UC1834
UC2834
UC3834
High Efficiency Linear Regulator
FEATURES
•Mi nimum V IN - VOUT Less Than
0.5V At 5A Load With Ext ernal
Pass Device
•Equally Usable For Either Positive
or Negative Regulator Design
•Adjustable Low Threshold Current
Sense Amplifier
•Under And Over-V o ltage F ault Alert
With Pr ogrammable Delay
•Over -Voltage F au lt Lat ch With
100mA Crowbar Drive Output
DESCRIPTION
The UC1834 family of integrated ci rcuits is optimized for the design of l ow
input-output differential linear regulators. A high gain amplifier and 200mA
sink or source drive outputs facilitate high output current designs which use
an external pass device. With both positive and negative precision refer-
ences, either pol arity of regulator can be implement ed. A c urrent sense am-
plifier with a low, adjustable, threshold can be used to sense and limit
currents in either the posit ive or negative supply lines.
In addition, this series of parts has a fault monitoring circuit which senses
both und er and ove r-voltage fault condi tions. Af ter a user defined delay for
transi ent reje cti on, this circuitry provides a fault alert output for either fault
condition. In the over-voltage case, a 100mA crowbar output is activated.
An ove r-voltage latch will maintai n the crowbar output and can be used to
shutdown the driver outputs. System control to the device can be accom-
modated at a singl e input which will act as both a supply reset and remote
shutdown terminal. These die are protected against excessive power dissi-
pation by an internal thermal shutdown funct ion.
BL OCK DIAG RAM
6/94
ABSOL UTE MAXIMUM RAT ING S (Note 1)
Input Supply Voltage, VIN + . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Driver Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400mA
Driver Source to Sink Voltag e . . . . . . . . . . . . . . . . . . . . . . . 40V
Crowba r Curren t. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −200mA
+ 1.5V Reference O ut pu t Curre nt . . . . . . . . . . . . . . . . . . −10mA
F ault Aler t Vo ltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
F ault Aler t Cu rr ent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15mA
Error Amplifier Inputs . . . . . . . . . . . . . . . . . . . . . . −0.5V to 35 V
Cu rrent Sense Inp ut s . . . . . . . . . . . . . . . . . . . . . . −0.5V t o 40V
O.V. Lat ch Out pu t Voltage . . . . . . . . . . . . . . . . . . −0. 5V to 40 V
O.V. Latch Output Current . . . . . . . . . . . . . . . . . . . . . . . . 15mA
Power Dissipation at TA = 25°C. . . . . . . . . . . . . . . . . . 1000m W
Power Dissipation at TC = 25°C. . . . . . . . . . . . . . . . . . 2000m W
Oper at ing Jun ctio n Tem per atur e. . . . . . . . . . −55°C to +150° C
Storage Temperature. . . . . . . . . . . . . . . . . . . −65°C to +150° C
Lead Tem per at ur e (sold ering , 10 secon ds). . . . . . . . . . . 300° C
Note 1: V olta ges ar e re fe ren ce to V
IN
−
, Pin 5.
Curre nt s are p osit ive in to, ne gat ive out of the spec ifie d
terminals.
Con sult Packag in g sect ion of Dat abo ok for ther m a l
limitat ions an d cons iderations of packa ge.
UC1834
UC2834
UC3834
CONNECTION DIAGRAMS
DIL -16, SO IC- 16 (T O P VI EW)
J or N Package, DW Packag e PLCC-20, L CC-20 (TO P VIEW)
Q, L Packages
PACKAGE PIN FUNCTION
FUNCTION PIN
N/C 1
VIN + 2
−2. 0V RE F 3
+ 1.5V R EF 4
T hre shold Adjus t 5
N/C 6
VIN−7
Sense−8
Sense+ 9
N.Inv. Input 10
N/C 11
Inv. Input 12
Fault Alert 13
Fault Delay 14
Driver Sink 15
N/C 16
Driver Source 17
Co mp ensa tion / Shutd own 18
O.V. Latch Output/Reset 19
Crowba r Gate 20
2
PARAMETER TEST CONDI TION S UC1834
UC2834 UC3834 UNITS
MIN TYP MAX MIN TYP MAX
Turn- on Char act er is tics
Standb y Supply Cur re nt 5 .5 7 5.5 1 0 mA
+1.5 Volt Reference
Out put Voltage TJ = 25°C 1.485 1.5 1.515 1.4 7 1.5 1.53 V
TJ(MIN) ≤ TJ ≤ TJ(MAX) 1.47 1.53 1.455 1.545
Line Reg ulat ion VIN+ = 5 to 35V 1 10 1 15 mV
Load Regulat ion I OUT = 0 to 2mA 1 10 1 15 mV
-2.0 Volt Refe ren ce (No te 2)
Out put Voltage ( Referenced
to VIN+)TJ = 25°C −2.04 −2−1.96 −2.06 −2−1.94 V
TJ(MIN) ≤ TJ ≤ TJ(MAX) −2.06 −1.94 −2.08 −1.92
Line Reg ulat ion VIN+ = 5 to 35V 1.5 15 1.5 20 mV
Out put Impedance 2 .3 2.3 kΩ
Error Amplifier Section
Input O ffs et Vo lta ge VCM = 1. 5 V 1 6 1 10 m V
Input Bias Current VCM = 1. 5 V −1−4−1−8µA
Input O ffs et Cu rr ent VCM = 1. 5 V 0 .1 1 0. 1 2 µA
Sma ll Signal Ope n Loop Ga in Ou tput @ Pin 14, Pin 12 = V IN+
Pin 13, 20 Ω to VIN−50 65 50 65 dB
CMRR VCM = 0. 5 to 33V, VIN+ = 35V 60 80 60 80 dB
PSRR VIN+ = 5 to 35V, VCM = 1.5V 70 100 70 100 dB
Drive r Sect io n
Maximu m Output Current 200 350 200 350 mA
Satur atio n Voltage I OUT = 100mA 0 .5 1.2 0.5 1 .5 V
Out put Leakage Curr ent Pin 12 = 35V, Pin 13 = V IN−, Pin 14 = V IN−0.1 50 0.1 50 µA
Shutdo wn In put Volta ge
at Pin 14 IOUT ≤ 100µA, Pin 13 = VIN−, Pin 12 =
VIN+ 0.4 1 0.4 1 V
Shutd o wn In put Current
at Pin 14 Pin 14 = VIN−, Pin 12 = VIN+
IOUT ≤ 100µA, Pin 13 = VIN−−100 −150 −100 −150 µA
Thermal Shut down (Note 3) 165 165 ° C
Fault Amplif ie r Sect i on
Under- and Over-Voltage
Fault Thr eshold VCM = 1.5V, @ E/A I n puts 12 0 150 1 8 0 11 0 150 1 90 mV
Comm on M ode Sen sitivit y V IN+ = 3 5V, V CM = 1. 5 t o 33 V −0.4 −0.8 −0.4 −1.0 %/v
Supply Sensitivity VCM = 1. 5V, VIN+ = 5 to 35V −0.5 −1.0 −0.5 −1.2 %/V
Fault Delay 30 45 60 30 45 60 ms/µF
Fault Alert Output Curren t 2 5 2 5 mA
Fault Alert Saturatio n Voltage IOUT = 1mA 0 .2 0. 5 0.2 0.5 V
O. V. La tch O ut put Curr ent 2 4 2 4 m A
O. V. Latc h Satura tion Voltag e IOUT = 1mA 1 .0 1. 3 1.0 1 .3 V
O. V. Latc h Out put Reset
Voltage 0.3 0.4 0.6 0.3 0.4 0.6 V
Crowbar Gate Current −100 −175 −100 −175 mA
Crowbar Gat e Leakage
Current VIN+ = 35V, Pin 16 = VIN−−0.5 −50 −0.5 −50 µA
No te 2: When using bot h the 1.5V and
−
2.0V refer enc es the current o ut of pin 3 sh ould be ba lanced by an equ ivalent cur ren t into
Pin 2. The
−
2.0V output will change
−
2.3mV per
µ
A of imbalance.
No te 3: Therm al shut down t ur ns off the drive r . If Pin 15 (O . V. Latch O utput ) is tied to Pin 14 (Com pe nsat ion/ Shu tdown) the
O.V. Latch will be re set.
UC1834
UC2834
UC3834
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA=−55°C to +125°C
for the UC1834, −40°C t o +85°C for the UC2834, and 0°C to +70°C for the
UC3834. VIN+ = 15V, VIN− = 0V, TA = TJ.
3
PARAMETER TEST CONDITIONS UC1834
UC2834 UC3834 UNITS
MIN TYP MAX MIN TYP MAX
Current Sense Amplifier Section
T hre shold Volt age Pin 4 Open, VCM = VIN+ or VIN−130 150 170 120 150 180 mV
Pin 4 = 0.5V, VCM = V IN+ or V IN−40 50 60 30 50 70
T hre shold Sup ply Sensit ivity Pin 4 Open, VCM = VIN−, VIN+ = 5 to 35V −0.1 −0.3 −0.1 −0.5 %/V
Ad j. Input Cur ren t Pin 4 = 0.5 V −2−10 −2−10 µA
Se nse Inpu t Bias Cur rent VCM = VIN+ 100 200 100 200 µA
VCM = VIN−−100 −200 −100 −200
UC1834
UC2834
UC3834
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA=−55°C to +125°C
for the UC1834, −40°C t o +85°C for the UC2834, and 0°C to +70°C for the
UC3834. VIN+ = 15V, VIN− = 0V. TA = TJ
Differen tial Vo ltage at Curren t Sense
Inputs - mV (reference to sense − input)
Curren t Sense T hresh old Adj ust ment Cur rent Limiting Knee Characteristics
Error Amplifier Gain and Phase
Frequency Response Current Sen se Ampl ifier Gai n an d Ph as e
Freq uen cy Respo n s e
4
UC1834
UC2834
UC3834
Both th e curren t sense and erro r amplifi ers on the UC1834
are tran sc onducta nce t ype ampl i fiers. As a res ult , the ir vol t-
age gain is a direct func tion of the load impedance at their
shared output pin, Pin 14. T heir small signal voltage gain as
a function of load and frequency is nominally given by;
A
V
E
⁄
A
=
Z
L
(
f
)
700Ω
and A
V
C
.
S
. ⁄
A
=
Z
L
(
f
)
70Ω
for: f
≤
500kHz and |Z
L
(f) |
≤
1 M
Ω
Where:
AV=S mall Sign al Volta ge Ga in to pi n 1 4.
ZL(f) = Load Impedance at Pin 14.
The UC1834 fault delay circuitry prevents the fault outputs
from responding to transient fault conditions. The delay reset
la tc h insur es th at the f ull, use r def ined, de lay p ass es befo re an
over-voltage fault response o ccurs. This prevents un neces sary
crowbar, or latched-off conditions, from occurring following
sharp under-voltage to over-voltage transients.
The crowbar output on the UC1834 is activated following a
sustained over-voltage condition. The crowbar output remains
high as long as the fault condition persists, or, as long as the
over-voltage latch is set. The latch is set with an over-voltage
fault if the voltage at Pin 15 is above the latch reset threshold,
typically 0.4V. When the latch is set, its Q− output will pull Pin
15 low through a series diode. As long as a nominal pull-up
lo ad ex ists , the series diode preve nts Q− from pulli ng Pin 15
below the reset threshold. However, Pin 15 is pulled low
enou gh to disable the dri ver outputs if Pins 15 and 14 are
tied together. With Pin 15 and 14 common, the regulator
will latch off in response to an over-voltage fault. If the
fault condition is cleared and Pins 14 and 15 are momen-
tarily pulled below the latch reset threshold, t he driver out-
puts are re-enabled.
APPL ICATI ON INF ORMATI ON Fo ldb ack Curren t L imiti n g
Settin g th e Thresho l d Adju st Vo lt age ( V ADJ)
5
TYPICAL APPLICATIONS
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
UC1834
UC2834
UC3834
5-10 Amp Positive Regulator
5-10 Amp Negative Regulator
6
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