPENSATION

(-) ERROR AMP

(+) ERROR AMP

(+) C.S.

(-) C.S.

V

REF

C.L./SOFTSTART

SHUTDOWN
+V

IN

OUTPUT B
V

C

GROUND
OUTPUT A
SYNC
R

T

2
3
4
5
6
7
8

1

13
12
11

14

15

10

9

16

C

T

COMPENSATION

(-) ERROR AMP

(+) ERROR AMP

(+) C.S.

(-) C.S.

V

REF

C.L./SOFTSTART

SHUTDOWN
+V

IN

OUTPUT B
V

C

GROUND
OUTPUT A
SYNC
R

T

4
5
6
7
8

321

911121310

14

15

16

17

18

20 19

1. N.C.

2. C.L./SOFTSTART

3. V

REF

4. (-) C.S.

5. (+) C.S.

6. N.C.

7. (+) ERROR AMP

8. (-) ERROR AMP

9. COMPENSATION

10. C

T

16-PIN WIDEBODY
PLASTIC S.O.I.C
DW - PACKAGE

SG2846DW -25°C to 85°C
SG3846DW 0°C to 70°C

16-PIN CERAMIC
FLAT PACK
F - PACKAGE (Note 3)

20-PIN CERAMIC
LEADLESS CHIP CARRIER
L - PACKAGE (Note 3)

SG1846L/883B -55°C to 125°C
SG1846L/DESC -55°C to 125°C
SG1846L -55°C to 125°C

SG1846F/DESC -55°C to 125°C