UC2856-Q1

Manufacturer Part NumberUC2856-Q1
DescriptionThe UC2856 is a high performance version of the popular UC2846 series of current mode controllers, and is intended for both design upgrades and new applications where speed and accuracy are important
ManufacturerTexas Instruments
UC2856-Q1 datasheet
 


Specifications of UC2856-Q1

TopologyBoost, Flyback, Forward, Full-Bridge, Half-Bridge, Push-PullControl MethodCurrent
Duty Cycle(max)(%)50Frequency(max)(khz)1000
Uvlo Thresholds On/off(v)7.7/7Pin/package16SOIC
Vin(min)(v)8Vin(max)(v)40
Regulated Outputs(#)2Operating Temperature Range(c)-40 to 125
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IMPROVED CURRENT-MODE PWM CONTROLLER
FEATURES
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Qualified for Automotive Applications
Pin-for-Pin Compatible With the UC2846
65-ns Typical Delay From Shutdown to
Outputs and 50-ns Typical Delay From Sync to
Outputs
Improved Current Sense Amplifier With
Reduced Noise Sensitivity
Differential Current Sense With 3-V
Common-Mode Range
Trimmed Oscillator Discharge Current for
Accurate Deadband Control
Accurate 1-V Shutdown Threshold
High Current Dual Totem Pole Outputs
(1.5-A Peak)
TTL Compatible Oscillator SYNC Pin
Thresholds
ESD Protection
– 4-kV Human-Body Model (HBM)
– 500-V Charged-Device Model (CDM)
DESCRIPTION
The UC2856 is a high performance version of the popular UC2846 series of current mode controllers, and is
intended for both design upgrades and new applications where speed and accuracy are important. All input to
output delays have been minimized, and the current sense output is slew rate limited to reduce noise sensitivity.
Fast 1.5-A peak output stages have been added to allow rapid switching of power FETs.
A low impedance TTL compatible sync output has been implemented with a 3-state function when used as a
sync input.
Internal chip grounding has been improved to minimize internal noise caused when driving large capacitive
loads. This, in conjunction with the improved differential current-sense amplifier, results in enhanced noise
immunity.
Other features include a trimmed oscillator current (8%) for accurate frequency and dead-time control, a 1-V 5%
shutdown threshold, and 4-kV minimum ESD protection (HBM) on all pins.
T
A
–40°C to 125°C
SOP – DW
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
(2) Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Check for Samples:
UC2856-Q1
CL SS
VREF
CS−
CS+
EA+
EA−
COMP
CT
ORDERING INFORMATION
(2)
PACKAGE
ORDERABLE PART NUMBER
Reel of 2000
UC2856QDWRQ1
UC2856-Q1
SLVS863B – JUNE 2008 – REVISED MAY 2011
DW PACKAGE
(TOP VIEW)
1
16
SHUTDOWN
2
15
VIN
3
14
BOUT
4
13
VC
5
12
GND
6
11
AOUT
7
10
SYNC
8
9
RT
(1)
TOP-SIDE MARKING
UC2856Q1
Copyright © 2008–2011, Texas Instruments Incorporated
P0008-01

UC2856-Q1 Summary of contents

  • Page 1

    ... Check for Samples: UC2856- VREF CS− CS+ EA+ EA− COMP CT ORDERING INFORMATION (2) PACKAGE ORDERABLE PART NUMBER Reel of 2000 UC2856QDWRQ1 UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 DW PACKAGE (TOP VIEW SHUTDOWN 2 15 VIN 3 14 BOUT ...

  • Page 2

    ... UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. VIN 15 SYNC 4.1 V CS− ...

  • Page 3

    ... VREF VREF VREF SYNC VREF 0 SYNC UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 UNIT 0 –0 VIN –0 –0 ±10 mA – ...

  • Page 4

    ... UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 ELECTRICAL CHARACTERISTICS (continued –40°C to 125°C, VIN = kΩ nF, and T A PARAMETER Error Amplifier Section Input offset voltage Input bias current Input offset current Common mode range Open loop gain ...

  • Page 5

    ... A J TEST CONDITIONS OUT I = 200 mA OUT I = –20 mA OUT I = –200 mA OUT VIN = OUT UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 (1) MIN TYP MAX UNIT 40 V 250 µA 0.1 0.5 V 0.5 2.6 12 ...

  • Page 6

    ... UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 APPLICATION AND OPERATION INFORMATION V REF COMP SYNC NOTE: Output deadtime is determined by the size of the external capacitor, C For large values 250 C T Oscillator frequency is approximated by the formula: NOTE: Error Amplifier can source up to 0.5 mA. ...

  • Page 7

    ... R − Output Load Resistance − Master SYNC COMP EA− SYNC COMP EA− Slave (Additional Units) Figure 5. Parallel Operation UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 G002 Output V OUT Filters S0021-01 7 ...

  • Page 8

    ... UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 I S (+) R (− REF R1 R2 NOTE: Peak current ( determined by the formula: S Figure 6. Pulse by Pulse Current Limiting SENSE 3 − 0 0.5 mA Current Limit 1 V REF R2 * 0.5 R1) www.ti.com COMP EA 7 COMP S0022-01 Copyright © ...

  • Page 9

    ... Copyright © 2008–2011, Texas Instruments Incorporated I SENSE + Current Limit SHUTDOWN 16 + − 1 0.8 mA, and a restart cycle is initiated Figure 7. Shutdown UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 COMP S − 0 REF SHUTDOWN Without Auto-Restart (Latched) S0023- REF 9 ...

  • Page 10

    ... UC2856-Q1 SLVS863B – JUNE 2008 – REVISED MAY 2011 Changes from Original (June 2008) to Revision A • Changed the Input bias current Min Value From: - To: -1 and the Max Value From: -1 To: 1 ............................................ • Changed the Input offset current Min Value From: - To: -1 .................................................................................................. ...

  • Page 11

    ... TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold Customer on an annual basis. OTHER QUALIFIED VERSIONS OF UC2856-Q1 : • ...

  • Page 12

    Catalog - TI's standard catalog product Military - QML certified for Military and Defense Applications • PACKAGE OPTION ADDENDUM Addendum-Page 2 27-May-2011 ...

  • Page 13

    ...

  • Page 14

    ... Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’ ...